Philippe Pepiot <ph@itsalwaysdns.eu> [Mon, 30 Mar 2020 15:45:40 +0200] rev 12962
[server] implement dynamic database pooler
Opening too much database connection has a cost at startup and also PostgreSQL
as a maximum number of connection (100 by default).
This get worse when starting multiple wsgi processes, since each process has
its own database pool.
Instead of opening `connections-pool-size` connections to the database at
startup, just open one and open more only when needed.
Philippe Pepiot <ph@itsalwaysdns.eu> [Mon, 30 Mar 2020 15:30:02 +0200] rev 12961
[server] use a LifoQueue in _CnxSetPool
In postgresql, some cache is attached to the connection. Using a LifoQueue
(last-in, first-out) makes a few connections to get the most load which give
best performance.
Philippe Pepiot <ph@itsalwaysdns.eu> [Mon, 30 Mar 2020 15:23:56 +0200] rev 12960
[server] extract creating a new cnxset in a _new_cnxset() helper
So we can move logic specific to _CnxSetPool here.
Philippe Pepiot <ph@itsalwaysdns.eu> [Mon, 30 Mar 2020 15:19:23 +0200] rev 12959
[server] avoid a possible race condition on _CnxSetPool.close()
The pool could become empty between time to check and time to use.