Thread: Problem while pg_xlog directory

Dear all,

I am doing some Performance tuning in Pgsql. I have changed several
Parameters in postgresql.conf file. Now I want to change my pg_xlog
directory to another disk.

I followed the below steps :

cd /hrd2-p/postgres_data
> /etc/init.d/postgresql-8.4 stop
> mkdir -p /opt/pg_xlog
> chown -R  postgres.postgres /opt/pg_xlog
> chmod 700 /opt/pg_xlog
> cp -rf pg_xlog/* /opt/pg_xlog
> mv pg_xlog pg_xlog_old
> ln -s /opt/pg_xlog pg_xlog
> /etc/init.d/postgresql-8.4 start

But me server fail to start and there is empty log in startup.log. I also checked my permissions and directories are
ownedby postgres user. 

Is I am failing something and there is some simple way.

Also, i want to know after Performance tuning following the below link :

http://wiki.postgresql.org/wiki/Performance_Optimization.

How much our performance increases.

I am selecting data from 5Gb file and it takes 229477 ms.
Still i execute same query in 226977 ms after some tuning.

Please help.


Best Regards

Adarsh Sharma

On Mon, Dec 13, 2010 at 8:47 AM, Adarsh Sharma <adarsh.sharma@orkash.com> wrote:
> But me server fail to start and there is empty log in startup.log. I also
> checked my permissions and directories are owned by postgres user.

So there are absolutely no warnings emitted to the screen or anywhere
else?  Seems very very unlikely to me.

Am Montag 13 Dezember 2010, um 14:47:03 schrieb Adarsh Sharma:

> > mv pg_xlog pg_xlog_old

> But me server fail to start and there is empty log in startup.log. I also

Hi,,
you have to move the contents from the old to the new pg_xlog directory as
well.

HTH, Jens