From 8fb13dd6ab5bffdbfafd8894ffcc5deb44d0c0b0 Mon Sep 17 00:00:00 2001 From: Nathan Bossart Date: Mon, 16 Oct 2023 12:41:55 -0500 Subject: [PATCH] Move extra code out of the Pre/PostRestoreCommand() section. If SIGTERM is received within this section, the startup process will immediately proc_exit() in the signal handler, so it is inadvisable to include any more code than is required there (as such code is unlikely to be compatible with doing proc_exit() in a signal handler). This commit moves the code recently added to this section (see 1b06d7bac9 and 7fed801135) to outside of the section. This ensures that the startup process only calls proc_exit() in its SIGTERM handler for the duration of the system() call, which is how this code worked from v8.4 to v14. Reported-by: Michael Paquier, Thomas Munro Analyzed-by: Andres Freund Suggested-by: Tom Lane Reviewed-by: Michael Paquier, Robert Haas, Thomas Munro, Andres Freund Discussion: https://postgr.es/m/Y9nGDSgIm83FHcad%40paquier.xyz Discussion: https://postgr.es/m/20230223231503.GA743455%40nathanxps13 Backpatch-through: 15 --- src/backend/access/transam/xlogarchive.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.c index f3fb92c8f9..524e80adb1 100644 --- a/src/backend/access/transam/xlogarchive.c +++ b/src/backend/access/transam/xlogarchive.c @@ -159,20 +159,27 @@ RestoreArchivedFile(char *path, const char *xlogfname, (errmsg_internal("executing restore command \"%s\"", xlogRestoreCmd))); + fflush(NULL); + pgstat_report_wait_start(WAIT_EVENT_RESTORE_COMMAND); + /* - * Check signals before restore command and reset afterwards. + * PreRestoreCommand() informs the SIGTERM handler for the startup process + * that it should proc_exit() right away. This is done for the duration + * of the system() call because there isn't a good way to break out while + * it is executing. Since we might call proc_exit() in a signal handler, + * it is best to put any additional logic before or after the + * PreRestoreCommand()/PostRestoreCommand() section. */ PreRestoreCommand(); /* * Copy xlog from archival storage to XLOGDIR */ - fflush(NULL); - pgstat_report_wait_start(WAIT_EVENT_RESTORE_COMMAND); rc = system(xlogRestoreCmd); - pgstat_report_wait_end(); PostRestoreCommand(); + + pgstat_report_wait_end(); pfree(xlogRestoreCmd); if (rc == 0)