Well, what we tried was swapping out <check-valid-connection-sql >select 'hello' from dual </check-valid-connection-sql > for <!--valid-connection-checker-class-name>org.jboss.resource.adapter.jdbc. vendor.OracleValidConnectionChecker</valid-connection-checker-class-name --> However that seems to generate an equal number of select 'x' from dual statements so I don't know that we've gained very much. Anyone have other suggestions? Jay Miller Sr. Oracle DBA 201.369.8355 ________________________________ From: Jared Still [mailto:jkstill@xxxxxxxxx] Sent: Thursday, October 23, 2008 6:10 PM To: Miller, Jay Cc: oracle-l@xxxxxxxxxxxxx Subject: Re: JBoss keeps sending select 'hello' from dual Don't keep us in suspense like that. What was it? Jared Still Certifiable Oracle DBA and Part Time Perl Evangelist On Thu, Oct 23, 2008 at 1:47 PM, <Jay.Miller@xxxxxxxxxxxxxxxx> wrote: Never mind. I tried some different search terms in Google after sending this out and think I've found the answer. Sorry about that. Jay Miller -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Jay.Miller@xxxxxxxxxxxxxxxx Sent: Thursday, October 23, 2008 4:34 PM To: oracle-l@xxxxxxxxxxxxx Subject: JBoss keeps sending select 'hello' from dual While investigating some performance issues on two unrelated databases one of the odd things we found was a huge number of "select 'hello' from dual" statements hitting the databases (as in over a million/hour). Further investigation leads us to believe that this is a standard feature of JBoss connection pooling and the method it uses to check if a connection is still alive but we couldn't find any real details on it. Just wondering if anyone else has encountered this before and can point me to additional information or any way of reducing its impact. Thanks, Jay Miller -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l