Hi Chew Yee Chuang, My apologies for the quite late response. On 24-05-2007 13:22:39 +0800, Chew Yee Chuang wrote:

Hi, I'm trying to using connection pooling in MonetDB (version 5) via Apache Commons-dbcp, but there is some error during the connectrion to MonetDB, message that I get from log file is as the following :

Caused by: org.apache.commons.dbcp.SQLNestedException: Cannot get a connection, pool exhausted ...... Caused by: java.util.NoSuchElementException: Could not create a validated object, cause: writable mode not supported ... 64 more

Writable resultsets are indeed not supported. If Mondrian needs that, then we're at a dead end, as we don't intend to implement such thing soon.

Can anyone show me the correct way to implement connection pooling with MonetDB ? Or it is not supported in the current release of MonetDB ?

Pooling works fine, unfortunately your application requires a feature we don't support.

Beside, I also found that the aliased columns not recognized after "group by... order by", my SQL statement could as the following...

SELECT name AS n FROM students ORDER BY name;

And the error message I get was ORDER BY: no such column "name".

Ah... I'm not sure what the standard says about that. It looks like a bug to me, however. Would you mind reporting a bug on that one?

Im very new to MonetDB, and wants to used it with Modrian OLAP for reporting purposes, I really appreciate any help in this. Thanks

I'm affraid some serious efforts need to be made to get MonetDB working with Mondrian. Regards