 | | | Subject: Re: table with keep as buffer pool see much more physical reads than the num | Subject: Re: table with keep as buffer pool see much more physical reads than the num 2007-11-01 - By Vlad Sadilovskiy
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Do you have other tables assigned to KEEP buffer pool? Other tables might
overflow into KEEP buffer pool if you just configured it. Do you have
relevant AWR report to look at? I'd compare AWR reports befor and after the
change and look for relevant clues.
Vlad Sadilovskiy
Oracle Database Tools
Web site: http://www.fourthelephant.com
Blog: http://vsadilovskiy.wordpress.com
On 10/31/07, qihua wu <staywithpin@(protected)> wrote:
>
> Hi, everyone, the oracle I use is 10.2.0.2 on HPUX IA64
>
> Our job ran very slow and from AWR report I can see that a table named
ATTRIBUTE_VALUE
> consumes most of the physical IO (Physical read was more than 2.5M), as I
> know the blocks the table has is only 0.3M(block size is 8K), so I created
> a keep buffer and set the buffer pool of ATTRIBUTE_VALUE to "keep buffer".
> I was doing this to hope that once ATTRIBUTE_VALUE is read into the keep
> buffer, it will never be paged out so there the physical read will not
> exceed 0.3M (the blocks the table has). I already set the size of the keep
> buffer large enough (4G) to hold all the blocks.
>
> But after that change, ATTRIBUTE_VALUE was still read physically much more
> times than 0.3M (about 1.6M). Shouldn't it be only 0.3M if the table was
> "kept" in the buffer?
>
>
<div>Do you have other tables assigned to KEEP buffer pool? Other tables might
overflow into KEEP buffer pool if you just configured it. Do you have relevant
AWR report to look at? I'd compare AWR reports befor and after the change
and look for relevant clues.
</div>
<div> </div>
<div>Vlad Sadilovskiy<br>Oracle Database Tools<br>Web site: <a href="http://www
.fourthelephant.com/">http://www.fourthelephant.com</a><br>Blog: <a href="http:/
/vsadilovskiy.wordpress.com/">http://vsadilovskiy.wordpress.com
</a><br><br><br> </div>
<div><span class="gmail_quote">On 10/31/07, <b class="gmail_sendername">qihua
wu</b> <<a href="mailto:staywithpin@(protected)">staywithpin@(protected)</a>>
wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0
.8ex; BORDER-LEFT: #ccc 1px solid">Hi, everyone, the oracle I use is <a onclick=
"return top.js.OpenExtLink(window,event,this)" href="http://10.2.0.2/" target="
_blank">
10.2.0.2</a> on HPUX IA64<br><br>Our job ran very slow and from AWR report I
can see that a table named <span style="FONT-SIZE: 8pt; COLOR: black; FONT
-FAMILY: Arial">ATTRIBUTE_VALUE </span>consumes most of the physical IO
(Physical read was more than
2.5M), as I know the blocks the table has is only 0.3M(block size is 8K), so I
created a keep buffer and set the buffer pool of <span style="FONT-SIZE: 8pt;
COLOR: black; FONT-FAMILY: Arial">ATTRIBUTE_VALUE </span>to "keep buffer
". I was doing this to hope that once
<span style="FONT-SIZE: 8pt; COLOR: black; FONT-FAMILY: Arial">ATTRIBUTE_VALUE
</span>is read into<span style="FONT-SIZE: 8pt; COLOR: black; FONT-FAMILY: Arial
"> </span>the keep buffer, it will never be paged out so there the physical read
will not exceed
0.3M (the blocks the table has). I already set the size of the keep buffer
large enough (4G) to hold all the blocks.<br><br>But after that change, <span
style="FONT-SIZE: 8pt; COLOR: black; FONT-FAMILY: Arial">ATTRIBUTE_VALUE
</span>was still read physically much more times than 0.3M (about 1.6M).
Shouldn't it be only 0.3M if the table was "kept" in the buffer?
<br><br></blockquote></div><br>
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