[GENERAL] PG_STANDBY ISSUE

[akp geek]

Hi experts -

                I am running into issue with pg_standby. May be my understanding is not correct. Please help. here is what I did .

1.     I made changes in the postgresql.conf  ( archive_mode = on ,archive_command = 'cp -i %p /opt/postgres/archive/%f' , archive_timeout = 60s )
2.     pg_ctl start -D $PGDATA -l /opt/postgres/logfile
3.    postgres=# select pg_start_backup('BKP_LBL');
4.    I have done the base backup  and I have used the following command for restore in the recovery.conf
5.   restore_command = 'pg_standby -d -s 3 -t /tmp/pg_standby.trigger.5432 /opt/postgres/archive/%f %p %r'
6.  postgres=# select pg_stop_backup();
7. Now I have made some changes to the master database  and I waited for 30 minutes 
8. I have stopped the master database
9. I have started the slave. But I did not find the changes I have done after I issued the command  elect pg_stop_backup();
10. The log files have shipped to archive folder

Is there some thing wrong with the I am doing the procedure. Please help

Regards

[akp geek]

Hi All - 

 Can you please help me with the issue when you get some time

regards

[Richard Huxton]

akp geek wrote:
> Hi experts -
>
> I am running into issue with pg_standby. May be my
> understanding is not correct. Please help. here is what I did .
>
>

> 1. I made changes in the postgresql.conf ( archive_mode = on

> ,archive_command = 'cp -i %p /opt/postgres/archive/%f' , archive_timeout =
> 60s )

> 2. pg_ctl start -D $PGDATA -l /opt/postgres/logfile
> 3. postgres=# select pg_start_backup('BKP_LBL');
> 4. I have done the base backup and I have used the following command

> for restore in the recovery.conf

> 5. restore_command = 'pg_standby -d -s 3 -t
> /tmp/pg_standby.trigger.5432 /opt/postgres/archive/%f %p %r'

From memory, do you not want a space between ".../archive/" and "%f" - I
think they're separate parameters.

Also, you'll want to redirect STDERR to a file - add the following to
the end of the command: 2>>/tmp/standby.log

That way we'll be able to see what's happening.

> 6. postgres=# select pg_stop_backup();
> 7. Now I have made some changes to the master database and I waited for
> 30 minutes

Or just generate lots of changes so WAL files get filled.

> 8. I have stopped the master database
> 9. I have started the slave. But I did not find the changes I have done

> after I issued the command elect pg_stop_backup();

> 10. The log files have shipped to archive folder

Good. That's a useful fact. Let's see if anything shows up in our
standby logfile once we have it.

--
Richard Huxton
Archonet Ltd

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[akp geek]

Thanks a lot Richard. The culprit in my case is the restore command , I modified it as follows per your instructions , it is fine now

 

restore_command = 'pg_standby -d -s 5  -t /tmp/pg_standby.trigger.5432 /opt/postgres/archive %f %p %r 2>>/tmp/standby.log'

 

One small doubt  I have is , do we have to keep the backup_label on the standby, I deleted it before I start the restore process , it still worked .. Just curious

 

appreicate your help

 

Regards

[Greg Smith]

akp geek wrote:
> One small doubt I have is , do we have to keep the backup_label on
> the standby, I deleted it before I start the restore process , it
> still worked .. Just curious

The backup label is strictly for you to read, to help make sure you got
all of the archived segments necessary for the backup to be useful. The
standby doesn't actually use it for anything, it's more of a helper for
a human trying to figure out what's going on.

--
Greg Smith 2ndQuadrant Baltimore, MD
PostgreSQL Training, Services and Support
gr...@2ndQuadrant.com www.2ndQuadrant.com