/*
* This is a copy of swap_relation_files in cluster.c, but it also swaps
* relfrozenxid.
*/
static void
swap_heap_or_index_files(Oid r1, Oid r2)
{
Relation relRelation;
HeapTuple reltup1,
reltup2;
Form_pg_class relform1,
relform2;
Oid swaptemp;
CatalogIndexState indstate;
/* We need writable copies of both pg_class tuples. */
relRelation = heap_open(RelationRelationId, RowExclusiveLock);
reltup1 = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(r1),
0, 0, 0);
if (!HeapTupleIsValid(reltup1))
elog(ERROR, "cache lookup failed for relation %u", r1);
relform1 = (Form_pg_class) GETSTRUCT(reltup1);
reltup2 = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(r2),
0, 0, 0);
if (!HeapTupleIsValid(reltup2))
elog(ERROR, "cache lookup failed for relation %u", r2);
relform2 = (Form_pg_class) GETSTRUCT(reltup2);
Assert(relform1->relkind == relform2->relkind);
/*
* Actually swap the fields in the two tuples
*/
swaptemp = relform1->relfilenode;
relform1->relfilenode = relform2->relfilenode;
relform2->relfilenode = swaptemp;
swaptemp = relform1->reltablespace;
relform1->reltablespace = relform2->reltablespace;
relform2->reltablespace = swaptemp;
swaptemp = relform1->reltoastrelid;
relform1->reltoastrelid = relform2->reltoastrelid;
relform2->reltoastrelid = swaptemp;
/* set rel1's frozen Xid to larger one */
if (TransactionIdIsNormal(relform1->relfrozenxid))
{
if (TransactionIdFollows(relform1->relfrozenxid,
relform2->relfrozenxid))
relform1->relfrozenxid = relform2->relfrozenxid;
else
relform2->relfrozenxid = relform1->relfrozenxid;
}
/* swap size statistics too, since new rel has freshly-updated stats */
{
#if PG_VERSION_NUM >= 90300
int32 swap_pages;
#else
int4 swap_pages;
#endif
float4 swap_tuples;
swap_pages = relform1->relpages;
relform1->relpages = relform2->relpages;
relform2->relpages = swap_pages;
swap_tuples = relform1->reltuples;
relform1->reltuples = relform2->reltuples;
relform2->reltuples = swap_tuples;
}
/* Update the tuples in pg_class */
simple_heap_update(relRelation, &reltup1->t_self, reltup1);
simple_heap_update(relRelation, &reltup2->t_self, reltup2);
/* Keep system catalogs current */
indstate = CatalogOpenIndexes(relRelation);
CatalogIndexInsert(indstate, reltup1);
CatalogIndexInsert(indstate, reltup2);
CatalogCloseIndexes(indstate);
/*
* If we have toast tables associated with the relations being swapped,
* change their dependency links to re-associate them with their new
* owning relations. Otherwise the wrong one will get dropped ...
*
* NOTE: it is possible that only one table has a toast table; this can
* happen in CLUSTER if there were dropped columns in the old table, and
* in ALTER TABLE when adding or changing type of columns.
*
* NOTE: at present, a TOAST table's only dependency is the one on its
* owning table. If more are ever created, we'd need to use something
* more selective than deleteDependencyRecordsFor() to get rid of only the
* link we want.
