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 15:52:00 -0400
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. 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.
Ken
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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