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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Suggestions Needed: Latch free - library cache
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It usually involves rewriting the application. Ideally, (in the perfect
world), each required SQL is hard parsed once (by whomever is the first
to execute it since the last bounce), that person should never need to
parse it again, just rebind and re-execute as needed. Users connecting
later will parse once (this will be a soft parse cause it's in the cache
from the first guy parsing it), and then rebind and re-execute as
needed. Often, with application designs the way they are, and
particularly with pre-packaged apps, this is difficult.
=20
-Mark
=20
=20
=20
=20
Mark J. Bobak=20
Oracle DBA=20
ProQuest Company=20
Ann Arbor, MI=20
"Imagination was given to man to compensate him for what he is not, and
a sense of humor was provided to console him for what he is." --Unknown
-----Original Message----- From: Ryan [mailto:ryan.gaffuri_at_cox.net]=20 Sent: Wednesday, January 07, 2004 7:15 PM To: Multiple recipients of list ORACLE-L Subject: Re: Suggestions Needed: Latch free - library cache
how do you limit excessive soft parsing?=20
Tracy, =20 What Oracle version? If you're not patched up to thelatest patchset for your release, it's always a good idea to do so, as library cache bugs seem to invariably appear in every release.
=20 Has your code changed recently? Has your usage increased recently? =20 Finally, library cache latch contention can be a sign ofexcessive soft parsing (hard parsing usually causes more shared pool latch contention). Do you have session_cached_cursors set?
=20 Just some thoughts.... =20 -Mark =20 =20 Mark J. Bobak=20 Oracle DBA=20 ProQuest Company=20 Ann Arbor, MI=20 "Imagination was given to man to compensate him for whathe is not, and a sense of humor was provided to console him for what he is." --Unknown
-----Original Message----- From: Tracy Rahmlow [mailto:tracy.rahmlow_at_aexp.com]=20 Sent: Wednesday, January 07, 2004 5:40 PM To: Multiple recipients of list ORACLE-L Subject: Suggestions Needed: Latch free - library cache =09 =09 We have experienced intermittent problems (slowresponse time) with our oltp database today. There appears to be a large number of latch free events and the p2 parameter is indicating an issue with the library cache. Any thoughts on where to go next?=20
American Express made the following annotations on 01/07/2004 03:36:25 PM
=09 "This message and any attachments are solely forthe intended recipient and may contain confidential or privileged information. If you are not the intended recipient, any disclosure, copying, use, or distribution of the information included in this message and any attachments is prohibited. If you have received this communication in error, please notify us by reply e-mail and immediately and permanently delete this message and any attachments. Thank you."
=09
=09
=09 =09
=09
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD><TITLE>Message</TITLE> <META http-equiv=3DContent-Type content=3D"text/html; =charset=3Dus-ascii">
<META content=3D"MSHTML 6.00.2713.1100" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV><SPAN class=3D551522500-08012004><FONT face=3DArial color=3D#0000ff =size=3D2>It=20
application designs the way they are, and particularly with pre-packaged =
apps,=20
this is difficult.</FONT></SPAN></DIV>
<DIV><SPAN class=3D551522500-08012004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D551522500-08012004><FONT face=3DArial color=3D#0000ff =
size=3D2>-Mark</FONT></SPAN></DIV>
<DIV><SPAN class=3D551522500-08012004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D551522500-08012004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2></FONT> </DIV> <DIV> </DIV><!-- Converted from text/rtf format --> <P><SPAN lang=3Den-us><FONT face=3D"Comic Sans MS" color=3D#008000 =size=3D2>Mark J.=20
size=3D2>Ann Arbor,=20 MI</FONT></SPAN> <BR><SPAN lang=3Den-us><B><FONT face=3DArial = size=3D2>"Imagination=20
[mailto:ryan.gaffuri_at_cox.net] <BR><B>Sent:</B> Wednesday, January 07, =
2004=20
7:15 PM<BR><B>To:</B> Multiple recipients of list =
ORACLE-L<BR><B>Subject:</B>=20
Re: Suggestions Needed: Latch free - library =
cache<BR><BR></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>how do you limit excessive soft =
