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?
>
Most JDBC drivers contact the server to parse and validate that the SQL
is actually correct, and that the tables that are part of the query
exist, and have the columns that are referenced. If the connection is
unable to communicate with the backend server then the JDBC driver would
throw a SQLException back.
From the sounds of things Sybase's driver is deferring the parse until
actual execution. Or its because a Sybase proxy table is really a
stored procedure which executes and fetches from the remote database
that is confusing things. I don't have access to Sybase - but I do
wonder if validation works with a regular table in the local database
the application server connects to, i.e. is it a problem for all tables
or just proxy tables?
>
>> * 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.
>
> So my question is: WHY is GlassFish not really fetching data from the driver in the table mode?
>
> 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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>
>