db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Knut Anders Hatlen <Knut.Hat...@Sun.COM>
Subject Re: Looking for a clue or a theory
Date Mon, 16 Feb 2009 14:50:58 GMT
Bryan Pendleton <bpendleton@amberpoint.com> writes:

> I'm studying the DERBY-2487 patch proposal, and have encountered some
> strange behavior that I don't understand. I'm hoping that somebody
> on the list can make a suggestion or offer some ideas about where
> I should look.
> Below are the results of several queries against the new system table
> SYS.SYSXPLAIN_RESULTSETS which is created by the patch, after I've caused
> a couple rows to be insert into the table using the new feature. The right rows
> appear to be getting stored in the table, but there's some sort of
> subtle corruption occuring, which I don't understand.
> Note the odd behavior of the 'no_opens' column, which sometimes appears
> to have the value NULL and sometimes has the value 1.

Perhaps you could try optimizer overrides to control whether the queries
use a table scan or an index scan. If table scans and index scans
produce different results, it could be something similar to DERBY-4032.

Knut Anders

View raw message