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Add nbtree skip scan optimization.

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Teach nbtree multi-column index scans to opportunistically skip over
irrelevant sections of the index given a query with no "=" conditions on
one or more prefix index columns.  When nbtree is passed input scan keys
derived from a predicate "WHERE b = 5", new nbtree preprocessing steps
output "WHERE a = ANY(<every possible 'a' value>) AND b = 5" scan keys.
That is, preprocessing generates a "skip array" (and an output scan key)
for the omitted prefix column "a", which makes it safe to mark the scan
key on "b" as required to continue the scan.  The scan is therefore able
to repeatedly reposition itself by applying both the "a" and "b" keys.

A skip array has "elements" that are generated procedurally and on
demand, but otherwise works just like a regular ScalarArrayOp array.
Preprocessing can freely add a skip array before or after any input
ScalarArrayOp arrays.  Index scans with a skip array decide when and
where to reposition the scan using the same approach as any other scan
with array keys.  This design builds on the design for array advancement
and primitive scan scheduling added to Postgres 17 by commit 5bf748b8.

Testing has shown that skip scans of an index with a low cardinality
skipped prefix column can be multiple orders of magnitude faster than an
equivalent full index scan (or sequential scan).  In general, the
cardinality of the scan's skipped column(s) limits the number of leaf
pages that can be skipped over.

The core B-Tree operator classes on most discrete types generate their
array elements with the help of their own custom skip support routine.
This infrastructure gives nbtree a way to generate the next required
array element by incrementing (or decrementing) the current array value.
It can reduce the number of index descents in cases where the next
possible indexable value frequently turns out to be the next value
stored in the index.  Opclasses that lack a skip support routine fall
back on having nbtree "increment" (or "decrement") a skip array's
current element by setting the NEXT (or PRIOR) scan key flag, without
directly changing the scan key's sk_argument.  These sentinel values
behave just like any other value from an array -- though they can never
locate equal index tuples (they can only locate the next group of index
tuples containing the next set of non-sentinel values that the scan's
arrays need to advance to).

A skip array's range is constrained by "contradictory" inequality keys.
For example, a skip array on "x" will only generate the values 1 and 2
given a qual such as "WHERE x BETWEEN 1 AND 2 AND y = 66".  Such a skip
array qual usually has near-identical performance characteristics to a
comparable SAOP qual "WHERE x = ANY('{1, 2}') AND y = 66".  However,
improved performance isn't guaranteed.  Much depends on physical index
characteristics.

B-Tree preprocessing is optimistic about skipping working out: it
applies static, generic rules when determining where to generate skip
arrays, which assumes that the runtime overhead of maintaining skip
arrays will pay for itself -- or lead to only a modest performance loss.
As things stand, these assumptions are much too optimistic: skip array
maintenance will lead to unacceptable regressions with unsympathetic
queries (queries whose scan can't skip over many irrelevant leaf pages).
An upcoming commit will address the problems in this area by enhancing
_bt_readpage's approach to saving cycles on scan key evaluation, making
it work in a way that directly considers the needs of = array keys
(particularly = skip array keys).

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Masahiro Ikeda <masahiro.ikeda@nttdata.com>
Reviewed-By: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Reviewed-By: Matthias van de Meent <boekewurm+postgres@gmail.com>
Reviewed-By: Tomas Vondra <tomas@vondra.me>
Reviewed-By: Aleksander Alekseev <aleksander@timescale.com>
Reviewed-By: Alena Rybakina <a.rybakina@postgrespro.ru>
Discussion: https://postgr.es/m/CAH2-Wzmn1YsLzOGgjAQZdn1STSG_y8qP__vggTaPAYXJP+G4bw@mail.gmail.com
pull/210/head
Peter Geoghegan 5 months ago
parent 3ba2cdaa45
commit 92fe23d93a
35 changed files with 3024 additions and 381 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 31
      doc/src/sgml/btree.sgml
  2. 3
      doc/src/sgml/indexam.sgml
  3. 68
      doc/src/sgml/indices.sgml
  4. 5
      doc/src/sgml/monitoring.sgml
  5. 32
      doc/src/sgml/perform.sgml
  6. 16
      doc/src/sgml/xindex.sgml
  7. 3
      src/backend/access/index/indexam.c
  8. 273
      src/backend/access/nbtree/nbtcompare.c
  9. 631
      src/backend/access/nbtree/nbtpreprocesskeys.c
  10. 196
      src/backend/access/nbtree/nbtree.c
  11. 130
      src/backend/access/nbtree/nbtsearch.c
  12. 756
      src/backend/access/nbtree/nbtutils.c
  13. 4
      src/backend/access/nbtree/nbtvalidate.c
  14. 25
      src/backend/commands/opclasscmds.c
  15. 1
      src/backend/utils/adt/Makefile
  16. 46
      src/backend/utils/adt/date.c
  17. 1
      src/backend/utils/adt/meson.build
  18. 491
      src/backend/utils/adt/selfuncs.c
  19. 61
      src/backend/utils/adt/skipsupport.c
  20. 48
      src/backend/utils/adt/timestamp.c
  21. 70
      src/backend/utils/adt/uuid.c
  22. 3
      src/include/access/amapi.h
  23. 34
      src/include/access/nbtree.h
  24. 2
      src/include/catalog/catversion.h
  25. 22
      src/include/catalog/pg_amproc.dat
  26. 27
      src/include/catalog/pg_proc.dat
  27. 98
      src/include/utils/skipsupport.h
  28. 10
      src/test/regress/expected/alter_generic.out
  29. 41
      src/test/regress/expected/btree_index.out
  30. 183
      src/test/regress/expected/create_index.out
  31. 3
      src/test/regress/expected/psql.out
  32. 5
      src/test/regress/sql/alter_generic.sql
  33. 21
      src/test/regress/sql/btree_index.sql
  34. 63
      src/test/regress/sql/create_index.sql
  35. 2
      src/tools/pgindent/typedefs.list

31
doc/src/sgml/btree.sgml
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@ -207,7 +207,7 @@
<para>
As shown in <xref linkend="xindex-btree-support-table"/>, btree defines
one required and four optional support functions. The five
one required and five optional support functions. The six
user-defined methods are:
</para>
<variablelist>
@ -583,6 +583,35 @@ options(<replaceable>relopts</replaceable> <type>local_relopts *</type>) returns
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><function>skipsupport</function></term>
<listitem>
<para>
Optionally, a btree operator family may provide a <firstterm>skip
support</firstterm> function, registered under support function number 6.
These functions give the B-tree code a way to iterate through every
possible value that can be represented by an operator class's underlying
input type, in key space order. This is used by the core code when it
applies the skip scan optimization. The APIs involved in this are
defined in <filename>src/include/utils/skipsupport.h</filename>.
</para>
<para>
Operator classes that do not provide a skip support function are still
eligible to use skip scan. The core code can still use its fallback
strategy, though that might be suboptimal for some discrete types. It
usually doesn't make sense (and may not even be feasible) for operator
classes on continuous types to provide a skip support function.
</para>
<para>
It is not sensible for an operator family to register a cross-type
<function>skipsupport</function> function, and attempting to do so will
result in an error. This is because determining the next indexable value
must happen by incrementing a value copied from an index tuple. The
values generated must all be of the same underlying data type (the
<quote>skipped</quote> index column's opclass input type).
</para>
</listitem>
</varlistentry>
</variablelist>
</sect2>

3
doc/src/sgml/indexam.sgml
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@ -835,7 +835,8 @@ amrestrpos (IndexScanDesc scan);
<para>
<programlisting>
Size
amestimateparallelscan (int nkeys,
amestimateparallelscan (Relation indexRelation,
int nkeys,
int norderbys);
</programlisting>
Estimate and return the number of bytes of dynamic shared memory which

68
doc/src/sgml/indices.sgml
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@ -460,20 +460,56 @@ CREATE INDEX test2_mm_idx ON test2 (major, minor);
efficient when there are constraints on the leading (leftmost) columns.
The exact rule is that equality constraints on leading columns, plus
any inequality constraints on the first column that does not have an
equality constraint, will be used to limit the portion of the index
equality constraint, will always be used to limit the portion of the index
that is scanned. Constraints on columns to the right of these columns
are checked in the index, so they save visits to the table proper, but
they do not reduce the portion of the index that has to be scanned.
are checked in the index, so they'll always save visits to the table
proper, but they do not necessarily reduce the portion of the index that
has to be scanned. If a B-tree index scan can apply the skip scan
optimization effectively, it will apply every column constraint when
navigating through the index via repeated index searches. This can reduce
the portion of the index that has to be read, even though one or more
columns (prior to the least significant index column from the query
predicate) lacks a conventional equality constraint. Skip scan works by
generating a dynamic equality constraint internally, that matches every
possible value in an index column (though only given a column that lacks
an equality constraint that comes from the query predicate, and only when
the generated constraint can be used in conjunction with a later column
constraint from the query predicate).
</para>
<para>
For example, given an index on <literal>(x, y)</literal>, and a query
condition <literal>WHERE y = 7700</literal>, a B-tree index scan might be
able to apply the skip scan optimization. This generally happens when the
query planner expects that repeated <literal>WHERE x = N AND y = 7700</literal>
searches for every possible value of <literal>N</literal> (or for every
<literal>x</literal> value that is actually stored in the index) is the
fastest possible approach, given the available indexes on the table. This
approach is generally only taken when there are so few distinct
<literal>x</literal> values that the planner expects the scan to skip over
most of the index (because most of its leaf pages cannot possibly contain
relevant tuples). If there are many distinct <literal>x</literal> values,
then the entire index will have to be scanned, so in most cases the planner
will prefer a sequential table scan over using the index.
</para>
<para>
The skip scan optimization can also be applied selectively, during B-tree
scans that have at least some useful constraints from the query predicate.
For example, given an index on <literal>(a, b, c)</literal> and a
query condition <literal>WHERE a = 5 AND b &gt;= 42 AND c &lt; 77</literal>,
the index would have to be scanned from the first entry with
<literal>a</literal> = 5 and <literal>b</literal> = 42 up through the last entry with
<literal>a</literal> = 5. Index entries with <literal>c</literal> &gt;= 77 would be
skipped, but they'd still have to be scanned through.
This index could in principle be used for queries that have constraints
on <literal>b</literal> and/or <literal>c</literal> with no constraint on <literal>a</literal>
&mdash; but the entire index would have to be scanned, so in most cases
the planner would prefer a sequential table scan over using the index.
the index might have to be scanned from the first entry with
<literal>a</literal> = 5 and <literal>b</literal> = 42 up through the last
entry with <literal>a</literal> = 5. Index entries with
<literal>c</literal> &gt;= 77 will never need to be filtered at the table
level, but it may or may not be profitable to skip over them within the
index. When skipping takes place, the scan starts a new index search to
reposition itself from the end of the current <literal>a</literal> = 5 and
<literal>b</literal> = N grouping (i.e. from the position in the index
where the first tuple <literal>a = 5 AND b = N AND c &gt;= 77</literal>
appears), to the start of the next such grouping (i.e. the position in the
index where the first tuple <literal>a = 5 AND b = N + 1</literal>
appears).
</para>
<para>
@ -669,9 +705,13 @@ CREATE INDEX test3_desc_index ON test3 (id DESC NULLS LAST);
multicolumn index on <literal>(x, y)</literal>. This index would typically be
more efficient than index combination for queries involving both
columns, but as discussed in <xref linkend="indexes-multicolumn"/>, it
would be almost useless for queries involving only <literal>y</literal>, so it
should not be the only index. A combination of the multicolumn index
and a separate index on <literal>y</literal> would serve reasonably well. For
would be less useful for queries involving only <literal>y</literal>. Just
how useful will depend on how effective the B-tree index skip scan
optimization is; if <literal>x</literal> has no more than several hundred
distinct values, skip scan will make searches for specific
<literal>y</literal> values execute reasonably efficiently. A combination
of a multicolumn index on <literal>(x, y)</literal> and a separate index on
<literal>y</literal> might also serve reasonably well. For
queries involving only <literal>x</literal>, the multicolumn index could be
used, though it would be larger and hence slower than an index on
<literal>x</literal> alone. The last alternative is to create all three

5
doc/src/sgml/monitoring.sgml
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@ -4263,7 +4263,10 @@ description | Waiting for a newly initialized WAL file to reach durable storage
<replaceable>column_name</replaceable> =
<replaceable>value2</replaceable> ...</literal> construct, though only
when the optimizer transforms the construct into an equivalent
multi-valued array representation.
multi-valued array representation. Similarly, when B-tree index scans use
the skip scan optimization, an index search is performed each time the
scan is repositioned to the next index leaf page that might have matching
tuples (see <xref linkend="indexes-multicolumn"/>).
</para>
</note>
<tip>

32
doc/src/sgml/perform.sgml
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@ -860,6 +860,38 @@ EXPLAIN ANALYZE SELECT * FROM tenk1 WHERE thousand IN (1, 2, 3, 4);
<structname>tenk1_thous_tenthous</structname> index leaf page.
</para>
<para>
The <quote>Index Searches</quote> line is also useful with B-tree index
scans that apply the <firstterm>skip scan</firstterm> optimization to
more efficiently traverse through an index:
<screen>
EXPLAIN ANALYZE SELECT four, unique1 FROM tenk1 WHERE four BETWEEN 1 AND 3 AND unique1 = 42;
QUERY PLAN
-------------------------------------------------------------------&zwsp;---------------------------------------------------------------
Index Only Scan using tenk1_four_unique1_idx on tenk1 (cost=0.29..6.90 rows=1 width=8) (actual time=0.006..0.007 rows=1.00 loops=1)
Index Cond: ((four &gt;= 1) AND (four &lt;= 3) AND (unique1 = 42))
Heap Fetches: 0
Index Searches: 3
Buffers: shared hit=7
Planning Time: 0.029 ms
Execution Time: 0.012 ms
</screen>
Here we see an Index-Only Scan node using
<structname>tenk1_four_unique1_idx</structname>, a multi-column index on the
<structname>tenk1</structname> table's <structfield>four</structfield> and
<structfield>unique1</structfield> columns. The scan performs 3 searches
that each read a single index leaf page:
<quote><literal>four = 1 AND unique1 = 42</literal></quote>,
<quote><literal>four = 2 AND unique1 = 42</literal></quote>, and
<quote><literal>four = 3 AND unique1 = 42</literal></quote>. This index
is generally a good target for skip scan, since, as discussed in
<xref linkend="indexes-multicolumn"/>, its leading column (the
<structfield>four</structfield> column) contains only 4 distinct values,
while its second/final column (the <structfield>unique1</structfield>
column) contains many distinct values.
</para>
<para>
Another type of extra information is the number of rows removed by a
filter condition:

16
doc/src/sgml/xindex.sgml
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@ -461,6 +461,13 @@
</entry>
<entry>5</entry>
</row>
<row>
<entry>
Return the addresses of C-callable skip support function(s)
(optional)
</entry>
<entry>6</entry>
</row>
</tbody>
</tgroup>
</table>
@ -1062,7 +1069,8 @@ DEFAULT FOR TYPE int8 USING btree FAMILY integer_ops AS
FUNCTION 1 btint8cmp(int8, int8) ,
FUNCTION 2 btint8sortsupport(internal) ,
FUNCTION 3 in_range(int8, int8, int8, boolean, boolean) ,
FUNCTION 4 btequalimage(oid) ;
FUNCTION 4 btequalimage(oid) ,
FUNCTION 6 btint8skipsupport(internal) ;
CREATE OPERATOR CLASS int4_ops
DEFAULT FOR TYPE int4 USING btree FAMILY integer_ops AS
@ -1075,7 +1083,8 @@ DEFAULT FOR TYPE int4 USING btree FAMILY integer_ops AS
FUNCTION 1 btint4cmp(int4, int4) ,
FUNCTION 2 btint4sortsupport(internal) ,
FUNCTION 3 in_range(int4, int4, int4, boolean, boolean) ,
FUNCTION 4 btequalimage(oid) ;
FUNCTION 4 btequalimage(oid) ,
FUNCTION 6 btint4skipsupport(internal) ;
CREATE OPERATOR CLASS int2_ops
DEFAULT FOR TYPE int2 USING btree FAMILY integer_ops AS
@ -1088,7 +1097,8 @@ DEFAULT FOR TYPE int2 USING btree FAMILY integer_ops AS
FUNCTION 1 btint2cmp(int2, int2) ,
FUNCTION 2 btint2sortsupport(internal) ,
FUNCTION 3 in_range(int2, int2, int2, boolean, boolean) ,
FUNCTION 4 btequalimage(oid) ;
FUNCTION 4 btequalimage(oid) ,
FUNCTION 6 btint2skipsupport(internal) ;
ALTER OPERATOR FAMILY integer_ops USING btree ADD
-- cross-type comparisons int8 vs int2

3
src/backend/access/index/indexam.c
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@ -489,7 +489,8 @@ index_parallelscan_estimate(Relation indexRelation, int nkeys, int norderbys,
if (parallel_aware &&
indexRelation->rd_indam->amestimateparallelscan != NULL)
nbytes = add_size(nbytes,
indexRelation->rd_indam->amestimateparallelscan(nkeys,
indexRelation->rd_indam->amestimateparallelscan(indexRelation,
nkeys,
norderbys));
return nbytes;

273
src/backend/access/nbtree/nbtcompare.c
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@ -58,6 +58,7 @@
#include <limits.h>
#include "utils/fmgrprotos.h"
#include "utils/skipsupport.h"
#include "utils/sortsupport.h"
#ifdef STRESS_SORT_INT_MIN
@ -78,6 +79,51 @@ btboolcmp(PG_FUNCTION_ARGS)
PG_RETURN_INT32((int32) a - (int32) b);
}
static Datum
bool_decrement(Relation rel, Datum existing, bool *underflow)
{
bool bexisting = DatumGetBool(existing);
if (bexisting == false)
{
/* return value is undefined */
*underflow = true;
return (Datum) 0;
}
*underflow = false;
return BoolGetDatum(bexisting - 1);
}
static Datum
bool_increment(Relation rel, Datum existing, bool *overflow)
{
bool bexisting = DatumGetBool(existing);
if (bexisting == true)
{
/* return value is undefined */
*overflow = true;
return (Datum) 0;
}
*overflow = false;
return BoolGetDatum(bexisting + 1);
}
Datum
btboolskipsupport(PG_FUNCTION_ARGS)
{
SkipSupport sksup = (SkipSupport) PG_GETARG_POINTER(0);
sksup->decrement = bool_decrement;
sksup->increment = bool_increment;
sksup->low_elem = BoolGetDatum(false);
sksup->high_elem = BoolGetDatum(true);
PG_RETURN_VOID();
}
Datum
btint2cmp(PG_FUNCTION_ARGS)
{
@ -105,6 +151,51 @@ btint2sortsupport(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
static Datum
int2_decrement(Relation rel, Datum existing, bool *underflow)
{
int16 iexisting = DatumGetInt16(existing);
if (iexisting == PG_INT16_MIN)
{
/* return value is undefined */
*underflow = true;
return (Datum) 0;
}
*underflow = false;
return Int16GetDatum(iexisting - 1);
}
static Datum
int2_increment(Relation rel, Datum existing, bool *overflow)
{
int16 iexisting = DatumGetInt16(existing);
if (iexisting == PG_INT16_MAX)
{
/* return value is undefined */
*overflow = true;
return (Datum) 0;
}
*overflow = false;
return Int16GetDatum(iexisting + 1);
}
Datum
btint2skipsupport(PG_FUNCTION_ARGS)
{
SkipSupport sksup = (SkipSupport) PG_GETARG_POINTER(0);
sksup->decrement = int2_decrement;
sksup->increment = int2_increment;
sksup->low_elem = Int16GetDatum(PG_INT16_MIN);
sksup->high_elem = Int16GetDatum(PG_INT16_MAX);
PG_RETURN_VOID();
}
Datum
btint4cmp(PG_FUNCTION_ARGS)
{
@ -128,6 +219,51 @@ btint4sortsupport(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
static Datum
int4_decrement(Relation rel, Datum existing, bool *underflow)
{
int32 iexisting = DatumGetInt32(existing);
if (iexisting == PG_INT32_MIN)
{
/* return value is undefined */
*underflow = true;
return (Datum) 0;
}
*underflow = false;
return Int32GetDatum(iexisting - 1);
}
static Datum
int4_increment(Relation rel, Datum existing, bool *overflow)
{
int32 iexisting = DatumGetInt32(existing);
if (iexisting == PG_INT32_MAX)
{
/* return value is undefined */
*overflow = true;
return (Datum) 0;
}
*overflow = false;
return Int32GetDatum(iexisting + 1);
}
Datum
btint4skipsupport(PG_FUNCTION_ARGS)
{
SkipSupport sksup = (SkipSupport) PG_GETARG_POINTER(0);
sksup->decrement = int4_decrement;
sksup->increment = int4_increment;
sksup->low_elem = Int32GetDatum(PG_INT32_MIN);
sksup->high_elem = Int32GetDatum(PG_INT32_MAX);
PG_RETURN_VOID();
}
Datum
btint8cmp(PG_FUNCTION_ARGS)
{
@ -171,6 +307,51 @@ btint8sortsupport(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
static Datum
int8_decrement(Relation rel, Datum existing, bool *underflow)
{
int64 iexisting = DatumGetInt64(existing);
if (iexisting == PG_INT64_MIN)
{
/* return value is undefined */
*underflow = true;
return (Datum) 0;
}
*underflow = false;
return Int64GetDatum(iexisting - 1);
}
static Datum
int8_increment(Relation rel, Datum existing, bool *overflow)
{
int64 iexisting = DatumGetInt64(existing);
if (iexisting == PG_INT64_MAX)
{
/* return value is undefined */
*overflow = true;
return (Datum) 0;
}
*overflow = false;
return Int64GetDatum(iexisting + 1);
}
Datum
btint8skipsupport(PG_FUNCTION_ARGS)
{
SkipSupport sksup = (SkipSupport) PG_GETARG_POINTER(0);
sksup->decrement = int8_decrement;
sksup->increment = int8_increment;
sksup->low_elem = Int64GetDatum(PG_INT64_MIN);
sksup->high_elem = Int64GetDatum(PG_INT64_MAX);
PG_RETURN_VOID();
}
Datum
btint48cmp(PG_FUNCTION_ARGS)
{
@ -292,6 +473,51 @@ btoidsortsupport(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
static Datum
oid_decrement(Relation rel, Datum existing, bool *underflow)
{
Oid oexisting = DatumGetObjectId(existing);
if (oexisting == InvalidOid)
{
/* return value is undefined */
*underflow = true;
return (Datum) 0;
}
*underflow = false;
return ObjectIdGetDatum(oexisting - 1);
}
static Datum
oid_increment(Relation rel, Datum existing, bool *overflow)
{
Oid oexisting = DatumGetObjectId(existing);
if (oexisting == OID_MAX)
{
/* return value is undefined */
*overflow = true;
return (Datum) 0;
}
*overflow = false;
return ObjectIdGetDatum(oexisting + 1);
}
Datum
btoidskipsupport(PG_FUNCTION_ARGS)
{
SkipSupport sksup = (SkipSupport) PG_GETARG_POINTER(0);
sksup->decrement = oid_decrement;
sksup->increment = oid_increment;
sksup->low_elem = ObjectIdGetDatum(InvalidOid);
sksup->high_elem = ObjectIdGetDatum(OID_MAX);
PG_RETURN_VOID();
}
Datum
btoidvectorcmp(PG_FUNCTION_ARGS)
{
@ -325,3 +551,50 @@ btcharcmp(PG_FUNCTION_ARGS)
/* Be careful to compare chars as unsigned */
PG_RETURN_INT32((int32) ((uint8) a) - (int32) ((uint8) b));
}
static Datum
char_decrement(Relation rel, Datum existing, bool *underflow)
{
uint8 cexisting = UInt8GetDatum(existing);
if (cexisting == 0)
{
/* return value is undefined */
*underflow = true;
return (Datum) 0;
}
*underflow = false;
return CharGetDatum((uint8) cexisting - 1);
}
static Datum
char_increment(Relation rel, Datum existing, bool *overflow)
{
uint8 cexisting = UInt8GetDatum(existing);
if (cexisting == UCHAR_MAX)
{
/* return value is undefined */
*overflow = true;
return (Datum) 0;
}
*overflow = false;
return CharGetDatum((uint8) cexisting + 1);
}
Datum
btcharskipsupport(PG_FUNCTION_ARGS)
{
SkipSupport sksup = (SkipSupport) PG_GETARG_POINTER(0);
sksup->decrement = char_decrement;
sksup->increment = char_increment;
/* btcharcmp compares chars as unsigned */
sksup->low_elem = UInt8GetDatum(0);
sksup->high_elem = UInt8GetDatum(UCHAR_MAX);
PG_RETURN_VOID();
}

