[Pgpool-general] replication/failover feature in Master/Slavemode

[Sandeep Thakkar]

PFA the pgpool.conf. I start pgpool using "pgpool -d -D -f  pgpool.conf"

Do let me know, if I'm missing anything. Thanks.




________________________________
From: Sandeep Thakkar <sandeeptt at yahoo.com>
To: Daniel.Crespo at l-3com.com; Guillaume Lelarge <guillaume at lelarge.info>
Cc: pgpool-general at pgfoundry.org
Sent: Fri, January 28, 2011 11:53:48 AM
Subject: Re: [Pgpool-general] replication/failover feature in Master/Slavemode


Yes, I'm aware that I need to create a trigger file (same as what is defined in 
recovery.conf) to start the failover and promote the Standby to Primary. I have 
tried this when I did not use pgpool and it worked fine. I thought, when pgpool 
is in picture, it will execute the failver_command, when it detects that primary 
is down. and since, the failover_command in my case is to "touch trigger file". 
Shouldn't pgpool execute the failover_command here and create that file 
automatically? I think, either pgpool is not able to detect that primary is down 
or it is unable to execute the failover_command. Am I missing to define anything 
in the configuration file?





________________________________
From: "Daniel.Crespo at l-3com.com" <Daniel.Crespo at l-3com.com>
To: Sandeep Thakkar <sandeeptt at yahoo.com>; Guillaume Lelarge 
<guillaume at lelarge.info>
Cc: pgpool-general at pgfoundry.org
Sent: Thu, January 27, 2011 9:33:01 PM
Subject: RE: [Pgpool-general] replication/failover feature in Master/Slavemode

 
“failover_command” entry in pgpool.conf allows you to do whatever you need to do 
when pgpool detects a database node degeneration. In your case you would need to 
touch the file where PostgreSQL 9.0+ expects it (specified in “trigger_file” 
within recovery.conf). Take a look at how postgresql 9.0’s built-in replication 
works, and then you’ll know what to touch and where.
 
-Daniel
 
From:pgpool-general-bounces at pgfoundry.org 
[mailto:pgpool-general-bounces at pgfoundry.org] On Behalf Of Sandeep Thakkar
Sent: Thursday, January 27, 2011 3:50 AM
To: Sandeep Thakkar; Guillaume Lelarge
Cc: pgpool-general at pgfoundry.org
Subject: Re: [Pgpool-general] replication/failover feature in Master/Slavemode
 
I was just testing the pgpool with one primary and one standby on the same box. 
Hot Standby, Streaming replication, load balancing, all are working fine. But, I 
see that failover is not happening when I shut down my primary server. When I 
manually touch the trigger file, failover happens. I thought, pgpool will 
execute the fail over command on it's own. Am I doing anything wrong?

Here is my related settings in pgpool.conf:
failover_command = 'touch <path_to_trigger_file>

My recovery.conf in the data directory of standby contains these variables:
standby_mode
primary_conninfo
restore_command
trigger_file

Please help. 
 
 

________________________________
 
From:Sandeep Thakkar <sandeeptt at yahoo.com>
To: Guillaume Lelarge <guillaume at lelarge.info>
Cc: pgpool-general at pgfoundry.org
Sent: Fri, January 14, 2011 2:40:52 PM
Subject: Re: [Pgpool-general] replication/failover feature in Master/Slave mode
Thanks Guillaume. 
 
 

________________________________
 
From:Guillaume Lelarge <guillaume at lelarge.info>
To: Sandeep Thakkar <sandeeptt at yahoo.com>
Cc: pgpool-general at pgfoundry.org
Sent: Wed, January 12, 2011 8:09:53 PM
Subject: Re: [Pgpool-general] replication/failover feature in Master/Slave mode

Hi,

Le 12/01/2011 15:10, Sandeep Thakkar a écrit :
> [...]
> I have a primary and a standby server on different boxes and both are running 
>on 
>
> different ports. I would like to use pgpool for Streaming Replication and 
> Failover. Hence, I selected Master/Slave mode with stream. Now, I have a 
> question, if I write anything on primary, how will the data be replicated on 
> standby? Will it happen automatically like it does in replication mode Or do I 

> need to look into Hot Standby feature of PG?
> 

You need to look at the streaming replication feature of PostgreSQL. You
need Hot Standby for example if you want to use the load balacing
feature of pgPool.

> Also, on failover (let's say primary goes down for some reason), and the 
>standby 
>
> now takes over. Will the standby has write operations?
> 

You need to write scripts for that.

> Also, in my application, will I use the pgpool port, so that I do not need to 
> change the configuration file in case of failover?? With Slony, we had to tell 

> the application to use the other port.
> 

The pgpool port, always.


-- 
Guillaume
http://www.postgresql.fr
http://dalibo.com

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