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Support for INCLUDE attributes in GiST indexes

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Similarly to B-tree, GiST index access method gets support of INCLUDE
attributes.  These attributes aren't used for tree navigation and aren't
present in non-leaf pages.  But they are present in leaf pages and can be
fetched during index-only scan.

The point of having INCLUDE attributes in GiST indexes is slightly different
from the point of having them in B-tree.  The main point of INCLUDE attributes
in B-tree is to define UNIQUE constraint over part of attributes enabled for
index-only scan.  In GiST the main point of INCLUDE attributes is to use
index-only scan for attributes, whose data types don't have GiST opclasses.

Discussion: https://postgr.es/m/73A1A452-AD5F-40D4-BD61-978622FF75C1%40yandex-team.ru
Author: Andrey Borodin, with small changes by me
Reviewed-by: Andreas Karlsson
This commit is contained in:
Alexander Korotkov
2019-03-10 11:36:47 +03:00
parent a0b7626268
commit f2e403803f
16 changed files with 382 additions and 48 deletions
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41
src/backend/access/gist/gist.c
View File

@ -75,7 +75,7 @@ gisthandler(PG_FUNCTION_ARGS)
amroutine->amclusterable = true;
amroutine->ampredlocks = true;
amroutine->amcanparallel = false;
amroutine->amcaninclude = false;
amroutine->amcaninclude = true;
amroutine->amkeytype = InvalidOid;
amroutine->ambuild = gistbuild;
@ -1382,8 +1382,10 @@ gistSplit(Relation r,
IndexTupleSize(itup[0]), GiSTPageSize,
RelationGetRelationName(r))));
memset(v.spl_lisnull, true, sizeof(bool) * giststate->tupdesc->natts);
memset(v.spl_risnull, true, sizeof(bool) * giststate->tupdesc->natts);
memset(v.spl_lisnull, true,
sizeof(bool) * giststate->nonLeafTupdesc->natts);
memset(v.spl_risnull, true,
sizeof(bool) * giststate->nonLeafTupdesc->natts);
gistSplitByKey(r, page, itup, len, giststate, &v, 0);
/* form left and right vector */
@ -1461,9 +1463,23 @@ initGISTstate(Relation index)
giststate->scanCxt = scanCxt;
giststate->tempCxt = scanCxt; /* caller must change this if needed */
giststate->tupdesc = index->rd_att;
giststate->leafTupdesc = index->rd_att;
for (i = 0; i < index->rd_att->natts; i++)
/*
* The truncated tupdesc for non-leaf index tuples, which doesn't contain
* the INCLUDE attributes.
*
* It is used to form tuples during tuple adjustement and page split.
* B-tree creates shortened tuple descriptor for every truncated tuple,
* because it is doing this less often: it does not have to form truncated
* tuples during page split. Also, B-tree is not adjusting tuples on
* internal pages the way GiST does.
*/
giststate->nonLeafTupdesc = CreateTupleDescCopyConstr(index->rd_att);
giststate->nonLeafTupdesc->natts =
IndexRelationGetNumberOfKeyAttributes(index);
for (i = 0; i < IndexRelationGetNumberOfKeyAttributes(index); i++)
{
fmgr_info_copy(&(giststate->consistentFn[i]),
index_getprocinfo(index, i + 1, GIST_CONSISTENT_PROC),
@ -1531,6 +1547,21 @@ initGISTstate(Relation index)
giststate->supportCollation[i] = DEFAULT_COLLATION_OID;
}
/* No opclass information for INCLUDE attributes */
for (; i < index->rd_att->natts; i++)
{
giststate->consistentFn[i].fn_oid = InvalidOid;
giststate->unionFn[i].fn_oid = InvalidOid;
giststate->compressFn[i].fn_oid = InvalidOid;
giststate->decompressFn[i].fn_oid = InvalidOid;
giststate->penaltyFn[i].fn_oid = InvalidOid;
giststate->picksplitFn[i].fn_oid = InvalidOid;
giststate->equalFn[i].fn_oid = InvalidOid;
giststate->distanceFn[i].fn_oid = InvalidOid;
giststate->fetchFn[i].fn_oid = InvalidOid;
giststate->supportCollation[i] = InvalidOid;
}
MemoryContextSwitchTo(oldCxt);
return giststate;