631
src/backend/access/nbtree/nbtpreprocesskeys.c
Unescape View File

@ -45,8 +45,15 @@ static bool _bt_compare_array_scankey_args(IndexScanDesc scan,
ScanKey arraysk, ScanKey skey,
FmgrInfo *orderproc, BTArrayKeyInfo *array,
bool *qual_ok);
static bool _bt_saoparray_shrink(IndexScanDesc scan, ScanKey arraysk,
ScanKey skey, FmgrInfo *orderproc,
BTArrayKeyInfo *array, bool *qual_ok);
static bool _bt_skiparray_shrink(IndexScanDesc scan, ScanKey skey,
BTArrayKeyInfo *array, bool *qual_ok);
static ScanKey _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys);
static void _bt_preprocess_array_keys_final(IndexScanDesc scan, int *keyDataMap);
static int _bt_num_array_keys(IndexScanDesc scan, Oid *skip_eq_ops_out,
int *numSkipArrayKeys_out);
static Datum _bt_find_extreme_element(IndexScanDesc scan, ScanKey skey,
Oid elemtype, StrategyNumber strat,
Datum *elems, int nelems);
@ -89,6 +96,8 @@ static int _bt_compare_array_elements(const void *a, const void *b, void *arg);
* within each attribute may be done as a byproduct of the processing here.
* That process must leave array scan keys (within an attribute) in the same
* order as corresponding entries from the scan's BTArrayKeyInfo array info.
* We might also construct skip array scan keys that weren't present in the
* original input keys; these are also output in standard attribute order.
*
* The output keys are marked with flags SK_BT_REQFWD and/or SK_BT_REQBKWD
* if they must be satisfied in order to continue the scan forward or backward
@ -101,10 +110,16 @@ static int _bt_compare_array_elements(const void *a, const void *b, void *arg);
* attributes with "=" keys are marked both SK_BT_REQFWD and SK_BT_REQBKWD.
* For the first attribute without an "=" key, any "<" and "<=" keys are
* marked SK_BT_REQFWD while any ">" and ">=" keys are marked SK_BT_REQBKWD.
* This can be seen to be correct by considering the above example. Note
* in particular that if there are no keys for a given attribute, the keys for
* subsequent attributes can never be required; for instance "WHERE y = 4"
* requires a full-index scan.
* This can be seen to be correct by considering the above example.
*
* If we never generated skip array scan keys, it would be possible for "gaps"
* to appear that make it unsafe to mark any subsequent input scan keys
* (copied from scan->keyData[]) as required to continue the scan. Prior to
* Postgres 18, a qual like "WHERE y = 4" always resulted in a full scan.
* This qual now becomes "WHERE x = ANY('{every possible x value}') and y = 4"
* on output. In other words, preprocessing now adds a skip array on "x".
* This has the potential to be much more efficient than a full index scan
* (though it behaves like a full scan when there's many distinct "x" values).
*
* If possible, redundant keys are eliminated: we keep only the tightest
* >/>= bound and the tightest </<= bound, and if there's an = key then
@ -137,11 +152,20 @@ static int _bt_compare_array_elements(const void *a, const void *b, void *arg);
* Again, missing cross-type operators might cause us to fail to prove the
* quals contradictory when they really are, but the scan will work correctly.
*
* Row comparison keys are currently also treated without any smarts:
* we just transfer them into the preprocessed array without any
* Skip array = keys will even be generated in the presence of "contradictory"
* inequality quals when it'll enable marking later input quals as required.
* We'll merge any such inequalities into the generated skip array by setting
* its array.low_compare or array.high_compare key field. The resulting skip
* array will generate its array elements from a range that's constrained by
* any merged input inequalities (which won't get output in so->keyData[]).
*
* Row comparison keys currently have a couple of notable limitations.
* Right now we just transfer them into the preprocessed array without any
* editorialization. We can treat them the same as an ordinary inequality
* comparison on the row's first index column, for the purposes of the logic
* about required keys.
* about required keys. Also, we are unable to merge a row comparison key
* into a skip array (only ordinary inequalities are merged). A key that
* comes after a Row comparison key is therefore never marked as required.
*
* Note: the reason we have to copy the preprocessed scan keys into private
* storage is that we are modifying the array based on comparisons of the
@ -200,6 +224,14 @@ _bt_preprocess_keys(IndexScanDesc scan)
/* Also maintain keyDataMap for remapping so->orderProcs[] later */
keyDataMap = MemoryContextAlloc(so->arrayContext,
numberOfKeys * sizeof(int));
/*
* Also enlarge output array when it might otherwise not have room for
* a skip array's scan key
*/
if (numberOfKeys > scan->numberOfKeys)
so->keyData = repalloc(so->keyData,
numberOfKeys * sizeof(ScanKeyData));
}
else
inkeys = scan->keyData;
@ -229,6 +261,7 @@ _bt_preprocess_keys(IndexScanDesc scan)
Assert(so->keyData[0].sk_flags & SK_SEARCHARRAY);
Assert(so->keyData[0].sk_strategy != BTEqualStrategyNumber ||
(so->arrayKeys[0].scan_key == 0 &&
!(so->keyData[0].sk_flags & SK_BT_SKIP) &&
OidIsValid(so->orderProcs[0].fn_oid)));
}
@ -288,7 +321,8 @@ _bt_preprocess_keys(IndexScanDesc scan)
* redundant. Note that this is no less true if the = key is
* SEARCHARRAY; the only real difference is that the inequality
* key _becomes_ redundant by making _bt_compare_scankey_args
* eliminate the subset of elements that won't need to be matched.
* eliminate the subset of elements that won't need to be matched
* (with SAOP arrays and skip arrays alike).
*
* If we have a case like "key = 1 AND key > 2", we set qual_ok to
* false and abandon further processing. We'll do the same thing
@ -345,7 +379,6 @@ _bt_preprocess_keys(IndexScanDesc scan)
return;
}
/* else discard the redundant non-equality key */
Assert(!array || array->num_elems > 0);
xform[j].inkey = NULL;
xform[j].inkeyi = -1;
}
@ -393,6 +426,11 @@ _bt_preprocess_keys(IndexScanDesc scan)
* Emit the cleaned-up keys into the so->keyData[] array, and then
* mark them if they are required. They are required (possibly
* only in one direction) if all attrs before this one had "=".
*
* In practice we'll rarely output non-required scan keys here;
* typically, _bt_preprocess_array_keys has already added "=" keys
* sufficient to form an unbroken series of "=" constraints on all
* attrs prior to the attr from the final scan->keyData[] key.
*/
for (j = BTMaxStrategyNumber; --j >= 0;)
{
@ -481,6 +519,7 @@ _bt_preprocess_keys(IndexScanDesc scan)
Assert(array->scan_key == i);
Assert(OidIsValid(orderproc->fn_oid));
Assert(!(inkey->sk_flags & SK_BT_SKIP));
}
else if (xform[j].inkey->sk_flags & SK_SEARCHARRAY)
{
@ -489,6 +528,7 @@ _bt_preprocess_keys(IndexScanDesc scan)
Assert(array->scan_key == xform[j].inkeyi);
Assert(OidIsValid(orderproc->fn_oid));
Assert(!(xform[j].inkey->sk_flags & SK_BT_SKIP));
}
/*
@ -508,8 +548,6 @@ _bt_preprocess_keys(IndexScanDesc scan)
/* Have all we need to determine redundancy */
if (test_result)
{
Assert(!array || array->num_elems > 0);
/*
* New key is more restrictive, and so replaces old key...
*/
@ -803,6 +841,9 @@ _bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
cmp_op;
StrategyNumber strat;
Assert(!((leftarg->sk_flags | rightarg->sk_flags) &
(SK_ROW_HEADER | SK_ROW_MEMBER)));
/*
* First, deal with cases where one or both args are NULL. This should
* only happen when the scankeys represent IS NULL/NOT NULL conditions.
@ -812,6 +853,22 @@ _bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
bool leftnull,
rightnull;
/* Handle skip array comparison with IS NOT NULL scan key */
if ((leftarg->sk_flags | rightarg->sk_flags) & SK_BT_SKIP)
{
/* Shouldn't generate skip array in presence of IS NULL key */
Assert(!((leftarg->sk_flags | rightarg->sk_flags) & SK_SEARCHNULL));
Assert((leftarg->sk_flags | rightarg->sk_flags) & SK_SEARCHNOTNULL);
/* Skip array will have no NULL element/IS NULL scan key */
Assert(array->num_elems == -1);
array->null_elem = false;
/* IS NOT NULL key (could be leftarg or rightarg) now redundant */
*result = true;
return true;
}
if (leftarg->sk_flags & SK_ISNULL)
{
Assert(leftarg->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
@ -885,6 +942,7 @@ _bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
{
/* Can't make the comparison */
*result = false; /* suppress compiler warnings */
Assert(!((leftarg->sk_flags | rightarg->sk_flags) & SK_BT_SKIP));
return false;
}
@ -978,24 +1036,56 @@ _bt_compare_scankey_args(IndexScanDesc scan, ScanKey op,
* Compare an array scan key to a scalar scan key, eliminating contradictory
* array elements such that the scalar scan key becomes redundant.
*
* If the opfamily is incomplete we may not be able to determine which
* elements are contradictory. When we return true we'll have validly set
* *qual_ok, guaranteeing that at least the scalar scan key can be considered
* redundant. We return false if the comparison could not be made (caller
* must keep both scan keys when this happens).
*
* Note: it's up to caller to deal with IS [NOT] NULL scan keys, as well as
* row comparison scan keys. We only deal with scalar scan keys.
*/
static bool
_bt_compare_array_scankey_args(IndexScanDesc scan, ScanKey arraysk, ScanKey skey,
FmgrInfo *orderproc, BTArrayKeyInfo *array,
bool *qual_ok)
{
Assert(arraysk->sk_attno == skey->sk_attno);
Assert(!(arraysk->sk_flags & (SK_ISNULL | SK_ROW_HEADER | SK_ROW_MEMBER)));
Assert((arraysk->sk_flags & SK_SEARCHARRAY) &&
arraysk->sk_strategy == BTEqualStrategyNumber);
/* don't expect to have to deal with NULLs/row comparison scan keys */
Assert(!(skey->sk_flags & (SK_ISNULL | SK_ROW_HEADER | SK_ROW_MEMBER)));
Assert(!(skey->sk_flags & SK_SEARCHARRAY) ||
skey->sk_strategy != BTEqualStrategyNumber);
/*
* Just call the appropriate helper function based on whether it's a SAOP
* array or a skip array. Both helpers will set *qual_ok in passing.
*/
if (array->num_elems != -1)
return _bt_saoparray_shrink(scan, arraysk, skey, orderproc, array,
qual_ok);
else
return _bt_skiparray_shrink(scan, skey, array, qual_ok);
}
/*
* Preprocessing of SAOP array scan key, used to determine which array
* elements are eliminated as contradictory by a non-array scalar key.
*
* _bt_compare_array_scankey_args helper function.
*
* Array elements can be eliminated as contradictory when excluded by some
* other operator on the same attribute. For example, with an index scan qual
* "WHERE a IN (1, 2, 3) AND a < 2", all array elements except the value "1"
* are eliminated, and the < scan key is eliminated as redundant. Cases where
* every array element is eliminated by a redundant scalar scan key have an
* unsatisfiable qual, which we handle by setting *qual_ok=false for caller.
*
* If the opfamily doesn't supply a complete set of cross-type ORDER procs we
* may not be able to determine which elements are contradictory. If we have
* the required ORDER proc then we return true (and validly set *qual_ok),
* guaranteeing that at least the scalar scan key can be considered redundant.
* We return false if the comparison could not be made (caller must keep both
* scan keys when this happens).
*/
static bool
_bt_compare_array_scankey_args(IndexScanDesc scan, ScanKey arraysk, ScanKey skey,
FmgrInfo *orderproc, BTArrayKeyInfo *array,
bool *qual_ok)
_bt_saoparray_shrink(IndexScanDesc scan, ScanKey arraysk, ScanKey skey,
FmgrInfo *orderproc, BTArrayKeyInfo *array, bool *qual_ok)
{
Relation rel = scan->indexRelation;
Oid opcintype = rel->rd_opcintype[arraysk->sk_attno - 1];
@ -1006,14 +1096,8 @@ _bt_compare_array_scankey_args(IndexScanDesc scan, ScanKey arraysk, ScanKey skey
FmgrInfo crosstypeproc;
FmgrInfo *orderprocp = orderproc;
Assert(arraysk->sk_attno == skey->sk_attno);
Assert(array->num_elems > 0);
Assert(!(arraysk->sk_flags & (SK_ISNULL | SK_ROW_HEADER | SK_ROW_MEMBER)));
Assert((arraysk->sk_flags & SK_SEARCHARRAY) &&
arraysk->sk_strategy == BTEqualStrategyNumber);
Assert(!(skey->sk_flags & (SK_ISNULL | SK_ROW_HEADER | SK_ROW_MEMBER)));
Assert(!(skey->sk_flags & SK_SEARCHARRAY) ||
skey->sk_strategy != BTEqualStrategyNumber);
Assert(!(arraysk->sk_flags & SK_BT_SKIP));
/*
* _bt_binsrch_array_skey searches an array for the entry best matching a
@ -1112,6 +1196,106 @@ _bt_compare_array_scankey_args(IndexScanDesc scan, ScanKey arraysk, ScanKey skey
return true;
}
/*
* Preprocessing of skip array scan key, used to determine redundancy against
* a non-array scalar scan key (must be an inequality).
*
* _bt_compare_array_scankey_args helper function.
*
* Skip arrays work by procedurally generating their elements as needed, so we
* just store the inequality as the skip array's low_compare or high_compare
* (except when there's already a more restrictive low_compare/high_compare).
* The array's final elements are the range of values that still satisfy the
* array's final low_compare and high_compare.
*/
static bool
_bt_skiparray_shrink(IndexScanDesc scan, ScanKey skey, BTArrayKeyInfo *array,
bool *qual_ok)
{
bool test_result;
Assert(array->num_elems == -1);
/*
* Array's index attribute will be constrained by a strict operator/key.
* Array must not "contain a NULL element" (i.e. the scan must not apply
* "IS NULL" qual when it reaches the end of the index that stores NULLs).
*/
array->null_elem = false;
*qual_ok = true;
/*
* Consider if we should treat caller's scalar scan key as the skip
* array's high_compare or low_compare.
*
* In general the current array element must either be a copy of a value
* taken from an index tuple, or a derivative value generated by opclass's
* skip support function. That way the scan can always safely assume that
* it's okay to use the only-input-opclass-type proc from so->orderProcs[]
* (they can be cross-type with SAOP arrays, but never with skip arrays).
*
* This approach is enabled by MINVAL/MAXVAL sentinel key markings, which
* can be thought of as representing either the lowest or highest matching
* array element (excluding the NULL element, where applicable, though as
* just discussed it isn't applicable to this range skip array anyway).
* Array keys marked MINVAL/MAXVAL never have a valid datum in their
* sk_argument field. The scan directly applies the array's low_compare
* key when it encounters MINVAL in the array key proper (just as it
* applies high_compare when it sees MAXVAL set in the array key proper).
* The scan must never use the array's so->orderProcs[] proc against
* low_compare's/high_compare's sk_argument, either (so->orderProcs[] is
* only intended to be used with rhs datums from the array proper/index).
*/
switch (skey->sk_strategy)
{
case BTLessStrategyNumber:
case BTLessEqualStrategyNumber:
if (array->high_compare)
{
/* replace existing high_compare with caller's key? */
if (!_bt_compare_scankey_args(scan, array->high_compare, skey,
array->high_compare, NULL, NULL,
&test_result))
return false; /* can't determine more restrictive key */
if (!test_result)
return true; /* no, just discard caller's key */
/* yes, replace existing high_compare with caller's key */
}
/* caller's key becomes skip array's high_compare */
array->high_compare = skey;
break;
case BTGreaterEqualStrategyNumber:
case BTGreaterStrategyNumber:
if (array->low_compare)
{
/* replace existing low_compare with caller's key? */
if (!_bt_compare_scankey_args(scan, array->low_compare, skey,
array->low_compare, NULL, NULL,
&test_result))
return false; /* can't determine more restrictive key */
if (!test_result)
return true; /* no, just discard caller's key */
/* yes, replace existing low_compare with caller's key */
}
/* caller's key becomes skip array's low_compare */
array->low_compare = skey;
break;
case BTEqualStrategyNumber:
default:
elog(ERROR, "unrecognized StrategyNumber: %d",
(int) skey->sk_strategy);
break;
}
return true;
}
/*
* _bt_preprocess_array_keys() -- Preprocess SK_SEARCHARRAY scan keys
*
@ -1137,6 +1321,12 @@ _bt_compare_array_scankey_args(IndexScanDesc scan, ScanKey arraysk, ScanKey skey
* one equality strategy array scan key per index attribute. We'll always be
* able to set things up that way when complete opfamilies are used.
*
* We're also responsible for generating skip arrays (and their associated
* scan keys) here. This enables skip scan. We do this for index attributes
* that initially lacked an equality condition within scan->keyData[], iff
* doing so allows a later scan key (that was passed to us in scan->keyData[])
* to be marked required by our _bt_preprocess_keys caller.
*
* We set the scan key references from the scan's BTArrayKeyInfo info array to
* offsets into the temp modified input array returned to caller. Scans that
* have array keys should call _bt_preprocess_array_keys_final when standard
@ -1144,49 +1334,45 @@ _bt_compare_array_scankey_args(IndexScanDesc scan, ScanKey arraysk, ScanKey skey
* references into references to the scan's so->keyData[] output scan keys.
*
* Note: the reason we need to return a temp scan key array, rather than just
* scribbling on scan->keyData, is that callers are permitted to call btrescan
* without supplying a new set of scankey data.
* modifying scan->keyData[], is that callers are permitted to call btrescan
* without supplying a new set of scankey data. Certain other preprocessing
* routines (e.g., _bt_fix_scankey_strategy) _can_ modify scan->keyData[], but
* we can't make that work here because our modifications are non-idempotent.
*/
static ScanKey
_bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
{
BTScanOpaque so = (BTScanOpaque) scan->opaque;
Relation rel = scan->indexRelation;
int numberOfKeys = scan->numberOfKeys;
int16 *indoption = rel->rd_indoption;
Oid skip_eq_ops[INDEX_MAX_KEYS];
int numArrayKeys,
output_ikey = 0;
numSkipArrayKeys,
numArrayKeyData;
AttrNumber attno_skip = 1;
int origarrayatt = InvalidAttrNumber,
origarraykey = -1;
Oid origelemtype = InvalidOid;
ScanKey cur;
MemoryContext oldContext;
ScanKey arrayKeyData; /* modified copy of scan->keyData */
Assert(numberOfKeys);
/* Quick check to see if there are any array keys */
numArrayKeys = 0;
for (int i = 0; i < numberOfKeys; i++)
{
cur = &scan->keyData[i];
if (cur->sk_flags & SK_SEARCHARRAY)
{
numArrayKeys++;
Assert(!(cur->sk_flags & (SK_ROW_HEADER | SK_SEARCHNULL | SK_SEARCHNOTNULL)));
/* If any arrays are null as a whole, we can quit right now. */
if (cur->sk_flags & SK_ISNULL)
{
so->qual_ok = false;
return NULL;
}
}
}
/*
* Check the number of input array keys within scan->keyData[] input keys
* (also checks if we should add extra skip arrays based on input keys)
*/
numArrayKeys = _bt_num_array_keys(scan, skip_eq_ops, &numSkipArrayKeys);
/* Quit if nothing to do. */
if (numArrayKeys == 0)
return NULL;
/*
* Estimated final size of arrayKeyData[] array we'll return to our caller
* is the size of the original scan->keyData[] input array, plus space for
* any additional skip array scan keys we'll need to generate below
*/
numArrayKeyData = scan->numberOfKeys + numSkipArrayKeys;
/*
* Make a scan-lifespan context to hold array-associated data, or reset it
* if we already have one from a previous rescan cycle.
@ -1201,18 +1387,20 @@ _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
oldContext = MemoryContextSwitchTo(so->arrayContext);
/* Create output scan keys in the workspace context */
arrayKeyData = (ScanKey) palloc(numberOfKeys * sizeof(ScanKeyData));
arrayKeyData = (ScanKey) palloc(numArrayKeyData * sizeof(ScanKeyData));
/* Allocate space for per-array data in the workspace context */
so->arrayKeys = (BTArrayKeyInfo *) palloc(numArrayKeys * sizeof(BTArrayKeyInfo));
/* Allocate space for ORDER procs used to help _bt_checkkeys */
so->orderProcs = (FmgrInfo *) palloc(numberOfKeys * sizeof(FmgrInfo));
so->orderProcs = (FmgrInfo *) palloc(numArrayKeyData * sizeof(FmgrInfo));
/* Now process each array key */
numArrayKeys = 0;
for (int input_ikey = 0; input_ikey < numberOfKeys; input_ikey++)
numArrayKeyData = 0;
for (int input_ikey = 0; input_ikey < scan->numberOfKeys; input_ikey++)
{
ScanKey inkey = scan->keyData + input_ikey,
cur;
FmgrInfo sortproc;
FmgrInfo *sortprocp = &sortproc;
Oid elemtype;
@ -1225,21 +1413,113 @@ _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
Datum *elem_values;
bool *elem_nulls;
int num_nonnulls;
int j;
/* set up next output scan key */
cur = &arrayKeyData[numArrayKeyData];
/* Backfill skip arrays for attrs < or <= input key's attr? */
while (numSkipArrayKeys && attno_skip <= inkey->sk_attno)
{
Oid opfamily = rel->rd_opfamily[attno_skip - 1];
Oid opcintype = rel->rd_opcintype[attno_skip - 1];
Oid collation = rel->rd_indcollation[attno_skip - 1];
Oid eq_op = skip_eq_ops[attno_skip - 1];
CompactAttribute *attr;
RegProcedure cmp_proc;
if (!OidIsValid(eq_op))
{
/*
* Attribute already has an = input key, so don't output a
* skip array for attno_skip. Just copy attribute's = input
* key into arrayKeyData[] once outside this inner loop.
*
* Note: When we get here there must be a later attribute that
* lacks an equality input key, and still needs a skip array
* (if there wasn't then numSkipArrayKeys would be 0 by now).
*/
Assert(attno_skip == inkey->sk_attno);
/* inkey can't be last input key to be marked required: */
Assert(input_ikey < scan->numberOfKeys - 1);
#if 0
/* Could be a redundant input scan key, so can't do this: */
Assert(inkey->sk_strategy == BTEqualStrategyNumber ||
(inkey->sk_flags & SK_SEARCHNULL));
#endif
attno_skip++;
break;
}
cmp_proc = get_opcode(eq_op);
if (!RegProcedureIsValid(cmp_proc))
elog(ERROR, "missing oprcode for skipping equals operator %u", eq_op);
ScanKeyEntryInitialize(cur,
SK_SEARCHARRAY | SK_BT_SKIP, /* flags */
attno_skip, /* skipped att number */
BTEqualStrategyNumber, /* equality strategy */
InvalidOid, /* opclass input subtype */
collation, /* index column's collation */
cmp_proc, /* equality operator's proc */
(Datum) 0); /* constant */
/* Initialize generic BTArrayKeyInfo fields */
so->arrayKeys[numArrayKeys].scan_key = numArrayKeyData;
so->arrayKeys[numArrayKeys].num_elems = -1;
/* Initialize skip array specific BTArrayKeyInfo fields */
attr = TupleDescCompactAttr(RelationGetDescr(rel), attno_skip - 1);
reverse = (indoption[attno_skip - 1] & INDOPTION_DESC) != 0;
so->arrayKeys[numArrayKeys].attlen = attr->attlen;
so->arrayKeys[numArrayKeys].attbyval = attr->attbyval;
so->arrayKeys[numArrayKeys].null_elem = true; /* for now */
so->arrayKeys[numArrayKeys].sksup =
PrepareSkipSupportFromOpclass(opfamily, opcintype, reverse);
so->arrayKeys[numArrayKeys].low_compare = NULL; /* for now */
so->arrayKeys[numArrayKeys].high_compare = NULL; /* for now */
/*
* We'll need a 3-way ORDER proc. Set that up now.
*/
_bt_setup_array_cmp(scan, cur, opcintype,
&so->orderProcs[numArrayKeyData], NULL);
numArrayKeys++;
numArrayKeyData++; /* keep this scan key/array */
/* set up next output scan key */
cur = &arrayKeyData[numArrayKeyData];
/* remember having output this skip array and scan key */
numSkipArrayKeys--;
attno_skip++;
}
/*
* Provisionally copy scan key into arrayKeyData[] array we'll return
* to _bt_preprocess_keys caller
*/
cur = &arrayKeyData[output_ikey];
*cur = scan->keyData[input_ikey];
*cur = *inkey;
if (!(cur->sk_flags & SK_SEARCHARRAY))
{
output_ikey++; /* keep this non-array scan key */
numArrayKeyData++; /* keep this non-array scan key */
continue;
}
/*
* Process SAOP array scan key
*/
Assert(!(cur->sk_flags & (SK_ROW_HEADER | SK_SEARCHNULL | SK_SEARCHNOTNULL)));
/* If array is null as a whole, the scan qual is unsatisfiable */
if (cur->sk_flags & SK_ISNULL)
{
so->qual_ok = false;
break;
}
/*
* Deconstruct the array into elements
*/
@ -1257,7 +1537,7 @@ _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
* all btree operators are strict.
*/
num_nonnulls = 0;
for (j = 0; j < num_elems; j++)
for (int j = 0; j < num_elems; j++)
{
if (!elem_nulls[j])
elem_values[num_nonnulls++] = elem_values[j];
@ -1295,7 +1575,7 @@ _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
_bt_find_extreme_element(scan, cur, elemtype,
BTGreaterStrategyNumber,
elem_values, num_nonnulls);
output_ikey++; /* keep this transformed scan key */
numArrayKeyData++; /* keep this transformed scan key */
continue;
case BTEqualStrategyNumber:
/* proceed with rest of loop */
@ -1306,7 +1586,7 @@ _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
_bt_find_extreme_element(scan, cur, elemtype,
BTLessStrategyNumber,
elem_values, num_nonnulls);
output_ikey++; /* keep this transformed scan key */
numArrayKeyData++; /* keep this transformed scan key */
continue;
default:
elog(ERROR, "unrecognized StrategyNumber: %d",
@ -1323,7 +1603,7 @@ _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
* sortproc just points to the same proc used during binary searches.
*/
_bt_setup_array_cmp(scan, cur, elemtype,
&so->orderProcs[output_ikey], &sortprocp);
&so->orderProcs[numArrayKeyData], &sortprocp);
/*
* Sort the non-null elements and eliminate any duplicates. We must
@ -1392,23 +1672,24 @@ _bt_preprocess_array_keys(IndexScanDesc scan, int *new_numberOfKeys)
origelemtype = elemtype;
}
/*
* And set up the BTArrayKeyInfo data.
*
* Note: _bt_preprocess_array_keys_final will fix-up each array's
* scan_key field later on, after so->keyData[] has been finalized.
*/
so->arrayKeys[numArrayKeys].scan_key = output_ikey;
/* Initialize generic BTArrayKeyInfo fields */
so->arrayKeys[numArrayKeys].scan_key = numArrayKeyData;
so->arrayKeys[numArrayKeys].num_elems = num_elems;
/* Initialize SAOP array specific BTArrayKeyInfo fields */
so->arrayKeys[numArrayKeys].elem_values = elem_values;
so->arrayKeys[numArrayKeys].cur_elem = -1; /* i.e. invalid */
numArrayKeys++;
output_ikey++; /* keep this scan key/array */
numArrayKeyData++; /* keep this scan key/array */
}
Assert(numSkipArrayKeys == 0);
/* Set final number of equality-type array keys */
so->numArrayKeys = numArrayKeys;
/* Set number of scan keys remaining in arrayKeyData[] */
*new_numberOfKeys = output_ikey;
/* Set number of scan keys in arrayKeyData[] */
*new_numberOfKeys = numArrayKeyData;
MemoryContextSwitchTo(oldContext);
@ -1514,7 +1795,14 @@ _bt_preprocess_array_keys_final(IndexScanDesc scan, int *keyDataMap)
{
BTArrayKeyInfo *array = &so->arrayKeys[arrayidx];
Assert(array->num_elems > 0);
/*
* All skip arrays must be marked required, and final column can
* never have a skip array
*/
Assert(array->num_elems > 0 || array->num_elems == -1);
Assert(array->num_elems != -1 || outkey->sk_flags & SK_BT_REQFWD);
Assert(array->num_elems != -1 ||
outkey->sk_attno < IndexRelationGetNumberOfKeyAttributes(rel));
if (array->scan_key == input_ikey)
{
@ -1575,6 +1863,199 @@ _bt_preprocess_array_keys_final(IndexScanDesc scan, int *keyDataMap)
so->numArrayKeys, INDEX_MAX_KEYS)));
}
/*
* _bt_num_array_keys() -- determine # of BTArrayKeyInfo entries
*
* _bt_preprocess_array_keys helper function. Returns the estimated size of
* the scan's BTArrayKeyInfo array, which is guaranteed to be large enough to
* fit every so->arrayKeys[] entry.
*
* Also sets *numSkipArrayKeys_out to the number of of skip arrays caller must
* add to the scan keys it'll output. Caller must add this many skip arrays:
* one array for each of the most significant attributes that lack a = input
* key (IS NULL keys count as = input keys here). The specific attributes
* that need skip arrays are indicated by initializing skip_eq_ops_out[] arg
* 0-based attribute offset to a valid = op strategy Oid. We'll only ever set
* skip_eq_ops_out[] entries to InvalidOid for attributes that already have an
* equality key in scan->keyData[] input keys -- and only when there's some
* later "attribute gap" for us to "fill-in" with a skip array.
*
* We're optimistic about skipping working out: we always add exactly the skip
* arrays needed to maximize the number of input scan keys that can ultimately
* be marked as required to continue the scan (but no more). Given a
* multi-column index on (a, b, c, d), we add skip arrays as follows:
*
* Input keys Output keys (after all preprocessing)
* ---------- -------------------------------------
* a = 1 a = 1 (no skip arrays)
* b = 42 skip a AND b = 42
* a = 1 AND b = 42 a = 1 AND b = 42 (no skip arrays)
* a >= 1 AND b = 42 range skip a AND b = 42
* a = 1 AND b > 42 a = 1 AND b > 42 (no skip arrays)
* a >= 1 AND a <= 3 AND b = 42 range skip a AND b = 42
* a = 1 AND c <= 27 a = 1 AND skip b AND c <= 27
* a = 1 AND d >= 1 a = 1 AND skip b AND skip c AND d >= 1
* a = 1 AND b >= 42 AND d > 1 a = 1 AND range skip b AND skip c AND d > 1
*/
static int
_bt_num_array_keys(IndexScanDesc scan, Oid *skip_eq_ops_out,
int *numSkipArrayKeys_out)
{
Relation rel = scan->indexRelation;
AttrNumber attno_skip = 1,
attno_inkey = 1;
bool attno_has_equal = false,
attno_has_rowcompare = false;
int numSAOPArrayKeys,
numSkipArrayKeys,
prev_numSkipArrayKeys;
Assert(scan->numberOfKeys);
/* Initial pass over input scan keys counts the number of SAOP arrays */
numSAOPArrayKeys = 0;
*numSkipArrayKeys_out = prev_numSkipArrayKeys = numSkipArrayKeys = 0;
for (int i = 0; i < scan->numberOfKeys; i++)
{
ScanKey inkey = scan->keyData + i;
if (inkey->sk_flags & SK_SEARCHARRAY)
numSAOPArrayKeys++;
}
#ifdef DEBUG_DISABLE_SKIP_SCAN
/* don't attempt to add skip arrays */
return numSAOPArrayKeys;
#endif
for (int i = 0;; i++)
{
ScanKey inkey = scan->keyData + i;
/*
* Backfill skip arrays for any wholly omitted attributes prior to
* attno_inkey
*/
while (attno_skip < attno_inkey)
{
Oid opfamily = rel->rd_opfamily[attno_skip - 1];
Oid opcintype = rel->rd_opcintype[attno_skip - 1];
/* Look up input opclass's equality operator (might fail) */
skip_eq_ops_out[attno_skip - 1] =
get_opfamily_member(opfamily, opcintype, opcintype,
BTEqualStrategyNumber);
if (!OidIsValid(skip_eq_ops_out[attno_skip - 1]))
{
/*
* Cannot generate a skip array for this or later attributes
* (input opclass lacks an equality strategy operator)
*/
*numSkipArrayKeys_out = prev_numSkipArrayKeys;
return numSAOPArrayKeys + prev_numSkipArrayKeys;
}
/* plan on adding a backfill skip array for this attribute */
numSkipArrayKeys++;
attno_skip++;
}
prev_numSkipArrayKeys = numSkipArrayKeys;
/*
* Stop once past the final input scan key. We deliberately never add
* a skip array for the last input scan key's attribute -- even when
* there are only inequality keys on that attribute.
*/
if (i == scan->numberOfKeys)
break;
/*
* Later preprocessing steps cannot merge a RowCompare into a skip
* array, so stop adding skip arrays once we see one. (Note that we
* can backfill skip arrays before a RowCompare, which will allow keys
* up to and including the RowCompare to be marked required.)
*
* Skip arrays work by maintaining a current array element value,
* which anchors lower-order keys via an implied equality constraint.
* This is incompatible with the current nbtree row comparison design,
* which compares all columns together, as an indivisible group.
* Alternative designs that can be used alongside skip arrays are
* possible, but it's not clear that they're really worth pursuing.
*
* A RowCompare qual "(a, b, c) > (10, 'foo', 42)" is equivalent to
* "(a=10 AND b='foo' AND c>42) OR (a=10 AND b>'foo') OR (a>10)".
* Decomposing this RowCompare into these 3 disjuncts allows each
* disjunct to be executed as a separate "single value" index scan.
* That'll give all 3 scans the ability to add skip arrays in the
* usual way (when there are any scalar keys after the RowCompare).
* Under this scheme, a qual "(a, b, c) > (10, 'foo', 42) AND d = 99"
* performs 3 separate scans, each of which can mark keys up to and
* including its "d = 99" key as required to continue the scan.
*/
if (attno_has_rowcompare)
break;
/*
* Now consider next attno_inkey (or keep going if this is an
* additional scan key against the same attribute)
*/
if (attno_inkey < inkey->sk_attno)
{
/*
* Now add skip array for previous scan key's attribute, though
* only if the attribute has no equality strategy scan keys
*/
if (attno_has_equal)
{
/* Attributes with an = key must have InvalidOid eq_op set */
skip_eq_ops_out[attno_skip - 1] = InvalidOid;
}
else
{
Oid opfamily = rel->rd_opfamily[attno_skip - 1];
Oid opcintype = rel->rd_opcintype[attno_skip - 1];
/* Look up input opclass's equality operator (might fail) */
skip_eq_ops_out[attno_skip - 1] =
get_opfamily_member(opfamily, opcintype, opcintype,
BTEqualStrategyNumber);
if (!OidIsValid(skip_eq_ops_out[attno_skip - 1]))
{
/*
* Input opclass lacks an equality strategy operator, so
* don't generate a skip array that definitely won't work
*/
break;
}
/* plan on adding a backfill skip array for this attribute */
numSkipArrayKeys++;
}
/* Set things up for this new attribute */
attno_skip++;
attno_inkey = inkey->sk_attno;
attno_has_equal = false;
}
/*
* Track if this attribute's scan keys include any equality strategy
* scan keys (IS NULL keys count as equality keys here). Also track
* if it has any RowCompare keys.
*/
if (inkey->sk_strategy == BTEqualStrategyNumber ||
(inkey->sk_flags & SK_SEARCHNULL))
attno_has_equal = true;
if (inkey->sk_flags & SK_ROW_HEADER)
attno_has_rowcompare = true;
}
*numSkipArrayKeys_out = numSkipArrayKeys;
return numSAOPArrayKeys + numSkipArrayKeys;
}
/*
* _bt_find_extreme_element() -- get least or greatest array element
*

