[Pgpool-general] Issue with connection queuing

[Tatsuo Ishii]

> If a client which connects directly to postgresql wants to establish more
> connections than the maximum configured in postgresql, an error is generated
> and the connection attempt is aborted. On the other hand, if a client which
> connects to pgpool tries to make more connections than pgpool childs
> available, it blocks until a connection is freed. No error is generated. In
> some cases, this may be an issue (e.g: when using checkers in order to know
> if the database is up or down).
> My question is: Can I tell pgpool not to queue incoming connections if there
> is no free pgpool childs available?.

The queue length is limited by OS. So you will get errors if there are
too many incoming connection requests.

> some cases, this may be an issue (e.g: when using checkers in order to know
> if the database is up or down).

superuser_reserved_connections will help you. This is default to 2, so
that should not be an issue if direct connecting clients do not use
PostgreSQL super user account AND pgpool's checker uses super user
account.
--
Tatsuo Ishii
SRA OSS, Inc. Japan