Hi Dustin,
As you note, the Derby query optimizer only considers left-deep trees. I
have logged an enhancement request for support for bushy query plans:
DERBY-4327. If many people vote for this issue, we can consider it for
the next Derby feature release.
Regards,
-Rick
Dustin T. Clifford wrote:
All,
We have implemented a star schema and we are noticing that queries
involving 5 or more joins perform very slowly. We have, also, noticed
that batch updates and deletes perform slowly. We support multiple
databases and, as we improve on performance in SQL Server and Oracle,
we notice a trend in the opposite direction with Derby.
I know that the Derby optimizer use to only consider left-deep
trees. Is this still true or is there another optimizer that we can
use? Does anybody have any advise on working in a manner that can
provide good performance on Derby, SQL Server and Oracle? Any advice
would be appreciated.
*Dustin Clifford*
