From a27f3a7f4159c5afaf33932df16ca4fed6689c06 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Mon, 15 Feb 2021 15:43:39 +1300 Subject: [PATCH] Default to wal_sync_method=fdatasync on FreeBSD. FreeBSD 13 gained O_DSYNC, which would normally cause wal_sync_method to choose open_datasync as its default value. That may not be a good choice for all systems, and performs worse than fdatasync in some scenarios. Let's preserve the existing default behavior for now. Like commit 576477e73c4, which did the same for Linux, back-patch to all supported releases. Discussion: https://postgr.es/m/CA%2BhUKGLsAMXBQrCxCXoW-JsUYmdOL8ALYvaX%3DCrHqWxm-nWbGA%40mail.gmail.com --- doc/src/sgml/config.sgml | 2 +- src/backend/utils/misc/postgresql.conf.sample | 2 +- src/include/port/freebsd.h | 9 +++++++++ 3 files changed, 11 insertions(+), 2 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index eaa7c26981..ffe9f2d287 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -2772,7 +2772,7 @@ include_dir 'conf.d' Not all of these choices are available on all platforms. The default is the first method in the above list that is supported by the platform, except that fdatasync is the default on - Linux. The default is not necessarily ideal; it might be + Linux and FreeBSD. The default is not necessarily ideal; it might be necessary to change this setting or other aspects of your system configuration in order to create a crash-safe configuration or achieve optimal performance. diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 451dfca14f..c7571ce0f6 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -200,7 +200,7 @@ #wal_sync_method = fsync # the default is the first option # supported by the operating system: # open_datasync - # fdatasync (default on Linux) + # fdatasync (default on Linux and FreeBSD) # fsync # fsync_writethrough # open_sync diff --git a/src/include/port/freebsd.h b/src/include/port/freebsd.h index 2e36d3da4f..2e2e749a6b 100644 --- a/src/include/port/freebsd.h +++ b/src/include/port/freebsd.h @@ -1 +1,10 @@ /* src/include/port/freebsd.h */ + +/* + * Set the default wal_sync_method to fdatasync. xlogdefs.h's normal rules + * would prefer open_datasync on FreeBSD 13+, but that is not a good choice on + * many systems. + */ +#ifdef HAVE_FDATASYNC +#define PLATFORM_DEFAULT_SYNC_METHOD SYNC_METHOD_FDATASYNC +#endif