Re: Jboss/Oracle/select 1 form dual

From: Martin Busik <>
Date: Fri, 8 May 2009 11:00:07 +0200
Message-Id: <>

> Personally, I would shoot anyone who configures a pointless additional
> select statement to check connectivity; I blogged on
> it<>a
> couple of years ago and it has come up several times on this list. But
> that's another matter.

It may become quite hard to find the one, who is doing a "pointless additional query".

The JDBC interface contains no ping (or isAlive or similiar) method.

Connection pool implementations rely on the JDBC interface, so to check if a connection
is valid/usable, they can only execute standard conform methods, typically a "select null from dual".

Without a connection check, application users (and in the next steps admins and developers) are
bored with more or less regular errors ("The first user on monday morning gets this exception")

So, a "select null from dual" is the least evil one can choose...


Received on Fri May 08 2009 - 04:00:07 CDT

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