[pgpool-general: 5951] Re: pgpool load balancing problem

Mathias Buresch mathias.buresch at de.clara.net
Thu Mar 1 01:15:11 JST 2018


I reported that problem yesterday too. Maybe someone did it already before me..

I don’t know if you can access this -> Re: [pgpool-general: 5939] Re: PgPool 3.7.2 forwards write statements to Standby
.. But here is the explanation in short:

Problem: (posted by Tatsuo Ishii)

Today I have just found a serious regression in 3.7.2: it does not
work if the primary is other than node 0, sending write queries to
node 0, which is the standby (In my testing, 3.7.2 does work if the
primary is node 0). I guess your primary is not node 0, right?

The cause was this commit [1]:
https://git.postgresql.org/gitweb/?p=pgpool2.git;a=commit;h=36517db60a829422d382debb7aa3256fac5da26d <https://git.postgresql.org/gitweb/?p=pgpool2.git;a=commit;h=36517db60a829422d382debb7aa3256fac5da26d>

So I today reverted the commit [2]:
https://git.postgresql.org/gitweb/?p=pgpool2.git;a=commit;h=e8baa3f0ee1a24f833cfa6cc5d0104b5cefe7b04 <https://git.postgresql.org/gitweb/?p=pgpool2.git;a=commit;h=e8baa3f0ee1a24f833cfa6cc5d0104b5cefe7b04>

Until 3.7.3 is released, you could:

1) Let node 0 to be the primary

2) down grade to 3.7.1

3) Apply the patch [2] to 3.7.2.

Sorry for the inconvenience.


If you compile the software by yourself you could enable the patch provided by him.
Or install the 3.7.1 for RedHat.
If you run Ubuntu (like me) then you can download old Deb and install the old packages (libpgpool0, pgpool2, postgresql-xx.pgpool2).
-> http://atalia.postgresql.org/morgue/p/pgpool2/ <http://atalia.postgresql.org/morgue/p/pgpool2/> (don’t forget to set packages on “hold”)

Mit herzlichen Grüßen

Mathias Buresch
Systems Engineer
mathias.buresch at de.clara.net
Tel: +49 (69) 40 80 18 - 265
Fax: +49 (69) 40 80 18 - 129

Claranet GmbH
Hanauer Landstraße 196
60314 Frankfurt

Geschäftsführung Olaf Fischer
Hrb 50381 AG Frankfurt am Main
Vat-ID de 812918694


> On 28. Feb 2018, at 17:05, Mariel Cherkassky <mariel.cherkassky at gmail.com> wrote:
> Hi,
> I found a problem that had a big impact on our servers. I'm using pgpool as a load balancer and pool connections manager. When a user tries to run a select query it redirects the query to the slave. If the user tries after that to run dml or ddl command he get error : 
> ERROR: cannot execute CREATE TABLE in a read-only transaction
> SQL state: 25006
> Is there any way to solve this issue ? It means that once the pool redirected your session to the slaves you cant run any ddl/dml actions ..
> _______________________________________________
> pgpool-general mailing list
> pgpool-general at pgpool.net
> http://www.pgpool.net/mailman/listinfo/pgpool-general

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