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Commit5ac5980

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More cleanup after failed reduced-lock-levels-for-DDL feature.
Turns out that use of ShareUpdateExclusiveLock or ShareRowExclusiveLockto protect DDL changes had gotten copied into several places that werenot touched by either of Simon's original patches for the feature, andthus neither he nor I thought to revert them. (Indeed, it appears thattwo of these uses were committed *after* the reversion, which just goesto show that git merging is no panacea.) Change these places to useAccessExclusiveLock again. If we ever manage to resurrect that feature,we're going to have to think a bit harder about how to keep lock levelusage in sync for DDL operations that aren't within the AlterTableinfrastructure.Two of these bugs are only in HEAD, but one is in the 9.1 branch too.Alvaro found one of them, I found the other two.
1 parentc8e8b5a commit5ac5980

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3 files changed

+9
-7
lines changed

3 files changed

+9
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lines changed

‎src/backend/catalog/toasting.c

Lines changed: 6 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -58,11 +58,13 @@ AlterTableCreateToastTable(Oid relOid, Datum reloptions)
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Relationrel;
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/*
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* Grab a DDL-exclusive lock on the target table, since we'll update the
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* pg_class tuple.This is redundant for all present users. Tuple
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* toasting behaves safely in the face of a concurrent TOAST table add.
61+
* Grab an exclusive lock on the target table, since we'll update its
62+
* pg_class tuple. This is redundant for all present uses, since caller
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* will have such a lock already. But the lock is needed to ensure that
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* concurrent readers of the pg_class tuple won't have visibility issues,
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* so let's be safe.
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*/
65-
rel=heap_open(relOid,ShareUpdateExclusiveLock);
67+
rel=heap_open(relOid,AccessExclusiveLock);
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/* create_toast_table does all the work */
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(void)create_toast_table(rel,InvalidOid,InvalidOid,reloptions);

‎src/backend/commands/trigger.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1038,7 +1038,7 @@ DropTrigger(RangeVar *relation, const char *trigname, DropBehavior behavior,
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ObjectAddressobject;
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/* lock level should match RemoveTriggerById */
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relid=RangeVarGetRelid(relation,ShareRowExclusiveLock, false, false);
1041+
relid=RangeVarGetRelid(relation,AccessExclusiveLock, false, false);
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object.classId=TriggerRelationId;
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object.objectId=get_trigger_oid(relid,trigname,missing_ok);

‎src/backend/rewrite/rewriteRemove.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -45,8 +45,8 @@ RemoveRewriteRule(RangeVar *relation, const char *ruleName,
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OidowningRel;
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ObjectAddressobject;
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48-
/* should match RemoveRewriteRuleById */
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owningRel=RangeVarGetRelid(relation,ShareUpdateExclusiveLock,
48+
/*lock levelshould match RemoveRewriteRuleById */
49+
owningRel=RangeVarGetRelid(relation,AccessExclusiveLock,
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false, false);
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/*

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