We are using MySQL 5.044 and have the following replication topology:
1 Master and 5 Slaves
Yesterday, we added another slave machine, and set the InnoDB Buffer Pool Size to 30 GB.
This machine is not yet used by our applications, and so it is only getting INSERT/DELETE/UPDATE statements from master through replication.
Today I looked at the InnoDB Buffer Pool and I see that over 2 GB are being used already. I was surprised. I was under the impression that only data from SELECTs should go there for faster retrieval. Am I wrong? Does some data from INSERT/DELETE/UPDATE also go there, or is there something else going on?