196
src/backend/access/nbtree/nbtree.c
Unescape View File

@ -31,6 +31,7 @@
#include "storage/ipc.h"
#include "storage/lmgr.h"
#include "storage/read_stream.h"
#include "utils/datum.h"
#include "utils/fmgrprotos.h"
#include "utils/index_selfuncs.h"
#include "utils/memutils.h"
@ -76,14 +77,26 @@ typedef struct BTParallelScanDescData
/*
* btps_arrElems is used when scans need to schedule another primitive
* index scan. Holds BTArrayKeyInfo.cur_elem offsets for scan keys.
* index scan with one or more SAOP arrays. Holds BTArrayKeyInfo.cur_elem
* offsets for each = scan key associated with a ScalarArrayOp array.
*/
int btps_arrElems[FLEXIBLE_ARRAY_MEMBER];
/*
* Additional space (at the end of the struct) is used when scans need to
* schedule another primitive index scan with one or more skip arrays.
* Holds a flattened datum representation for each = scan key associated
* with a skip array.
*/
} BTParallelScanDescData;
typedef struct BTParallelScanDescData *BTParallelScanDesc;
static void _bt_parallel_serialize_arrays(Relation rel, BTParallelScanDesc btscan,
BTScanOpaque so);
static void _bt_parallel_restore_arrays(Relation rel, BTParallelScanDesc btscan,
BTScanOpaque so);
static void btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats,
IndexBulkDeleteCallback callback, void *callback_state,
BTCycleId cycleid);
@ -541,10 +554,167 @@ btrestrpos(IndexScanDesc scan)
* btestimateparallelscan -- estimate storage for BTParallelScanDescData
*/
Size
btestimateparallelscan(int nkeys, int norderbys)
btestimateparallelscan(Relation rel, int nkeys, int norderbys)
{
int16 nkeyatts = IndexRelationGetNumberOfKeyAttributes(rel);
Size estnbtreeshared,
genericattrspace;
/*
* Pessimistically assume that every input scan key will be output with
* its own SAOP array
*/
estnbtreeshared = offsetof(BTParallelScanDescData, btps_arrElems) +
sizeof(int) * nkeys;
/* Single column indexes cannot possibly use a skip array */
if (nkeyatts == 1)
return estnbtreeshared;
/*
* Pessimistically assume that all attributes prior to the least
* significant attribute require a skip array (and an associated key)
*/
genericattrspace = datumEstimateSpace((Datum) 0, false, true,
sizeof(Datum));
for (int attnum = 1; attnum < nkeyatts; attnum++)
{
CompactAttribute *attr;
/*
* We make the conservative assumption that every index column will
* also require a skip array.
*
* Every skip array must have space to store its scan key's sk_flags.
*/
estnbtreeshared = add_size(estnbtreeshared, sizeof(int));
/* Consider space required to store a datum of opclass input type */
attr = TupleDescCompactAttr(rel->rd_att, attnum - 1);
if (attr->attbyval)
{
/* This index attribute stores pass-by-value datums */
Size estfixed = datumEstimateSpace((Datum) 0, false,
true, attr->attlen);
estnbtreeshared = add_size(estnbtreeshared, estfixed);
continue;
}
/*
* This index attribute stores pass-by-reference datums.
*
* Assume that serializing this array will use just as much space as a
* pass-by-value datum, in addition to space for the largest possible
* whole index tuple (this is not just a per-datum portion of the
* largest possible tuple because that'd be almost as large anyway).
*
* This is quite conservative, but it's not clear how we could do much
* better. The executor requires an up-front storage request size
* that reliably covers the scan's high watermark memory usage. We
* can't be sure of the real high watermark until the scan is over.
*/
estnbtreeshared = add_size(estnbtreeshared, genericattrspace);
estnbtreeshared = add_size(estnbtreeshared, BTMaxItemSize);
}
return estnbtreeshared;
}
/*
* _bt_parallel_serialize_arrays() -- Serialize parallel array state.
*
* Caller must have exclusively locked btscan->btps_lock when called.
*/
static void
_bt_parallel_serialize_arrays(Relation rel, BTParallelScanDesc btscan,
BTScanOpaque so)
{
char *datumshared;
/* Space for serialized datums begins immediately after btps_arrElems[] */
datumshared = ((char *) &btscan->btps_arrElems[so->numArrayKeys]);
for (int i = 0; i < so->numArrayKeys; i++)
{
BTArrayKeyInfo *array = &so->arrayKeys[i];
ScanKey skey = &so->keyData[array->scan_key];
if (array->num_elems != -1)
{
/* Save SAOP array's cur_elem (no need to copy key/datum) */
Assert(!(skey->sk_flags & SK_BT_SKIP));
btscan->btps_arrElems[i] = array->cur_elem;
continue;
}
/* Save all mutable state associated with skip array's key */
Assert(skey->sk_flags & SK_BT_SKIP);
memcpy(datumshared, &skey->sk_flags, sizeof(int));
datumshared += sizeof(int);
if (skey->sk_flags & (SK_BT_MINVAL | SK_BT_MAXVAL))
{
/* No sk_argument datum to serialize */
Assert(skey->sk_argument == 0);
continue;
}
datumSerialize(skey->sk_argument, (skey->sk_flags & SK_ISNULL) != 0,
array->attbyval, array->attlen, &datumshared);
}
}
/*
* _bt_parallel_restore_arrays() -- Restore serialized parallel array state.
*
* Caller must have exclusively locked btscan->btps_lock when called.
*/
static void
_bt_parallel_restore_arrays(Relation rel, BTParallelScanDesc btscan,
BTScanOpaque so)
{
/* Pessimistically assume all input scankeys will be output with arrays */
return offsetof(BTParallelScanDescData, btps_arrElems) + sizeof(int) * nkeys;
char *datumshared;
/* Space for serialized datums begins immediately after btps_arrElems[] */
datumshared = ((char *) &btscan->btps_arrElems[so->numArrayKeys]);
for (int i = 0; i < so->numArrayKeys; i++)
{
BTArrayKeyInfo *array = &so->arrayKeys[i];
ScanKey skey = &so->keyData[array->scan_key];
bool isnull;
if (array->num_elems != -1)
{
/* Restore SAOP array using its saved cur_elem */
Assert(!(skey->sk_flags & SK_BT_SKIP));
array->cur_elem = btscan->btps_arrElems[i];
skey->sk_argument = array->elem_values[array->cur_elem];
continue;
}
/* Restore skip array by restoring its key directly */
if (!array->attbyval && skey->sk_argument)
pfree(DatumGetPointer(skey->sk_argument));
skey->sk_argument = (Datum) 0;
memcpy(&skey->sk_flags, datumshared, sizeof(int));
datumshared += sizeof(int);
Assert(skey->sk_flags & SK_BT_SKIP);
if (skey->sk_flags & (SK_BT_MINVAL | SK_BT_MAXVAL))
{
/* No sk_argument datum to restore */
continue;
}
skey->sk_argument = datumRestore(&datumshared, &isnull);
if (isnull)
{
Assert(skey->sk_argument == 0);
Assert(skey->sk_flags & SK_SEARCHNULL);
Assert(skey->sk_flags & SK_ISNULL);
}
}
}
/*
@ -613,6 +783,7 @@ bool
_bt_parallel_seize(IndexScanDesc scan, BlockNumber *next_scan_page,
BlockNumber *last_curr_page, bool first)
{
Relation rel = scan->indexRelation;
BTScanOpaque so = (BTScanOpaque) scan->opaque;
bool exit_loop = false,
status = true,
@ -679,14 +850,9 @@ _bt_parallel_seize(IndexScanDesc scan, BlockNumber *next_scan_page,
{
/* Can start scheduled primitive scan right away, so do so */
btscan->btps_pageStatus = BTPARALLEL_ADVANCING;
for (int i = 0; i < so->numArrayKeys; i++)
{
BTArrayKeyInfo *array = &so->arrayKeys[i];
ScanKey skey = &so->keyData[array->scan_key];
array->cur_elem = btscan->btps_arrElems[i];
skey->sk_argument = array->elem_values[array->cur_elem];
}
/* Restore scan's array keys from serialized values */
_bt_parallel_restore_arrays(rel, btscan, so);
exit_loop = true;
}
else
@ -831,6 +997,7 @@ _bt_parallel_done(IndexScanDesc scan)
void
_bt_parallel_primscan_schedule(IndexScanDesc scan, BlockNumber curr_page)
{
Relation rel = scan->indexRelation;
BTScanOpaque so = (BTScanOpaque) scan->opaque;
ParallelIndexScanDesc parallel_scan = scan->parallel_scan;
BTParallelScanDesc btscan;
@ -849,12 +1016,7 @@ _bt_parallel_primscan_schedule(IndexScanDesc scan, BlockNumber curr_page)
btscan->btps_pageStatus = BTPARALLEL_NEED_PRIMSCAN;
/* Serialize scan's current array keys */
for (int i = 0; i < so->numArrayKeys; i++)
{
BTArrayKeyInfo *array = &so->arrayKeys[i];
btscan->btps_arrElems[i] = array->cur_elem;
}
_bt_parallel_serialize_arrays(rel, btscan, so);
}
LWLockRelease(&btscan->btps_lock);
}

