I have a problem with some performance_schema tables (*_by_host_* and *_by_account_*) taking up too much RAM. It is caused by clients connecting from a /19 subnet (8190 unique addresses). The connections aren't long-lasting: clients connect, perform a task and quit. Which settings can I tweak to limit the memory usage and what are the downsides of each limit?

The DB is on AWS RDS and I would like to keep Performance Insights with as much data as possible.

1 Answer 1


Shrink innodb_buffer_pool_size to provide some spare RAM.

There may ways to expand or shrink the limits inside P_S -- but this might not let you monitor all 8K addresses.

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