parsing?=20
</FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV><DIV=20
<A title=3DMark.Bobak_at_il.proquest.com=20 href=3D"mailto:Mark.Bobak_at_il.proquest.com">Bobak, Mark</A> </DIV> <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A = title=3DORACLE-L_at_fatcity.com=20
href=3D"mailto:ORACLE-L_at_fatcity.com">Multiple recipients of list = ORACLE-L</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Wednesday, January 07, =
2004 5:59=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> RE: Suggestions =
Needed: Latch=20
free - library cache</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>Tracy,</FONT></SPAN></DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>What Oracle version? If you're not patched up to the = latest=20
patchset for your release, it's always a good idea to do so, as = library=20
cache bugs seem to invariably appear in every = release.</FONT></SPAN></DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial = color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>Has your code changed recently? Has your usage = increased=20
recently?</FONT></SPAN></DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>Finally, library cache latch contention can be a sign of = excessive=20
soft parsing (hard parsing usually causes more shared pool latch=20
contention). Do you have session_cached_cursors=20
set?</FONT></SPAN></DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>Just some thoughts....</FONT></SPAN></DIV> <DIV><SPAN class=3D394255522-07012004><FONT face=3DArial = color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D394255522-07012004><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>-Mark</FONT></SPAN></DIV>
<DIV> </DIV> <DIV> </DIV><!-- Converted from text/rtf format --> <P><SPAN lang=3Den-us><FONT face=3D"Comic Sans MS" color=3D#008000 =size=3D2>Mark J.=20
Bobak</FONT></SPAN> <BR><SPAN lang=3Den-us><FONT face=3D"Comic Sans = MS"=20
color=3D#008000 size=3D2>Oracle DBA</FONT></SPAN> <BR><SPAN = lang=3Den-us><FONT=20
face=3D"Comic Sans MS" color=3D#008000 size=3D2>ProQuest = Company</FONT></SPAN>=20
<BR><SPAN lang=3Den-us><FONT face=3D"Comic Sans MS" color=3D#008000 = size=3D2>Ann=20
Arbor, MI</FONT></SPAN> <BR><SPAN lang=3Den-us><B><FONT face=3DArial =
size=3D2>"Imagination was given to man to compensate him for what he = is not,=20
and a sense of humor was provided to console him for what he = is." =20
--Unknown</FONT></B></SPAN></P>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV></DIV> <DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr = align=3Dleft><FONT=20 face=3DTahoma size=3D2>-----Original Message-----<BR><B>From:</B> = Tracy=20 Rahmlow [mailto:tracy.rahmlow_at_aexp.com] <BR><B>Sent:</B> = Wednesday,=20 January 07, 2004 5:40 PM<BR><B>To:</B> Multiple recipients of list = ORACLE-L<BR><B>Subject:</B> Suggestions Needed: Latch free - = library=20 cache<BR><BR></FONT></DIV><BR><FONT face=3Dsans-serif size=3D2>We = have=20 experienced intermittent problems (slow response time) with our = oltp=20 database today. There appears to be a large number of latch = free=20 events and the p2 parameter is indicating an issue with the = library cache.=20 Any thoughts on where to go next? </FONT> <P>American Express made the following<BR>annotations on = 01/07/2004=20 03:36:25=20 = PM<BR>-------------------------------------------------------------------= -----------<BR>**********************************************************= ********************<BR><BR>"This=20 message and any attachments are solely for the intended recipient = and may=20 contain confidential or privileged information. If you are not the = intended recipient, any disclosure, copying, use, or distribution = of the=20 information included in this message and any attachments is = prohibited. If=20 you have received this communication in error, please notify us by = reply=20 e-mail and immediately and permanently delete this message and any = attachments. Thank=20 = you."<BR><BR>************************************************************= ******************<BR><BR><BR>=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D==3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Bobak, Mark INET: Mark.Bobak_at_il.proquest.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Wed Jan 07 2004 - 18:29:26 CST
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