RDS Memory Monitoring is almost full but nothing is happenning on the server

Question

I don't understand how to read the Memory monitoring graph.

Thank you for your advices.

score 1 · Answer 1 · answered Dec 08 '16 at 16:28

1

First, database engine itself consumes memory.

Second, data is usually cached and not pushed out of RAM until RDBMS needs to. There might be cached data from previous queries.

answered Dec 08 '16 at 16:28

Sergey Kovalev

This doesn't really go far enough but it is essentially correct. Between the OS cache and memory structures like the buffer pool in InnoDB, it's completely normal, even optimal/desirable, for an RDBMS that is warmed up but completely idle to have as little as 20% or even less of the system's memory remain free. It would make no sense to evict data from memory that would just have to be loaded in from disk to serve a subsequent query. – Michael - sqlbot Dec 08 '16 at 22:18

1 Answers1