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Fix assorted bugs in CREATE INDEX CONCURRENTLY.

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This patch changes CREATE INDEX CONCURRENTLY so that the pg_index
flag changes it makes without exclusive lock on the index are made via
heap_inplace_update() rather than a normal transactional update.  The
latter is not very safe because moving the pg_index tuple could result in
concurrent SnapshotNow scans finding it twice or not at all, thus possibly
resulting in index corruption.

In addition, fix various places in the code that ought to check to make
sure that the indexes they are manipulating are valid and/or ready as
appropriate.  These represent bugs that have existed since 8.2, since
a failed CREATE INDEX CONCURRENTLY could leave a corrupt or invalid
index behind, and we ought not try to do anything that might fail with
such an index.

Also fix RelationReloadIndexInfo to ensure it copies all the pg_index
columns that are allowed to change after initial creation.  Previously we
could have been left with stale values of some fields in an index relcache
entry.  It's not clear whether this actually had any user-visible
consequences, but it's at least a bug waiting to happen.

This is a subset of a patch already applied in 9.2 and HEAD.  Back-patch
into all earlier supported branches.

Tom Lane and Andres Freund
This commit is contained in:
Tom Lane
2012-11-29 14:50:39 -05:00
parent 3dfdf28152
commit 1dbd02dc37
11 changed files with 206 additions and 75 deletions
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41
src/backend/commands/indexcmds.c
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@ -147,9 +147,6 @@ DefineIndex(RangeVar *heapRelation,
LockRelId heaprelid;
LOCKTAG heaplocktag;
Snapshot snapshot;
Relation pg_index;
HeapTuple indexTuple;
Form_pg_index indexForm;
int i;
/*
@ -595,23 +592,7 @@ DefineIndex(RangeVar *heapRelation,
* commit this transaction, any new transactions that open the table must
* insert new entries into the index for insertions and non-HOT updates.
*/
pg_index = heap_open(IndexRelationId, RowExclusiveLock);
indexTuple = SearchSysCacheCopy1(INDEXRELID,
ObjectIdGetDatum(indexRelationId));
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexRelationId);
indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
Assert(!indexForm->indisready);
Assert(!indexForm->indisvalid);
indexForm->indisready = true;
simple_heap_update(pg_index, &indexTuple->t_self, indexTuple);
CatalogUpdateIndexes(pg_index, indexTuple);
heap_close(pg_index, RowExclusiveLock);
index_set_state_flags(indexRelationId, INDEX_CREATE_SET_READY);
/* we can do away with our snapshot */
PopActiveSnapshot();
@ -735,23 +716,7 @@ DefineIndex(RangeVar *heapRelation,
/*
* Index can now be marked valid -- update its pg_index entry
*/
pg_index = heap_open(IndexRelationId, RowExclusiveLock);
indexTuple = SearchSysCacheCopy1(INDEXRELID,
ObjectIdGetDatum(indexRelationId));
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexRelationId);
indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
Assert(indexForm->indisready);
Assert(!indexForm->indisvalid);
indexForm->indisvalid = true;
simple_heap_update(pg_index, &indexTuple->t_self, indexTuple);
CatalogUpdateIndexes(pg_index, indexTuple);
heap_close(pg_index, RowExclusiveLock);
index_set_state_flags(indexRelationId, INDEX_CREATE_SET_VALID);
/*
* The pg_index update will cause backends (including this one) to update
@ -759,7 +724,7 @@ DefineIndex(RangeVar *heapRelation,
* relcache inval on the parent table to force replanning of cached plans.
* Otherwise existing sessions might fail to use the new index where it
* would be useful. (Note that our earlier commits did not create reasons
* to replan; relcache flush on the index itself was sufficient.)
* to replan; so relcache flush on the index itself was sufficient.)
*/
CacheInvalidateRelcacheByRelid(heaprelid.relId);