Invalidating query cache entries table egg quad updating discriminator

28 Oct

Replication delay for server2 starts growing, replication delay for server3 stays zero : server2 is done with query one, starts processing query two. Server3 will be done with query 3, replication delay jumps back to zero, and then back up to 10 as it processes the next query.So, the jumpy behaviour is caused by not using a global timestamp for replication delay, but simply the delay behind the last "hop" in the replication chain.First because i dont't see the servers processing anything, and second, because as i mentiomed in update4, the server stops processing and gets stuck on invalidating cache on the old non-Percona servers which caused the replication to halt until the cache was invalidated (Which took a lot of time). id=60696 We solved the issue by moving entirely to Percona My SQL server v5.5 which has the ability to disable Query Cache completely.We lately mved to My SQL V5.5 on Cent OS release 6.7 with master and 2 slaves.

I'm running a 4 servers master-master cluster of My Sql. Replication topology: 1 - 1 UPDATE It seems that server 3 has its SBM at 0, while the other servers are jumping up and down. It looks like the server is busy doing something, and there is a huge delay between when the server gets the statement, and when it executes it. After disabling cache, server 4 is ok but 1&2 are still having this issue. id=60696 If anyone knows how to fix it, i would be glad to hear There is one flaw with mysql's seconds_behind_master value: it only takes into account the position relative to one upstream hop away.

Queries that happened a month ago are probably no longer useful now.

So if it's storing those query results then it's completely worthless because chances are no one is going to run that same exact query again.

If you set it to on demand, then you have to explicitly state which queries you want cached when you issue them.

The classic tip is “set global query_cache_size=0” .