Re: Does primary key structure impact UPDATE performance?
- From: Tanel Põder <tanel.poder.003@xxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 17 May 2004 18:47:26 +0300
Assuming, that you're running on decent CPUs, it seems strange that 2371
consistent reads and 1 current read require 1,72 seconds of CPU time (even
in the very unlikely event when CPU usage between every physical IO would
heve been overaccounted due quantization error).
This PL/SQL loop, does it open a cursor and keep it open for a long time?
That way several rollback segment block gets might be required to satisfy a
consistent read, that could explain high CPU usage per LIO in extreme cases.
(But it wouldn't explain why there is such a difference between two tables
w. different indexes).
Maybe query definitions + execution plans would give some more clues...
Tanel.
----- Original Message -----
From: "Khedr, Waleed" <Waleed.Khedr@xxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Monday, May 17, 2004 5:18 PM
Subject: RE: Does primary key structure impact UPDATE performance?
> This should be found easily by getting the execution plan out of the =
> trace file (the STATS lines) and see if there is a UNIQUE SCAN or =
> something else.
>
> Waleed
>
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