On Sat, 2008-02-16 at 21:46 +0800, Frank Wang wrote:

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Hi, Our mail system uses dovecot-1.0-1.2.rc15.el5 in Centos-5.1 as our imap server. It connects to a pgsql database in another server as authentication backend. It works fine except occasionally fails to reconnect to the database after temporary network block, and dovecot has to be restarted to work again in such case.

It's most likely fixed in newer versions. For example there is one PostgreSQL fix in v1.0.4 and another in v1.0.rc26. There may be other fixes as well.

You can find newer Dovecot RPMs for CentOS 5 from atrpms.net.

Thanks for the quick reply. I've tested the dovecot-1.0.10-0_66.el5 from atrpms.net. The reconnection problem hasn't occur during the test so far, good! I'll need sometime to test the stability though, as it's marked test in the repo.

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Google led me to http://www.dovecot.org/list/dovecot/2008-January/027899.html. I followed the thread to modify my dovecot-sql.conf containing "connect = host=pgsql1 host=pgsql2 dbname=xxxx user=xxxx"

Currently this works only with MySQL. Is it possible to achieve similar failover using pgsql backend? As we had built other systems using the same pgsql database, migrate to mysql is not an option here.

Regards, Frank Wang

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Is it possible to achieve similar failover using pgsql backend?

It would require writing code to support that, but I'm not going to get around to it anytime soon. The MySQL-specific connection pooling code should probably be moved to generic code that works with all SQL backends.

Yeah, with generic pooling code, it'll definitely increase dovecot's availability for more situation. Thanks for your nice work!

Regards, Frank Wang

Everything that replaces a package in RHEL5/CentOS5 is in the testing repo and will never become stable.

E.g. just replace the "testing" label with "replaces vendor packages" in this case. Still you should give it a good test anyways.

Thanks for pointing it out.