RE: more on 'high cpu...'
- From: "Randy Johnson" <randyjo@xxxxxxxxxxxxx>
- To: "'ORACLE-L'" <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 2 Jul 2007 11:22:19 -0500
Yes. By doing a distinct you are basically telling Oracle not to send you
anything until it has fetched the entire results. When you take out the
distinct then Oracle can start sending you results while it continues to
execute the query. This is because In order to give you a "distinct" set it
must retrieve the complete result set then do a sort on it to find the
unique values. Without the distinct qualifier you are probably getting a
"first rows" type execution.
-Randy
Randy Johnson
Sr. Technical Consultant
Enkitec, LLP
Office ..... 817-255-3580
Mobile .... 817-564-6583
Email ..... randy.johnson@xxxxxxxxxxx
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Joe Armstrong-Champ
Sent: Monday, July 02, 2007 10:35 AM
To: ORACLE-L
Subject: more on 'high cpu...'
I'm still doing the traces but in the meantime I thought I'd ask a follow up
question. The query is selecting from a view. The view returns hundreds of
rows relatively quickly. The query itself is selecting DISTINCT rows from
the view. When I take out the distinct it returns almost instantaneously.
With the distinct in it takes 40 - 50 secs. Does this ring a bell with
anyone?
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