Обсуждение: JDBC Transaction Isolation level 4 - Serializable problem

I can't seem to get the JDBC driver to accept serializable transaction
isolation levels.

Does the driver support it ?

I have tried with pg73jdbc1.jar, pg73jdbc2.jar, pg73jdbc2ee.jar,
pg73jdbc3.jar and devpgjdbc3.jar.

The error that I am getting is :

org.postgresql.util.PSQLException: Transaction isolation level 4 is not
supported.
    at
org.postgresql.jdbc1.AbstractJdbc1Connection.setTransactionIsolation(AbstractJdbc1Connection.java:1414)

If this is the case (that it's not supported) are there plans to
implement it ?

I can't fund any specific information on the driver's features on the
internet.  Either at jdbc.postgresql.org or through google.

Thanks,

Cameron

--
Any damn fool can write code that a computer can understand...
The trick is to write code that humans can understand.
[Martin Fowler http://www.martinfowler.com/distributedComputing/refactoring.pdf]

On Thu, Nov 20, 2003 at 02:53:34PM +1000, Cameron Braid wrote:
> I can't seem to get the JDBC driver to accept serializable transaction
> isolation levels.
>
> Does the driver support it ?
>
> I have tried with pg73jdbc1.jar, pg73jdbc2.jar, pg73jdbc2ee.jar,
> pg73jdbc3.jar and devpgjdbc3.jar.
>
> The error that I am getting is :
>
> org.postgresql.util.PSQLException: Transaction isolation level 4 is not
> supported.
>    at
> org.postgresql.jdbc1.AbstractJdbc1Connection.setTransactionIsolation(AbstractJdbc1Connection.java:1414)
>
> If this is the case (that it's not supported) are there plans to
> implement it ?

Level 4 is Connection.TRANSACTION_REPEATABLE_READ according to my javadoc.
TRANSACTION_SERIALIZABLE is 8 and should be supported.

There was some discussion about whether the driver should use the
next-higher level rather than failing in this case but I think the
conclusion was it's better to only set the levels that are directly
supported by the backend (READ_COMMITTED and SERIALIZABLE), and that the
application can upgrade the level it requests if needed based on querying
the driver's DatabaseMetaData.

-O

On Thu, 20 Nov 2003, Oliver Jowett wrote:

> There was some discussion about whether the driver should use the
> next-higher level rather than failing in this case but I think the
> conclusion was it's better to only set the levels that are directly
> supported by the backend (READ_COMMITTED and SERIALIZABLE), and that the
> application can upgrade the level it requests if needed based on querying
> the driver's DatabaseMetaData.
>

Recently the backend was changed to do the automatic transaction level
upgrade, so perhaps we should too.

Kris Jurka