From fa5dd460c1805a00a6fcc909b7e1f826663bcce3 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Wed, 22 Feb 2023 10:14:56 +0900 Subject: Fix corruption of templates after CREATE DATABASE .. STRATEGY WAL_LOG WAL_LOG does a scan of the template's pg_class to determine the set of relations that need to be copied from a template database to the new one. However, as coded in 9c08aea, this copy strategy would load the pages of pg_class without considering it as a permanent relation, causing the loaded pages to never be flushed when they should. Any modification of the template's pg_class, mostly through DDLs, would then be missed, causing corruptions. STRATEGY = WAL_LOG is the default over FILE_COPY since it has been introduced, so any changes done to pg_class on a database template would be gone. Updates of database templates should be a rare thing, so the impact of this bug should be hopefully limited. The pre-14 default strategy FILE_COPY is safe, and can be used as a workaround. Ryo Matsumura has found and analyzed the issue, and Nathan has written a test able to reproduce the failure (with few tweaks from me). Backpatch down to 15, where STRATEGY = WAL_LOG has been introduced. Author: Nathan Bossart, Ryo Matsumura Reviewed-by: Dilip Kumar, Michael Paquier Discussion: https://postgr.es/m/TYCPR01MB6868677E499C9AD5123084B5E8A39@TYCPR01MB6868.jpnprd01.prod.outlook.com Backpatch-through: 15 --- src/backend/commands/dbcommands.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/backend/commands/dbcommands.c') diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c index 5f342478296..ef737356f27 100644 --- a/src/backend/commands/dbcommands.c +++ b/src/backend/commands/dbcommands.c @@ -296,7 +296,7 @@ ScanSourceDatabasePgClass(Oid tbid, Oid dbid, char *srcpath) CHECK_FOR_INTERRUPTS(); buf = ReadBufferWithoutRelcache(rnode, MAIN_FORKNUM, blkno, - RBM_NORMAL, bstrategy, false); + RBM_NORMAL, bstrategy, true); LockBuffer(buf, BUFFER_LOCK_SHARE); page = BufferGetPage(buf); -- cgit v1.2.3