Kevin Grittner wrote: > Simon Riggs wrote: >> On 6 October 2012 00:56, Tom Lane <t...@sss.pgh.pa.us> wrote: > >>> 2. DROP INDEX CONCURRENTLY doesn't bother to do >>> TransferPredicateLocksToHeapRelation until long after it's >>> invalidated the index. Surely that's no good? Is it even possible >>> to do that correctly, when we don't have a lock that will prevent >>> new predicate locks from being taken out meanwhile? >> >> No idea there. Input appreciated. > If the creation of a new tuple by insert or update would not > perform the related index tuple insertion, and the lock has not yet > been transfered to the heap relation, yes we have a problem. Will > take a look at the code. > > Creation of new predicate locks while in this state has no bearing > on the issue as long as locks are transferred to the heap relation > after the last scan using the index has completed. To put that another way, it should be done at a time when it is sure that no query sees indisvalid = true and no query has yet seen indisready = false. Patch attached. Will apply if nobody sees a problem with it.
-Kevin
*** a/src/backend/catalog/index.c --- b/src/backend/catalog/index.c *************** *** 1316,1321 **** index_drop(Oid indexId, bool concurrent) --- 1316,1326 ---- * table lock strong enough to prevent all queries on the table from * proceeding until we commit and send out a shared-cache-inval notice * that will make them update their index lists. + * + * All predicate locks on the index are about to be made invalid. Promote + * them to relation locks on the heap. For correctness this must be done + * after the index was last seen with indisready = true and before it is + * seen with indisvalid = false. */ heapId = IndexGetRelation(indexId, false); if (concurrent) *************** *** 1349,1354 **** index_drop(Oid indexId, bool concurrent) --- 1354,1361 ---- */ indexRelation = heap_open(IndexRelationId, RowExclusiveLock); + TransferPredicateLocksToHeapRelation(userIndexRelation); + tuple = SearchSysCacheCopy1(INDEXRELID, ObjectIdGetDatum(indexId)); if (!HeapTupleIsValid(tuple)) *************** *** 1438,1449 **** index_drop(Oid indexId, bool concurrent) userHeapRelation = heap_open(heapId, ShareUpdateExclusiveLock); userIndexRelation = index_open(indexId, AccessExclusiveLock); } ! ! /* ! * All predicate locks on the index are about to be made invalid. Promote ! * them to relation locks on the heap. ! */ ! TransferPredicateLocksToHeapRelation(userIndexRelation); /* * Schedule physical removal of the files --- 1445,1452 ---- userHeapRelation = heap_open(heapId, ShareUpdateExclusiveLock); userIndexRelation = index_open(indexId, AccessExclusiveLock); } ! else ! TransferPredicateLocksToHeapRelation(userIndexRelation); /* * Schedule physical removal of the files
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