Re: What is WAL used for?
От | Cott Lang |
---|---|
Тема | Re: What is WAL used for? |
Дата | |
Msg-id | 1070727587.4679.23.camel@blackbox обсуждение исходный текст |
Ответ на | Re: What is WAL used for? (Thierry Missimilly <THIERRY.MISSIMILLY@BULL.NET>) |
Список | pgsql-general |
On Fri, 2003-12-05 at 02:40, Thierry Missimilly wrote: > With the data=writeback mode, I increase the TPS by 18% and dicrease the wait > I/O from 54% to 30%. > I did not change my filesystem to ext2 as I have to have to cancel the partition > and recreate all the database. Futhermore, i have understood that journaled > filesystem allowed better and faster fsck after a Power off crash and it is not > redundant with the WAL Crash recovery. > I think that "journaling" is at file system level and WAL is above in the > Database level. What happen if the xlog filesystem has been breakdown by a power > off. All the Data concisentcy done by PG will be lost. I hope that data stored > in the FS journal, can avoid that. What's the recommended method of changing an ext3 partition to data=writeback mode on RH9? I tried the tune2fs -j method to set the default journal type and rebooted, but saw *no* performance differences, so I was wondering if setting the default actually put it in writeback mode. Does anyone know if there's an easy way to verify the mode, or if I'm setting it wrong ?
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