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Implement the basic form of UNNEST, ie unnest(anyarray) returns setof

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anyelement.  This lacks the WITH ORDINALITY option, as well as the multiple
input arrays option added in the most recent SQL specs.  But it's still a
pretty useful subset of the spec's functionality, and it is enough to
allow obsoleting contrib/intagg.
REL8_5_ALPHA1_BRANCH
Tom Lane 17 years ago
parent 5b9453bcd3
commit c889ebce0a
7 changed files with 193 additions and 6 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. 13
      doc/src/sgml/func.sgml
  2. 106
      src/backend/utils/adt/arrayfuncs.c
  3. 4
      src/include/catalog/catversion.h
  4. 4
      src/include/catalog/pg_proc.h
  5. 3
      src/include/utils/array.h
  6. 62
      src/test/regress/expected/arrays.out
  7. 7
      src/test/regress/sql/arrays.sql

13
doc/src/sgml/func.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.459 2008/11/13 23:01:09 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.460 2008/11/14 00:51:46 tgl Exp $ -->
<chapter id="functions">
<title>Functions and Operators</title>
@ -9482,6 +9482,17 @@ SELECT NULLIF(value, '(none)') ...
<entry><literal>string_to_array('xx~^~yy~^~zz', '~^~')</literal></entry>
<entry><literal>{xx,yy,zz}</literal></entry>
</row>
<row>
<entry>
<literal>
<function>unnest</function>(<type>anyarray</type>)
</literal>
</entry>
<entry><type>setof anyelement</type></entry>
<entry>expand an array to a set of rows</entry>
<entry><literal>unnest(ARRAY[1,2])</literal></entry>
<entry><literal>1</literal><para><literal>2</literal></para> (2 rows)</entry>
</row>
</tbody>
</tgroup>
</table>

106
src/backend/utils/adt/arrayfuncs.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.149 2008/11/12 13:09:27 petere Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.150 2008/11/14 00:51:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -4635,3 +4635,107 @@ array_fill_internal(ArrayType *dims, ArrayType *lbs,
return result;
}
/*
* UNNEST
*/
Datum
array_unnest(PG_FUNCTION_ARGS)
{
typedef struct
{
ArrayType *arr;
int nextelem;
int numelems;
char *elemdataptr; /* this moves with nextelem */
bits8 *arraynullsptr; /* this does not */
int16 elmlen;
bool elmbyval;
char elmalign;
} array_unnest_fctx;
FuncCallContext *funcctx;
array_unnest_fctx *fctx;
MemoryContext oldcontext;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
ArrayType *arr = PG_GETARG_ARRAYTYPE_P(0);
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* allocate memory for user context */
fctx = (array_unnest_fctx *) palloc(sizeof(array_unnest_fctx));
/*
* Initialize state. Note we assume that the originally passed
* array will stick around for the whole call series.
*/
fctx->arr = arr;
fctx->nextelem = 0;
fctx->numelems = ArrayGetNItems(ARR_NDIM(arr), ARR_DIMS(arr));
fctx->elemdataptr = ARR_DATA_PTR(arr);
fctx->arraynullsptr = ARR_NULLBITMAP(arr);
get_typlenbyvalalign(ARR_ELEMTYPE(arr),
&fctx->elmlen,
&fctx->elmbyval,
&fctx->elmalign);
funcctx->user_fctx = fctx;
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
fctx = funcctx->user_fctx;
if (fctx->nextelem < fctx->numelems)
{
int offset = fctx->nextelem++;
Datum elem;
/*
* Check for NULL array element
*/
if (array_get_isnull(fctx->arraynullsptr, offset))
{
fcinfo->isnull = true;
elem = (Datum) 0;
/* elemdataptr does not move */
}
else
{
/*
* OK, get the element
*/
char *ptr = fctx->elemdataptr;
fcinfo->isnull = false;
elem = ArrayCast(ptr, fctx->elmbyval, fctx->elmlen);
/*
* Advance elemdataptr over it
*/
ptr = att_addlength_pointer(ptr, fctx->elmlen, ptr);
ptr = (char *) att_align_nominal(ptr, fctx->elmalign);
fctx->elemdataptr = ptr;
}
SRF_RETURN_NEXT(funcctx, elem);
}
else
{
/* do when there is no more left */
SRF_RETURN_DONE(funcctx);
}
}

