MySQL 5.1 screws my nuts. I am literaly freaked out. I have no answer why MySQL 5.1 is so poor as compare to MySQL 4.1 atleast on my side. I am desperate to use new features of MySQL 5.1. But there are serious performance issues on MySQL 5.1.
We have 8 slaves & 1 master which is on MySQL 4.1.22. Half of our slaves are using MySQL 4.1.22 and half of them are on MySQL 5.1.32.
MySQL 4.1 slaves running without any issues.
On MySQL 5.1 we are facing error “Too many connections” 3 to 4 times per day. We are using (max-connections=200) on every slave.
We have all of our db tables MyISAM except 1 0r 2 on INNODB. We have long query queue on MySQL 5.1 when we have error of max connections. When we tries to KILL problematic query which running long and reason for connections growth on MySQL 5.1 it shows KILLED in STATE column of SHOW PROCESSLIST. We have lot of query queue behind that query stucks in processlist because of LOCKED are also not executing because problematic query didn’t cleaned up smoothly. It still arrives in SHOW PROCESSLIST.
While on MySQL 4.1 when we kills any query vanishes quickly and gives room to waiting queries to run. But on MySQL 5.1 don’t know why query comes in SHOW PROCESSLIST and it didn’t gives room to other upcoming queries on same table they were LOCKED. Because problematic query is not dissapeared. Surprisingly in information_schema.Processlist table it doesn’t shows up means it giving me different results from information_schema database (not showing KILLED queries) which from mysql client it shows KILLED queries. That’s the real problem.
Please let me know why this happening. Is anyone else having problems on MySQL 5.1. I upgraded MySQL 5.1 from MySQL 4.1 through cpanel mysqlup script. Please also look for following forum link for more info that what problems MySQL 5.1 have: