Re: [HACKERS] Wal sync odirect

2013-07-22 Thread Craig Ringer
On 07/21/2013 10:01 PM, Миша Тюрин wrote: hi, list. there are my proposal. i would like to tell about odirect in wal sync in wal_level is higher than minimal. i think in my case when wal traffic is up to 1gb per 2-3 minutes but discs hardware with 2gb bbu cache (or maybe ssd under wal) -

[HACKERS] Re: [HACKERS] Wal sync odirect

2013-07-22 Thread Миша Тюрин
i tell about wal_level is higher than MINIMAL wal_level != minimal http://doxygen.postgresql.org/xlogdefs_8h_source.html 48   * Because O_DIRECT bypasses the kernel buffers, and because we never 49   * read those buffers except during crash recovery or if wal_level != minimal hi, list.

Re: [HACKERS] Re: [HACKERS] Wal sync odirect

2013-07-22 Thread Craig Ringer
On 07/22/2013 03:30 PM, Миша Тюрин wrote: i tell about wal_level is higher than MINIMAL OK, so you want to be able to force O_DIRECT for wal_level = archive ? I guess that makes sense if you expect the archive_command to read the file out of the RAID controller's write cache before it gets

Re: [HACKERS] Re: [HACKERS] Wal sync odirect

2013-07-22 Thread Cédric Villemain
Le lundi 22 juillet 2013 09:39:50, Craig Ringer a écrit : On 07/22/2013 03:30 PM, Миша Тюрин wrote: i tell about wal_level is higher than MINIMAL OK, so you want to be able to force O_DIRECT for wal_level = archive ? I guess that makes sense if you expect the archive_command to read

[HACKERS] Wal sync odirect

2013-07-21 Thread Миша Тюрин
hi, list. there are my proposal. i would like to tell about odirect in wal sync in wal_level is higher than minimal. i think in my case when wal traffic is up to 1gb per 2-3 minutes but discs hardware with 2gb bbu cache (or maybe ssd under wal) - there would be better if wall traffic could not