[Pgpool-general] Unable to accept new connection after terminating pgpool backend process

[Arthur Chang]

Hi,

I have a question regarding terminating pgpool backend processes. We are
running one Postgres 8.4.4 node (with 2 databases on it) and using pgpool-II
2.3.3 (max_pool = 2) as a connection pool.

>From this e-mail thread (
http://www.mail-archive.com/pgpool-general@pgfoundry.org/msg01941.html), I
understand that when a backend process is killed (kill the Postgres process
manually, or using pg_terminate_backend), pgpool gets the same error code as
database down, so it initiates the failover process. However, in our
environment, we do not have a failover node. Database is unlikely to go
offline, and it is more likely that we need to manually kill a long running
query.

What we like to have is the ability to:
- Treat the error code got back from pg_terminate_backend (or the kill
command) as a regular disconnect
- Safely disconnect this particular pgpool child from the killed backend
process. If this child has more than one connections, only close the one
connects to the killed process. The other connection is not being affected.
- Other pgpool child processes are not being affected.

1) Is there a patch that we can apply to achieve this?
2) Is there a plan to introduce this as a configuration option in future
releases? I saw in the 3.0.0 release note: "- If there's only one DB node
and it triggers failover, pgpool-II will automatically connects if the DB
node coming up(Tatsuo)". Is this the same as I described? I tested 3.0.1,
but still seeing the same problem.

Btw, when I tested 3.0.1, I applied this md5 authentication patch:
http://abdulyadi.wordpress.com/2010/09/25/pgpool-ii-3-0-bug-fixes/

Thanks.
-Arthur Chang
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