[Pgpool-general] Is there a option

[Daniel.Crespo at l-3com.com]

You are welcome.

 

> So this is done by using pcp_recovery_node command?

 

Yes. That command will trigger everything I explained. Also, be aware
that your database needs to have the pgpool stored procedures installed
in order for it to work. And for them to be installed, your database
needs to have the proper pl languages installed, I don't remember which
one, but got to be either plpgsql or plperlu. I think it's the former.
Read the pgpool tutorial for info on all this.

 

Daniel

 

________________________________

From: DM [mailto:dm.aeqa at gmail.com] 
Sent: Tuesday, March 17, 2009 4:57 PM
To: Crespo, Daniel @ SDS
Cc: pgpool-general at pgfoundry.org
Subject: Re: [Pgpool-general] Is there a option

 

Thanks Daniel, Great Answer. 

So this is done by using pcp_recovery_node command?

Thanks
Deepak

On Tue, Mar 17, 2009 at 1:30 PM, <Daniel.Crespo at l-3com.com> wrote:

Let's say you have two backends: backend0 and backend1. Supposing
backend1 has failed, recoverying it (by re-synchronizing data from
backend0) is expected to have a pgpool client reconnection. From the
point of view of pgpool, the clients must disconnect and reconnect in
order to complete a data synchronization. However, this disconnection
can be very quick. The interesting part is that data synchronization (a
kind of copy of the postgresql data directory) will happen while
backend0 is available por reads and writes. At the end of the data
transfer (1st  stage), a postgresql feature (WAL archiving) helps with
the synchronization of newer data (2nd stage) that has been transferred
at the 1st stage. At 2nd stage is when clients must disconnect and
reconnect. Pgpool has the ability to normally accept connections during
1st stage. At 2nd stage, pgpool waits until clients disconnect or until
client_idle_limit_in_recovery seconds happen. Then clients get
disconnected. If clients try to connect while 2nd stage happen, pgpool
will block them until it finishes. Clients won't get disconnected, just
will sit waiting until connection happens.

 

I hope this helps.

 

Daniel

 

________________________________

From: Crespo, Daniel @ SDS 
Sent: Tuesday, March 17, 2009 4:05 PM
To: 'DM'; pgpool-general at pgfoundry.org
Subject: RE: [Pgpool-general] Is there a option

 

Yes. Look for the following keywords:

 

pcp_recovery_node (pgpool client program)

client_idle_limit_in_recovery (parameter in pgpool.conf)

pgpool_copy_backup (script)

pgpool_switch_xlog (script)

pgpool_remote_start (script)

 

Daniel

 

________________________________

From: pgpool-general-bounces at pgfoundry.org
[mailto:pgpool-general-bounces at pgfoundry.org] On Behalf Of DM
Sent: Tuesday, March 17, 2009 2:57 PM
To: pgpool-general at pgfoundry.org
Subject: Re: [Pgpool-general] Is there a option

 

Hi All,



Sorry I wanted to ask the question the other way round.

In Pgpool is it possible to recover / sync the 2nd DB without quiescing
the first.

Thanks
Deepak 

On Tue, Mar 17, 2009 at 9:48 AM, DM <dm.aeqa at gmail.com> wrote:

Hi All,

In pgpool Is it possible to do quiescing of a db while
(recovering)/syncing the 2nd DB?

Thanks
Deepak

 

 

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