IDS Forum

RE: Performance Issues

Posted By: Simmons, Keith
Date: Tuesday, 17 May 2005, at 6:00 a.m.

In Response To: Performance Issues (SUE SIMMONDS)

Sue
on_archive is not supplied as it is unreliable, get off it NOW, even =
ontape is better, more reliable, simple to use etc. etc.
Have you run 'update statistics' recently?
=20
Keith

-----Original Message-----
From: sues@hmgcc.gsi.gov.uk [mailto:sues@hmgcc.gsi.gov.uk]
Sent: Tuesday, May 17, 2005 10:42 AM
To: Simmons, Keith; ids@iiug.org
Subject: Re: Performance Issues [4950]=20


=20
If I reset the stats (onstat -z) the % writes cached figure starts =
initially at about=20
onstat -p is now showing=20

Informix Dynamic Server 2000 Version 9.21.HC6X6 -- On-Line -- Up =
21:46:09 -- 377200 Kbytes
=20
Profile
dskreads pagreads bufreads Êched dskwrits pagwrits bufwrits Êched
1599258 7628062 139203779 98.85 1297984 773787 1091868 0.00 =20
=20
I know we are running an old patched version of the engine but we are =
currently running on-archive for our backups and on-archive is not =
supported, or even supplied with 9.4. I am currently trying to upgrade =
to on-bar before upgrading to 9.4, but that is another issue !!!
=20
Fuzzy Checkpoints are generally taking between 1 and 3 seconds but =
occassionally as long as 30 !!!
=20
onstat -F shows
=20

Fg Writes LRU Writes Chunk Writes=20
0 500148 108425 =20
=20
And yes the users have been complaining, things are obviously running =
slower than they used to.
=20
I also need to check the fragmentation of the main table in my document =
management system, as suggested by Robert Roussey in a previous posting.
=20
=20
Sue
=20



----- Original Message -----=20
From: Simmons, Keith <mailto:keith.simmons@office2office.biz> =20
To: sues@hmgcc.gsi.gov.uk ; ids@iiug.org=20
Sent: 17 May 2005 9:12 AM
Subject: RE: Performance Issues [4950]=20


Sue

Êched reads now looks OK, don't believe the cached writes ! ,I think =
the engine is lying. IDS 9.21 is very old, any chance of updating to =
9.4? The X in HC6X6 indicates a patched engine, even more reason to =
upgrade to a more supported version.
What are your checkpoints like? What about onstat -F? I there any user =
perception of slow running?

Keith

-----Original Message-----
From: sues@hmgcc.gsi.gov.uk [mailto:sues@hmgcc.gsi.gov.uk]
Sent: Monday, May 16, 2005 2:10 PM
To: Simmons, Keith; ids@iiug.org
Subject: Re: Performance Issues [4950]=20

I have now increased the buffers from 40000 to 80000, LRU from 10 to 20 =
and CLEANERS from 12 to 24 and bounced the server.=20
The server has been up for just over 1 hour and onstat -p shows

Informix Dynamic Server 2000 Version 9.21.HC6X6 -- On-Line -- Up =
01:22:18 -- 377200 Kbytes

Profile
dskreads pagreads bufreads Êched dskwrits pagwrits bufwrits Êched
96659 125354 23467579 99.59 151039 104045 101784 0.00 =20

isamtot open start read write rewrite delete commit =
rollbk
24314753 800197 1291125 15254883 3177 232 2364 588 =
3

gp_read gp_write gp_rewrt gp_del gp_alloc gp_free gp_curs=20
24609 12 2271 8 0 0 22 =20

ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes=20
0 0 0 1004.44 50.46 17 36 =20

bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans
3239 28 25717535 1 0 5 491 12376 =20

ixda-RA idx-RA da-RA RA-pgsused lchwaits
4422 136 32039 36480 71 =20

Sue

----- Original Message -----=20
From: Simmons, Keith=20
To: SUE SIMMONDS ; ids@iiug.org=20
Sent: 16 May 2005 9:21 AM
Subject: RE: Performance Issues [4950]=20


Sue

40,000 buffers seems a bit low, especially as you have hit
some foreground writes. What does a full onstat -p show (especially
over a period of time, what is changing the most). How long are
checkpoints taking?
If you have the memory available I would try doubling buffers as a
first step and are fully monitor checkpoints with a view to reducing
LRU percentages. Probably need to double (or more) number of LRUs
and CLEANERs.
Any clues from Unix side? sar -d ? sar ?

Keith


-> -----Original Message-----
-> From: SUE SIMMONDS [mailto:sues@hmgcc.gsi.gov.uk]
-> Sent: Friday, May 13, 2005 10:33 PM
-> To: ids@iiug.org
-> Subject: Performance Issues [4950]=20
->=20
->=20
-> I am running IDS 9.21.HC6 on HP UX 11.0. Until recently=20
-> everything has been running smothly but over the last 2/3=20
-> weeks users have reported problems with one of our=20
-> applications delivered over the web.
->=20
-> I have also noticed that the % reads cached figure (onstat=20
-> -p) is very low, sometimes 0%, so I knew something was very wrong !!
->=20
-> Last week I noticed multiple ETXFilterServers running (for=20
-> the Excalibur index in the database). I killed off the=20
-> excess and bounced the server. And all seemed OK. The %=20
-> reads cached figure was up in the 70's, not as good as it=20
-> should be but better.
->=20
-> At the weekend I was running lots of dbexports/dbimports and=20
-> the =CAched figure was about 85%, as expected. As soon as the=20
-> users logged on this morning and started running our web=20
-> applications the =CAched figure slowly dropped and is now 19.44%.
->=20
-> I have 40000 buffers defined for 8 LRU queues,
->=20
-> onstat -b shows 836 modified, 0 resident, 40000 total
->=20
-> onstat -F shows 2 Fg write, 534203 LRU writes, 57178 Chunk writes
->=20
-> onstat -R shows 5 dirty, 40000 queued, 40000 total, start clean at 4%
-> (160), stop at 2%
->=20
-> As far as I am aware nothing has changed on the Database=20
-> server but I am not sure about the Web Server. I am also not=20
-> very familiar with the Excalibur Text Search Datablade and=20
-> the ETXFilterServers.
->=20
-> Our web applicaiton is a document management system=20
-> delivered over the web and users are experiencing problems=20
-> bookings documents back in, as it seems to ages and=20
-> sometimes the browser is timing out (we currently have a 5=20
-> minute timeout set on the server).
->=20
-> Does anyone have any ideas what might be causing these=20
-> problems, or anything else I need to check/monitor ???
->=20
-> Sue=20
->=20

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The information contained in this message (and any attachments) may be =
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the intended recipient is unauthorised. If you are not the intended =
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Messages In This Thread

• Performance Issues
  SUE SIMMONDS -- Friday, 13 May 2005, at 5:32 p.m.
  • RE: Performance Issues
    Simmons, Keith -- Monday, 16 May 2005, at 4:27 a.m.
  • RE: Performance Issues
    Simmons, Keith -- Tuesday, 17 May 2005, at 4:18 a.m.
  • RE: Performance Issues
    Simmons, Keith -- Tuesday, 17 May 2005, at 6:00 a.m.
  • RE: Performance Issues
    Simmons, Keith -- Tuesday, 17 May 2005, at 8:26 a.m.
    • Re: Performance Issues
      Michael Hoffman -- Tuesday, 17 May 2005, at 11:34 a.m.

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