I've asked this question on stack overflow, which you can find here.

I'm seeing very slow session related MySQL queries in my production environment, using Symfony2 (2.8.22), AWS EC2 and RDS. I asked a similar question (#18863) a while back, when I was using the default Symfony file system session handler. I'm now using the MySQL handler, which is perhaps even more problematic.

These slow lookups have been particularly aggravating over the pas 12hrs or so, during which time the average throughput of my application was about 80-90 requests per minute.

Other MySQL queries seem perfectly performant, and the issue seems to be isolated to session handling. On other transactions, I might see MySQL sessions delete, which also takes 60%-90% of the total transaction time. One answer in my previous question proposed that the slowness might be due to session locking, in which case I'd ask: is there anything I can do to speed this process up? ~20sec to handle sessions is unacceptable.

I've attached a couple reports from New Relic that illustrate the hang ups. Please let me know what additional information I can supply to help get to the bottom of this.