Re: [Sqlrelay-discussion] Patch to fix MySQL auto-reconnect (MYSQL_OPT_RECONNECT option)
Brought to you by:
mused
Menu
▾
▴
Re: [Sqlrelay-discussion] Patch to fix MySQL auto-reconnect (MYSQL_OPT_RECONNECT option)
|
From: David M. <dav...@fi...> - 2008-02-19 19:02:19
|
When I disable the MYSQL_OPT_RECONNECT line and test it, I get an error message: "mysql server has gone away". SQL Relay detects that string, re-logs in and everything works. I did discover a bug though, because it should have caught the CR_SERVER_GONE_ERROR error instead of having to resort to testing the error string, but I was checking the result of mysql_stmt_execute/mysql_real_query rather than the result of mysql_stmt_errno/mysql_errno. I have a fuzzy memory though of some version around 4.0 returning CR_SERVER_GONE_ERROR as the result of the query rather than in errno, so maybe that wasn't a bug. At any rate, the mysql connection daemon code gets the errno now and detects CR_SERVER_GONE_ERROR instead of having to test the actual error string. But that still doesn't explain why it works for me but not for anyone else. I do remember an issue way back where running create,drop,start,begin and a few other queries through the mysql stmt api caused a CR_SREVER_GONE_ERROR and somehow triggered a loop-up when sqlrelay tried to re-log in. I don't remember the exact details. The fix was to run those queries using the older mysql api. I'm pretty sure you guys are seeing something similar but I'm at a loss for how to reproduce it. Granted I'm not running on Centos, just Fedora, maybe that's the key. Could you post your /etc/my.cnf file? Maybe there's some other odd mysql parameter that's triggering the issue. Thanks, Dave dav...@fi... On Tue, 2008-02-19 at 11:46 -0500, Chris Coyle wrote: > Centos 4.4 (Generally) > Mysql 5.0.22 or 5.0.41 > > > Test Case > - Set the wait_timeout on the mysql server to 10 seconds > - open local sqlrsh instance to mysql server > - run a few queries > - let it sit for > 10s > - run another query > > > Without auto_reconnect enabled, sqlrelay will hang indefinitely (or > not, I've never been that patient). With reconnect enabled you can > sit there and every 15 seconds select session_id() and watch it > increment. > > > It may be that the API treats a timeout or other non-server failure > based disconnect differently from the server bouncing (? vaguely > recall something like this from when I was digging through docs, but > not sure). > > > Hope this helps, > - Chris > > > On Feb 19, 2008 10:16 AM, David Muse <dav...@fi...> > wrote: > This patch appears to be more correct that the code I had > before, so > I'll apply it. Though even without this patch, I can't > replicate the > problem that several folks have reported. > > If I run an instance of mysql, run sqlrelay against it, run > some queries > through sqlrsh, stop the mysql server, run a query through > sqlrsh, then > restart the mysql server, sqlrelay successfully reconnects and > the query > goes through. I've tried several different versions of mysql > and tried > restart vs. stop/start, and other things, but I can't seem to > reproduce > the error. > > Could someone who's had trouble with this send me some more > info. What > version of mysql are you using, what platform, and exactly > what steps > are you using to reproduce the error? > > Thanks, > > David Muse > dav...@fi... > > > On Fri, 2008-02-15 at 00:17 -0500, David Muse wrote: > > Cool. I'll give it a try and should be able to include it > in the next > > release. > > > > Thanks! > > > > Dave Muse > > dav...@fi... > > > > > > On Mon, 2008-02-11 at 18:05 -0800, Renaud Amar wrote: > > > I wrote a small patch which fixes an issue I've noticed > with the SQL > > > Relay connection daemons for MySQL: > > > > > > the connection daemon doesn't automatically reconnect to > the MySQL > > > database once it's been disconnected (either when > restarting mysqld or > > > when the connection times out). I've also noticed that > after being > > > disconnected, the connection daemon usually gets stuck in > a weird loop > > > where it keeps trying to unsuccessfully send a query over > and over. > > > > > > > > > > > > After looking through the mysql connection daemon code, I > noticed that > > > the code that is supposed to enable the > MYSQL_OPT_RECONNECT option > > > (in mysqlconnection.h and mysqlconnection.C) was ifdef'ed > using a > > > different #define symbol as the one used in the config.h > file. > > > > > > Namely, it's using "#ifdef MYSQL_OPT_RECONNECT" while > config.h defines > > > "HAVE_MYSQL_OPT_RECONNECT". > > > > > > This patch simply modifies mysqlconnection.h and > mysqlconnection.C to > > > use HAVE_MYSQL_OPT_RECONNECT. > > > > > > > > > > > > This is probably the same issue Abraham Müller mentioned > in a previous > > > post (here: > > > > http://sourceforge.net/mailarchive/forum.php?thread_name=47739600.8090800%40gmx.de&forum_name=sqlrelay-discussion). > > > > > > Hopefully, this patch will fix this issue as well. > > > > > > > > > > > > > > > > > > > > > > > > Renaud. > > > > > > > > > > > > > > > > > > PS: when applying the patch in your spec file, in the % > prep section, > > > make sure you call it with the –p1 option, in order to > strip one level > > > of directories from the paths in the patch file. > > > > > > > > > > > > > > > __________________________________________________ > > > D O T E A S Y - "Join the web hosting revolution!" > > > http://www.doteasy.com > > > > ------------------------------------------------------------------------- > > > This SF.net email is sponsored by: Microsoft > > > Defy all challenges. Microsoft(R) Visual Studio 2008. > > > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > > > _______________________________________________ > Sqlrelay-discussion mailing list > Sql...@li... > https://lists.sourceforge.net/lists/listinfo/sqlrelay-discussion > > > > __________________________________________________ > D O T E A S Y - "Join the web hosting revolution!" > http://www.doteasy.com > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Sqlrelay-discussion mailing list > Sql...@li... > https://lists.sourceforge.net/lists/listinfo/sqlrelay-discussion > > > > __________________________________________________ > D O T E A S Y - "Join the web hosting revolution!" > http://www.doteasy.com __________________________________________________ D O T E A S Y - "Join the web hosting revolution!" http://www.doteasy.com |
