Fix incorrect code in new REINDEX CONCURRENTLY code

The previous code was adding pointers to transient variables to a
list, but by the time the list was read, the variable might be gone,
depending on the compiler.  Fix it by making copies in the proper
memory context.

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index c68d8d58167f159222c6870cd10118087044c100..ea07be69dbdf5fa15e7d4c215045d99c1cb0f67f 100644 (file)
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2813,7 +2813,7 @@ ReindexRelationConcurrently(Oid relationOid, int options)
                Relation        indexRel;
                Relation        heapRel;
                Relation        newIndexRel;
-               LockRelId       lockrelid;
+               LockRelId  *lockrelid;
 
                indexRel = index_open(indexId, ShareUpdateExclusiveLock);
                heapRel = table_open(indexRel->rd_index->indrelid,
@@ -2847,10 +2847,12 @@ ReindexRelationConcurrently(Oid relationOid, int options)
                 * avoid multiple locks taken on the same relation, instead we rely on
                 * parentRelationIds built earlier.
                 */
-               lockrelid = indexRel->rd_lockInfo.lockRelId;
-               relationLocks = lappend(relationLocks, &lockrelid);
-               lockrelid = newIndexRel->rd_lockInfo.lockRelId;
-               relationLocks = lappend(relationLocks, &lockrelid);
+               lockrelid = palloc(sizeof(*lockrelid));
+               *lockrelid = indexRel->rd_lockInfo.lockRelId;
+               relationLocks = lappend(relationLocks, lockrelid);
+               lockrelid = palloc(sizeof(*lockrelid));
+               *lockrelid = newIndexRel->rd_lockInfo.lockRelId;
+               relationLocks = lappend(relationLocks, lockrelid);
 
                MemoryContextSwitchTo(oldcontext);
 
@@ -2866,19 +2868,21 @@ ReindexRelationConcurrently(Oid relationOid, int options)
        foreach(lc, heapRelationIds)
        {
                Relation        heapRelation = table_open(lfirst_oid(lc), ShareUpdateExclusiveLock);
-               LockRelId       lockrelid = heapRelation->rd_lockInfo.lockRelId;
+               LockRelId  *lockrelid;
                LOCKTAG    *heaplocktag;
 
                /* Save the list of locks in private context */
                oldcontext = MemoryContextSwitchTo(private_context);
 
                /* Add lockrelid of heap relation to the list of locked relations */
-               relationLocks = lappend(relationLocks, &lockrelid);
+               lockrelid = palloc(sizeof(*lockrelid));
+               *lockrelid = heapRelation->rd_lockInfo.lockRelId;
+               relationLocks = lappend(relationLocks, lockrelid);
 
                heaplocktag = (LOCKTAG *) palloc(sizeof(LOCKTAG));
 
                /* Save the LOCKTAG for this parent relation for the wait phase */
-               SET_LOCKTAG_RELATION(*heaplocktag, lockrelid.dbId, lockrelid.relId);
+               SET_LOCKTAG_RELATION(*heaplocktag, lockrelid->dbId, lockrelid->relId);
                lockTags = lappend(lockTags, heaplocktag);
 
                MemoryContextSwitchTo(oldcontext);
@@ -2890,9 +2894,9 @@ ReindexRelationConcurrently(Oid relationOid, int options)
        /* Get a session-level lock on each table. */
        foreach(lc, relationLocks)
        {
-               LockRelId       lockRel = *((LockRelId *) lfirst(lc));
+               LockRelId   *lockrelid = (LockRelId *) lfirst(lc);
 
-               LockRelationIdForSession(&lockRel, ShareUpdateExclusiveLock);
+               LockRelationIdForSession(lockrelid, ShareUpdateExclusiveLock);
        }
 
        PopActiveSnapshot();
@@ -3127,9 +3131,9 @@ ReindexRelationConcurrently(Oid relationOid, int options)
         */
        foreach(lc, relationLocks)
        {
-               LockRelId       lockRel = *((LockRelId *) lfirst(lc));
+               LockRelId   *lockrelid = (LockRelId *) lfirst(lc);
 
-               UnlockRelationIdForSession(&lockRel, ShareUpdateExclusiveLock);
+               UnlockRelationIdForSession(lockrelid, ShareUpdateExclusiveLock);
        }
 
        /* Start a new transaction to finish process properly */