From e2f65f42555ff531c6d7c8f151526b4ef7c016f8 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Sat, 7 May 2022 15:19:52 +1200 Subject: Fix old-fd issues using global barriers everywhere. Commits 4eb21763 and b74e94dc introduced a way to force every backend to close all relation files, to fix an ancient Windows-only bug. This commit extends that behavior to all operating systems and adds a couple of extra barrier points, to fix a totally different class of bug: the reuse of relfilenodes in scenarios that have no other kind of cache invalidation to prevent file descriptor mix-ups. In all releases, data corruption could occur when you moved a database to another tablespace and then back again. Despite that, no back-patch for now as the infrastructure required is too new and invasive. In master only, since commit aa010514, it could also happen when using CREATE DATABASE with a user-supplied OID or via pg_upgrade. Author: Andres Freund Reviewed-by: Robert Haas Reviewed-by: Thomas Munro Discussion: https://postgr.es/m/20220209220004.kb3dgtn2x2k2gtdm%40alap3.anarazel.de --- src/backend/commands/dbcommands.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'src/backend/commands/dbcommands.c') diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c index 9d0f83cde31..6da58437c58 100644 --- a/src/backend/commands/dbcommands.c +++ b/src/backend/commands/dbcommands.c @@ -1687,10 +1687,8 @@ dropdb(const char *dbname, bool missing_ok, bool force) */ RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT); -#if defined(USE_BARRIER_SMGRRELEASE) /* Close all smgr fds in all backends. */ WaitForProcSignalBarrier(EmitProcSignalBarrier(PROCSIGNAL_BARRIER_SMGRRELEASE)); -#endif /* * Remove all tablespace subdirs belonging to the database. @@ -1940,10 +1938,8 @@ movedb(const char *dbname, const char *tblspcname) RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT | CHECKPOINT_FLUSH_ALL); -#if defined(USE_BARRIER_SMGRRELEASE) /* Close all smgr fds in all backends. */ WaitForProcSignalBarrier(EmitProcSignalBarrier(PROCSIGNAL_BARRIER_SMGRRELEASE)); -#endif /* * Now drop all buffers holding data of the target database; they should @@ -3054,6 +3050,9 @@ dbase_redo(XLogReaderState *record) */ FlushDatabaseBuffers(xlrec->src_db_id); + /* Close all sgmr fds in all backends. */ + WaitForProcSignalBarrier(EmitProcSignalBarrier(PROCSIGNAL_BARRIER_SMGRRELEASE)); + /* * Copy this subdirectory to the new location * @@ -3111,10 +3110,8 @@ dbase_redo(XLogReaderState *record) /* Clean out the xlog relcache too */ XLogDropDatabase(xlrec->db_id); -#if defined(USE_BARRIER_SMGRRELEASE) /* Close all sgmr fds in all backends. */ WaitForProcSignalBarrier(EmitProcSignalBarrier(PROCSIGNAL_BARRIER_SMGRRELEASE)); -#endif for (i = 0; i < xlrec->ntablespaces; i++) { -- cgit v1.2.3