>From 1768680b672bcb037446230323cabcf9960f7f9a Mon Sep 17 00:00:00 2001 From: Abhijit Menon-Sen Date: Fri, 1 May 2015 17:59:51 +0530 Subject: Recursively fsync PGDATA on the next restart after fsync was disabled Even if we didn't crash, we want to fsync PGDATA on startup if we know the server ran with fsync=off at some point since the previous restart. Otherwise, starting the server with fsync=off for initial data loading and then restarting it opens you to data loss on a power failure after the restart. --- src/backend/access/transam/xlog.c | 9 +++++++-- src/bin/pg_controldata/pg_controldata.c | 2 ++ src/include/catalog/pg_control.h | 8 +++++++- 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 084174d..af12992 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -4823,6 +4823,7 @@ BootStrapXLOG(void) ControlFile->checkPoint = checkPoint.redo; ControlFile->checkPointCopy = checkPoint; ControlFile->unloggedLSN = 1; + ControlFile->fsync_disabled = false; /* Set important parameter values for use when replaying WAL */ ControlFile->MaxConnections = MaxConnections; @@ -5893,10 +5894,12 @@ StartupXLOG(void) */ if (enableFsync && - (ControlFile->state != DB_SHUTDOWNED && - ControlFile->state != DB_SHUTDOWNED_IN_RECOVERY)) + (ControlFile->fsync_disabled || + (ControlFile->state != DB_SHUTDOWNED && + ControlFile->state != DB_SHUTDOWNED_IN_RECOVERY))) { fsync_pgdata(data_directory); + ControlFile->fsync_disabled = false; } if (ControlFile->state == DB_SHUTDOWNED) @@ -8272,6 +8275,8 @@ CreateCheckPoint(int flags) /* crash recovery should always recover to the end of WAL */ ControlFile->minRecoveryPoint = InvalidXLogRecPtr; ControlFile->minRecoveryPointTLI = 0; + if (!enableFsync) + ControlFile->fsync_disabled = true; /* * Persist unloggedLSN value. It's reset on crash recovery, so this goes diff --git a/src/bin/pg_controldata/pg_controldata.c b/src/bin/pg_controldata/pg_controldata.c index d8cfe5e..e99014f 100644 --- a/src/bin/pg_controldata/pg_controldata.c +++ b/src/bin/pg_controldata/pg_controldata.c @@ -290,6 +290,8 @@ main(int argc, char *argv[]) (uint32) ControlFile.backupEndPoint); printf(_("End-of-backup record required: %s\n"), ControlFile.backupEndRequired ? _("yes") : _("no")); + printf(_("Fsync disabled at runtime: %s\n"), + ControlFile.fsync_disabled ? _("yes") : _("no")); printf(_("Current wal_level setting: %s\n"), wal_level_str(ControlFile.wal_level)); printf(_("Current wal_log_hints setting: %s\n"), diff --git a/src/include/catalog/pg_control.h b/src/include/catalog/pg_control.h index 2e4c381..a71d73e 100644 --- a/src/include/catalog/pg_control.h +++ b/src/include/catalog/pg_control.h @@ -21,7 +21,7 @@ /* Version identifier for this pg_control format */ -#define PG_CONTROL_VERSION 942 +#define PG_CONTROL_VERSION 943 /* * Body of CheckPoint XLOG records. This is declared here because we keep @@ -182,6 +182,12 @@ typedef struct ControlFileData bool track_commit_timestamp; /* + * Indicates whether fsync was ever disabled since the last restart. + * Tested and set at checkpoints, reset at startup. + */ + bool fsync_disabled; + + /* * This data is used to check for hardware-architecture compatibility of * the database and the backend executable. We need not check endianness * explicitly, since the pg_control version will surely look wrong to a -- 1.9.1