Re: Poor Oracle performance? getting rid of bind variables
Re: Poor Oracle performance? getting rid of bind variables
- Subject: Re: Poor Oracle performance? getting rid of bind variables
- From: Ken Anderson <email@hidden>
- Date: Tue, 21 Aug 2007 16:17:15 -0400
Sorry Chuck - now that this has been solved, no time to
investigate... but thanks!
On Aug 21, 2007, at 4:05 PM, Chuck Hill wrote:
On Aug 21, 2007, at 12:52 PM, Ken Anderson wrote:
According to the DBA, we're using the Rule Based Optimizer, not
the Cost Based Optimizer, so therefore, no statistics.
They claim there are indexes in on the table, but running a query
against user_indexes returns 0 rows.
Unfortunately, their contention is that I must be crazy, and are
not paying much attention to me.
That reminds me of how much I enjoy using FrontBase. ;-)
There aren't any other WO developers here, so they are not very
helpful when I tell them that I can do queries without bind
variables.
Lastly, it's clear that JDBCExpression can't create non-bind
qualifiers, since trying Chuck's hack results in getting no data
back from the DB... weird.
I might have missed something, that was totally off the top of my
head. What SQL did it generate?
Try adding this to OracleExpressionNoBindings:
public boolean useBindVariables() {
return true;
}
Chuck
On Aug 21, 2007, at 3:45 PM, Wiktor Moskwa wrote:
Guido Neitzer wrote:
That makes no sense if it works with non-bound variables. You
need the
statistics for both ...
No you don't statistics for executing a query.
In absence of them the Rule Based Optimizer was used in releases
prior to 10g. I'm not sure about 10g's behaviour.
In this case statistics are probably incomplete: not available for
all necessary columns or not for all indexes. Or some indexes are
missing.
On the other hand low cardinality column "Is_option_contract" can
confuse the optimizer.
Of course without knowledge about that particular table we can only
guess.
--
Wiktor Moskwa
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