4
src/include/catalog/catversion.h
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@ -37,7 +37,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.505 2008/11/13 15:59:50 petere Exp $
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.506 2008/11/14 00:51:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 200811131
#define CATALOG_VERSION_NO 200811132
#endif

4
src/include/catalog/pg_proc.h
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.527 2008/11/13 15:59:50 petere Exp $
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.528 2008/11/14 00:51:46 tgl Exp $
*
* NOTES
* The script catalog/genbki.sh reads this file and generates .bki
@ -1022,6 +1022,8 @@ DATA(insert OID = 1193 ( array_fill PGNSP PGUID 12 1 0 0 f f f f i 2 2277 "2283
DESCR("array constructor with value");
DATA(insert OID = 1286 ( array_fill PGNSP PGUID 12 1 0 0 f f f f i 3 2277 "2283 1007 1007" _null_ _null_ _null_ array_fill_with_lower_bounds _null_ _null_ _null_ ));
DESCR("array constructor with value");
DATA(insert OID = 2331 ( unnest PGNSP PGUID 12 1 100 0 f f t t i 1 2283 "2277" _null_ _null_ _null_ array_unnest _null_ _null_ _null_ ));
DESCR("expand array to set of rows");
DATA(insert OID = 2333 ( array_agg_transfn PGNSP PGUID 12 1 0 0 f f f f i 2 2281 "2281 2283" _null_ _null_ _null_ array_agg_transfn _null_ _null_ _null_ ));
DESCR("array_agg transition function");
DATA(insert OID = 2334 ( array_agg_finalfn PGNSP PGUID 12 1 0 0 f f f f i 1 2277 "2281" _null_ _null_ _null_ array_agg_finalfn _null_ _null_ _null_ ));

3
src/include/utils/array.h
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@ -49,7 +49,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/utils/array.h,v 1.71 2008/11/13 15:59:50 petere Exp $
* $PostgreSQL: pgsql/src/include/utils/array.h,v 1.72 2008/11/14 00:51:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -206,6 +206,7 @@ extern Datum generate_subscripts(PG_FUNCTION_ARGS);
extern Datum generate_subscripts_nodir(PG_FUNCTION_ARGS);
extern Datum array_fill(PG_FUNCTION_ARGS);
extern Datum array_fill_with_lower_bounds(PG_FUNCTION_ARGS);
extern Datum array_unnest(PG_FUNCTION_ARGS);
extern Datum array_ref(ArrayType *array, int nSubscripts, int *indx,
int arraytyplen, int elmlen, bool elmbyval, char elmalign,

62
src/test/regress/expected/arrays.out
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@ -1161,3 +1161,65 @@ select array_agg(unique1) from tenk1 where unique1 < -15;
(1 row)
select unnest(array[1,2,3]);
unnest
--------
1
2
3
(3 rows)
select * from unnest(array[1,2,3]);
unnest
--------
1
2
3
(3 rows)
select unnest(array[1,2,3,4.5]::float8[]);
unnest
--------
1
2
3
4.5
(4 rows)
select unnest(array[1,2,3,4.5]::numeric[]);
unnest
--------
1
2
3
4.5
(4 rows)
select unnest(array[1,2,3,null,4,null,null,5,6]);
unnest
--------
1
2
3
4
5
6
(9 rows)
select unnest(array[1,2,3,null,4,null,null,5,6]::text[]);
unnest
--------
1
2
3
4
5
6
(9 rows)

7
src/test/regress/sql/arrays.sql
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@ -402,3 +402,10 @@ select array_agg(nullif(ten, 4)) from tenk1 where unique1 < 15;
select cardinality(array_agg(unique1)) from tenk1 where unique1 < 15;
select array_agg(unique1) from (select * from tenk1 order by unique1 asc) as tab where unique1 < 15;
select array_agg(unique1) from tenk1 where unique1 < -15;
select unnest(array[1,2,3]);
select * from unnest(array[1,2,3]);
select unnest(array[1,2,3,4.5]::float8[]);
select unnest(array[1,2,3,4.5]::numeric[]);
select unnest(array[1,2,3,null,4,null,null,5,6]);
select unnest(array[1,2,3,null,4,null,null,5,6]::text[]);

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