Common MySQL errors
- What are they?
- How to fix them?
- Best practice
Common errors
- MySQL server has gone away
- Too many connections
- Got timeout reading communication packets
- Error while sending QUERY packet
MySQL server has gone away
- Server timed out and closed the connection
- Increase wait_timeout
- Server dropped an incorrect or too large packet
- Increase max_allowed_packet
Too many connections
- Open too many connections
- Increase max_connections
- Or don't open too much connections e.g. limit number of queue messages (or worker) processing at the same time
- Connection is not closed when the job is finish
- $entityManager->close()
Got timeout reading communication packets
-
Connection is kept for too long
- Increase wait_timeout
- $entityManager->close()
Error while sending QUERY packet
- Because of Got timeout reading communication packets
- Solution in the previous slide
Best practice
- Don't let your PHP worker work directly with MySQL
- Create sub process for each message received
- Limit number of workers
