#ifdef CATCACHE_STATS
#include "storage/ipc.h" /* for on_proc_exit */
#endif
+#include "storage/lmgr.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
{
Relation idesc;
+ /*
+ * We must lock the underlying catalog before opening the index to
+ * avoid deadlock, since index_open could possibly result in reading
+ * this same catalog, and if anyone else is exclusive-locking this
+ * catalog and index they'll be doing it in that order.
+ */
+ LockRelationOid(cache->cc_reloid, AccessShareLock);
idesc = index_open(cache->cc_indexoid, AccessShareLock);
index_close(idesc, AccessShareLock);
+ UnlockRelationOid(cache->cc_reloid, AccessShareLock);
}
}
* We assume that at the time we are called, we have at least AccessShareLock
* on the target index. (Note: in the calls from RelationClearRelation,
* this is legitimate because we know the rel has positive refcount.)
+ *
+ * If the target index is an index on pg_class or pg_index, we'd better have
+ * previously gotten at least AccessShareLock on its underlying catalog,
+ * else we are at risk of deadlock against someone trying to exclusive-lock
+ * the heap and index in that order. This is ensured in current usage by
+ * only applying this to indexes being opened or having positive refcount.
*/
static void
RelationReloadIndexInfo(Relation relation)
* Attribute numbers are offset by FirstLowInvalidHeapAttributeNumber so that
* we can include system attributes (e.g., OID) in the bitmap representation.
*
+ * Caller had better hold at least RowExclusiveLock on the target relation
+ * to ensure that it has a stable set of indexes. This also makes it safe
+ * (deadlock-free) for us to take locks on the relation's indexes.
+ *
* The returned result is palloc'd in the caller's memory context and should
* be bms_free'd when not needed anymore.
*/