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 14:58:32 -0400
Wiktor,
Here's the query:
SELECT t0.Hub_ID, t0.Is_option_contract, t0.Market_id, t0.Product_ID,
t0.Settlement_change, t0.Settlement_price_date, t0.Settlement_price,
t0.Settlement_price_id, t0.Strip, t0.Strip_begin_date,
t0.Strip_end_date, t0.Strip_type FROM Settlement_prices t0 WHERE
(t0.Product_ID = 451 AND t0.Hub_ID = 620 AND t0.Settlement_price_date
= '20-Aug-07' AND t0.Is_option_contract = 'N')
When generated from EOF, all 4 where clause are bind variables.
Unfortunately, I don't have access to much database wise... all I
can do is complain to the DBAs.
How can I find out what indexes are on the table, and/or what a plan
would be? Also, is there a way to run a query with bind variables
from isqlplus?
Thanks much,
Ken
On Aug 21, 2007, at 2:47 PM, Wiktor Moskwa wrote:
Ken Anderson wrote:
I'm killing my database now. I'm querying against a table that has
millions of rows, but I only need 20-30. With bind variables, it
takes
over 20 seconds - without them, a few hundred milliseconds.
That means for 99% that statistics are not available.
Gather them and check the query plan again.
The other 1% percent is reserved for certain cases when optimizer
needs to be hinted or special indexes created.
If you post the statement and table/index DDL I'll be glad to help.
By not using bind variables every SQL statement will have to be hard
parsed every time it is send to the database. Hard parsing basically
means serializing access to some parts of database's shared memory.
--
Wiktor Moskwa
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