130
src/backend/access/nbtree/nbtsearch.c
Unescape View File

@ -983,7 +983,21 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
* one we use --- by definition, they are either redundant or
* contradictory.
*
* Any regular (not SK_SEARCHNULL) key implies a NOT NULL qualifier.
* In practice we rarely see any "attribute boundary key gaps" here.
* Preprocessing can usually backfill skip array keys for any attributes
* that were omitted from the original scan->keyData[] input keys. All
* array keys are always considered = keys, but we'll sometimes need to
* treat the current key value as if we were using an inequality strategy.
* This happens with range skip arrays, which store inequality keys in the
* array's low_compare/high_compare fields (used to find the first/last
* set of matches, when = key will lack a usable sk_argument value).
* These are always preferred over any redundant "standard" inequality
* keys on the same column (per the usual rule about preferring = keys).
* Note also that any column with an = skip array key can never have an
* additional, contradictory = key.
*
* All keys (with the exception of SK_SEARCHNULL keys and SK_BT_SKIP
* array keys whose array is "null_elem=true") imply a NOT NULL qualifier.
* If the index stores nulls at the end of the index we'll be starting
* from, and we have no boundary key for the column (which means the key
* we deduced NOT NULL from is an inequality key that constrains the other
@ -1040,8 +1054,54 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
if (i >= so->numberOfKeys || cur->sk_attno != curattr)
{
/*
* Done looking at keys for curattr. If we didn't find a
* usable boundary key, see if we can deduce a NOT NULL key.
* Done looking at keys for curattr.
*
* If this is a scan key for a skip array whose current
* element is MINVAL, choose low_compare (when scanning
* backwards it'll be MAXVAL, and we'll choose high_compare).
*
* Note: if the array's low_compare key makes 'chosen' NULL,
* then we behave as if the array's first element is -inf,
* except when !array->null_elem implies a usable NOT NULL
* constraint.
*/
if (chosen != NULL &&
(chosen->sk_flags & (SK_BT_MINVAL | SK_BT_MAXVAL)))
{
int ikey = chosen - so->keyData;
ScanKey skipequalitykey = chosen;
BTArrayKeyInfo *array = NULL;
for (int arridx = 0; arridx < so->numArrayKeys; arridx++)
{
array = &so->arrayKeys[arridx];
if (array->scan_key == ikey)
break;
}
if (ScanDirectionIsForward(dir))
{
Assert(!(skipequalitykey->sk_flags & SK_BT_MAXVAL));
chosen = array->low_compare;
}
else
{
Assert(!(skipequalitykey->sk_flags & SK_BT_MINVAL));
chosen = array->high_compare;
}
Assert(chosen == NULL ||
chosen->sk_attno == skipequalitykey->sk_attno);
if (!array->null_elem)
impliesNN = skipequalitykey;
else
Assert(chosen == NULL && impliesNN == NULL);
}
/*
* If we didn't find a usable boundary key, see if we can
* deduce a NOT NULL key
*/
if (chosen == NULL && impliesNN != NULL &&
((impliesNN->sk_flags & SK_BT_NULLS_FIRST) ?
@ -1084,9 +1144,40 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
break;
/*
* Done if that was the last attribute, or if next key is not
* in sequence (implying no boundary key is available for the
* next attribute).
* If the key that we just added to startKeys[] is a skip
* array = key whose current element is marked NEXT or PRIOR,
* make strat_total > or < (and stop adding boundary keys).
* This can only happen with opclasses that lack skip support.
*/
if (chosen->sk_flags & (SK_BT_NEXT | SK_BT_PRIOR))
{
Assert(chosen->sk_flags & SK_BT_SKIP);
Assert(strat_total == BTEqualStrategyNumber);
if (ScanDirectionIsForward(dir))
{
Assert(!(chosen->sk_flags & SK_BT_PRIOR));
strat_total = BTGreaterStrategyNumber;
}
else
{
Assert(!(chosen->sk_flags & SK_BT_NEXT));
strat_total = BTLessStrategyNumber;
}
/*
* We're done. We'll never find an exact = match for a
* NEXT or PRIOR sentinel sk_argument value. There's no
* sense in trying to add more keys to startKeys[].
*/
break;
}
/*
* Done if that was the last scan key output by preprocessing.
* Also done if there is a gap index attribute that lacks a
* usable key (only possible when preprocessing was unable to
* generate a skip array key to "fill in the gap").
*/
if (i >= so->numberOfKeys ||
cur->sk_attno != curattr + 1)
@ -1581,31 +1672,10 @@ _bt_readpage(IndexScanDesc scan, ScanDirection dir, OffsetNumber offnum,
* We skip this for the first page read by each (primitive) scan, to avoid
* slowing down point queries. They typically don't stand to gain much
* when the optimization can be applied, and are more likely to notice the
* overhead of the precheck.
*
* The optimization is unsafe and must be avoided whenever _bt_checkkeys
* just set a low-order required array's key to the best available match
* for a truncated -inf attribute value from the prior page's high key
* (array element 0 is always the best available match in this scenario).
* It's quite likely that matches for array element 0 begin on this page,
* but the start of matches won't necessarily align with page boundaries.
* When the start of matches is somewhere in the middle of this page, it
* would be wrong to treat page's final non-pivot tuple as representative.
* Doing so might lead us to treat some of the page's earlier tuples as
* being part of a group of tuples thought to satisfy the required keys.
*
* Note: Conversely, in the case where the scan's arrays just advanced
* using the prior page's HIKEY _without_ advancement setting scanBehind,
* the start of matches must be aligned with page boundaries, which makes
* it safe to attempt the optimization here now. It's also safe when the
* prior page's HIKEY simply didn't need to advance any required array. In
* both cases we can safely assume that the _first_ tuple from this page
* must be >= the current set of array keys/equality constraints. And so
* if the final tuple is == those same keys (and also satisfies any
* required < or <= strategy scan keys) during the precheck, we can safely
* assume that this must also be true of all earlier tuples from the page.
* overhead of the precheck. Also avoid it during scans with array keys,
* which might be using skip scan (XXX fixed in next commit).
*/
if (!pstate.firstpage && !so->scanBehind && minoff < maxoff)
if (!pstate.firstpage && !arrayKeys && minoff < maxoff)
{
ItemId iid;
IndexTuple itup;

