Hello: Thanks a lot! I am worrying about the overhead,because I don't know what iBatis3 will do when I enable poolPingQuery. I will try your idea soon.Thanks again!
陈抒 Best regards http://blog.csdn.net/sheismylife 2010/5/12 François Schiettecatte <fschietteca...@gmail.com> > 陈抒 > > Not sure which RDBMS you are using. Ideally you want to set the idle > connection timeout in your pool to a value smaller than the idle connection > timeout on the server end, the errors you were seeing suggests that the > server has dropped the connection while the pool thinks it is still ok. From > my limited experience 'autoReconnect=true' is not recommended, here is an > excerpt from the MySQL documentation: > > ---- > Should the driver try to re-establish stale and/or dead connections? If > enabled the driver will throw an exception for a queries issued on a stale > or dead connection, which belong to the current transaction, but will > attempt reconnect before the next query issued on the connection in a new > transaction. The use of this feature is not recommended, because it has side > effects related to session state and data consistency when applications > don't handle SQLExceptions properly, and is only designed to be used when > you are unable to configure your application to handle SQLExceptions > resulting from dead and stale connections properly. Alternatively, > investigate setting the MySQL server variable "wait_timeout" to some high > value rather than the default of 8 hours. > ---- > > What you are doing will work but there is overhead associated with it, and > you might want use a query like 'select 1' rather than hitting the jobstatus > table. And you might want to read up on 'poolPingConnectionsNotUsedFor' on > page 20 of the documentation, the default value is 0 which means the > connection is pinged before every use. > > I would recommend you check into these parameters to see if you can do away > with the ping query: > > <property name="poolMaximumActiveConnections" value="10" /> > <property name="poolMaximumIdleConnections" value="5" /> > <property name="poolMaximumCheckoutTime" value="20000" /> > <property name="poolTimeToWait" value="20000" /> > > Cheers > > François > > On May 12, 2010, at 6:57 AM, 陈抒 wrote: > > > I don't know. > > But I took one hour to test my application again,it works fine if the > 'time out' problem doesn't occurs. > > Now I add two properties,let's wait and see if it can solve this or not. > > <property name="poolPingQuery" value="select * from jobstatus"/> > > <property name="poolPingEnabled" value="true"/> > > > > 陈抒 > > Best regards > > http://blog.csdn.net/sheismylife > > > > > > On Wed, May 12, 2010 at 6:46 PM, Martin Ellis <mar...@ellis.name> wrote: > > On 12 May 2010 02:31, 陈抒 <csfreeb...@gmail.com> wrote: > > > Caused by: java.lang.NullPointerException > > > at freebird.business.Email.getReceiverList(Email.java:105) > > > > What caused this NullPointerException? > > Is it really related to the connection option? > > > > Martin > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: user-java-unsubscr...@ibatis.apache.org > > For additional commands, e-mail: user-java-h...@ibatis.apache.org > > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-java-unsubscr...@ibatis.apache.org > For additional commands, e-mail: user-java-h...@ibatis.apache.org > >
