[Sqlrelay-discussion] Working instance becomes problematic w/o obvious reason

[Christian H. <chr...@bo...>]

Hi all


We are running sql-relay 0.39.4 with perl and mysql 5.0 with multiple
server-connections with upwards 100K queries per day.

While everything works fine, we do have, from time to time, the problem
that one of the connections simply hangs for whatever reason.

Once this problem occurs we get a "Couldnt connect to the listener"
error message. After running sqlr-stop and sqlr-start the problem is
solved again. 

We have spent weeks examining this problem but couldnt get any further.
There simply is no obvious reason. The connection works fine and then
suddenly the listener hangs it self. We first figured we created too
much traffic, but the problem also occurs at times when there is less
than 5 queries per minute. 

We also tried to create this problem manually to verify it or to examine
it. However, we failed. We simply are not able to cause the
listener/connection to hang it self and to report this error. Even after
pushing the multiple amount of statements sqlr usually has to process.
Nothing. We can not recreate the problem manually


Today, for the first time, while being logged in to the server (console)
and running sqlr-stop & sqlr-start on the specific instance after we had
the problem, I got error messages dumped to the console. Unfortunately,
I could not find any hint on the web when researching the error string:

handleQuery called with reexceute flag set to 0
processQuery got ... [correct SQL Statement]

Excerpt from the sqlrelay.conf file :

<instance id="d02w" port="9022" socket="" dbase="mysql" connections="10"
maxconnections="10" maxqueuelength="10" growby="2" ttl="10"
endofsession="commit" sessiontimeout="600" runasuser="sqlrelay"
runasgroup="sqlrelay" cursors="5" authtier="listener" handoff="pass"
deniedips="" allowedips="127.0.0.1" addresses="127.0.0.1" debug="none"
maxquerysize="65536" maxstringbindvaluelength="4000"
maxlobbindvaluelength="71680" idleclienttimeout="-1" maxlisteners="-1"
listenertimeout="2">
     <users>
             <user user="XXXXXXXXXX" password="XXXXXXXX"/>
     </users>
     <connections>
        <connection connectionid="d02w"
string="user=XXXXXX;password=XXXXX;db=flyocache4w;host=172.16.37.XXX;port=XXXX;" metric="10" behindloadbalancer="no"/>
     </connections>
     <router>
     </router>    
</instance>


Anybody has any hints ?

TIA,

Chris