Re: (ITS#5796) back-sql intermittently failing

[ando@sys-net.it]

Robert Brooks wrote:
> Pierangelo Masarati wrote:
>> I have no possibility to setup a back-sql with mysql right now.  Can 
>> you post your configuration?  Can you post some (verbose) logs of 
>> operations affecting back-sql (e.g. with BACKSQL_TRACE manually 
>> #defined in back-sql/back-sql.h)?  Can you step thru a search into 
>> backsql_search() and see if it gets called and why it doesn't get to 
>> contacting the rdbms?
> 
> I'm compiling with BACKSQL_TRACE defined right now.
> 
> After further prodding I have discovered...
> 
> ejabberd (a jabber daemon) makes connections to ldap, which it keeps 
> open indefinitely. It appears mysql's odbc connector will time out an 
> idle mysql connection after 8 hours. Since this is the slave system it's 
> entirely possible for it not touch mysql connections for at least 8 hours.
> 
> If we restart mysql some ldap queries fail on back-sql portion until we 
> kill ejabberd (to close it's ldap connections).
> 
> I'll give you logs with tracing enabled asap, but this looks like a big 
> clue as to what is happening.

OK, this makes sense.  In fact, back-sql does not seem to specifically 
handle broken connections to the odbc.  It appears it would need 
something similar to idle-timeout as in back-ldap and back-meta.

p.


Ing. Pierangelo Masarati
OpenLDAP Core Team

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