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Revert "Prevent incorrect updates of pg_index while reindexing pg_index itself."

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This reverts commit 8835284e0d903156632f76eea941cf5c592717ec of 2011-04-15.
There's a better way to do it, which will follow shortly.
This commit is contained in:
Tom Lane 2011-04-19 16:58:53 -04:00
parent 8835284e0d
commit 1f0ad40656
1 changed files with 21 additions and 48 deletions
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69
src/backend/catalog/index.c
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@ -1423,13 +1423,6 @@ index_build(Relation heapRelation,
HeapTuple indexTuple;
Form_pg_index indexForm;
/*
* Broken HOT chains should not get reported in system catalogs; in
* particular it would be quite dangerous to try to modify the index's
* pg_index entry if we are reindexing pg_index itself.
*/
Assert(!IsSystemRelation(heapRelation));
pg_index = heap_open(IndexRelationId, RowExclusiveLock);
indexTuple = SearchSysCacheCopy(INDEXRELID,
@ -1489,13 +1482,7 @@ index_build(Relation heapRelation,
* A side effect is to set indexInfo->ii_BrokenHotChain to true if we detect
* any potentially broken HOT chains. Currently, we set this if there are
* any RECENTLY_DEAD entries in a HOT chain, without trying very hard to
* detect whether they're really incompatible with the chain tip. However,
* we do not ever set ii_BrokenHotChain true when the relation is a system
* catalog. This is to avoid problematic behavior when reindexing pg_index
* itself: we can't safely change the index's indcheckxmin field when we're
* partway through such an operation. It should be okay since the set of
* indexes on a system catalog ought not change during concurrent operations,
* so that no HOT chain in it could ever become broken.
* detect whether they're really incompatible with the chain tip.
*/
double
IndexBuildHeapScan(Relation heapRelation,
@ -1505,7 +1492,6 @@ IndexBuildHeapScan(Relation heapRelation,
IndexBuildCallback callback,
void *callback_state)
{
bool is_system_catalog;
HeapScanDesc scan;
HeapTuple heapTuple;
Datum values[INDEX_MAX_KEYS];
@ -1525,9 +1511,6 @@ IndexBuildHeapScan(Relation heapRelation,
*/
Assert(OidIsValid(indexRelation->rd_rel->relam));
/* Remember if it's a system catalog */
is_system_catalog = IsSystemRelation(heapRelation);
/*
* Need an EState for evaluation of index expressions and partial-index
* predicates. Also a slot to hold the current tuple.
@ -1666,8 +1649,7 @@ IndexBuildHeapScan(Relation heapRelation,
{
indexIt = false;
/* mark the index as unsafe for old snapshots */
if (!is_system_catalog)
indexInfo->ii_BrokenHotChain = true;
indexInfo->ii_BrokenHotChain = true;
}
else if (indexInfo->ii_BrokenHotChain)
indexIt = false;
@ -1756,8 +1738,7 @@ IndexBuildHeapScan(Relation heapRelation,
{
indexIt = false;
/* mark the index as unsafe for old snapshots */
if (!is_system_catalog)
indexInfo->ii_BrokenHotChain = true;
indexInfo->ii_BrokenHotChain = true;
}
else if (indexInfo->ii_BrokenHotChain)
indexIt = false;
@ -2371,35 +2352,27 @@ reindex_index(Oid indexId)
* We can also reset indcheckxmin, because we have now done a
* non-concurrent index build, *except* in the case where index_build
* found some still-broken HOT chains.
*
* When reindexing a system catalog, don't do any of this --- it would be
* particularly risky to try to modify pg_index while we are reindexing
* pg_index itself. We don't support CREATE INDEX CONCURRENTLY on system
* catalogs anyway, and they should never have indcheckxmin set either.
*/
if (!IsSystemRelation(heapRelation))
pg_index = heap_open(IndexRelationId, RowExclusiveLock);
indexTuple = SearchSysCacheCopy(INDEXRELID,
ObjectIdGetDatum(indexId),
0, 0, 0);
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexId);
indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
if (!indexForm->indisvalid || !indexForm->indisready ||
(indexForm->indcheckxmin && !indexInfo->ii_BrokenHotChain))
{
pg_index = heap_open(IndexRelationId, RowExclusiveLock);
indexTuple = SearchSysCacheCopy(INDEXRELID,
ObjectIdGetDatum(indexId),
0, 0, 0);
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexId);
indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
if (!indexForm->indisvalid || !indexForm->indisready ||
(indexForm->indcheckxmin && !indexInfo->ii_BrokenHotChain))
{
indexForm->indisvalid = true;
indexForm->indisready = true;
if (!indexInfo->ii_BrokenHotChain)
indexForm->indcheckxmin = false;
simple_heap_update(pg_index, &indexTuple->t_self, indexTuple);
CatalogUpdateIndexes(pg_index, indexTuple);
}
heap_close(pg_index, RowExclusiveLock);
indexForm->indisvalid = true;
indexForm->indisready = true;
if (!indexInfo->ii_BrokenHotChain)
indexForm->indcheckxmin = false;
simple_heap_update(pg_index, &indexTuple->t_self, indexTuple);
CatalogUpdateIndexes(pg_index, indexTuple);
}
heap_close(pg_index, RowExclusiveLock);
/* Close rels, but keep locks */
index_close(iRel, NoLock);