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Finish reverting "recheck_on_update" patch.

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This reverts commit c203d6cf8 and some follow-on fixes, completing the
task begun in commit 5d28c9bd7.  If that feature is ever resurrected,
the code will look quite a bit different from this, so it seems best
to start from a clean slate.

The v11 branch is not touched; in that branch, the recheck_on_update
storage option remains present, but nonfunctional and undocumented.

Discussion: https://postgr.es/m/20190114223409.3tcvejfhlvbucrv5@alap3.anarazel.de
This commit is contained in:
Tom Lane
2019-01-15 12:07:10 -05:00
parent 0944ec54de
commit 1c53c4dec3
8 changed files with 21 additions and 277 deletions
Download Patch File Download Diff File Expand all files Collapse all files

109
src/backend/access/heap/heapam.c
View File

@ -57,7 +57,6 @@
#include "access/xlogutils.h"
#include "catalog/catalog.h"
#include "catalog/namespace.h"
#include "catalog/index.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "port/atomics.h"
@ -76,9 +75,7 @@
#include "utils/snapmgr.h"
#include "utils/syscache.h"
#include "utils/tqual.h"
#include "utils/memutils.h"
#include "nodes/execnodes.h"
#include "executor/executor.h"
/* GUC variable */
bool synchronize_seqscans = true;
@ -130,7 +127,6 @@ static bool ConditionalMultiXactIdWait(MultiXactId multi, MultiXactStatus status
static XLogRecPtr log_heap_new_cid(Relation relation, HeapTuple tup);
static HeapTuple ExtractReplicaIdentity(Relation rel, HeapTuple tup, bool key_modified,
bool *copy);
static bool ProjIndexIsUnchanged(Relation relation, HeapTuple oldtup, HeapTuple newtup);
/*
@ -3511,7 +3507,6 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
HTSU_Result result;
TransactionId xid = GetCurrentTransactionId();
Bitmapset *hot_attrs;
Bitmapset *proj_idx_attrs;
Bitmapset *key_attrs;
Bitmapset *id_attrs;
Bitmapset *interesting_attrs;
@ -3575,11 +3570,12 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
* Note that we get copies of each bitmap, so we need not worry about
* relcache flush happening midway through.
*/
hot_attrs = RelationGetIndexAttrBitmap(relation, INDEX_ATTR_BITMAP_HOT);
proj_idx_attrs = RelationGetIndexAttrBitmap(relation, INDEX_ATTR_BITMAP_PROJ);
hot_attrs = RelationGetIndexAttrBitmap(relation, INDEX_ATTR_BITMAP_ALL);
key_attrs = RelationGetIndexAttrBitmap(relation, INDEX_ATTR_BITMAP_KEY);
id_attrs = RelationGetIndexAttrBitmap(relation,
INDEX_ATTR_BITMAP_IDENTITY_KEY);
block = ItemPointerGetBlockNumber(otid);
buffer = ReadBuffer(relation, block);
page = BufferGetPage(buffer);
@ -3599,7 +3595,6 @@ heap_update(Relation relation, ItemPointer otid, HeapTuple newtup,
if (!PageIsFull(page))
{
interesting_attrs = bms_add_members(interesting_attrs, hot_attrs);
interesting_attrs = bms_add_members(interesting_attrs, proj_idx_attrs);
hot_attrs_checked = true;
}
interesting_attrs = bms_add_members(interesting_attrs, key_attrs);
@ -3883,7 +3878,6 @@ l2:
if (vmbuffer != InvalidBuffer)
ReleaseBuffer(vmbuffer);
bms_free(hot_attrs);
bms_free(proj_idx_attrs);
bms_free(key_attrs);
bms_free(id_attrs);
bms_free(modified_attrs);
@ -4191,18 +4185,11 @@ l2:
/*
* Since the new tuple is going into the same page, we might be able
* to do a HOT update. Check if any of the index columns have been
* changed, or if we have projection functional indexes, check whether
* the old and the new values are the same. If the page was already
* full, we may have skipped checking for index columns. If so, HOT
* update is possible.
* changed. If the page was already full, we may have skipped checking
* for index columns. If so, HOT update is possible.
*/
if (hot_attrs_checked
&& !bms_overlap(modified_attrs, hot_attrs)
&& (!bms_overlap(modified_attrs, proj_idx_attrs)
|| ProjIndexIsUnchanged(relation, &oldtup, newtup)))
{
if (hot_attrs_checked && !bms_overlap(modified_attrs, hot_attrs))
use_hot_update = true;
}
}
else
{
@ -4364,7 +4351,6 @@ l2:
heap_freetuple(old_key_tuple);
bms_free(hot_attrs);
bms_free(proj_idx_attrs);
bms_free(key_attrs);
bms_free(id_attrs);
bms_free(modified_attrs);
@ -4450,87 +4436,6 @@ heap_tuple_attr_equals(TupleDesc tupdesc, int attrnum,
}
}
/*
* Check whether the value is unchanged after update of a projection
* functional index. Compare the new and old values of the indexed
* expression to see if we are able to use a HOT update or not.
*/
static bool
ProjIndexIsUnchanged(Relation relation, HeapTuple oldtup, HeapTuple newtup)
{
ListCell *l;
List *indexoidlist = RelationGetIndexList(relation);
EState *estate = CreateExecutorState();
ExprContext *econtext = GetPerTupleExprContext(estate);
TupleTableSlot *slot = MakeSingleTupleTableSlot(RelationGetDescr(relation),
&TTSOpsHeapTuple);
bool equals = true;
Datum old_values[INDEX_MAX_KEYS];
bool old_isnull[INDEX_MAX_KEYS];
Datum new_values[INDEX_MAX_KEYS];
bool new_isnull[INDEX_MAX_KEYS];
int indexno = 0;
econtext->ecxt_scantuple = slot;
foreach(l, indexoidlist)
{
if (bms_is_member(indexno, relation->rd_projidx))
{
Oid indexOid = lfirst_oid(l);
Relation indexDesc = index_open(indexOid, AccessShareLock);
IndexInfo *indexInfo = BuildIndexInfo(indexDesc);
int i;
ResetExprContext(econtext);
ExecStoreHeapTuple(oldtup, slot, false);
FormIndexDatum(indexInfo,
slot,
estate,
old_values,
old_isnull);
ExecStoreHeapTuple(newtup, slot, false);
FormIndexDatum(indexInfo,
slot,
estate,
new_values,
new_isnull);
for (i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
{
if (old_isnull[i] != new_isnull[i])
{
equals = false;
break;
}
else if (!old_isnull[i])
{
Form_pg_attribute att = TupleDescAttr(RelationGetDescr(indexDesc), i);
if (!datumIsEqual(old_values[i], new_values[i], att->attbyval, att->attlen))
{
equals = false;
break;
}
}
}
index_close(indexDesc, AccessShareLock);
if (!equals)
{
break;
}
}
indexno += 1;
}
ExecDropSingleTupleTableSlot(slot);
FreeExecutorState(estate);
return equals;
}
/*
* Check which columns are being updated.
*