On Wed, 2008-10-29 at 17:14 +0100, Markus Karg wrote:
> > Table based validation will do a
> > select count(*) from table. Yes, its the jdbc-driver that is not doing
> > fetch from database.
> > * What database and driver do you use ?
>
> Sybase SQL Anywhere 11.0, iAnywhere driver
>
> > There are two other modes, auto-commit and meta-data. Now a days, these
> > are cached by several jdbc drivers and the reliable mode is 'table'.
> > http://blogs.sun.com/JagadishPrasath/entry/connection_validation_in_gla
> > ssfish_jdbc
>
> Well, as it seems it is *not* reliable since the JDBC driver does not do a FETCH. I assume that the driver has no fault but instead GlassFish is not really asking it to do a fetch?
So far, I have not seen any other jdbc-driver doing so.
Validation would be done for every get connection. It will have (more)
performance impact if it were to scroll through the results. Wouldn't a
select query be enough ?
>
> > * Probably, you can try these other modes and see whether the issue is
> > resolved.
>
> Unfortunately due to technical reasons I really need to check exactly for that specific table -- it is a proxy forwarding to another server, so it is my only chance. All the other modes do not help me.
Interesting. What happens if you do
select count(*) from TABLE_THAT_IS_PROXY on a simple java client ? I
would expect that the jdbc-driver will not communicate with the server.
What happens if you give the actual table name instead of proxy table ?
>
> So my question is: WHY is GlassFish not really fetching data from the driver in the table mode?
Please refer my first response above.
Thanks,
-Jagadish
>
> Thanks
> Markus
>
> >
> > Thanks,
> > -Jagadish
> >
> >
> > On Tue, 2008-10-28 at 08:15 +0100, Markus Karg wrote:
> > > Dear Community,
> > >
> > >
> > >
> > > it seems as if the "table" method for JDBC Connection Validation just
> > > checks whether the SQL is correct, but not really tries to fetch any
> > > data from that table. The problem is that this is completely answered
> > > by the JDBC driver of my dbms, even if the connection is broken! How
> > > can I tell GlassFish that it really must fetch data?
> > >
> > >
> > >
> > > Thanks
> > >
> > > Markus
> > >
> > >
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