[pgpool-general: 3094] Re: max number of connection - for more pool nodes

Tatsuo Ishii ishii at postgresql.org
Fri Aug 1 07:48:51 JST 2014

> Hi!
> Sorry, but it's still not clean for me:
> OK, I can count/plan the number of connections according to this document,
> or a similar one:
> http://www.pgpool.net/mediawiki/index.php/Relationship_between_max_pool,_num_init_children,_and_max_connections
> But... it is not clean that the pgpool cluster is counted as one, or the
> numbers are for a single node.

Yes, the numbers are for a single node.

> to be more specific:
> pool-1 and
> pool-2 are the pgpool nodes, with the same settings:
> num_init_children: 48
> max_pool: 3
> and the same backend databases (one master, one RO slave)
> There are a few apps on pool-1 and pool-2 as well, all connects its "own
> pool" locally
> Now how many connection can exists from the pool nodes alltogether to the
> backends?

In this case max_connections of PostgreSQL should be rougly more than
48*3*2 (2 for two pgpool nodes).

> In other words: are the pools in the same "cluster" sharing the connection
> data?
> Currently we are facing the problem, that after a while, when the app is
> tested against many connections, pool connections just hangs, and never get
> a backend connection to run on.
> Regards,
> Attila

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