I had experience with such type of error, It was due lack of resources available to MySql, max connections exceeds on the server. you can write a simple script which will grab and store output of 'show processlist' every min. and later you cna investigate the issue.
On Wed, May 25, 2011 at 3:34 AM, Aveek Misra <ave...@yahoo-inc.com> wrote: > Nothing in the error log or the slow query log that suggests that the query > size is too large or us taking too much time to execute. > > Thanks > Aveek > > On May 25, 2011, at 3:53 PM, Rik Wasmus wrote: > > >> failed to execute " SELECT * FROM cluster_info WHERE cluster = > ?": > >> MySQL server has gone away > >> > >> The error "MySQL server has gone away" is the error from the db handle. > Can > >> anyone give me any pointers on why that happens? I looked up the > >> documentation in MySQL docs and the most common reason seems to be that > it > >> happens if the query size is very large or if there is a timeout. None > of > >> them seems to be a probable cause. The "max_allowed_packet" on the > server > >> is 16 MB and as can be seen in the query above, the query is very small > >> and nowhere near the size limit. We also have a timeout setting > >> (wait_timeout) of 10 minutes and the above query for us cannot possibly > >> take that amount of time. In any case, given the same query, it executes > >> correctly 99% of time (so to speak). It fails intermittently with the > >> above error. What possibly could be the reason? I also looked at the max > >> connections on the server at that time (around ~80) and it is much less > >> than the limit we have (limit is 1000). How can I extract more > information > >> when this happens? This error message sucks since it does not tell me > what > >> exactly happened. The server version is 5.1.45. > > > > Can you access the error log of the server? That can probably shed more > light > > on the issue... > > -- > > Rik Wasmus > > > > -- > > MySQL General Mailing List > > For list archives: http://lists.mysql.com/mysql > > To unsubscribe: > http://lists.mysql.com/mysql?unsub=ave...@yahoo-inc.com > > > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/mysql?unsub=aim.prab...@gmail.com > > -- Best Regards, Prabhat Kumar MySQL DBA My Blog: http://adminlinux.blogspot.com My LinkedIn: http://www.linkedin.com/in/profileprabhat
