Re: Rescue data after power off

I have checked SHOW fsync, It is ON.
When I view table dmvt on PgAdmin, it only has 1332 rows, but command
"SELECT count(*) FROM dmvt" return 2449 rows.

My postgresql.conf is default of EnterpriseDB Postgres 8.3.9.

Please help me. Sorry for my English.
Tuan Hoang Anh.

On Mon, Jul 19, 2010 at 9:36 PM, Craig Ringer
<craig(at)postnewspapers(dot)com(dot)au>wrote:

> On 19/07/10 19:02, Jayadevan M wrote:
> >> Yesterday my server is power off, when i start server, some of table is
> > blank. Is there anyway to rescue it.
> > The "Power Off" - is it a planned/regular one? If yes, it makes sense to
> > have a normal shutdown of the database before the "Power Off".
>
> ... but even if you yank the power plug out of the back of the server,
> PostgreSQL should *NEVER* lose comitted data (unless you've told it its
> allowed to with a commit delay) and should certainly NEVER damage the
> database structure. It's one of PostgreSQL's most important and basic
> features.
>
> Unless you have set "fsync=off" in postgresl.conf, in which case the
> data loss is entirely your own fault, this should not happen. If you do
> not know if fsync is on or off, check by running "SHOW fsync;" in psql
> or PgAdmin. It should say "on". If it says "off" then you or someone
> else manually told the database not to try to protect your data from
> power loss or other failures.
>
> If you have lost data and fsync is on, then most likely your RAID
> controller/disks are doing something they should not be like caching
> writes in volatile storage. Make sure your RAID controller has write
> caching disabled or has a tested and working battery backup unit. If in
> doubt, your raid controller should have its write cache turned off, ie
> it should be in "write-through" mode and NOT in "write-back" mode.
>
> --
> Craig Ringer
>