On Sat, 2004-01-17 at 17:04, Nicholas wrote: > What is a good estimation model for determining the > prepared statement cache size ? > > About how much memory (or other overhead > considerations) would anyone estimate a cached > prepared statement will consume ?
One thing you need to remember is that prepared statements are cached per connection. The more connections you have, the more prepared statements you get (even when they are the same query). But it depends upon the db, jdbc driver and your queries. If you hold a prepared statement open, you are asking the db to precompile an access plan to handle the query. Some dbs might even create a temporary index. On others it might do little more than parse and validate the query. You avoid some parsing/metadata lookups because they are stored in the prepared statement. This can use memory within jboss, but it depends on the jdbc driver. This can be a common source of memory leaks so check your driver provider for patches. Also remember the prepared statement is not closed. You have to explicity close result sets yourself, something that is normally done at statement close. I can't give any more advice other than measure it, don't forget to analysis the impact on your db. Theory must always be validated by experiment. Regards, Adrian > > Thanks. > > //Nicholas > > ===== > Nicholas Whitehead > Home: (973) 377 9335 > Cell: (201) 615 2716 > [EMAIL PROTECTED] > Get Your News From The Crowbar: http://crowbar.dnsalias.com:443/crowbar/ > > > ------------------------------------------------------- > The SF.Net email is sponsored by EclipseCon 2004 > Premiere Conference on Open Tools Development and Integration > See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. > http://www.eclipsecon.org/osdn > _______________________________________________ > JBoss-user mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/jboss-user -- xxxxxxxxxxxxxxxxxxxxxxxx Adrian Brock Director of Support Back Office JBoss Group, LLC xxxxxxxxxxxxxxxxxxxxxxxx ------------------------------------------------------- The SF.Net email is sponsored by EclipseCon 2004 Premiere Conference on Open Tools Development and Integration See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. http://www.eclipsecon.org/osdn _______________________________________________ JBoss-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-user
