This commit breaks any code that assumes that the mere act of forming a tuple
(without writing it to disk) does not "toast" any fields. While all available
regression tests pass, I'm not totally sure that we've fixed every nook and
cranny, especially in contrib.
Greg Stark with some help from Tom Lane
Get rid of VARATT_SIZE and VARATT_DATA, which were simply redundant with
VARSIZE and VARDATA, and as a consequence almost no code was using the
longer names. Rename the length fields of struct varlena and various
derived structures to catch anyplace that was accessing them directly;
and clean up various places so caught. In itself this patch doesn't
change any behavior at all, but it is necessary infrastructure if we hope
to play any games with the representation of varlena headers.
Greg Stark and Tom Lane
keeping private state in each backend that has inserted and deleted the same
tuple during its current top-level transaction. This is sufficient since
there is no need to be able to determine the cmin/cmax from any other
transaction. This gets us back down to 23-byte headers, removing a penalty
paid in 8.0 to support subtransactions. Patch by Heikki Linnakangas, with
minor revisions by moi, following a design hashed out awhile back on the
pghackers list.
HeapTuple that is no longer allocated as a single palloc() block; if
used carelessly, this might result in a subsequent memory leak after
heap_freetuple().
discussion (including making def_arg allow reserved words), add missed
opt_definition for UNIQUE case. Put the reloptions support code in a less
random place (I chose to make a new file access/common/reloptions.c).
Eliminate header inclusion creep. Make the index options functions safely
user-callable (seems like client apps might like to be able to test validity
of options before trying to make an index). Reduce overhead for normal case
with no options by allowing rd_options to be NULL. Fix some unmaintainably
klugy code, including getting rid of Natts_pg_class_fixed at long last.
Some stylistic cleanup too, and pay attention to keeping comments in sync
with code.
Documentation still needs work, though I did fix the omissions in
catalogs.sgml and indexam.sgml.
tuples with less header overhead than a regular HeapTuple, per my
recent proposal. Teach TupleTableSlot code how to deal with these.
As proof of concept, change tuplestore.c to store MinimalTuples instead
of HeapTuples. Future patches will expand the concept to other places
where it is useful.
#define HIGHBIT (0x80)
#define IS_HIGHBIT_SET(ch) ((unsigned char)(ch) & HIGHBIT)
and removed CSIGNBIT and mapped it uses to HIGHBIT. I have also added
uses for IS_HIGHBIT_SET where appropriate. This change is
purely for code clarity.
comment line where output as too long, and update typedefs for /lib
directory. Also fix case where identifiers were used as variable names
in the backend, but as typedefs in ecpg (favor the backend for
indenting).
Backpatch to 8.1.X.
generated from subquery outputs: use the type info stored in the Var
itself. To avoid making ExecEvalVar and slot_getattr more complex
and slower, I split out the whole-row case into a separate ExecEval routine.
type ID information even when it's a record type. This is needed to
handle whole-row Vars referencing subquery outputs. Per example from
Richard Huxton.
convention for isnull flags. Also, remove the useless InsertIndexResult
return struct from index AM aminsert calls --- there is no reason for
the caller to know where in the index the tuple was inserted, and we
were wasting a palloc cycle per insert to deliver this uninteresting
value (plus nontrivial complexity in some AMs).
I forced initdb because of the change in the signature of the aminsert
routines, even though nothing really looks at those pg_proc entries...
of tuples when passing data up through multiple plan nodes. A slot can now
hold either a normal "physical" HeapTuple, or a "virtual" tuple consisting
of Datum/isnull arrays. Upper plan levels can usually just copy the Datum
arrays, avoiding heap_formtuple() and possible subsequent nocachegetattr()
calls to extract the data again. This work extends Atsushi Ogawa's earlier
patch, which provided the key idea of adding Datum arrays to TupleTableSlots.
(I believe however that something like this was foreseen way back in Berkeley
days --- see the old comment on ExecProject.) A test case involving many
levels of join of fairly wide tables (about 80 columns altogether) showed
about 3x overall speedup, though simple queries will probably not be
helped very much.
I have also duplicated some code in heaptuple.c in order to provide versions
of heap_formtuple and friends that use "bool" arrays to indicate null
attributes, instead of the old convention of "char" arrays containing either
'n' or ' '. This provides a better match to the convention used by
ExecEvalExpr. While I have not made a concerted effort to get rid of uses
of the old routines, I think they should be deprecated and eventually removed.
a tuple are being accessed via ExecEvalVar and the attcacheoff shortcut
isn't usable (due to nulls and/or varlena columns). To do this, cache
Datums extracted from a tuple in the associated TupleTableSlot.
Also some code cleanup in and around the TupleTable handling.
Atsushi Ogawa with some kibitzing by Tom Lane.
1. Solve the problem of not having TOAST references hiding inside composite
values by establishing the rule that toasting only goes one level deep:
a tuple can contain toasted fields, but a composite-type datum that is
to be inserted into a tuple cannot. Enforcing this in heap_formtuple
is relatively cheap and it avoids a large increase in the cost of running
the tuptoaster during final storage of a row.
2. Fix some interesting problems in expansion of inherited queries that
reference whole-row variables. We never really did this correctly before,
but it's now relatively painless to solve by expanding the parent's
whole-row Var into a RowExpr() selecting the proper columns from the
child.
If you dike out the preventive check in CheckAttributeType(),
composite-type columns now seem to actually work. However, we surely
cannot ship them like this --- without I/O for composite types, you
can't get pg_dump to dump tables containing them. So a little more
work still to do.
loop over the fields instead of a loop around heap_getattr. This is
considerably faster (O(N) instead of O(N^2)) when there are nulls or
varlena fields, since those prevent use of attcacheoff. Replace loops
over heap_getattr with heap_deformtuple in situations where all or most
of the fields have to be fetched, such as printtup and tuptoaster.
