1
0
mirror of https://github.com/postgres/postgres.git synced 2025-08-27 07:42:10 +03:00

Pass down "logically unchanged index" hint.

Add an executor aminsert() hint mechanism that informs index AMs that
the incoming index tuple (the tuple that accompanies the hint) is not
being inserted by execution of an SQL statement that logically modifies
any of the index's key columns.

The hint is received by indexes when an UPDATE takes place that does not
apply an optimization like heapam's HOT (though only for indexes where
all key columns are logically unchanged).  Any index tuple that receives
the hint on insert is expected to be a duplicate of at least one
existing older version that is needed for the same logical row.  Related
versions will typically be stored on the same index page, at least
within index AMs that apply the hint.

Recognizing the difference between MVCC version churn duplicates and
true logical row duplicates at the index AM level can help with cleanup
of garbage index tuples.  Cleanup can intelligently target tuples that
are likely to be garbage, without wasting too many cycles on less
promising tuples/pages (index pages with little or no version churn).

This is infrastructure for an upcoming commit that will teach nbtree to
perform bottom-up index deletion.  No index AM actually applies the hint
just yet.

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Victor Yegorov <vyegorov@gmail.com>
Discussion: https://postgr.es/m/CAH2-Wz=CEKFa74EScx_hFVshCOn6AA5T-ajFASTdzipdkLTNQQ@mail.gmail.com
This commit is contained in:
Peter Geoghegan
2021-01-13 08:11:00 -08:00
parent 39b03690b5
commit 9dc718bdf2
31 changed files with 214 additions and 25 deletions

View File

@@ -151,6 +151,7 @@ bool
brininsert(Relation idxRel, Datum *values, bool *nulls,
ItemPointer heaptid, Relation heapRel,
IndexUniqueCheck checkUnique,
bool indexUnchanged,
IndexInfo *indexInfo)
{
BlockNumber pagesPerRange;

View File

@@ -328,7 +328,7 @@ toast_save_datum(Relation rel, Datum value,
toastrel,
toastidxs[i]->rd_index->indisunique ?
UNIQUE_CHECK_YES : UNIQUE_CHECK_NO,
NULL);
false, NULL);
}
/*

View File

@@ -488,6 +488,7 @@ bool
gininsert(Relation index, Datum *values, bool *isnull,
ItemPointer ht_ctid, Relation heapRel,
IndexUniqueCheck checkUnique,
bool indexUnchanged,
IndexInfo *indexInfo)
{
GinState *ginstate = (GinState *) indexInfo->ii_AmCache;

View File

@@ -156,6 +156,7 @@ bool
gistinsert(Relation r, Datum *values, bool *isnull,
ItemPointer ht_ctid, Relation heapRel,
IndexUniqueCheck checkUnique,
bool indexUnchanged,
IndexInfo *indexInfo)
{
GISTSTATE *giststate = (GISTSTATE *) indexInfo->ii_AmCache;

View File

@@ -247,6 +247,7 @@ bool
hashinsert(Relation rel, Datum *values, bool *isnull,
ItemPointer ht_ctid, Relation heapRel,
IndexUniqueCheck checkUnique,
bool indexUnchanged,
IndexInfo *indexInfo)
{
Datum index_values[1];

View File

@@ -1956,6 +1956,7 @@ heapam_index_validate_scan(Relation heapRelation,
heapRelation,
indexInfo->ii_Unique ?
UNIQUE_CHECK_YES : UNIQUE_CHECK_NO,
false,
indexInfo);
state->tups_inserted += 1;

View File

@@ -179,6 +179,7 @@ index_insert(Relation indexRelation,
ItemPointer heap_t_ctid,
Relation heapRelation,
IndexUniqueCheck checkUnique,
bool indexUnchanged,
IndexInfo *indexInfo)
{
RELATION_CHECKS;
@@ -191,7 +192,8 @@ index_insert(Relation indexRelation,
return indexRelation->rd_indam->aminsert(indexRelation, values, isnull,
heap_t_ctid, heapRelation,
checkUnique, indexInfo);
checkUnique, indexUnchanged,
indexInfo);
}
/*

View File

@@ -199,6 +199,7 @@ bool
btinsert(Relation rel, Datum *values, bool *isnull,
ItemPointer ht_ctid, Relation heapRel,
IndexUniqueCheck checkUnique,
bool indexUnchanged,
IndexInfo *indexInfo)
{
bool result;

View File

@@ -207,6 +207,7 @@ bool
spginsert(Relation index, Datum *values, bool *isnull,
ItemPointer ht_ctid, Relation heapRel,
IndexUniqueCheck checkUnique,
bool indexUnchanged,
IndexInfo *indexInfo)
{
SpGistState spgstate;