RE: checkpoint incomplete issue

I've said it many times, many ways... You /cannot/ predict whether a candidate performance improvement investment will produce a relevant improvement by looking at a Statspack report. It is mathematically impossible.

Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
* Nullius in verba *

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-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Alexander Gorbachev
Sent: Saturday, November 20, 2004 3:11 AM To: Cary Millsap; oracle-l_at_freelists.org Subject: Re: checkpoint incomplete issue

Right. So there is a tradeof between concept of reusing open cursors to avoid even soft parsing and amount of redo logs generated. Unfortunately, some time ago there was a recomendation to avoid soft parses which were _too_high_ in a statspack report. On the other hand, I coundn't see that soft parses were really bad for the system - CPU consuption was relatively low and no visible latches contention. So this suggestion was something like "you have too many extents - it's bad".

-- 
Best regards,
Alex Gorbachev

On Fri, 19 Nov 2004 16:47:59 -0600, Cary Millsap
<cary.millsap_at_hotsos.com> wrote:


> Yes, of course. And it would be practically impossible to write shareable

> SQL that would allow for the update of:

> 

>        Just column 1

>        Just column 2

>        ...

>        Just column n

>        Just columns 1 and 2

>        Just columns 1 and 3

>        ...

>        Just columns 1 and n

>        Just columns 1, 2, and 3

>        Just columns 1, 2, and 4

>        ...

>        Columns 1, 2, 3, ..., and n

> 

> Unimaginable, really. But doing nothing about the problem results in

exactly


> what you've observed. A developer ought to at least be able to branch

around


> the update if /none/ of the columns' values have changed.

> 

> 

> 

> 

> Cary Millsap

> Hotsos Enterprises, Ltd.

> http://www.hotsos.com

> * Nullius in verba *

> 

> Upcoming events:

> - Performance Diagnosis 101: 1/4 Calgary

> - SQL Optimization 101: 11/8 Dallas, 12/13 Atlanta

> - Hotsos Symposium 2005: March 6-10 Dallas

> - Visit www.hotsos.com for schedule details...

> 

> -----Original Message-----

> From: Alexander Gorbachev [mailto:gorbyx_at_gmail.com]

> Sent: Friday, November 19, 2004 4:42 PM

> To: cary.millsap_at_hotsos.com

> Subject: Re: checkpoint incomplete issue

> 

> We have recently figured that out on one of our applications.

> Developers were "smart" enough updating the whole record (tens of

> fields) when even one was changed. Sometimes there are cases when

> nothing changed, but update to the whole row is made. Of course, this

> would be difficult to address for packaged applications or similar

> situation.

>
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