postgres.git / summary / log / commit / refs

commit    de0bea8d4d810c44c72d20ce7e0f51cc717c34ef
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Mon Oct 01 15:42:12 2018 +0000
First released in: 9.3.25

    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


 src/backend/commands/matview.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index f2edece89cd..374325c3c02 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. */


[parent: 00d00b5b0d12]