*/
if (relform1->reltoastrelid || relform2->reltoastrelid)
{
ObjectAddress baseobject,
toastobject;
long count;
/* Delete old dependencies */
if (relform1->reltoastrelid)
{
count = deleteDependencyRecordsFor(RelationRelationId,
relform1->reltoastrelid,
false);
if (count != 1)
elog(ERROR, "expected one dependency record for TOAST table, found %ld",
count);
}
if (relform2->reltoastrelid)
{
count = deleteDependencyRecordsFor(RelationRelationId,
relform2->reltoastrelid,
false);
if (count != 1)
elog(ERROR, "expected one dependency record for TOAST table, found %ld",
count);
}
/* Register new dependencies */
baseobject.classId = RelationRelationId;
baseobject.objectSubId = 0;
toastobject.classId = RelationRelationId;
toastobject.objectSubId = 0;
if (relform1->reltoastrelid)
{
baseobject.objectId = r1;
toastobject.objectId = relform1->reltoastrelid;
recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);
}
if (relform2->reltoastrelid)
{
baseobject.objectId = r2;
toastobject.objectId = relform2->reltoastrelid;
recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);
}
}
/*
* Blow away the old relcache entries now. We need this kluge because
* relcache.c keeps a link to the smgr relation for the physical file, and
* that will be out of date as soon as we do CommandCounterIncrement.
* Whichever of the rels is the second to be cleared during cache
* invalidation will have a dangling reference to an already-deleted smgr
* relation. Rather than trying to avoid this by ordering operations just
* so, it's easiest to not have the relcache entries there at all.
* (Fortunately, since one of the entries is local in our transaction,
* it's sufficient to clear out our own relcache this way; the problem
* cannot arise for other backends when they see our update on the
* non-local relation.)
*/
RelationForgetRelation(r1);
RelationForgetRelation(r2);
/* Clean up. */
heap_freetuple(reltup1);
heap_freetuple(reltup2);
heap_close(relRelation, RowExclusiveLock);
}
/*
* index_drop
*
* NOTE: this routine should now only be called through performDeletion(),
* else associated dependencies won't be cleaned up.
*/
void
index_drop(Oid indexId)
{
Oid heapId;
Relation userHeapRelation;
Relation userIndexRelation;
Relation indexRelation;
HeapTuple tuple;
int i;
Assert(OidIsValid(indexId));
/*
* To drop an index safely, we must grab exclusive lock on its parent
* table; otherwise there could be other backends using the index!
* Exclusive lock on the index alone is insufficient because another
* backend might be in the midst of devising a query plan that will
* use the index. The parser and planner take care to hold an
* appropriate lock on the parent table while working, but having them
* hold locks on all the indexes too seems overly complex. We do grab
* exclusive lock on the index too, just to be safe. Both locks must
* be held till end of transaction, else other backends will still see
* this index in pg_index.
*/
heapId = IndexGetRelation(indexId);
userHeapRelation = heap_open(heapId, AccessExclusiveLock);
userIndexRelation = index_open(indexId);
LockRelation(userIndexRelation, AccessExclusiveLock);
/*
* fix RELATION relation
*/
DeleteRelationTuple(indexId);
/*
* fix ATTRIBUTE relation
*/
DeleteAttributeTuples(indexId);
/*
* fix INDEX relation
*/
indexRelation = heap_openr(IndexRelationName, RowExclusiveLock);
tuple = SearchSysCache(INDEXRELID,
ObjectIdGetDatum(indexId),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for index %u", indexId);
simple_heap_delete(indexRelation, &tuple->t_self);
ReleaseSysCache(tuple);
heap_close(indexRelation, RowExclusiveLock);
/*
* flush buffer cache and physically remove the file
*/
i = FlushRelationBuffers(userIndexRelation, (BlockNumber) 0);
if (i < 0)
elog(ERROR, "FlushRelationBuffers returned %d", i);
smgrunlink(DEFAULT_SMGR, userIndexRelation);
/*
* We are presently too lazy to attempt to compute the new correct
* value of relhasindex (the next VACUUM will fix it if necessary). So
* there is no need to update the pg_class tuple for the owning
* relation. But we must send out a shared-cache-inval notice on the
* owning relation to ensure other backends update their relcache
* lists of indexes.
*/
CacheInvalidateRelcache(heapId);
/*
* Close rels, but keep locks
*/
index_close(userIndexRelation);
heap_close(userHeapRelation, NoLock);
RelationForgetRelation(indexId);
}