756
src/backend/access/nbtree/nbtutils.c
Unescape View File

@ -30,6 +30,17 @@
static inline int32 _bt_compare_array_skey(FmgrInfo *orderproc,
Datum tupdatum, bool tupnull,
Datum arrdatum, ScanKey cur);
static void _bt_binsrch_skiparray_skey(bool cur_elem_trig, ScanDirection dir,
Datum tupdatum, bool tupnull,
BTArrayKeyInfo *array, ScanKey cur,
int32 *set_elem_result);
static void _bt_skiparray_set_element(Relation rel, ScanKey skey, BTArrayKeyInfo *array,
int32 set_elem_result, Datum tupdatum, bool tupnull);
static void _bt_skiparray_set_isnull(Relation rel, ScanKey skey, BTArrayKeyInfo *array);
static void _bt_array_set_low_or_high(Relation rel, ScanKey skey,
BTArrayKeyInfo *array, bool low_not_high);
static bool _bt_array_decrement(Relation rel, ScanKey skey, BTArrayKeyInfo *array);
static bool _bt_array_increment(Relation rel, ScanKey skey, BTArrayKeyInfo *array);
static bool _bt_advance_array_keys_increment(IndexScanDesc scan, ScanDirection dir);
static void _bt_rewind_nonrequired_arrays(IndexScanDesc scan, ScanDirection dir);
static bool _bt_tuple_before_array_skeys(IndexScanDesc scan, ScanDirection dir,
@ -207,6 +218,7 @@ _bt_compare_array_skey(FmgrInfo *orderproc,
int32 result = 0;
Assert(cur->sk_strategy == BTEqualStrategyNumber);
Assert(!(cur->sk_flags & (SK_BT_MINVAL | SK_BT_MAXVAL)));
if (tupnull) /* NULL tupdatum */
{
@ -283,6 +295,8 @@ _bt_binsrch_array_skey(FmgrInfo *orderproc,
Datum arrdatum;
Assert(cur->sk_flags & SK_SEARCHARRAY);
Assert(!(cur->sk_flags & SK_BT_SKIP));
Assert(!(cur->sk_flags & SK_ISNULL)); /* SAOP arrays never have NULLs */
Assert(cur->sk_strategy == BTEqualStrategyNumber);
if (cur_elem_trig)
@ -405,6 +419,186 @@ _bt_binsrch_array_skey(FmgrInfo *orderproc,
return low_elem;
}
/*
* _bt_binsrch_skiparray_skey() -- "Binary search" within a skip array
*
* Does not return an index into the array, since skip arrays don't really
* contain elements (they generate their array elements procedurally instead).
* Our interface matches that of _bt_binsrch_array_skey in every other way.
*
* Sets *set_elem_result just like _bt_binsrch_array_skey would with a true
* array. The value 0 indicates that tupdatum/tupnull is within the range of
* the skip array. We return -1 when tupdatum/tupnull is lower that any value
* within the range of the array, and 1 when it is higher than every value.
* Caller should pass *set_elem_result to _bt_skiparray_set_element to advance
* the array.
*
* cur_elem_trig indicates if array advancement was triggered by this array's
* scan key. We use this to optimize-away comparisons that are known by our
* caller to be unnecessary from context, just like _bt_binsrch_array_skey.
*/
static void
_bt_binsrch_skiparray_skey(bool cur_elem_trig, ScanDirection dir,
Datum tupdatum, bool tupnull,
BTArrayKeyInfo *array, ScanKey cur,
int32 *set_elem_result)
{
Assert(cur->sk_flags & SK_BT_SKIP);
Assert(cur->sk_flags & SK_SEARCHARRAY);
Assert(cur->sk_flags & SK_BT_REQFWD);
Assert(array->num_elems == -1);
Assert(!ScanDirectionIsNoMovement(dir));
if (array->null_elem)
{
Assert(!array->low_compare && !array->high_compare);
*set_elem_result = 0;
return;
}
if (tupnull) /* NULL tupdatum */
{
if (cur->sk_flags & SK_BT_NULLS_FIRST)
*set_elem_result = -1; /* NULL "<" NOT_NULL */
else
*set_elem_result = 1; /* NULL ">" NOT_NULL */
return;
}
/*
* Array inequalities determine whether tupdatum is within the range of
* caller's skip array
*/
*set_elem_result = 0;
if (ScanDirectionIsForward(dir))
{
/*
* Evaluate low_compare first (unless cur_elem_trig tells us that it
* cannot possibly fail to be satisfied), then evaluate high_compare
*/
if (!cur_elem_trig && array->low_compare &&
!DatumGetBool(FunctionCall2Coll(&array->low_compare->sk_func,
array->low_compare->sk_collation,
tupdatum,
array->low_compare->sk_argument)))
*set_elem_result = -1;
else if (array->high_compare &&
!DatumGetBool(FunctionCall2Coll(&array->high_compare->sk_func,
array->high_compare->sk_collation,
tupdatum,
array->high_compare->sk_argument)))
*set_elem_result = 1;
}
else
{
/*
* Evaluate high_compare first (unless cur_elem_trig tells us that it
* cannot possibly fail to be satisfied), then evaluate low_compare
*/
if (!cur_elem_trig && array->high_compare &&
!DatumGetBool(FunctionCall2Coll(&array->high_compare->sk_func,
array->high_compare->sk_collation,
tupdatum,
array->high_compare->sk_argument)))
*set_elem_result = 1;
else if (array->low_compare &&
!DatumGetBool(FunctionCall2Coll(&array->low_compare->sk_func,
array->low_compare->sk_collation,
tupdatum,
array->low_compare->sk_argument)))
*set_elem_result = -1;
}
/*
* Assert that any keys that were assumed to be satisfied already (due to
* caller passing cur_elem_trig=true) really are satisfied as expected
*/
#ifdef USE_ASSERT_CHECKING
if (cur_elem_trig)
{
if (ScanDirectionIsForward(dir) && array->low_compare)
Assert(DatumGetBool(FunctionCall2Coll(&array->low_compare->sk_func,
array->low_compare->sk_collation,
tupdatum,
array->low_compare->sk_argument)));
if (ScanDirectionIsBackward(dir) && array->high_compare)
Assert(DatumGetBool(FunctionCall2Coll(&array->high_compare->sk_func,
array->high_compare->sk_collation,
tupdatum,
array->high_compare->sk_argument)));
}
#endif
}
/*
* _bt_skiparray_set_element() -- Set skip array scan key's sk_argument
*
* Caller passes set_elem_result returned by _bt_binsrch_skiparray_skey for
* caller's tupdatum/tupnull.
*
* We copy tupdatum/tupnull into skey's sk_argument iff set_elem_result == 0.
* Otherwise, we set skey to either the lowest or highest value that's within
* the range of caller's skip array (whichever is the best available match to
* tupdatum/tupnull that is still within the range of the skip array according
* to _bt_binsrch_skiparray_skey/set_elem_result).
*/
static void
_bt_skiparray_set_element(Relation rel, ScanKey skey, BTArrayKeyInfo *array,
int32 set_elem_result, Datum tupdatum, bool tupnull)
{
Assert(skey->sk_flags & SK_BT_SKIP);
Assert(skey->sk_flags & SK_SEARCHARRAY);
if (set_elem_result)
{
/* tupdatum/tupnull is out of the range of the skip array */
Assert(!array->null_elem);
_bt_array_set_low_or_high(rel, skey, array, set_elem_result < 0);
return;
}
/* Advance skip array to tupdatum (or tupnull) value */
if (unlikely(tupnull))
{
_bt_skiparray_set_isnull(rel, skey, array);
return;
}
/* Free memory previously allocated for sk_argument if needed */
if (!array->attbyval && skey->sk_argument)
pfree(DatumGetPointer(skey->sk_argument));
/* tupdatum becomes new sk_argument/new current element */
skey->sk_flags &= ~(SK_SEARCHNULL | SK_ISNULL |
SK_BT_MINVAL | SK_BT_MAXVAL |
SK_BT_NEXT | SK_BT_PRIOR);
skey->sk_argument = datumCopy(tupdatum, array->attbyval, array->attlen);
}
/*
* _bt_skiparray_set_isnull() -- set skip array scan key to NULL
*/
static void
_bt_skiparray_set_isnull(Relation rel, ScanKey skey, BTArrayKeyInfo *array)
{
Assert(skey->sk_flags & SK_BT_SKIP);
Assert(skey->sk_flags & SK_SEARCHARRAY);
Assert(array->null_elem && !array->low_compare && !array->high_compare);
/* Free memory previously allocated for sk_argument if needed */
if (!array->attbyval && skey->sk_argument)
pfree(DatumGetPointer(skey->sk_argument));
/* NULL becomes new sk_argument/new current element */
skey->sk_argument = (Datum) 0;
skey->sk_flags &= ~(SK_BT_MINVAL | SK_BT_MAXVAL |
SK_BT_NEXT | SK_BT_PRIOR);
skey->sk_flags |= (SK_SEARCHNULL | SK_ISNULL);
}
/*
* _bt_start_array_keys() -- Initialize array keys at start of a scan
*
@ -414,29 +608,355 @@ _bt_binsrch_array_skey(FmgrInfo *orderproc,
void
_bt_start_array_keys(IndexScanDesc scan, ScanDirection dir)
{
Relation rel = scan->indexRelation;
BTScanOpaque so = (BTScanOpaque) scan->opaque;
int i;
Assert(so->numArrayKeys);
Assert(so->qual_ok);
for (i = 0; i < so->numArrayKeys; i++)
for (int i = 0; i < so->numArrayKeys; i++)
{
BTArrayKeyInfo *curArrayKey = &so->arrayKeys[i];
ScanKey skey = &so->keyData[curArrayKey->scan_key];
BTArrayKeyInfo *array = &so->arrayKeys[i];
ScanKey skey = &so->keyData[array->scan_key];
Assert(curArrayKey->num_elems > 0);
Assert(skey->sk_flags & SK_SEARCHARRAY);
if (ScanDirectionIsBackward(dir))
curArrayKey->cur_elem = curArrayKey->num_elems - 1;
else
curArrayKey->cur_elem = 0;
skey->sk_argument = curArrayKey->elem_values[curArrayKey->cur_elem];
_bt_array_set_low_or_high(rel, skey, array,
ScanDirectionIsForward(dir));
}
so->scanBehind = so->oppositeDirCheck = false; /* reset */
}
/*
* _bt_array_set_low_or_high() -- Set array scan key to lowest/highest element
*
* Caller also passes associated scan key, which will have its argument set to
* the lowest/highest array value in passing.
*/
static void
_bt_array_set_low_or_high(Relation rel, ScanKey skey, BTArrayKeyInfo *array,
bool low_not_high)
{
Assert(skey->sk_flags & SK_SEARCHARRAY);
if (array->num_elems != -1)
{
/* set low or high element for SAOP array */
int set_elem = 0;
Assert(!(skey->sk_flags & SK_BT_SKIP));
if (!low_not_high)
set_elem = array->num_elems - 1;
/*
* Just copy over array datum (only skip arrays require freeing and
* allocating memory for sk_argument)
*/
array->cur_elem = set_elem;
skey->sk_argument = array->elem_values[set_elem];
return;
}
/* set low or high element for skip array */
Assert(skey->sk_flags & SK_BT_SKIP);
Assert(array->num_elems == -1);
/* Free memory previously allocated for sk_argument if needed */
if (!array->attbyval && skey->sk_argument)
pfree(DatumGetPointer(skey->sk_argument));
/* Reset flags */
skey->sk_argument = (Datum) 0;
skey->sk_flags &= ~(SK_SEARCHNULL | SK_ISNULL |
SK_BT_MINVAL | SK_BT_MAXVAL |
SK_BT_NEXT | SK_BT_PRIOR);
if (array->null_elem &&
(low_not_high == ((skey->sk_flags & SK_BT_NULLS_FIRST) != 0)))
{
/* Requested element (either lowest or highest) has the value NULL */
skey->sk_flags |= (SK_SEARCHNULL | SK_ISNULL);
}
else if (low_not_high)
{
/* Setting array to lowest element (according to low_compare) */
skey->sk_flags |= SK_BT_MINVAL;
}
else
{
/* Setting array to highest element (according to high_compare) */
skey->sk_flags |= SK_BT_MAXVAL;
}
}
/*
* _bt_array_decrement() -- decrement array scan key's sk_argument
*
* Return value indicates whether caller's array was successfully decremented.
* Cannot decrement an array whose current element is already the first one.
*/
static bool
_bt_array_decrement(Relation rel, ScanKey skey, BTArrayKeyInfo *array)
{
bool uflow = false;
Datum dec_sk_argument;
Assert(skey->sk_flags & SK_SEARCHARRAY);
Assert(!(skey->sk_flags & (SK_BT_MAXVAL | SK_BT_NEXT | SK_BT_PRIOR)));
/* SAOP array? */
if (array->num_elems != -1)
{
Assert(!(skey->sk_flags & (SK_BT_SKIP | SK_BT_MINVAL | SK_BT_MAXVAL)));
if (array->cur_elem > 0)
{
/*
* Just decrement current element, and assign its datum to skey
* (only skip arrays need us to free existing sk_argument memory)
*/
array->cur_elem--;
skey->sk_argument = array->elem_values[array->cur_elem];
/* Successfully decremented array */
return true;
}
/* Cannot decrement to before first array element */
return false;
}
/* Nope, this is a skip array */
Assert(skey->sk_flags & SK_BT_SKIP);
/*
* The sentinel value that represents the minimum value within the range
* of a skip array (often just -inf) is never decrementable
*/
if (skey->sk_flags & SK_BT_MINVAL)
return false;
/*
* When the current array element is NULL, and the lowest sorting value in
* the index is also NULL, we cannot decrement before first array element
*/
if ((skey->sk_flags & SK_ISNULL) && (skey->sk_flags & SK_BT_NULLS_FIRST))
return false;
/*
* Opclasses without skip support "decrement" the scan key's current
* element by setting the PRIOR flag. The true prior value is determined
* by repositioning to the last index tuple < existing sk_argument/current
* array element. Note that this works in the usual way when the scan key
* is already marked ISNULL (i.e. when the current element is NULL).
*/
if (!array->sksup)
{
/* Successfully "decremented" array */
skey->sk_flags |= SK_BT_PRIOR;
return true;
}
/*
* Opclasses with skip support directly decrement sk_argument
*/
if (skey->sk_flags & SK_ISNULL)
{
Assert(!(skey->sk_flags & SK_BT_NULLS_FIRST));
/*
* Existing sk_argument/array element is NULL (for an IS NULL qual).
*
* "Decrement" from NULL to the high_elem value provided by opclass
* skip support routine.
*/
skey->sk_flags &= ~(SK_SEARCHNULL | SK_ISNULL);
skey->sk_argument = datumCopy(array->sksup->high_elem,
array->attbyval, array->attlen);
return true;
}
/*
* Ask opclass support routine to provide decremented copy of existing
* non-NULL sk_argument
*/
dec_sk_argument = array->sksup->decrement(rel, skey->sk_argument, &uflow);
if (unlikely(uflow))
{
/* dec_sk_argument has undefined value (so no pfree) */
if (array->null_elem && (skey->sk_flags & SK_BT_NULLS_FIRST))
{
_bt_skiparray_set_isnull(rel, skey, array);
/* Successfully "decremented" array to NULL */
return true;
}
/* Cannot decrement to before first array element */
return false;
}
/*
* Successfully decremented sk_argument to a non-NULL value. Make sure
* that the decremented value is still within the range of the array.
*/
if (array->low_compare &&
!DatumGetBool(FunctionCall2Coll(&array->low_compare->sk_func,
array->low_compare->sk_collation,
dec_sk_argument,
array->low_compare->sk_argument)))
{
/* Keep existing sk_argument after all */
if (!array->attbyval)
pfree(DatumGetPointer(dec_sk_argument));
/* Cannot decrement to before first array element */
return false;
}
/* Accept value returned by opclass decrement callback */
if (!array->attbyval && skey->sk_argument)
pfree(DatumGetPointer(skey->sk_argument));
skey->sk_argument = dec_sk_argument;
/* Successfully decremented array */
return true;
}
/*
* _bt_array_increment() -- increment array scan key's sk_argument
*
* Return value indicates whether caller's array was successfully incremented.
* Cannot increment an array whose current element is already the final one.
*/
static bool
_bt_array_increment(Relation rel, ScanKey skey, BTArrayKeyInfo *array)
{
bool oflow = false;
Datum inc_sk_argument;
Assert(skey->sk_flags & SK_SEARCHARRAY);
Assert(!(skey->sk_flags & (SK_BT_MINVAL | SK_BT_NEXT | SK_BT_PRIOR)));
/* SAOP array? */
if (array->num_elems != -1)
{
Assert(!(skey->sk_flags & (SK_BT_SKIP | SK_BT_MINVAL | SK_BT_MAXVAL)));
if (array->cur_elem < array->num_elems - 1)
{
/*
* Just increment current element, and assign its datum to skey
* (only skip arrays need us to free existing sk_argument memory)
*/
array->cur_elem++;
skey->sk_argument = array->elem_values[array->cur_elem];
/* Successfully incremented array */
return true;
}
/* Cannot increment past final array element */
return false;
}
/* Nope, this is a skip array */
Assert(skey->sk_flags & SK_BT_SKIP);
/*
* The sentinel value that represents the maximum value within the range
* of a skip array (often just +inf) is never incrementable
*/
if (skey->sk_flags & SK_BT_MAXVAL)
return false;
/*
* When the current array element is NULL, and the highest sorting value
* in the index is also NULL, we cannot increment past the final element
*/
if ((skey->sk_flags & SK_ISNULL) && !(skey->sk_flags & SK_BT_NULLS_FIRST))
return false;
/*
* Opclasses without skip support "increment" the scan key's current
* element by setting the NEXT flag. The true next value is determined by
* repositioning to the first index tuple > existing sk_argument/current
* array element. Note that this works in the usual way when the scan key
* is already marked ISNULL (i.e. when the current element is NULL).
*/
if (!array->sksup)
{
/* Successfully "incremented" array */
skey->sk_flags |= SK_BT_NEXT;
return true;
}
/*
* Opclasses with skip support directly increment sk_argument
*/
if (skey->sk_flags & SK_ISNULL)
{
Assert(skey->sk_flags & SK_BT_NULLS_FIRST);
/*
* Existing sk_argument/array element is NULL (for an IS NULL qual).
*
* "Increment" from NULL to the low_elem value provided by opclass
* skip support routine.
*/
skey->sk_flags &= ~(SK_SEARCHNULL | SK_ISNULL);
skey->sk_argument = datumCopy(array->sksup->low_elem,
array->attbyval, array->attlen);
return true;
}
/*
* Ask opclass support routine to provide incremented copy of existing
* non-NULL sk_argument
*/
inc_sk_argument = array->sksup->increment(rel, skey->sk_argument, &oflow);
if (unlikely(oflow))
{
/* inc_sk_argument has undefined value (so no pfree) */
if (array->null_elem && !(skey->sk_flags & SK_BT_NULLS_FIRST))
{
_bt_skiparray_set_isnull(rel, skey, array);
/* Successfully "incremented" array to NULL */
return true;
}
/* Cannot increment past final array element */
return false;
}
/*
* Successfully incremented sk_argument to a non-NULL value. Make sure
* that the incremented value is still within the range of the array.
*/
if (array->high_compare &&
!DatumGetBool(FunctionCall2Coll(&array->high_compare->sk_func,
array->high_compare->sk_collation,
inc_sk_argument,
array->high_compare->sk_argument)))
{
/* Keep existing sk_argument after all */
if (!array->attbyval)
pfree(DatumGetPointer(inc_sk_argument));
/* Cannot increment past final array element */
return false;
}
/* Accept value returned by opclass increment callback */
if (!array->attbyval && skey->sk_argument)
pfree(DatumGetPointer(skey->sk_argument));
skey->sk_argument = inc_sk_argument;
/* Successfully incremented array */
return true;
}
/*
* _bt_advance_array_keys_increment() -- Advance to next set of array elements
*
@ -452,6 +972,7 @@ _bt_start_array_keys(IndexScanDesc scan, ScanDirection dir)
static bool
_bt_advance_array_keys_increment(IndexScanDesc scan, ScanDirection dir)
{
Relation rel = scan->indexRelation;
BTScanOpaque so = (BTScanOpaque) scan->opaque;
/*
@ -461,29 +982,30 @@ _bt_advance_array_keys_increment(IndexScanDesc scan, ScanDirection dir)
*/
for (int i = so->numArrayKeys - 1; i >= 0; i--)
{
BTArrayKeyInfo *curArrayKey = &so->arrayKeys[i];
ScanKey skey = &so->keyData[curArrayKey->scan_key];
int cur_elem = curArrayKey->cur_elem;
int num_elems = curArrayKey->num_elems;
bool rolled = false;
BTArrayKeyInfo *array = &so->arrayKeys[i];
ScanKey skey = &so->keyData[array->scan_key];
if (ScanDirectionIsForward(dir) && ++cur_elem >= num_elems)
if (ScanDirectionIsForward(dir))
{
cur_elem = 0;
rolled = true;
if (_bt_array_increment(rel, skey, array))
return true;
}
else if (ScanDirectionIsBackward(dir) && --cur_elem < 0)
else
{
cur_elem = num_elems - 1;
rolled = true;
if (_bt_array_decrement(rel, skey, array))
return true;
}
curArrayKey->cur_elem = cur_elem;
skey->sk_argument = curArrayKey->elem_values[cur_elem];
if (!rolled)
return true;
/*
* Couldn't increment (or decrement) array. Handle array roll over.
*
* Start over at the array's lowest sorting value (or its highest
* value, for backward scans)...
*/
_bt_array_set_low_or_high(rel, skey, array,
ScanDirectionIsForward(dir));
/* Need to advance next array key, if any */
/* ...then increment (or decrement) next most significant array */
}
/*
@ -507,7 +1029,7 @@ _bt_advance_array_keys_increment(IndexScanDesc scan, ScanDirection dir)
}
/*
* _bt_rewind_nonrequired_arrays() -- Rewind non-required arrays
* _bt_rewind_nonrequired_arrays() -- Rewind SAOP arrays not marked required
*
* Called when _bt_advance_array_keys decides to start a new primitive index
* scan on the basis of the current scan position being before the position
@ -539,10 +1061,15 @@ _bt_advance_array_keys_increment(IndexScanDesc scan, ScanDirection dir)
*
* Note: _bt_verify_arrays_bt_first is called by an assertion to enforce that
* everybody got this right.
*
* Note: In practice almost all SAOP arrays are marked required during
* preprocessing (if necessary by generating skip arrays). It is hardly ever
* truly necessary to call here, but consistently doing so is simpler.
*/
static void
_bt_rewind_nonrequired_arrays(IndexScanDesc scan, ScanDirection dir)
{
Relation rel = scan->indexRelation;
BTScanOpaque so = (BTScanOpaque) scan->opaque;
int arrayidx = 0;
@ -550,7 +1077,6 @@ _bt_rewind_nonrequired_arrays(IndexScanDesc scan, ScanDirection dir)
{
ScanKey cur = so->keyData + ikey;
BTArrayKeyInfo *array = NULL;
int first_elem_dir;
if (!(cur->sk_flags & SK_SEARCHARRAY) ||
cur->sk_strategy != BTEqualStrategyNumber)
@ -562,16 +1088,10 @@ _bt_rewind_nonrequired_arrays(IndexScanDesc scan, ScanDirection dir)
if ((cur->sk_flags & (SK_BT_REQFWD | SK_BT_REQBKWD)))
continue;
if (ScanDirectionIsForward(dir))
first_elem_dir = 0;
else
first_elem_dir = array->num_elems - 1;
Assert(array->num_elems != -1); /* No non-required skip arrays */
if (array->cur_elem != first_elem_dir)
{
array->cur_elem = first_elem_dir;
cur->sk_argument = array->elem_values[first_elem_dir];
}
_bt_array_set_low_or_high(rel, cur, array,
ScanDirectionIsForward(dir));
}
}
@ -696,9 +1216,77 @@ _bt_tuple_before_array_skeys(IndexScanDesc scan, ScanDirection dir,
tupdatum = index_getattr(tuple, cur->sk_attno, tupdesc, &tupnull);
result = _bt_compare_array_skey(&so->orderProcs[ikey],
tupdatum, tupnull,
cur->sk_argument, cur);
if (likely(!(cur->sk_flags & (SK_BT_MINVAL | SK_BT_MAXVAL))))
{
/* Scankey has a valid/comparable sk_argument value */
result = _bt_compare_array_skey(&so->orderProcs[ikey],
tupdatum, tupnull,
cur->sk_argument, cur);
if (result == 0)
{
/*
* Interpret result in a way that takes NEXT/PRIOR into
* account
*/
if (cur->sk_flags & SK_BT_NEXT)
result = -1;
else if (cur->sk_flags & SK_BT_PRIOR)
result = 1;
Assert(result == 0 || (cur->sk_flags & SK_BT_SKIP));
}
}
else
{
BTArrayKeyInfo *array = NULL;
/*
* Current array element/array = scan key value is a sentinel
* value that represents the lowest (or highest) possible value
* that's still within the range of the array.
*
* Like _bt_first, we only see MINVAL keys during forwards scans
* (and similarly only see MAXVAL keys during backwards scans).
* Even if the scan's direction changes, we'll stop at some higher
* order key before we can ever reach any MAXVAL (or MINVAL) keys.
* (However, unlike _bt_first we _can_ get to keys marked either
* NEXT or PRIOR, regardless of the scan's current direction.)
*/
Assert(ScanDirectionIsForward(dir) ?
!(cur->sk_flags & SK_BT_MAXVAL) :
!(cur->sk_flags & SK_BT_MINVAL));
/*
* There are no valid sk_argument values in MINVAL/MAXVAL keys.
* Check if tupdatum is within the range of skip array instead.
*/
for (int arrayidx = 0; arrayidx < so->numArrayKeys; arrayidx++)
{
array = &so->arrayKeys[arrayidx];
if (array->scan_key == ikey)
break;
}
_bt_binsrch_skiparray_skey(false, dir, tupdatum, tupnull,
array, cur, &result);
if (result == 0)
{
/*
* tupdatum satisfies both low_compare and high_compare, so
* it's time to advance the array keys.
*
* Note: It's possible that the skip array will "advance" from
* its MINVAL (or MAXVAL) representation to an alternative,
* logically equivalent representation of the same value: a
* representation where the = key gets a valid datum in its
* sk_argument. This is only possible when low_compare uses
* the >= strategy (or high_compare uses the <= strategy).
*/
return false;
}
}
/*
* Does this comparison indicate that caller must _not_ advance the
@ -1017,18 +1605,9 @@ _bt_advance_array_keys(IndexScanDesc scan, BTReadPageState *pstate,
*/
if (beyond_end_advance)
{
int final_elem_dir;
if (ScanDirectionIsBackward(dir) || !array)
final_elem_dir = 0;
else
final_elem_dir = array->num_elems - 1;
if (array && array->cur_elem != final_elem_dir)
{
array->cur_elem = final_elem_dir;
cur->sk_argument = array->elem_values[final_elem_dir];
}
if (array)
_bt_array_set_low_or_high(rel, cur, array,
ScanDirectionIsBackward(dir));
continue;
}
@ -1053,18 +1632,9 @@ _bt_advance_array_keys(IndexScanDesc scan, BTReadPageState *pstate,
*/
if (!all_required_satisfied || cur->sk_attno > tupnatts)
{
int first_elem_dir;
if (ScanDirectionIsForward(dir) || !array)
first_elem_dir = 0;
else
first_elem_dir = array->num_elems - 1;
if (array && array->cur_elem != first_elem_dir)
{
array->cur_elem = first_elem_dir;
cur->sk_argument = array->elem_values[first_elem_dir];
}
if (array)
_bt_array_set_low_or_high(rel, cur, array,
ScanDirectionIsForward(dir));
continue;
}
@ -1080,14 +1650,22 @@ _bt_advance_array_keys(IndexScanDesc scan, BTReadPageState *pstate,
bool cur_elem_trig = (sktrig_required && ikey == sktrig);
/*
* Binary search for closest match that's available from the array
* "Binary search" by checking if tupdatum/tupnull are within the
* range of the skip array
*/
set_elem = _bt_binsrch_array_skey(&so->orderProcs[ikey],
cur_elem_trig, dir,
tupdatum, tupnull, array, cur,
&result);
if (array->num_elems == -1)
_bt_binsrch_skiparray_skey(cur_elem_trig, dir,
tupdatum, tupnull, array, cur,
&result);
Assert(set_elem >= 0 && set_elem < array->num_elems);
/*
* Binary search for the closest match from the SAOP array
*/
else
set_elem = _bt_binsrch_array_skey(&so->orderProcs[ikey],
cur_elem_trig, dir,
tupdatum, tupnull, array, cur,
&result);
}
else
{
@ -1163,11 +1741,21 @@ _bt_advance_array_keys(IndexScanDesc scan, BTReadPageState *pstate,
}
}
/* Advance array keys, even when set_elem isn't an exact match */
if (array && array->cur_elem != set_elem)
/* Advance array keys, even when we don't have an exact match */
if (array)
{
array->cur_elem = set_elem;
cur->sk_argument = array->elem_values[set_elem];
if (array->num_elems == -1)
{
/* Skip array's new element is tupdatum (or MINVAL/MAXVAL) */
_bt_skiparray_set_element(rel, cur, array, result,
tupdatum, tupnull);
}
else if (array->cur_elem != set_elem)
{
/* SAOP array's new element is set_elem datum */
array->cur_elem = set_elem;
cur->sk_argument = array->elem_values[set_elem];
}
}
}
@ -1581,10 +2169,11 @@ _bt_verify_keys_with_arraykeys(IndexScanDesc scan)
if (array->scan_key != ikey)
return false;
if (array->num_elems <= 0)
if (array->num_elems == 0 || array->num_elems < -1)
return false;
if (cur->sk_argument != array->elem_values[array->cur_elem])
if (array->num_elems != -1 &&
cur->sk_argument != array->elem_values[array->cur_elem])
return false;
if (last_sk_attno > cur->sk_attno)
return false;
@ -1914,6 +2503,20 @@ _bt_check_compare(IndexScanDesc scan, ScanDirection dir,
continue;
}
/*
* A skip array scan key uses one of several sentinel values. We just
* fall back on _bt_tuple_before_array_skeys when we see such a value.
*/
if (key->sk_flags & (SK_BT_MINVAL | SK_BT_MAXVAL |
SK_BT_NEXT | SK_BT_PRIOR))
{
Assert(key->sk_flags & SK_SEARCHARRAY);
Assert(key->sk_flags & SK_BT_SKIP);
*continuescan = false;
return false;
}
/* row-comparison keys need special processing */
if (key->sk_flags & SK_ROW_HEADER)
{
@ -1939,6 +2542,7 @@ _bt_check_compare(IndexScanDesc scan, ScanDirection dir,
else
{
Assert(key->sk_flags & SK_SEARCHNOTNULL);
Assert(!(key->sk_flags & SK_BT_SKIP));
if (!isNull)
continue; /* tuple satisfies this qual */
}

4
src/backend/access/nbtree/nbtvalidate.c
Unescape View File

@ -106,6 +106,10 @@ btvalidate(Oid opclassoid)
case BTOPTIONS_PROC:
ok = check_amoptsproc_signature(procform->amproc);
break;
case BTSKIPSUPPORT_PROC:
ok = check_amproc_signature(procform->amproc, VOIDOID, true,
1, 1, INTERNALOID);
break;
default:
ereport(INFO,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),

25
src/backend/commands/opclasscmds.c
Unescape View File

@ -1331,6 +1331,31 @@ assignProcTypes(OpFamilyMember *member, Oid amoid, Oid typeoid,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("ordering equal image functions must not be cross-type")));
}
else if (member->number == BTSKIPSUPPORT_PROC)
{
if (procform->pronargs != 1 ||
procform->proargtypes.values[0] != INTERNALOID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("btree skip support functions must accept type \"internal\"")));
if (procform->prorettype != VOIDOID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("btree skip support functions must return void")));
/*
* pg_amproc functions are indexed by (lefttype, righttype), but a
* skip support function doesn't make sense in cross-type
* scenarios. The same opclass opcintype OID is always used for
* lefttype and righttype. Providing a cross-type routine isn't
* sensible. Reject cross-type ALTER OPERATOR FAMILY ... ADD
* FUNCTION 6 statements here.
*/
if (member->lefttype != member->righttype)
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("btree skip support functions must not be cross-type")));
}
}
else if (GetIndexAmRoutineByAmId(amoid, false)->amcanhash)
{

1
src/backend/utils/adt/Makefile
Unescape View File

@ -99,6 +99,7 @@ OBJS = \
rowtypes.o \
ruleutils.o \
selfuncs.o \
skipsupport.o \
tid.o \
timestamp.o \
trigfuncs.o \

46
src/backend/utils/adt/date.c
Unescape View File

@ -34,6 +34,7 @@
#include "utils/date.h"
#include "utils/datetime.h"
#include "utils/numeric.h"
#include "utils/skipsupport.h"
#include "utils/sortsupport.h"
/*
@ -462,6 +463,51 @@ date_sortsupport(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
static Datum
date_decrement(Relation rel, Datum existing, bool *underflow)
{
DateADT dexisting = DatumGetDateADT(existing);
if (dexisting == DATEVAL_NOBEGIN)
{
/* return value is undefined */
*underflow = true;
return (Datum) 0;
}
*underflow = false;
return DateADTGetDatum(dexisting - 1);
}
static Datum
date_increment(Relation rel, Datum existing, bool *overflow)
{
DateADT dexisting = DatumGetDateADT(existing);
if (dexisting == DATEVAL_NOEND)
{
/* return value is undefined */
*overflow = true;
return (Datum) 0;
}
*overflow = false;
return DateADTGetDatum(dexisting + 1);
}
Datum
date_skipsupport(PG_FUNCTION_ARGS)
{
SkipSupport sksup = (SkipSupport) PG_GETARG_POINTER(0);
sksup->decrement = date_decrement;
sksup->increment = date_increment;
sksup->low_elem = DateADTGetDatum(DATEVAL_NOBEGIN);
sksup->high_elem = DateADTGetDatum(DATEVAL_NOEND);
PG_RETURN_VOID();
}
Datum
hashdate(PG_FUNCTION_ARGS)
{

