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Change currtid functions to use an MVCC snapshot, not SnapshotNow.
This has a slight performance cost, but the only known consumers of these functions, known at the SQL level as currtid and currtid2, is pgsql-odbc; whose usage, we hope, is not sufficiently intensive to make this a problem. Per discussion.
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@ -30,6 +30,7 @@
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#include "utils/acl.h"
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#include "utils/builtins.h"
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#include "utils/rel.h"
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#include "utils/snapmgr.h"
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#include "utils/tqual.h"
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@ -332,6 +333,7 @@ currtid_byreloid(PG_FUNCTION_ARGS)
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ItemPointer result;
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Relation rel;
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AclResult aclresult;
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Snapshot snapshot;
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result = (ItemPointer) palloc(sizeof(ItemPointerData));
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if (!reloid)
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@ -352,7 +354,10 @@ currtid_byreloid(PG_FUNCTION_ARGS)
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return currtid_for_view(rel, tid);
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ItemPointerCopy(tid, result);
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heap_get_latest_tid(rel, SnapshotNow, result);
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snapshot = RegisterSnapshot(GetLatestSnapshot());
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heap_get_latest_tid(rel, snapshot, result);
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UnregisterSnapshot(snapshot);
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heap_close(rel, AccessShareLock);
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@ -368,6 +373,7 @@ currtid_byrelname(PG_FUNCTION_ARGS)
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RangeVar *relrv;
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Relation rel;
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AclResult aclresult;
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Snapshot snapshot;
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relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
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rel = heap_openrv(relrv, AccessShareLock);
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@ -384,7 +390,9 @@ currtid_byrelname(PG_FUNCTION_ARGS)
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result = (ItemPointer) palloc(sizeof(ItemPointerData));
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ItemPointerCopy(tid, result);
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heap_get_latest_tid(rel, SnapshotNow, result);
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snapshot = RegisterSnapshot(GetLatestSnapshot());
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heap_get_latest_tid(rel, snapshot, result);
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UnregisterSnapshot(snapshot);
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heap_close(rel, AccessShareLock);
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