From: Tom Lane Date: Mon, 1 Oct 2018 15:42:12 +0000 (-0400) Subject: Lock relation used to generate fresh data for RMV. X-Git-Tag: REL9_3_25~29 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=de0bea8d4d810c44c72d20ce7e0f51cc717c34ef;p=postgresql Lock relation used to generate fresh data for RMV. Back-patch the 9.4-era commit 2636ecf78 into 9.3, as that fixes a case where we open a relation while not holding any lock on it. It's probably mostly safe anyway, since no other session could touch the newly-created table; but I think CheckTableNotInUse could be fooled if one tried. Per testing with a patch that complains if we open a relation without holding any lock on it. I don't plan to back-patch that patch, but we should close the holes it identifies in all supported branches. Discussion: https://postgr.es/m/2038.1538335244@sss.pgh.pa.us --- diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c index f2edece89c..374325c3c0 100644 --- a/src/backend/commands/matview.c +++ b/src/backend/commands/matview.c @@ -26,6 +26,7 @@ #include "executor/executor.h" #include "miscadmin.h" #include "rewrite/rewriteHandler.h" +#include "storage/lmgr.h" #include "storage/smgr.h" #include "tcop/tcopprot.h" #include "utils/rel.h" @@ -208,8 +209,13 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString, tableSpace = matviewRel->rd_rel->reltablespace; - /* Create the transient table that will receive the regenerated data. */ + /* + * Create the transient table that will receive the regenerated data. Lock + * it against access by any other process until commit (by which time it + * will be gone). + */ OIDNewHeap = make_new_heap(matviewOid, tableSpace); + LockRelationOid(OIDNewHeap, AccessExclusiveLock); dest = CreateTransientRelDestReceiver(OIDNewHeap); /* Generate the data, if wanted. */