PG 9.2 slave restarted - cache not impacted

[Lucas Possamai <drum.lucas@xxxxxxxxx>]

Hi guys,

I'm a bit confused about PG cache.

I have a PostgreSQL 9.2 cluster (yes, we're planning on upgrading it to 12) with a master and a slave database.

The application is sending all read requests to the slave, where the master processes the writes.

A while ago we had to restart the master database server, and the application was slow for a couple of days while PG cache was warmed up.

Yesterday, we had to restart the slave database server and we did not have the same problem.

I would like to understand why?

Thanks!