The combination of max_allowed_packet variable and replication in MySQL is a common source of headaches. In a nutshell, max_allowed_packet is the maximum size of a MySQL network protocol packet that the server can create or read. It has a default value of 1MB (<= 5.6.5) or 4MB (>= 5.6.6) and a maximum size of 1GB. This adds some constraints in our replication environment:
- The master server shouldn’t write events to the binary log larger than max_allowed_packet
- All the slaves in the replication chain should have the same max_allowed_packet as the master server
Sometimes, even following those two basic rules we can have problems.
For example, there are situations (also called[Read more...]