1
src/backend/utils/adt/meson.build
Unescape View File

@ -86,6 +86,7 @@ backend_sources += files(
'rowtypes.c',
'ruleutils.c',
'selfuncs.c',
'skipsupport.c',
'tid.c',
'timestamp.c',
'trigfuncs.c',

491
src/backend/utils/adt/selfuncs.c
Unescape View File

@ -193,6 +193,8 @@ static double convert_timevalue_to_scalar(Datum value, Oid typid,
bool *failure);
static void examine_simple_variable(PlannerInfo *root, Var *var,
VariableStatData *vardata);
static void examine_indexcol_variable(PlannerInfo *root, IndexOptInfo *index,
int indexcol, VariableStatData *vardata);
static bool get_variable_range(PlannerInfo *root, VariableStatData *vardata,
Oid sortop, Oid collation,
Datum *min, Datum *max);
@ -214,6 +216,8 @@ static bool get_actual_variable_endpoint(Relation heapRel,
MemoryContext outercontext,
Datum *endpointDatum);
static RelOptInfo *find_join_input_rel(PlannerInfo *root, Relids relids);
static double btcost_correlation(IndexOptInfo *index,
VariableStatData *vardata);
/*
@ -5943,6 +5947,92 @@ examine_simple_variable(PlannerInfo *root, Var *var,
}
}
/*
* examine_indexcol_variable
* Try to look up statistical data about an index column/expression.
* Fill in a VariableStatData struct to describe the column.
*
* Inputs:
* root: the planner info
* index: the index whose column we're interested in
* indexcol: 0-based index column number (subscripts index->indexkeys[])
*
* Outputs: *vardata is filled as follows:
* var: the input expression (with any binary relabeling stripped, if
* it is or contains a variable; but otherwise the type is preserved)
* rel: RelOptInfo for table relation containing variable.
* statsTuple: the pg_statistic entry for the variable, if one exists;
* otherwise NULL.
* freefunc: pointer to a function to release statsTuple with.
*
* Caller is responsible for doing ReleaseVariableStats() before exiting.
*/
static void
examine_indexcol_variable(PlannerInfo *root, IndexOptInfo *index,
int indexcol, VariableStatData *vardata)
{
AttrNumber colnum;
Oid relid;
if (index->indexkeys[indexcol] != 0)
{
/* Simple variable --- look to stats for the underlying table */
RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
Assert(rte->rtekind == RTE_RELATION);
relid = rte->relid;
Assert(relid != InvalidOid);
colnum = index->indexkeys[indexcol];
vardata->rel = index->rel;
if (get_relation_stats_hook &&
(*get_relation_stats_hook) (root, rte, colnum, vardata))
{
/*
* The hook took control of acquiring a stats tuple. If it did
* supply a tuple, it'd better have supplied a freefunc.
*/
if (HeapTupleIsValid(vardata->statsTuple) &&
!vardata->freefunc)
elog(ERROR, "no function provided to release variable stats with");
}
else
{
vardata->statsTuple = SearchSysCache3(STATRELATTINH,
ObjectIdGetDatum(relid),
Int16GetDatum(colnum),
BoolGetDatum(rte->inh));
vardata->freefunc = ReleaseSysCache;
}
}
else
{
/* Expression --- maybe there are stats for the index itself */
relid = index->indexoid;
colnum = indexcol + 1;
if (get_index_stats_hook &&
(*get_index_stats_hook) (root, relid, colnum, vardata))
{
/*
* The hook took control of acquiring a stats tuple. If it did
* supply a tuple, it'd better have supplied a freefunc.
*/
if (HeapTupleIsValid(vardata->statsTuple) &&
!vardata->freefunc)
elog(ERROR, "no function provided to release variable stats with");
}
else
{
vardata->statsTuple = SearchSysCache3(STATRELATTINH,
ObjectIdGetDatum(relid),
Int16GetDatum(colnum),
BoolGetDatum(false));
vardata->freefunc = ReleaseSysCache;
}
}
}
/*
* Check whether it is permitted to call func_oid passing some of the
* pg_statistic data in vardata. We allow this either if the user has SELECT
@ -7007,6 +7097,53 @@ add_predicate_to_index_quals(IndexOptInfo *index, List *indexQuals)
return list_concat(predExtraQuals, indexQuals);
}
/*
* Estimate correlation of btree index's first column.
*
* If we can get an estimate of the first column's ordering correlation C
* from pg_statistic, estimate the index correlation as C for a single-column
* index, or C * 0.75 for multiple columns. The idea here is that multiple
* columns dilute the importance of the first column's ordering, but don't
* negate it entirely.
*
* We already filled in the stats tuple for *vardata when called.
*/
static double
btcost_correlation(IndexOptInfo *index, VariableStatData *vardata)
{
Oid sortop;
AttStatsSlot sslot;
double indexCorrelation = 0;
Assert(HeapTupleIsValid(vardata->statsTuple));
sortop = get_opfamily_member(index->opfamily[0],
index->opcintype[0],
index->opcintype[0],
BTLessStrategyNumber);
if (OidIsValid(sortop) &&
get_attstatsslot(&sslot, vardata->statsTuple,
STATISTIC_KIND_CORRELATION, sortop,
ATTSTATSSLOT_NUMBERS))
{
double varCorrelation;
Assert(sslot.nnumbers == 1);
varCorrelation = sslot.numbers[0];
if (index->reverse_sort[0])
varCorrelation = -varCorrelation;
if (index->nkeycolumns > 1)
indexCorrelation = varCorrelation * 0.75;
else
indexCorrelation = varCorrelation;
free_attstatsslot(&sslot);
}
return indexCorrelation;
}
void
btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
@ -7016,17 +7153,19 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
{
IndexOptInfo *index = path->indexinfo;
GenericCosts costs = {0};
Oid relid;
AttrNumber colnum;
VariableStatData vardata = {0};
double numIndexTuples;
Cost descentCost;
List *indexBoundQuals;
List *indexSkipQuals;
int indexcol;
bool eqQualHere;
bool found_saop;
bool found_row_compare;
bool found_array;
bool found_is_null_op;
bool have_correlation = false;
double num_sa_scans;
double correlation = 0.0;
ListCell *lc;
/*
@ -7037,19 +7176,24 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
* it's OK to count them in indexSelectivity, but they should not count
* for estimating numIndexTuples. So we must examine the given indexquals
* to find out which ones count as boundary quals. We rely on the
* knowledge that they are given in index column order.
* knowledge that they are given in index column order. Note that nbtree
* preprocessing can add skip arrays that act as leading '=' quals in the
* absence of ordinary input '=' quals, so in practice _most_ input quals
* are able to act as index bound quals (which we take into account here).
*
* For a RowCompareExpr, we consider only the first column, just as
* rowcomparesel() does.
*
* If there's a ScalarArrayOpExpr in the quals, we'll actually perform up
* to N index descents (not just one), but the ScalarArrayOpExpr's
* If there's a SAOP or skip array in the quals, we'll actually perform up
* to N index descents (not just one), but the underlying array key's
* operator can be considered to act the same as it normally does.
*/
indexBoundQuals = NIL;
indexSkipQuals = NIL;
indexcol = 0;
eqQualHere = false;
found_saop = false;
found_row_compare = false;
found_array = false;
found_is_null_op = false;
num_sa_scans = 1;
foreach(lc, path->indexclauses)
@ -7057,17 +7201,203 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
IndexClause *iclause = lfirst_node(IndexClause, lc);
ListCell *lc2;
if (indexcol != iclause->indexcol)
if (indexcol < iclause->indexcol)
{
/* Beginning of a new column's quals */
if (!eqQualHere)
break; /* done if no '=' qual for indexcol */
double num_sa_scans_prev_cols = num_sa_scans;
/*
* Beginning of a new column's quals.
*
* Skip scans use skip arrays, which are ScalarArrayOp style
* arrays that generate their elements procedurally and on demand.
* Given a multi-column index on "(a, b)", and an SQL WHERE clause
* "WHERE b = 42", a skip scan will effectively use an indexqual
* "WHERE a = ANY('{every col a value}') AND b = 42". (Obviously,
* the array on "a" must also return "IS NULL" matches, since our
* WHERE clause used no strict operator on "a").
*
* Here we consider how nbtree will backfill skip arrays for any
* index columns that lacked an '=' qual. This maintains our
* num_sa_scans estimate, and determines if this new column (the
* "iclause->indexcol" column, not the prior "indexcol" column)
* can have its RestrictInfos/quals added to indexBoundQuals.
*
* We'll need to handle columns that have inequality quals, where
* the skip array generates values from a range constrained by the
* quals (not every possible value). We've been maintaining
* indexSkipQuals to help with this; it will now contain all of
* the prior column's quals (that is, indexcol's quals) when they
* might be used for this.
*/
if (found_row_compare)
{
/*
* Skip arrays can't be added after a RowCompare input qual
* due to limitations in nbtree
*/
break;
}
if (eqQualHere)
{
/*
* Don't need to add a skip array for an indexcol that already
* has an '=' qual/equality constraint
*/
indexcol++;
indexSkipQuals = NIL;
}
eqQualHere = false;
indexcol++;
while (indexcol < iclause->indexcol)
{
double ndistinct;
bool isdefault = true;
found_array = true;
/*
* A skipped attribute's ndistinct forms the basis of our
* estimate of the total number of "array elements" used by
* its skip array at runtime. Look that up first.
*/
examine_indexcol_variable(root, index, indexcol, &vardata);
ndistinct = get_variable_numdistinct(&vardata, &isdefault);
if (indexcol == 0)
{
/*
* Get an estimate of the leading column's correlation in
* passing (avoids rereading variable stats below)
*/
if (HeapTupleIsValid(vardata.statsTuple))
correlation = btcost_correlation(index, &vardata);
have_correlation = true;
}
ReleaseVariableStats(vardata);
/*
* If ndistinct is a default estimate, conservatively assume
* that no skipping will happen at runtime
*/
if (isdefault)
{
num_sa_scans = num_sa_scans_prev_cols;
break; /* done building indexBoundQuals */
}
/*
* Apply indexcol's indexSkipQuals selectivity to ndistinct
*/
if (indexSkipQuals != NIL)
{
List *partialSkipQuals;
Selectivity ndistinctfrac;
/*
* If the index is partial, AND the index predicate with
* the index-bound quals to produce a more accurate idea
* of the number of distinct values for prior indexcol
*/
partialSkipQuals = add_predicate_to_index_quals(index,
indexSkipQuals);
ndistinctfrac = clauselist_selectivity(root, partialSkipQuals,
index->rel->relid,
JOIN_INNER,
NULL);
/*
* If ndistinctfrac is selective (on its own), the scan is
* unlikely to benefit from repositioning itself using
* later quals. Do not allow iclause->indexcol's quals to
* be added to indexBoundQuals (it would increase descent
* costs, without lowering numIndexTuples costs by much).
*/
if (ndistinctfrac < DEFAULT_RANGE_INEQ_SEL)
{
num_sa_scans = num_sa_scans_prev_cols;
break; /* done building indexBoundQuals */
}
/* Adjust ndistinct downward */
ndistinct = rint(ndistinct * ndistinctfrac);
ndistinct = Max(ndistinct, 1);
}
/*
* When there's no inequality quals, account for the need to
* find an initial value by counting -inf/+inf as a value.
*
* We don't charge anything extra for possible next/prior key
* index probes, which are sometimes used to find the next
* valid skip array element (ahead of using the located
* element value to relocate the scan to the next position
* that might contain matching tuples). It seems hard to do
* better here. Use of the skip support infrastructure often
* avoids most next/prior key probes. But even when it can't,
* there's a decent chance that most individual next/prior key
* probes will locate a leaf page whose key space overlaps all
* of the scan's keys (even the lower-order keys) -- which
* also avoids the need for a separate, extra index descent.
* Note also that these probes are much cheaper than non-probe
* primitive index scans: they're reliably very selective.
*/
if (indexSkipQuals == NIL)
ndistinct += 1;
/*
* Update num_sa_scans estimate by multiplying by ndistinct.
*
* We make the pessimistic assumption that there is no
* naturally occurring cross-column correlation. This is
* often wrong, but it seems best to err on the side of not
* expecting skipping to be helpful...
*/
num_sa_scans *= ndistinct;
/*
* ...but back out of adding this latest group of 1 or more
* skip arrays when num_sa_scans exceeds the total number of
* index pages (revert to num_sa_scans from before indexcol).
* This causes a sharp discontinuity in cost (as a function of
* the indexcol's ndistinct), but that is representative of
* actual runtime costs.
*
* Note that skipping is helpful when each primitive index
* scan only manages to skip over 1 or 2 irrelevant leaf pages
* on average. Skip arrays bring savings in CPU costs due to
* the scan not needing to evaluate indexquals against every
* tuple, which can greatly exceed any savings in I/O costs.
* This test is a test of whether num_sa_scans implies that
* we're past the point where the ability to skip ceases to
* lower the scan's costs (even qual evaluation CPU costs).
*/
if (index->pages < num_sa_scans)
{
num_sa_scans = num_sa_scans_prev_cols;
break; /* done building indexBoundQuals */
}
indexcol++;
indexSkipQuals = NIL;
}
/*
* Finished considering the need to add skip arrays to bridge an
* initial eqQualHere gap between the old and new index columns
* (or there was no initial eqQualHere gap in the first place).
*
* If an initial gap could not be bridged, then new column's quals
* (i.e. iclause->indexcol's quals) won't go into indexBoundQuals,
* and so won't affect our final numIndexTuples estimate.
*/
if (indexcol != iclause->indexcol)
break; /* no quals at all for indexcol */
break; /* done building indexBoundQuals */
}
Assert(indexcol == iclause->indexcol);
/* Examine each indexqual associated with this index clause */
foreach(lc2, iclause->indexquals)
{
@ -7087,6 +7417,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
RowCompareExpr *rc = (RowCompareExpr *) clause;
clause_op = linitial_oid(rc->opnos);
found_row_compare = true;
}
else if (IsA(clause, ScalarArrayOpExpr))
{
@ -7095,7 +7426,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
double alength = estimate_array_length(root, other_operand);
clause_op = saop->opno;
found_saop = true;
found_array = true;
/* estimate SA descents by indexBoundQuals only */
if (alength > 1)
num_sa_scans *= alength;
@ -7107,7 +7438,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
if (nt->nulltesttype == IS_NULL)
{
found_is_null_op = true;
/* IS NULL is like = for selectivity purposes */
/* IS NULL is like = for selectivity/skip scan purposes */
eqQualHere = true;
}
}
@ -7126,19 +7457,28 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
}
indexBoundQuals = lappend(indexBoundQuals, rinfo);
/*
* We apply inequality selectivities to estimate index descent
* costs with scans that use skip arrays. Save this indexcol's
* RestrictInfos if it looks like they'll be needed for that.
*/
if (!eqQualHere && !found_row_compare &&
indexcol < index->nkeycolumns - 1)
indexSkipQuals = lappend(indexSkipQuals, rinfo);
}
}
/*
* If index is unique and we found an '=' clause for each column, we can
* just assume numIndexTuples = 1 and skip the expensive
* clauselist_selectivity calculations. However, a ScalarArrayOp or
* NullTest invalidates that theory, even though it sets eqQualHere.
* clauselist_selectivity calculations. However, an array or NullTest
* always invalidates that theory (even when eqQualHere has been set).
*/
if (index->unique &&
indexcol == index->nkeycolumns - 1 &&
eqQualHere &&
!found_saop &&
!found_array &&
!found_is_null_op)
numIndexTuples = 1.0;
else
@ -7160,7 +7500,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
numIndexTuples = btreeSelectivity * index->rel->tuples;
/*
* btree automatically combines individual ScalarArrayOpExpr primitive
* btree automatically combines individual array element primitive
* index scans whenever the tuples covered by the next set of array
* keys are close to tuples covered by the current set. That puts a
* natural ceiling on the worst case number of descents -- there
@ -7178,16 +7518,18 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
* of leaf pages (we make it 1/3 the total number of pages instead) to
* give the btree code credit for its ability to continue on the leaf
* level with low selectivity scans.
*
* Note: num_sa_scans includes both ScalarArrayOp array elements and
* skip array elements whose qual affects our numIndexTuples estimate.
*/
num_sa_scans = Min(num_sa_scans, ceil(index->pages * 0.3333333));
num_sa_scans = Max(num_sa_scans, 1);
/*
* As in genericcostestimate(), we have to adjust for any
* ScalarArrayOpExpr quals included in indexBoundQuals, and then round
* to integer.
* As in genericcostestimate(), we have to adjust for any array quals
* included in indexBoundQuals, and then round to integer.
*
* It is tempting to make genericcostestimate behave as if SAOP
* It is tempting to make genericcostestimate behave as if array
* clauses work in almost the same way as scalar operators during
* btree scans, making the top-level scan look like a continuous scan
* (as opposed to num_sa_scans-many primitive index scans). After
@ -7220,7 +7562,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
* comparisons to descend a btree of N leaf tuples. We charge one
* cpu_operator_cost per comparison.
*
* If there are ScalarArrayOpExprs, charge this once per estimated SA
* If there are SAOP or skip array keys, charge this once per estimated
* index descent. The ones after the first one are not startup cost so
* far as the overall plan goes, so just add them to "total" cost.
*/
@ -7240,110 +7582,25 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
* cost is somewhat arbitrarily set at 50x cpu_operator_cost per page
* touched. The number of such pages is btree tree height plus one (ie,
* we charge for the leaf page too). As above, charge once per estimated
* SA index descent.
* SAOP/skip array descent.
*/
descentCost = (index->tree_height + 1) * DEFAULT_PAGE_CPU_MULTIPLIER * cpu_operator_cost;
costs.indexStartupCost += descentCost;
costs.indexTotalCost += costs.num_sa_scans * descentCost;
/*
* If we can get an estimate of the first column's ordering correlation C
* from pg_statistic, estimate the index correlation as C for a
* single-column index, or C * 0.75 for multiple columns. (The idea here
* is that multiple columns dilute the importance of the first column's
* ordering, but don't negate it entirely. Before 8.0 we divided the
* correlation by the number of columns, but that seems too strong.)
*/
if (index->indexkeys[0] != 0)
if (!have_correlation)
{
/* Simple variable --- look to stats for the underlying table */
RangeTblEntry *rte = planner_rt_fetch(index->rel->relid, root);
Assert(rte->rtekind == RTE_RELATION);
relid = rte->relid;
Assert(relid != InvalidOid);
colnum = index->indexkeys[0];
if (get_relation_stats_hook &&
(*get_relation_stats_hook) (root, rte, colnum, &vardata))
{
/*
* The hook took control of acquiring a stats tuple. If it did
* supply a tuple, it'd better have supplied a freefunc.
*/
if (HeapTupleIsValid(vardata.statsTuple) &&
!vardata.freefunc)
elog(ERROR, "no function provided to release variable stats with");
}
else
{
vardata.statsTuple = SearchSysCache3(STATRELATTINH,
ObjectIdGetDatum(relid),
Int16GetDatum(colnum),
BoolGetDatum(rte->inh));
vardata.freefunc = ReleaseSysCache;
}
examine_indexcol_variable(root, index, 0, &vardata);
if (HeapTupleIsValid(vardata.statsTuple))
costs.indexCorrelation = btcost_correlation(index, &vardata);
ReleaseVariableStats(vardata);
}
else
{
/* Expression --- maybe there are stats for the index itself */
relid = index->indexoid;
colnum = 1;
if (get_index_stats_hook &&
(*get_index_stats_hook) (root, relid, colnum, &vardata))
{
/*
* The hook took control of acquiring a stats tuple. If it did
* supply a tuple, it'd better have supplied a freefunc.
*/
if (HeapTupleIsValid(vardata.statsTuple) &&
!vardata.freefunc)
elog(ERROR, "no function provided to release variable stats with");
}
else
{
vardata.statsTuple = SearchSysCache3(STATRELATTINH,
ObjectIdGetDatum(relid),
Int16GetDatum(colnum),
BoolGetDatum(false));
vardata.freefunc = ReleaseSysCache;
}
/* btcost_correlation already called earlier on */
costs.indexCorrelation = correlation;
}
if (HeapTupleIsValid(vardata.statsTuple))
{
Oid sortop;
AttStatsSlot sslot;
sortop = get_opfamily_member(index->opfamily[0],
index->opcintype[0],
index->opcintype[0],
BTLessStrategyNumber);
if (OidIsValid(sortop) &&
get_attstatsslot(&sslot, vardata.statsTuple,
STATISTIC_KIND_CORRELATION, sortop,
ATTSTATSSLOT_NUMBERS))
{
double varCorrelation;
Assert(sslot.nnumbers == 1);
varCorrelation = sslot.numbers[0];
if (index->reverse_sort[0])
varCorrelation = -varCorrelation;
if (index->nkeycolumns > 1)
costs.indexCorrelation = varCorrelation * 0.75;
else
costs.indexCorrelation = varCorrelation;
free_attstatsslot(&sslot);
}
}
ReleaseVariableStats(vardata);
*indexStartupCost = costs.indexStartupCost;
*indexTotalCost = costs.indexTotalCost;
*indexSelectivity = costs.indexSelectivity;

61
src/backend/utils/adt/skipsupport.c
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@ -0,0 +1,61 @@
/*-------------------------------------------------------------------------
*
* skipsupport.c
* Support routines for B-Tree skip scan.
*
*
* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/utils/adt/skipsupport.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/nbtree.h"
#include "utils/lsyscache.h"
#include "utils/skipsupport.h"
/*
* Fill in SkipSupport given an operator class (opfamily + opcintype).
*
* On success, returns skip support struct, allocating in caller's memory
* context. Otherwise returns NULL, indicating that operator class has no
* skip support function.
*/
SkipSupport
PrepareSkipSupportFromOpclass(Oid opfamily, Oid opcintype, bool reverse)
{
Oid skipSupportFunction;
SkipSupport sksup;
/* Look for a skip support function */
skipSupportFunction = get_opfamily_proc(opfamily, opcintype, opcintype,
BTSKIPSUPPORT_PROC);
if (!OidIsValid(skipSupportFunction))
return NULL;
sksup = palloc(sizeof(SkipSupportData));
OidFunctionCall1(skipSupportFunction, PointerGetDatum(sksup));
if (reverse)
{
/*
* DESC/reverse case: swap low_elem with high_elem, and swap decrement
* with increment
*/
Datum low_elem = sksup->low_elem;
SkipSupportIncDec decrement = sksup->decrement;
sksup->low_elem = sksup->high_elem;
sksup->decrement = sksup->increment;
sksup->high_elem = low_elem;
sksup->increment = decrement;
}
return sksup;
}

