mbruker/Cockatrice — comment on commit 50e53fbe5395ef698d1ca78ac6308533dd3c6c15
File:  line 0
By mbruker:

The database doesn't significantly contribute to the CPU usage, but as servatrice isn't threaded yet, calls to the database block the server for all players (with each login attempt etc). The calls happen often enough so that they'll increase the overall latency of the server if they are executed slowly.
I think it can be overcome by using replication though. However, the way I'm seeing it now, it implies that the local databases are read-only and insert/update statements have to be forwarded to the master in a non-blocking way.