From 0b6517a3b79ae02fb95731d8b1dc70b10cf7b532 Mon Sep 17 00:00:00 2001 From: Noah Misch Date: Thu, 1 Feb 2024 13:44:19 -0800 Subject: [PATCH] Sync PG_VERSION file in CREATE DATABASE. An OS crash could leave PG_VERSION empty or missing. The same symptom appeared in a backup by block device snapshot, taken after the next checkpoint and before the OS flushes the PG_VERSION blocks. Device snapshots are not a documented backup method, however. Back-patch to v15, where commit 9c08aea6a3090a396be334cc58c511edab05776a introduced STRATEGY=WAL_LOG and made it the default. Discussion: https://postgr.es/m/20240130195003.0a.nmisch@google.com --- src/backend/commands/dbcommands.c | 8 ++++++++ src/backend/utils/activity/wait_event_names.txt | 1 + 2 files changed, 9 insertions(+) diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c index dc420acae9..41ed2d3bd9 100644 --- a/src/backend/commands/dbcommands.c +++ b/src/backend/commands/dbcommands.c @@ -508,6 +508,14 @@ CreateDirAndVersionFile(char *dbpath, Oid dbid, Oid tsid, bool isRedo) } pgstat_report_wait_end(); + pgstat_report_wait_start(WAIT_EVENT_VERSION_FILE_SYNC); + if (pg_fsync(fd) != 0) + ereport(data_sync_elevel(ERROR), + (errcode_for_file_access(), + errmsg("could not fsync file \"%s\": %m", versionfile))); + fsync_fname(dbpath, true); + pgstat_report_wait_end(); + /* Close the version file. */ CloseTransientFile(fd); diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt index cd22dca702..6464386b77 100644 --- a/src/backend/utils/activity/wait_event_names.txt +++ b/src/backend/utils/activity/wait_event_names.txt @@ -236,6 +236,7 @@ TIMELINE_HISTORY_WRITE "Waiting for a write of a newly created timeline history TWOPHASE_FILE_READ "Waiting for a read of a two phase state file." TWOPHASE_FILE_SYNC "Waiting for a two phase state file to reach durable storage." TWOPHASE_FILE_WRITE "Waiting for a write of a two phase state file." +VERSION_FILE_SYNC "Waiting for the version file to reach durable storage while creating a database." VERSION_FILE_WRITE "Waiting for the version file to be written while creating a database." WALSENDER_TIMELINE_HISTORY_READ "Waiting for a read from a timeline history file during a walsender timeline command." WAL_BOOTSTRAP_SYNC "Waiting for WAL to reach durable storage during bootstrapping."