48
src/backend/utils/adt/timestamp.c
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@ -37,6 +37,7 @@
#include "utils/datetime.h"
#include "utils/float.h"
#include "utils/numeric.h"
#include "utils/skipsupport.h"
#include "utils/sortsupport.h"
/*
@ -2304,6 +2305,53 @@ timestamp_sortsupport(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
/* note: this is used for timestamptz also */
static Datum
timestamp_decrement(Relation rel, Datum existing, bool *underflow)
{
Timestamp texisting = DatumGetTimestamp(existing);
if (texisting == PG_INT64_MIN)
{
/* return value is undefined */
*underflow = true;
return (Datum) 0;
}
*underflow = false;
return TimestampGetDatum(texisting - 1);
}
/* note: this is used for timestamptz also */
static Datum
timestamp_increment(Relation rel, Datum existing, bool *overflow)
{
Timestamp texisting = DatumGetTimestamp(existing);
if (texisting == PG_INT64_MAX)
{
/* return value is undefined */
*overflow = true;
return (Datum) 0;
}
*overflow = false;
return TimestampGetDatum(texisting + 1);
}
Datum
timestamp_skipsupport(PG_FUNCTION_ARGS)
{
SkipSupport sksup = (SkipSupport) PG_GETARG_POINTER(0);
sksup->decrement = timestamp_decrement;
sksup->increment = timestamp_increment;
sksup->low_elem = TimestampGetDatum(PG_INT64_MIN);
sksup->high_elem = TimestampGetDatum(PG_INT64_MAX);
PG_RETURN_VOID();
}
Datum
timestamp_hash(PG_FUNCTION_ARGS)
{

70
src/backend/utils/adt/uuid.c
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@ -13,6 +13,7 @@
#include "postgres.h"
#include <limits.h>
#include <time.h> /* for clock_gettime() */
#include "common/hashfn.h"
@ -21,6 +22,7 @@
#include "port/pg_bswap.h"
#include "utils/fmgrprotos.h"
#include "utils/guc.h"
#include "utils/skipsupport.h"
#include "utils/sortsupport.h"
#include "utils/timestamp.h"
#include "utils/uuid.h"
@ -418,6 +420,74 @@ uuid_abbrev_convert(Datum original, SortSupport ssup)
return res;
}
static Datum
uuid_decrement(Relation rel, Datum existing, bool *underflow)
{
pg_uuid_t *uuid;
uuid = (pg_uuid_t *) palloc(UUID_LEN);
memcpy(uuid, DatumGetUUIDP(existing), UUID_LEN);
for (int i = UUID_LEN - 1; i >= 0; i--)
{
if (uuid->data[i] > 0)
{
uuid->data[i]--;
*underflow = false;
return UUIDPGetDatum(uuid);
}
uuid->data[i] = UCHAR_MAX;
}
pfree(uuid); /* cannot leak memory */
/* return value is undefined */
*underflow = true;
return (Datum) 0;
}
static Datum
uuid_increment(Relation rel, Datum existing, bool *overflow)
{
pg_uuid_t *uuid;
uuid = (pg_uuid_t *) palloc(UUID_LEN);
memcpy(uuid, DatumGetUUIDP(existing), UUID_LEN);
for (int i = UUID_LEN - 1; i >= 0; i--)
{
if (uuid->data[i] < UCHAR_MAX)
{
uuid->data[i]++;
*overflow = false;
return UUIDPGetDatum(uuid);
}
uuid->data[i] = 0;
}
pfree(uuid); /* cannot leak memory */
/* return value is undefined */
*overflow = true;
return (Datum) 0;
}
Datum
uuid_skipsupport(PG_FUNCTION_ARGS)
{
SkipSupport sksup = (SkipSupport) PG_GETARG_POINTER(0);
pg_uuid_t *uuid_min = palloc(UUID_LEN);
pg_uuid_t *uuid_max = palloc(UUID_LEN);
memset(uuid_min->data, 0x00, UUID_LEN);
memset(uuid_max->data, 0xFF, UUID_LEN);
sksup->decrement = uuid_decrement;
sksup->increment = uuid_increment;
sksup->low_elem = UUIDPGetDatum(uuid_min);
sksup->high_elem = UUIDPGetDatum(uuid_max);
PG_RETURN_VOID();
}
/* hash index support */
Datum
uuid_hash(PG_FUNCTION_ARGS)

3
src/include/access/amapi.h
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@ -214,7 +214,8 @@ typedef void (*amrestrpos_function) (IndexScanDesc scan);
*/
/* estimate size of parallel scan descriptor */
typedef Size (*amestimateparallelscan_function) (int nkeys, int norderbys);
typedef Size (*amestimateparallelscan_function) (Relation indexRelation,
int nkeys, int norderbys);
/* prepare for parallel index scan */
typedef void (*aminitparallelscan_function) (void *target);

34
src/include/access/nbtree.h
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@ -24,6 +24,7 @@
#include "lib/stringinfo.h"
#include "storage/bufmgr.h"
#include "storage/shm_toc.h"
#include "utils/skipsupport.h"
/* There's room for a 16-bit vacuum cycle ID in BTPageOpaqueData */
typedef uint16 BTCycleId;
@ -707,6 +708,10 @@ BTreeTupleGetMaxHeapTID(IndexTuple itup)
* (BTOPTIONS_PROC). These procedures define a set of user-visible
* parameters that can be used to control operator class behavior. None of
* the built-in B-Tree operator classes currently register an "options" proc.
*
* To facilitate more efficient B-Tree skip scans, an operator class may
* choose to offer a sixth amproc procedure (BTSKIPSUPPORT_PROC). For full
* details, see src/include/utils/skipsupport.h.
*/
#define BTORDER_PROC 1
@ -714,7 +719,8 @@ BTreeTupleGetMaxHeapTID(IndexTuple itup)
#define BTINRANGE_PROC 3
#define BTEQUALIMAGE_PROC 4
#define BTOPTIONS_PROC 5
#define BTNProcs 5
#define BTSKIPSUPPORT_PROC 6
#define BTNProcs 6
/*
* We need to be able to tell the difference between read and write
@ -1027,10 +1033,21 @@ typedef BTScanPosData *BTScanPos;
/* We need one of these for each equality-type SK_SEARCHARRAY scan key */
typedef struct BTArrayKeyInfo
{
/* fields set for both kinds of array (SAOP arrays and skip arrays) */
int scan_key; /* index of associated key in keyData */
int cur_elem; /* index of current element in elem_values */
int num_elems; /* number of elems in current array value */
int num_elems; /* number of elems (-1 means skip array) */
/* fields set for ScalarArrayOpExpr arrays only */
Datum *elem_values; /* array of num_elems Datums */
int cur_elem; /* index of current element in elem_values */
/* fields set for skip arrays only */
int16 attlen; /* attr's length, in bytes */
bool attbyval; /* attr's FormData_pg_attribute.attbyval */
bool null_elem; /* NULL is lowest/highest element? */
SkipSupport sksup; /* skip support (NULL if opclass lacks it) */
ScanKey low_compare; /* array's > or >= lower bound */
ScanKey high_compare; /* array's < or <= upper bound */
} BTArrayKeyInfo;
typedef struct BTScanOpaqueData
@ -1119,6 +1136,15 @@ typedef struct BTReadPageState
*/
#define SK_BT_REQFWD 0x00010000 /* required to continue forward scan */
#define SK_BT_REQBKWD 0x00020000 /* required to continue backward scan */
#define SK_BT_SKIP 0x00040000 /* skip array on column without input = */
/* SK_BT_SKIP-only flags (set and unset by array advancement) */
#define SK_BT_MINVAL 0x00080000 /* invalid sk_argument, use low_compare */
#define SK_BT_MAXVAL 0x00100000 /* invalid sk_argument, use high_compare */
#define SK_BT_NEXT 0x00200000 /* positions the scan > sk_argument */
#define SK_BT_PRIOR 0x00400000 /* positions the scan < sk_argument */
/* Remaps pg_index flag bits to uppermost SK_BT_* byte */
#define SK_BT_INDOPTION_SHIFT 24 /* must clear the above bits */
#define SK_BT_DESC (INDOPTION_DESC << SK_BT_INDOPTION_SHIFT)
#define SK_BT_NULLS_FIRST (INDOPTION_NULLS_FIRST << SK_BT_INDOPTION_SHIFT)
@ -1165,7 +1191,7 @@ extern bool btinsert(Relation rel, Datum *values, bool *isnull,
bool indexUnchanged,
struct IndexInfo *indexInfo);
extern IndexScanDesc btbeginscan(Relation rel, int nkeys, int norderbys);
extern Size btestimateparallelscan(int nkeys, int norderbys);
extern Size btestimateparallelscan(Relation rel, int nkeys, int norderbys);
extern void btinitparallelscan(void *target);
extern bool btgettuple(IndexScanDesc scan, ScanDirection dir);
extern int64 btgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);

2
src/include/catalog/catversion.h
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@ -57,6 +57,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 202504031
#define CATALOG_VERSION_NO 202504041
#endif

22
src/include/catalog/pg_amproc.dat
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@ -21,6 +21,8 @@
amprocrighttype => 'bit', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/bool_ops', amproclefttype => 'bool',
amprocrighttype => 'bool', amprocnum => '1', amproc => 'btboolcmp' },
{ amprocfamily => 'btree/bool_ops', amproclefttype => 'bool',
amprocrighttype => 'bool', amprocnum => '6', amproc => 'btboolskipsupport' },
{ amprocfamily => 'btree/bool_ops', amproclefttype => 'bool',
amprocrighttype => 'bool', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/bpchar_ops', amproclefttype => 'bpchar',
@ -41,12 +43,16 @@
amprocrighttype => 'char', amprocnum => '1', amproc => 'btcharcmp' },
{ amprocfamily => 'btree/char_ops', amproclefttype => 'char',
amprocrighttype => 'char', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/char_ops', amproclefttype => 'char',
amprocrighttype => 'char', amprocnum => '6', amproc => 'btcharskipsupport' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'date',
amprocrighttype => 'date', amprocnum => '1', amproc => 'date_cmp' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'date',
amprocrighttype => 'date', amprocnum => '2', amproc => 'date_sortsupport' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'date',
amprocrighttype => 'date', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'date',
amprocrighttype => 'date', amprocnum => '6', amproc => 'date_skipsupport' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'date',
amprocrighttype => 'timestamp', amprocnum => '1',
amproc => 'date_cmp_timestamp' },
@ -60,6 +66,9 @@
amproc => 'timestamp_sortsupport' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'timestamp',
amprocrighttype => 'timestamp', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'timestamp',
amprocrighttype => 'timestamp', amprocnum => '6',
amproc => 'timestamp_skipsupport' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'timestamp',
amprocrighttype => 'date', amprocnum => '1', amproc => 'timestamp_cmp_date' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'timestamp',
@ -74,6 +83,9 @@
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'timestamptz',
amprocrighttype => 'timestamptz', amprocnum => '4',
amproc => 'btequalimage' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'timestamptz',
amprocrighttype => 'timestamptz', amprocnum => '6',
amproc => 'timestamp_skipsupport' },
{ amprocfamily => 'btree/datetime_ops', amproclefttype => 'timestamptz',
amprocrighttype => 'date', amprocnum => '1',
amproc => 'timestamptz_cmp_date' },
@ -122,6 +134,8 @@
amprocrighttype => 'int2', amprocnum => '2', amproc => 'btint2sortsupport' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int2',
amprocrighttype => 'int2', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int2',
amprocrighttype => 'int2', amprocnum => '6', amproc => 'btint2skipsupport' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int2',
amprocrighttype => 'int4', amprocnum => '1', amproc => 'btint24cmp' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int2',
@ -141,6 +155,8 @@
amprocrighttype => 'int4', amprocnum => '2', amproc => 'btint4sortsupport' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int4',
amprocrighttype => 'int4', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int4',
amprocrighttype => 'int4', amprocnum => '6', amproc => 'btint4skipsupport' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int4',
amprocrighttype => 'int8', amprocnum => '1', amproc => 'btint48cmp' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int4',
@ -160,6 +176,8 @@
amprocrighttype => 'int8', amprocnum => '2', amproc => 'btint8sortsupport' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int8',
amprocrighttype => 'int8', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int8',
amprocrighttype => 'int8', amprocnum => '6', amproc => 'btint8skipsupport' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int8',
amprocrighttype => 'int4', amprocnum => '1', amproc => 'btint84cmp' },
{ amprocfamily => 'btree/integer_ops', amproclefttype => 'int8',
@ -193,6 +211,8 @@
amprocrighttype => 'oid', amprocnum => '2', amproc => 'btoidsortsupport' },
{ amprocfamily => 'btree/oid_ops', amproclefttype => 'oid',
amprocrighttype => 'oid', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/oid_ops', amproclefttype => 'oid',
amprocrighttype => 'oid', amprocnum => '6', amproc => 'btoidskipsupport' },
{ amprocfamily => 'btree/oidvector_ops', amproclefttype => 'oidvector',
amprocrighttype => 'oidvector', amprocnum => '1',
amproc => 'btoidvectorcmp' },
@ -261,6 +281,8 @@
amprocrighttype => 'uuid', amprocnum => '2', amproc => 'uuid_sortsupport' },
{ amprocfamily => 'btree/uuid_ops', amproclefttype => 'uuid',
amprocrighttype => 'uuid', amprocnum => '4', amproc => 'btequalimage' },
{ amprocfamily => 'btree/uuid_ops', amproclefttype => 'uuid',
amprocrighttype => 'uuid', amprocnum => '6', amproc => 'uuid_skipsupport' },
{ amprocfamily => 'btree/record_ops', amproclefttype => 'record',
amprocrighttype => 'record', amprocnum => '1', amproc => 'btrecordcmp' },
{ amprocfamily => 'btree/record_image_ops', amproclefttype => 'record',

27
src/include/catalog/pg_proc.dat
Unescape View File

@ -1004,18 +1004,27 @@
{ oid => '3129', descr => 'sort support',
proname => 'btint2sortsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btint2sortsupport' },
{ oid => '9290', descr => 'skip support',
proname => 'btint2skipsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btint2skipsupport' },
{ oid => '351', descr => 'less-equal-greater',
proname => 'btint4cmp', proleakproof => 't', prorettype => 'int4',
proargtypes => 'int4 int4', prosrc => 'btint4cmp' },
{ oid => '3130', descr => 'sort support',
proname => 'btint4sortsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btint4sortsupport' },
{ oid => '9291', descr => 'skip support',
proname => 'btint4skipsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btint4skipsupport' },
{ oid => '842', descr => 'less-equal-greater',
proname => 'btint8cmp', proleakproof => 't', prorettype => 'int4',
proargtypes => 'int8 int8', prosrc => 'btint8cmp' },
{ oid => '3131', descr => 'sort support',
proname => 'btint8sortsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btint8sortsupport' },
{ oid => '9292', descr => 'skip support',
proname => 'btint8skipsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btint8skipsupport' },
{ oid => '354', descr => 'less-equal-greater',
proname => 'btfloat4cmp', proleakproof => 't', prorettype => 'int4',
proargtypes => 'float4 float4', prosrc => 'btfloat4cmp' },
@ -1034,12 +1043,18 @@
{ oid => '3134', descr => 'sort support',
proname => 'btoidsortsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btoidsortsupport' },
{ oid => '9293', descr => 'skip support',
proname => 'btoidskipsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btoidskipsupport' },
{ oid => '404', descr => 'less-equal-greater',
proname => 'btoidvectorcmp', proleakproof => 't', prorettype => 'int4',
proargtypes => 'oidvector oidvector', prosrc => 'btoidvectorcmp' },
{ oid => '358', descr => 'less-equal-greater',
proname => 'btcharcmp', proleakproof => 't', prorettype => 'int4',
proargtypes => 'char char', prosrc => 'btcharcmp' },
{ oid => '9294', descr => 'skip support',
proname => 'btcharskipsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btcharskipsupport' },
{ oid => '359', descr => 'less-equal-greater',
proname => 'btnamecmp', proleakproof => 't', prorettype => 'int4',
proargtypes => 'name name', prosrc => 'btnamecmp' },
@ -2300,6 +2315,9 @@
{ oid => '3136', descr => 'sort support',
proname => 'date_sortsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'date_sortsupport' },
{ oid => '9295', descr => 'skip support',
proname => 'date_skipsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'date_skipsupport' },
{ oid => '4133', descr => 'window RANGE support',
proname => 'in_range', prorettype => 'bool',
proargtypes => 'date date interval bool bool',
@ -4497,6 +4515,9 @@
{ oid => '1693', descr => 'less-equal-greater',
proname => 'btboolcmp', proleakproof => 't', prorettype => 'int4',
proargtypes => 'bool bool', prosrc => 'btboolcmp' },
{ oid => '9296', descr => 'skip support',
proname => 'btboolskipsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'btboolskipsupport' },
{ oid => '1688', descr => 'hash',
proname => 'time_hash', prorettype => 'int4', proargtypes => 'time',
@ -6376,6 +6397,9 @@
{ oid => '3137', descr => 'sort support',
proname => 'timestamp_sortsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'timestamp_sortsupport' },
{ oid => '9297', descr => 'skip support',
proname => 'timestamp_skipsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'timestamp_skipsupport' },
{ oid => '4134', descr => 'window RANGE support',
proname => 'in_range', prorettype => 'bool',
@ -9431,6 +9455,9 @@
{ oid => '3300', descr => 'sort support',
proname => 'uuid_sortsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'uuid_sortsupport' },
{ oid => '9298', descr => 'skip support',
proname => 'uuid_skipsupport', prorettype => 'void',
proargtypes => 'internal', prosrc => 'uuid_skipsupport' },
{ oid => '2961', descr => 'I/O',
proname => 'uuid_recv', prorettype => 'uuid', proargtypes => 'internal',
prosrc => 'uuid_recv' },

98
src/include/utils/skipsupport.h
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@ -0,0 +1,98 @@
/*-------------------------------------------------------------------------
*
* skipsupport.h
* Support routines for B-Tree skip scan.
*
* B-Tree operator classes for discrete types can optionally provide a support
* function for skipping. This is used during skip scans.
*
* A B-tree operator class that implements skip support provides B-tree index
* scans with a way of enumerating and iterating through every possible value
* from the domain of indexable values. This gives scans a way to determine
* the next value in line for a given skip array/scan key/skipped attribute.
* Scans request the next (or previous) value whenever they run out of tuples
* matching the skip array's current element value. The next (or previous)
* value can be used to relocate the scan; it is applied in combination with
* at least one additional lower-order non-skip key, taken from the query.
*
* Skip support is used by discrete type (e.g., integer and date) opclasses.
* Indexes with an attribute whose input opclass is of one of these types tend
* to store adjacent values in adjoining groups of index tuples. Each time a
* skip scan with skip support successfully guesses that the next value in the
* index (for a given skipped column) is indeed the value that skip support
* just incremented its skip array to, it will have saved the scan some work.
* The scan will have avoided an index probe that directly finds the next
* value that appears in the index. (When skip support guesses wrong, then it
* won't have saved any work, but it also won't have added any useless work.
* The failed attempt to locate exactly-matching index tuples acts just like
* an explicit probe would; it'll still find the index's true next value.)
*
* It usually isn't feasible to implement skip support for an opclass whose
* input type is continuous. The B-Tree code falls back on next-key sentinel
* values for any opclass that doesn't provide its own skip support function.
* This isn't really an implementation restriction; there is no benefit to
* providing skip support for an opclass where guessing that the next indexed
* value is the next possible indexable value never (or hardly ever) works out.
*
*
* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/utils/skipsupport.h
*
*-------------------------------------------------------------------------
*/
#ifndef SKIPSUPPORT_H
#define SKIPSUPPORT_H
#include "utils/relcache.h"
typedef struct SkipSupportData *SkipSupport;
typedef Datum (*SkipSupportIncDec) (Relation rel,
Datum existing,
bool *overflow);
/*
* State/callbacks used by skip arrays to procedurally generate elements.
*
* A BTSKIPSUPPORT_PROC function must set each and every field when called
* (there are no optional fields).
*/
typedef struct SkipSupportData
{
/*
* low_elem and high_elem must be set with the lowest and highest possible
* values from the domain of indexable values (assuming ascending order)
*/
Datum low_elem; /* lowest sorting/leftmost non-NULL value */
Datum high_elem; /* highest sorting/rightmost non-NULL value */
/*
* Decrement/increment functions.
*
* Returns a decremented/incremented copy of caller's existing datum,
* allocated in caller's memory context (for pass-by-reference types).
* It's not okay for these functions to leak any memory.
*
* When the decrement function (or increment function) is called with a
* value that already matches low_elem (or high_elem), function must set
* the *overflow argument. The return value is treated as undefined by
* the B-Tree code; it shouldn't need to be (and won't be) pfree'd.
*
* The B-Tree code's "existing" datum argument is often just a straight
* copy of a value from an index tuple. Operator classes must accept
* every possible representational variation within the underlying type.
* On the other hand, opclasses are _not_ required to preserve information
* that doesn't affect how datums are sorted (e.g., skip support for a
* fixed precision numeric type needn't preserve datum display scale).
* Operator class decrement/increment functions will never be called with
* a NULL "existing" argument, either.
*/
SkipSupportIncDec decrement;
SkipSupportIncDec increment;
} SkipSupportData;
extern SkipSupport PrepareSkipSupportFromOpclass(Oid opfamily, Oid opcintype,
bool reverse);
#endif /* SKIPSUPPORT_H */

