>From pgpool doc: <dt>max_pool</dt> <dd> <p>The maximum number of cached connections in pgpool-II children processes. pgpool-II reuses the cached connection if an incoming connection is connecting to the same database with the same username. If not, pgpool-II creates a new connection to the backend. If the number of cached connections exceeds max_pool, the oldest connection will be discarded, and uses that slot for the new connection.
max_pool is only related to number of username/database combo. Say, you have 2 combos (for example, "user1/mydb" and "user2/mydb") you can assumes it as a constant 2 in the fomula repsented in the pgpool doc. max_pool*num_init_children <= (max_connections - superuser_reserved_connections) (no query canceling needed) max_pool*num_init_children*2 <= (max_connections - superuser_reserved_connections) (query canceling nee BTW I'm not sure what you mean by "replication servers". -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp > Yes, I've seen that, but going from 3 (physical) replication servers to 5 > replication servers, would I need to increase max_pool in that formula from > 4 to 6? Or a more extreme example would going from 2 replication servers to > 128 with an expected 100 simultaneous "UPDATE" queries on each server result > in going from 200 postgres-connections on each server to 12800 > postgres-connections on each server? > >>From my experiment with 3 servers it looked like the need for connections on > each server would increase when I add servers. I just want to make sure that > is the right conclusion before making a decision on how to use pgpool. > > Regars > John Andre Taule > > -----Original Message----- > From: Tatsuo Ishii [mailto:is...@sraoss.co.jp] > Sent: 24. januar 2011 08:39 > To: p...@johnandre.net > Cc: pgpool-general@pgfoundry.org > Subject: Re: [Pgpool-general] Replication and number of postgres processes > > There is a formula for this in the pgpool documentation. > See the "num_init_children" section. > -- > Tatsuo Ishii > SRA OSS, Inc. Japan > English: http://www.sraoss.co.jp/index_en.php > Japanese: http://www.sraoss.co.jp > >> Will the number of postgres processes needed increase by how many >> servers is used for replication? >> Example 100 connections by the frontend application. >> 2 replication servers: 200 connections >> 3 replication servers: 300 connections >> N replication servers: n*100 connections >> Is my understanding of resources needed correct? >> Regards >> John Andre Taule >> > _______________________________________________ Pgpool-general mailing list Pgpool-general@pgfoundry.org http://pgfoundry.org/mailman/listinfo/pgpool-general