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Connection pool - check what blocks connections

Michal Glowacki
Ranch Hand

Joined: Mar 14, 2006
Posts: 114
hi all,

I have sometimes a problem with connections being blocked in pool. I use JBoss AS and Postgres, connection pool with standard params: max size 100, blocking timeout 30000ms. Usually I see that 0-5 connections are in use, but there are moments (once per few days, but as I keep getting more and more visitors it's more often now) when I got 60, and even 100 and start getting 'no managed connections available' error. Flushing pool helps.

Probably some parts of the code are blocking connections. How can I find them?

Scott Selikoff
Saloon Keeper

Joined: Oct 23, 2005
Posts: 3739

I'd guess there are cases where connections aren't properly closed. All places where connections are established should be followed by a finally {} block that closes the connection.

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It is sorta covered in the JavaRanch Style Guide.
subject: Connection pool - check what blocks connections