On Friday 15 October 2010 16:53:40 Victor Duchovni wrote: > On Fri, Oct 15, 2010 at 03:05:33PM +0200, Stefan wrote: > > in the appendix you will find a patch against Postfix 2.7.1 which adds > > write support to Postfix' MySQL client. > > > > If someone like to test it, then he will find Postfix RPMs with MySQL > > write support for recent versions of *SUSE linux here: > > http://download.opensuse.org/repositories/home:/rusjako/ > > > > To use a MySQL verify db, you have to: > > - add "address_verify_map = mysql:/etc/postfix/verify.cf" to your main.cf > > - Content of /etc/postfix/verify.cf: > > user = postfix > > password = <secret> > > dbname = postfix > > query = SELECT data FROM verify WHERE address='%s' > > delete = DELETE FROM verify WHERE address='%s' > > insert = INSERT verify SET address='%s', data='%v' > > update = UPDATE verify SET data='%v' WHERE address='%s' > > sequence = SELECT address,data FROM verify > > Have you found any issues with lock contention between the > "sequence" pseudo-thread and INSERT/DELETE/UPDATE operations during a > garbage-collection sweep?
No. > Is the code known to be safe against dead-lock? I'am not aware of any dead-lock issues. The sequence pseudo-thread will query the database only once with the first key. For every next key the sequence pseudo-thread is working with the results in the memory. With a very large database the size of the response may be a problem. But a INSERT/DELETE/UPDATE operation will not conflict with the sequence pseudo-thread. Finally, I can not prove if the code is dead-lock safe. > Also it probably makes sense to retain a compatible db_common_expand() > wrapper around the extended code that also handles a second "value" > element in addition to lookup the key. This would obviate the need > to modify the other table drivers that don't do updates... Yes, good idea. I fixed that in the appended patch. Best regards Stefan
postfix-mysql-write-support.patch.gz
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