10
src/test/regress/expected/alter_generic.out
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@ -362,9 +362,9 @@ ERROR: invalid operator number 0, must be between 1 and 5
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD OPERATOR 1 < ; -- operator without argument types
ERROR: operator argument types must be specified in ALTER OPERATOR FAMILY
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD FUNCTION 0 btint42cmp(int4, int2); -- invalid options parsing function
ERROR: invalid function number 0, must be between 1 and 5
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD FUNCTION 6 btint42cmp(int4, int2); -- function number should be between 1 and 5
ERROR: invalid function number 6, must be between 1 and 5
ERROR: invalid function number 0, must be between 1 and 6
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD FUNCTION 7 btint42cmp(int4, int2); -- function number should be between 1 and 6
ERROR: invalid function number 7, must be between 1 and 6
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD STORAGE invalid_storage; -- Ensure STORAGE is not a part of ALTER OPERATOR FAMILY
ERROR: STORAGE cannot be specified in ALTER OPERATOR FAMILY
DROP OPERATOR FAMILY alt_opf4 USING btree;
@ -505,6 +505,10 @@ ALTER OPERATOR FAMILY alt_opf18 USING btree ADD
ALTER OPERATOR FAMILY alt_opf18 USING btree
ADD FUNCTION 4 (int4, int2) btequalimage(oid);
ERROR: ordering equal image functions must not be cross-type
-- Should fail. Not allowed to have cross-type skip support function.
ALTER OPERATOR FAMILY alt_opf18 USING btree
ADD FUNCTION 6 (int4, int2) btint4skipsupport(internal);
ERROR: btree skip support functions must not be cross-type
ALTER OPERATOR FAMILY alt_opf18 USING btree DROP FUNCTION 2 (int4, int4);
ERROR: function 2(integer,integer) does not exist in operator family "alt_opf18"
DROP OPERATOR FAMILY alt_opf18 USING btree;

41
src/test/regress/expected/btree_index.out
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@ -581,6 +581,47 @@ alter table btree_tall_tbl alter COLUMN t set storage plain;
create index btree_tall_idx on btree_tall_tbl (t, id) with (fillfactor = 10);
insert into btree_tall_tbl select g, repeat('x', 250)
from generate_series(1, 130) g;
insert into btree_tall_tbl select g, NULL
from generate_series(50, 60) g;
--
-- Test for skip scan with type that lacks skip support (text)
--
set enable_seqscan to false;
set enable_bitmapscan to false;
-- Forwards scan
SELECT id FROM btree_tall_tbl WHERE id = 55 ORDER BY t, id;
id
----
55
55
(2 rows)
explain (costs off)
SELECT id FROM btree_tall_tbl WHERE id = 55 ORDER BY t, id;
QUERY PLAN
--------------------------------------------------------
Index Only Scan using btree_tall_idx on btree_tall_tbl
Index Cond: (id = 55)
(2 rows)
-- Backwards scan
SELECT id FROM btree_tall_tbl WHERE id = 55 ORDER BY t DESC, id DESC;
id
----
55
55
(2 rows)
explain (costs off)
SELECT id FROM btree_tall_tbl WHERE id = 55 ORDER BY t DESC, id DESC;
QUERY PLAN
-----------------------------------------------------------------
Index Only Scan Backward using btree_tall_idx on btree_tall_tbl
Index Cond: (id = 55)
(2 rows)
reset enable_seqscan;
reset enable_bitmapscan;
--
-- Test for multilevel page deletion
--

183
src/test/regress/expected/create_index.out
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@ -1637,7 +1637,9 @@ DROP TABLE syscol_table;
-- Tests for IS NULL/IS NOT NULL with b-tree indexes
--
CREATE TABLE onek_with_null AS SELECT unique1, unique2 FROM onek;
INSERT INTO onek_with_null (unique1,unique2) VALUES (NULL, -1), (NULL, NULL);
INSERT INTO onek_with_null(unique1, unique2)
VALUES (NULL, -1), (NULL, 2_147_483_647), (NULL, NULL),
(100, NULL), (500, NULL);
CREATE UNIQUE INDEX onek_nulltest ON onek_with_null (unique2,unique1);
SET enable_seqscan = OFF;
SET enable_indexscan = ON;
@ -1645,7 +1647,7 @@ SET enable_bitmapscan = ON;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL;
count
-------
2
3
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NULL;
@ -1657,13 +1659,13 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL;
count
-------
1000
1002
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NOT NULL;
count
-------
1
2
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL AND unique1 > 500;
@ -1678,12 +1680,18 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique1 > 500;
0
(1 row)
SELECT unique1, unique2 FROM onek_with_null WHERE unique1 = 500 ORDER BY unique2 DESC, unique1 DESC LIMIT 1;
unique1 | unique2
---------+---------
500 |
(1 row)
DROP INDEX onek_nulltest;
CREATE UNIQUE INDEX onek_nulltest ON onek_with_null (unique2 desc,unique1);
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL;
count
-------
2
3
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NULL;
@ -1695,13 +1703,13 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL;
count
-------
1000
1002
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NOT NULL;
count
-------
1
2
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL AND unique1 > 500;
@ -1722,12 +1730,18 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IN (-1, 0,
1
(1 row)
SELECT unique1, unique2 FROM onek_with_null WHERE unique1 = 500 ORDER BY unique2 DESC, unique1 DESC LIMIT 1;
unique1 | unique2
---------+---------
500 |
(1 row)
DROP INDEX onek_nulltest;
CREATE UNIQUE INDEX onek_nulltest ON onek_with_null (unique2 desc nulls last,unique1);
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL;
count
-------
2
3
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NULL;
@ -1739,13 +1753,13 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL;
count
-------
1000
1002
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NOT NULL;
count
-------
1
2
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL AND unique1 > 500;
@ -1760,12 +1774,18 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique1 > 500;
0
(1 row)
SELECT unique1, unique2 FROM onek_with_null WHERE unique1 = 500 ORDER BY unique2 DESC, unique1 DESC LIMIT 1;
unique1 | unique2
---------+---------
500 |
(1 row)
DROP INDEX onek_nulltest;
CREATE UNIQUE INDEX onek_nulltest ON onek_with_null (unique2 nulls first,unique1);
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL;
count
-------
2
3
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NULL;
@ -1777,13 +1797,13 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL;
count
-------
1000
1002
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NOT NULL;
count
-------
1
2
(1 row)
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL AND unique1 > 500;
@ -1798,6 +1818,12 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique1 > 500;
0
(1 row)
SELECT unique1, unique2 FROM onek_with_null WHERE unique1 = 500 ORDER BY unique2 DESC, unique1 DESC LIMIT 1;
unique1 | unique2
---------+---------
500 |
(1 row)
DROP INDEX onek_nulltest;
-- Check initial-positioning logic too
CREATE UNIQUE INDEX onek_nulltest ON onek_with_null (unique2);
@ -1829,20 +1855,24 @@ SELECT unique1, unique2 FROM onek_with_null WHERE unique2 >= 0
(2 rows)
SELECT unique1, unique2 FROM onek_with_null
ORDER BY unique2 DESC LIMIT 2;
unique1 | unique2
---------+---------
|
278 | 999
(2 rows)
ORDER BY unique2 DESC LIMIT 5;
unique1 | unique2
---------+------------
500 |
100 |
|
| 2147483647
278 | 999
(5 rows)
SELECT unique1, unique2 FROM onek_with_null WHERE unique2 >= -1
ORDER BY unique2 DESC LIMIT 2;
unique1 | unique2
---------+---------
278 | 999
0 | 998
(2 rows)
ORDER BY unique2 DESC LIMIT 3;
unique1 | unique2
---------+------------
| 2147483647
278 | 999
0 | 998
(3 rows)
SELECT unique1, unique2 FROM onek_with_null WHERE unique2 < 999
ORDER BY unique2 DESC LIMIT 2;
@ -2247,7 +2277,8 @@ SELECT count(*) FROM dupindexcols
(1 row)
--
-- Check that index scans with =ANY indexquals return rows in index order
-- Check that index scans with SAOP array and/or skip array indexquals
-- return rows in index order
--
explain (costs off)
SELECT unique1 FROM tenk1
@ -2269,7 +2300,7 @@ ORDER BY unique1;
42
(3 rows)
-- Non-required array scan key on "tenthous":
-- Skip array on "thousand", SAOP array on "tenthous":
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand < 2 AND tenthous IN (1001,3000)
@ -2289,7 +2320,7 @@ ORDER BY thousand;
1 | 1001
(2 rows)
-- Non-required array scan key on "tenthous", backward scan:
-- Skip array on "thousand", SAOP array on "tenthous", backward scan:
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand < 2 AND tenthous IN (1001,3000)
@ -2309,6 +2340,25 @@ ORDER BY thousand DESC, tenthous DESC;
0 | 3000
(2 rows)
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand > 995 and tenthous in (998, 999)
ORDER BY thousand desc;
QUERY PLAN
--------------------------------------------------------------------------------
Index Only Scan Backward using tenk1_thous_tenthous on tenk1
Index Cond: ((thousand > 995) AND (tenthous = ANY ('{998,999}'::integer[])))
(2 rows)
SELECT thousand, tenthous FROM tenk1
WHERE thousand > 995 and tenthous in (998, 999)
ORDER BY thousand desc;
thousand | tenthous
----------+----------
999 | 999
998 | 998
(2 rows)
--
-- Check elimination of redundant and contradictory index quals
--
@ -2339,6 +2389,45 @@ SELECT unique1 FROM tenk1 WHERE unique1 = ANY('{7, 14, 22}') and unique1 = ANY('
---------
(0 rows)
explain (costs off)
SELECT unique1 FROM tenk1 WHERE unique1 = ANY(NULL);
QUERY PLAN
-------------------------------------------------
Index Only Scan using tenk1_unique1 on tenk1
Index Cond: (unique1 = ANY (NULL::integer[]))
(2 rows)
SELECT unique1 FROM tenk1 WHERE unique1 = ANY(NULL);
unique1
---------
(0 rows)
explain (costs off)
SELECT unique1 FROM tenk1 WHERE unique1 = ANY('{NULL,NULL,NULL}');
QUERY PLAN
---------------------------------------------------------------
Index Only Scan using tenk1_unique1 on tenk1
Index Cond: (unique1 = ANY ('{NULL,NULL,NULL}'::integer[]))
(2 rows)
SELECT unique1 FROM tenk1 WHERE unique1 = ANY('{NULL,NULL,NULL}');
unique1
---------
(0 rows)
explain (costs off)
SELECT unique1 FROM tenk1 WHERE unique1 IS NULL AND unique1 IS NULL;
QUERY PLAN
---------------------------------------------------------
Index Only Scan using tenk1_unique1 on tenk1
Index Cond: ((unique1 IS NULL) AND (unique1 IS NULL))
(2 rows)
SELECT unique1 FROM tenk1 WHERE unique1 IS NULL AND unique1 IS NULL;
unique1
---------
(0 rows)
explain (costs off)
SELECT unique1 FROM tenk1 WHERE unique1 IN (1, 42, 7) and unique1 = 1;
QUERY PLAN
@ -2462,6 +2551,44 @@ SELECT unique1 FROM tenk1 WHERE (thousand, tenthous) > (NULL, 5);
---------
(0 rows)
-- Skip array redundancy (pair of redundant low_compare inequalities)
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand > -1 and thousand >= 0 AND tenthous = 3000
ORDER BY thousand;
QUERY PLAN
--------------------------------------------------------------------------------------
Index Only Scan using tenk1_thous_tenthous on tenk1
Index Cond: ((thousand > '-1'::integer) AND (thousand >= 0) AND (tenthous = 3000))
(2 rows)
SELECT thousand, tenthous FROM tenk1
WHERE thousand > -1 and thousand >= 0 AND tenthous = 3000
ORDER BY thousand;
thousand | tenthous
----------+----------
0 | 3000
(1 row)
-- Skip array redundancy (pair of redundant high_compare inequalities)
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand < 3 and thousand <= 2 AND tenthous = 1001
ORDER BY thousand;
QUERY PLAN
--------------------------------------------------------------------------
Index Only Scan using tenk1_thous_tenthous on tenk1
Index Cond: ((thousand < 3) AND (thousand <= 2) AND (tenthous = 1001))
(2 rows)
SELECT thousand, tenthous FROM tenk1
WHERE thousand < 3 and thousand <= 2 AND tenthous = 1001
ORDER BY thousand;
thousand | tenthous
----------+----------
1 | 1001
(1 row)
--
-- Check elimination of constant-NULL subexpressions
--

3
src/test/regress/expected/psql.out
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@ -5332,9 +5332,10 @@ Function | in_range(time without time zone,time without time zone,i
btree | uuid_ops | uuid | uuid | 1 | uuid_cmp
btree | uuid_ops | uuid | uuid | 2 | uuid_sortsupport
btree | uuid_ops | uuid | uuid | 4 | btequalimage
btree | uuid_ops | uuid | uuid | 6 | uuid_skipsupport
hash | uuid_ops | uuid | uuid | 1 | uuid_hash
hash | uuid_ops | uuid | uuid | 2 | uuid_hash_extended
(5 rows)
(6 rows)
-- check \dconfig
set work_mem = 10240;

5
src/test/regress/sql/alter_generic.sql
Unescape View File

@ -310,7 +310,7 @@ ALTER OPERATOR FAMILY alt_opf4 USING btree ADD OPERATOR 6 < (int4, int2); -- ope
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD OPERATOR 0 < (int4, int2); -- operator number should be between 1 and 5
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD OPERATOR 1 < ; -- operator without argument types
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD FUNCTION 0 btint42cmp(int4, int2); -- invalid options parsing function
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD FUNCTION 6 btint42cmp(int4, int2); -- function number should be between 1 and 5
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD FUNCTION 7 btint42cmp(int4, int2); -- function number should be between 1 and 6
ALTER OPERATOR FAMILY alt_opf4 USING btree ADD STORAGE invalid_storage; -- Ensure STORAGE is not a part of ALTER OPERATOR FAMILY
DROP OPERATOR FAMILY alt_opf4 USING btree;
@ -444,6 +444,9 @@ ALTER OPERATOR FAMILY alt_opf18 USING btree ADD
-- Should fail. Not allowed to have cross-type equalimage function.
ALTER OPERATOR FAMILY alt_opf18 USING btree
ADD FUNCTION 4 (int4, int2) btequalimage(oid);
-- Should fail. Not allowed to have cross-type skip support function.
ALTER OPERATOR FAMILY alt_opf18 USING btree
ADD FUNCTION 6 (int4, int2) btint4skipsupport(internal);
ALTER OPERATOR FAMILY alt_opf18 USING btree DROP FUNCTION 2 (int4, int4);
DROP OPERATOR FAMILY alt_opf18 USING btree;

21
src/test/regress/sql/btree_index.sql
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@ -327,6 +327,27 @@ alter table btree_tall_tbl alter COLUMN t set storage plain;
create index btree_tall_idx on btree_tall_tbl (t, id) with (fillfactor = 10);
insert into btree_tall_tbl select g, repeat('x', 250)
from generate_series(1, 130) g;
insert into btree_tall_tbl select g, NULL
from generate_series(50, 60) g;
--
-- Test for skip scan with type that lacks skip support (text)
--
set enable_seqscan to false;
set enable_bitmapscan to false;
-- Forwards scan
SELECT id FROM btree_tall_tbl WHERE id = 55 ORDER BY t, id;
explain (costs off)
SELECT id FROM btree_tall_tbl WHERE id = 55 ORDER BY t, id;
-- Backwards scan
SELECT id FROM btree_tall_tbl WHERE id = 55 ORDER BY t DESC, id DESC;
explain (costs off)
SELECT id FROM btree_tall_tbl WHERE id = 55 ORDER BY t DESC, id DESC;
reset enable_seqscan;
reset enable_bitmapscan;
--
-- Test for multilevel page deletion

63
src/test/regress/sql/create_index.sql
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@ -650,7 +650,9 @@ DROP TABLE syscol_table;
--
CREATE TABLE onek_with_null AS SELECT unique1, unique2 FROM onek;
INSERT INTO onek_with_null (unique1,unique2) VALUES (NULL, -1), (NULL, NULL);
INSERT INTO onek_with_null(unique1, unique2)
VALUES (NULL, -1), (NULL, 2_147_483_647), (NULL, NULL),
(100, NULL), (500, NULL);
CREATE UNIQUE INDEX onek_nulltest ON onek_with_null (unique2,unique1);
SET enable_seqscan = OFF;
@ -663,6 +665,7 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NOT NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL AND unique1 > 500;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique1 > 500;
SELECT unique1, unique2 FROM onek_with_null WHERE unique1 = 500 ORDER BY unique2 DESC, unique1 DESC LIMIT 1;
DROP INDEX onek_nulltest;
@ -675,6 +678,7 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NOT NUL
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL AND unique1 > 500;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique1 > 500;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IN (-1, 0, 1);
SELECT unique1, unique2 FROM onek_with_null WHERE unique1 = 500 ORDER BY unique2 DESC, unique1 DESC LIMIT 1;
DROP INDEX onek_nulltest;
@ -686,6 +690,7 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NOT NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL AND unique1 > 500;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique1 > 500;
SELECT unique1, unique2 FROM onek_with_null WHERE unique1 = 500 ORDER BY unique2 DESC, unique1 DESC LIMIT 1;
DROP INDEX onek_nulltest;
@ -697,6 +702,7 @@ SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique2 IS NOT NULL;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NOT NULL AND unique1 > 500;
SELECT count(*) FROM onek_with_null WHERE unique1 IS NULL AND unique1 > 500;
SELECT unique1, unique2 FROM onek_with_null WHERE unique1 = 500 ORDER BY unique2 DESC, unique1 DESC LIMIT 1;
DROP INDEX onek_nulltest;
@ -716,9 +722,9 @@ SELECT unique1, unique2 FROM onek_with_null WHERE unique2 >= 0
ORDER BY unique2 LIMIT 2;
SELECT unique1, unique2 FROM onek_with_null
ORDER BY unique2 DESC LIMIT 2;
ORDER BY unique2 DESC LIMIT 5;
SELECT unique1, unique2 FROM onek_with_null WHERE unique2 >= -1
ORDER BY unique2 DESC LIMIT 2;
ORDER BY unique2 DESC LIMIT 3;
SELECT unique1, unique2 FROM onek_with_null WHERE unique2 < 999
ORDER BY unique2 DESC LIMIT 2;
@ -852,7 +858,8 @@ SELECT count(*) FROM dupindexcols
WHERE f1 BETWEEN 'WA' AND 'ZZZ' and id < 1000 and f1 ~<~ 'YX';
--
-- Check that index scans with =ANY indexquals return rows in index order
-- Check that index scans with SAOP array and/or skip array indexquals
-- return rows in index order
--
explain (costs off)
@ -864,7 +871,7 @@ SELECT unique1 FROM tenk1
WHERE unique1 IN (1,42,7)
ORDER BY unique1;
-- Non-required array scan key on "tenthous":
-- Skip array on "thousand", SAOP array on "tenthous":
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand < 2 AND tenthous IN (1001,3000)
@ -874,7 +881,7 @@ SELECT thousand, tenthous FROM tenk1
WHERE thousand < 2 AND tenthous IN (1001,3000)
ORDER BY thousand;
-- Non-required array scan key on "tenthous", backward scan:
-- Skip array on "thousand", SAOP array on "tenthous", backward scan:
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand < 2 AND tenthous IN (1001,3000)
@ -884,6 +891,15 @@ SELECT thousand, tenthous FROM tenk1
WHERE thousand < 2 AND tenthous IN (1001,3000)
ORDER BY thousand DESC, tenthous DESC;
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand > 995 and tenthous in (998, 999)
ORDER BY thousand desc;
SELECT thousand, tenthous FROM tenk1
WHERE thousand > 995 and tenthous in (998, 999)
ORDER BY thousand desc;
--
-- Check elimination of redundant and contradictory index quals
--
@ -897,6 +913,21 @@ SELECT unique1 FROM tenk1 WHERE unique1 = ANY('{7, 14, 22}') and unique1 = ANY('
SELECT unique1 FROM tenk1 WHERE unique1 = ANY('{7, 14, 22}') and unique1 = ANY('{33, 44}'::bigint[]);
explain (costs off)
SELECT unique1 FROM tenk1 WHERE unique1 = ANY(NULL);
SELECT unique1 FROM tenk1 WHERE unique1 = ANY(NULL);
explain (costs off)
SELECT unique1 FROM tenk1 WHERE unique1 = ANY('{NULL,NULL,NULL}');
SELECT unique1 FROM tenk1 WHERE unique1 = ANY('{NULL,NULL,NULL}');
explain (costs off)
SELECT unique1 FROM tenk1 WHERE unique1 IS NULL AND unique1 IS NULL;
SELECT unique1 FROM tenk1 WHERE unique1 IS NULL AND unique1 IS NULL;
explain (costs off)
SELECT unique1 FROM tenk1 WHERE unique1 IN (1, 42, 7) and unique1 = 1;
@ -942,6 +973,26 @@ SELECT unique1 FROM tenk1 WHERE (thousand, tenthous) > (NULL, 5);
SELECT unique1 FROM tenk1 WHERE (thousand, tenthous) > (NULL, 5);
-- Skip array redundancy (pair of redundant low_compare inequalities)
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand > -1 and thousand >= 0 AND tenthous = 3000
ORDER BY thousand;
SELECT thousand, tenthous FROM tenk1
WHERE thousand > -1 and thousand >= 0 AND tenthous = 3000
ORDER BY thousand;
-- Skip array redundancy (pair of redundant high_compare inequalities)
explain (costs off)
SELECT thousand, tenthous FROM tenk1
WHERE thousand < 3 and thousand <= 2 AND tenthous = 1001
ORDER BY thousand;
SELECT thousand, tenthous FROM tenk1
WHERE thousand < 3 and thousand <= 2 AND tenthous = 1001
ORDER BY thousand;
--
-- Check elimination of constant-NULL subexpressions
--

2
src/tools/pgindent/typedefs.list
Unescape View File

@ -2754,6 +2754,8 @@ SimpleStringListCell
SingleBoundSortItem
Size
SkipPages
SkipSupport
SkipSupportData
SlabBlock
SlabContext
SlabSlot

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