Profiling done more than a year ago shows that this should be a nice
win for situations involving many-column tables.
results with tuples as ordinary varlena Datums. This commit does not
in itself do much for us, except eliminate the horrid memory leak
associated with evaluation of whole-row variables. However, it lays the
groundwork for allowing composite types as table columns, and perhaps
some other useful features as well. Per my proposal of a few days ago.
tuptoaster.c --- fields that are compressed in-line are not a reason
to invoke the toaster. Along the way, add a couple more htup.h macros
to eliminate confusing negated tests, and get rid of the already
vestigial TUPLE_TOASTER_ACTIVE symbol.
no reason to worry about the tuple commit status bits until the tuple
is inserted in a relation by heapam.c. Also, improve comments for
heap_addheader().
(overlaying low byte of page size) and add HEAP_HASOID bit to t_infomask,
per earlier discussion. Simplify scheme for overlaying fields in tuple
header (no need for cmax to live in more than one place). Don't try to
clear infomask status bits in tqual.c --- not safe to do it there. Don't
try to force output table of a SELECT INTO to have OIDs, either. Get rid
of unnecessarily complex three-state scheme for TupleDesc.tdhasoids, which
has already caused one recent failure. Improve documentation.
width types and varlena types, since with the introduction of CSTRING as
a more-or-less-real type, these concepts aren't identical. I've tried to
use varlena consistently to denote datatypes with typlen = -1, ie, they
have a length word and are potentially TOASTable; while the term variable
width covers both varlena and cstring (and, perhaps, someday other types
with other rules for computing the actual width). No code changes in this
commit except for renaming a couple macros.
value '-2' is used to indicate a variable-width type whose width is
computed as strlen(datum)+1. Everything that looks at typlen is updated
except for array support, which Joe Conway is working on; at the moment
it wouldn't work to try to create an array of cstring.
bitmap, if present).
Per Tom Lane's suggestion the information whether a tuple has an oid
or not is carried in the tuple descriptor. For debugging reasons
tdhasoid is of type char, not bool. There are predefined values for
WITHOID, WITHOUTOID and UNDEFOID.
This patch has been generated against a cvs snapshot from last week
and I don't expect it to apply cleanly to current sources. While I
post it here for public review, I'm working on a new version against a
current snapshot. (There's been heavy activity recently; hope to
catch up some day ...)
This is a long patch; if it is too hard to swallow, I can provide it
in smaller pieces:
Part 1: Accessor macros
Part 2: tdhasoid in TupDesc
Part 3: Regression test
Part 4: Parameter withoid to heap_addheader
Part 5: Eliminate t_oid from HeapTupleHeader
Part 2 is the most hairy part because of changes in the executor and
even in the parser; the other parts are straightforward.
Up to part 4 the patched postmaster stays binary compatible to
databases created with an unpatched version. Part 5 is small (100
lines) and finally breaks compatibility.
Manfred Koizar
HeapTupleHeaderData in setter and getter macros called
HeapTupleHeaderGetXmin, HeapTupleHeaderSetXmin etc.
It also introduces a "virtual" field xvac by defining
HeapTupleHeaderGetXvac and HeapTupleHeaderSetXvac. Xvac is used by
VACUUM, in fact it is stored in t_cmin.
Manfred Koizar
where the latter is made slightly larger to allow for in-memory tuples
containing resjunk attributes. Responds to today's complaint that one
cannot UPDATE a table containing the allegedly-legal maximum number of
columns.
Also, apply Manfred Koizar's recent patch to avoid extra alignment padding
when there is a null bitmap. This saves bytes in some cases while not
creating any backward-compatibility problem AFAICS.
pg_database now has unique indexes on oid and on datname.
pg_shadow now has unique indexes on usename and on usesysid.
pg_am now has unique index on oid.
pg_opclass now has unique index on oid.
pg_amproc now has unique index on amid+amopclaid+amprocnum.
Remove pg_rewrite's unnecessary index on oid, delete unused RULEOID syscache.
Remove index on pg_listener and associated syscache for performance reasons
(caching rows that are certain to change before you need 'em again is
rather pointless).
Change pg_attrdef's nonunique index on adrelid into a unique index on
adrelid+adnum.
Fix various incorrect settings of pg_class.relisshared, make that the
primary reference point for whether a relation is shared or not.
IsSharedSystemRelationName() is now only consulted to initialize relisshared
during initial creation of tables and indexes. In theory we might now
support shared user relations, though it's not clear how one would get
entries for them into pg_class &etc of multiple databases.
Fix recently reported bug that pg_attribute rows created for an index all have
the same OID. (Proof that non-unique OID doesn't matter unless it's
actually used to do lookups ;-))
There's no need to treat pg_trigger, pg_attrdef, pg_relcheck as bootstrap
relations. Convert them into plain system catalogs without hardwired
entries in pg_class and friends.
Unify global.bki and template1.bki into a single init script postgres.bki,
since the alleged distinction between them was misleading and pointless.
Not to mention that it didn't work for setting up indexes on shared
system relations.
Rationalize locking of pg_shadow, pg_group, pg_attrdef (no need to use
AccessExclusiveLock where ExclusiveLock or even RowExclusiveLock will do).
Also, hold locks until transaction commit where necessary.
1. Distinguish cases where a Datum representing a tuple datatype is an OID
from cases where it is a pointer to TupleTableSlot, and make sure we use
the right typlen in each case.
2. Make fetchatt() and related code support 8-byte by-value datatypes on
machines where Datum is 8 bytes. Centralize knowledge of the available
by-value datatype sizes in two macros in tupmacs.h, so that this will be
easier if we ever have to do it again.
Tom Lane