Обсуждение: fsync on 7.1
If I turn off fsync on 7.1 does that mean that the wal file is sync'd (according to WAL_SYNC_METHOD in the log file) and other files are not? Or does fsync apply to all file equally? -- Joseph Shraibman jks@selectacast.net Increase signal to noise ratio. http://www.targabot.com
Joseph Shraibman <jks@selectacast.net> writes:
> If I turn off fsync on 7.1 does that mean that the wal file is sync'd
> (according to WAL_SYNC_METHOD in the log file) and other files are not?
> Or does fsync apply to all file equally?
The latter. Note where the docs say:
The WAL_SYNC_METHOD parameter determines how Postgres will ask the
kernel to force WAL updates out to disk. All the options should be the
same as far as reliability goes, but it's quite platform-specific which
one will be the fastest. Note that this parameter is irrelevant if FSYNC
has been turned off.
regards, tom lane
Tom Lane wrote: > > Joseph Shraibman <jks@selectacast.net> writes: > > If I turn off fsync on 7.1 does that mean that the wal file is sync'd > > (according to WAL_SYNC_METHOD in the log file) and other files are not? > > Or does fsync apply to all file equally? > > The latter. Note where the docs say: > > The WAL_SYNC_METHOD parameter determines how Postgres will ask the > kernel to force WAL updates out to disk. All the options should be the > same as far as reliability goes, but it's quite platform-specific which > one will be the fastest. Note that this parameter is irrelevant if FSYNC > has been turned off. > > regards, tom lane Err... where is that? I'm looking at /usr/local/pgsql/doc/html/runtime-config.html#RUNTIME-CONFIG-WAL -- Joseph Shraibman jks@selectacast.net Increase signal to noise ratio. http://www.targabot.com