RE: IDS/BaaN performance issues

Posted in 1999

Topics: Performance & Tuning, Installation, Setup & Upgrades, Server Administration, Platform-Specific Issues

Willem Roos — Wed, 29 Sep 1999 10:51:28 +0200 — source: Informix-list mailing list archive (1991-1998)

This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01BF0A57.D17E5254 Content-Type: text/plain; charset="iso-8859-1" Does this buffer management funniness hold for all releases prior to 7.30.UC7? Like 7.30.UC2 which i'm running (no BaaN/SAP/etc) T -----Original Message----- From: Greg [mailto:greg@fastlane.net] Sent: Wednesday, September 29, 1999 2:06 AM To: informix-list@iiug.org Subject: Re: IDS/BaaN performance issues Russ - keep in mind I can barely spell BaaN, but SAP has gotten bit hard by 7.30 releases prior to 7.30.UC7XK. There's a bug in the new buffer management that eventually leaves you all but unable to keep a data page in memory, producing low buffer hit ratios like you have. The XK release essentially turns it off, reverting to the 7.2x style. Your BUFFERS probably do need to be higher, but as long as you have this bug, it won't help. Actually, it will probably hurt. And UC5 was particularly bad - there were customers who switched within (2) days to another release looking for relief. Greg russ_kahler@andersonsinc.com wrote: > Greetings, > > We are running IDS version 7.30.uc5 on a 4-way HP 9000 K-250 with 2.25 > GB of memory, and HP-UX 10.20. We are also a BaaN installation running > b40c4 with about 20 production users, and 25 test users. > > We have been experiencing performance difficulties with BaaN, and I have > modified our onconfig to try to adjust for this. I recently added memory > to bring it up to 2.25 GB, and also adjusted the SHMVIRTSIZE,BUFFERS,and > CLEANERS to try and make better use of the added memory. What I saw > however in onstat -p was a decline in both read cache % and write cache > %. Are buffers still an issue here? > > Also, where I do an onstat -g glo, it seems as if the virtual processors > are not balancing the loads between them, as one processor seems to be > doing 2X the work of the other two. I am able to confirm this by running > glance- as the oninit processes are using only 20 -40% of the CPU, while > the rest sit idle. Informix technical support says this is normal, but > that just doesn't seem right. > > Thanks for any help you can give. Here is the info: > > onstat -p :> > Informix Dynamic Server Version 7.30.UC5 -- On-Line -- Up 14:20:53 -- > 421160 K > bytes > > Profile > dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached > 7536503 12194535 78503378 90.40 111959 163941 661937 83.09 > > isamtot open start read write rewrite delete commit > rollbk > 36612289 443031 1916363 29251116 68550 113615 19749 51768 > 0 > > gp_read gp_write gp_rewrt gp_del gp_alloc gp_free gp_curs > 0 0 0 0 0 0 0 > > ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes > 0 0 0 6499.98 1867.23 69 344 > > bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans > 526588 0 30721288 0 0 15 8138 13609 > > ixda-RA idx-RA da-RA RA-pgsused lchwaits > 4436892 11 1311 4423770 3720 > > onstat -g glo> > Informix Dynamic Server Version 7.30.UC5 -- On-Line -- Up 14:22:21 -- > 421160 K > bytes > > ------_=_NextPart_001_01BF0A57.D17E5254 Content-Type: text/html; charset="iso-8859-1" <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <META NAME="Generator" CONTENT="MS Exchange Server version 5.5.2448.0"> <TITLE>RE: IDS/BaaN performance issues</TITLE> </HEAD> <BODY> Does this buffer management funniness hold for all releases prior to 7.30.UC7? Like 7.30.UC2 which i'm running (no BaaN/SAP/etc) T -----Original Message----- From: Greg [<A HREF="mailto:greg@fastlane.net">mailto:greg@fastlane.net</A>] Sent: Wednesday, September 29, 1999 2:06 AM To: informix-list@iiug.org Subject: Re: IDS/BaaN performance issues Russ - keep in mind I can barely spell BaaN, but SAP has gotten bit hard by 7.30 releases prior to 7.30.UC7XK.  There's a bug in the new buffer management that eventually leaves you all but unable to keep a data page in memory, producing low buffer hit ratios like you have.  The XK release essentially turns it off, reverting to the 7.2x style.  Your BUFFERS probably do need to be higher, but as long as you have this bug, it won't help.   Actually, it will probably hurt.   And UC5 was particularly bad - there were customers who switched within (2) days to another release looking for relief. Greg russ_kahler@andersonsinc.com wrote: > Greetings, > > We are running IDS version 7.30.uc5 on a 4-way HP 9000 K-250 with 2.25 > GB of memory, and HP-UX 10.20. We are also a BaaN installation running > b40c4 with about 20 production users, and 25 test users. > > We have been experiencing performance difficulties with BaaN, and I have > modified our onconfig to try to adjust for this. I recently added memory > to bring it up to 2.25 GB, and also adjusted the SHMVIRTSIZE,BUFFERS,and > CLEANERS to try and make better use of the added memory. What I saw > however in onstat -p was a decline in both read cache % and write cache > %. Are buffers still an issue here? > > Also, where I do an onstat -g glo, it seems as if the virtual processors > are not balancing the loads between them, as one processor seems to be > doing 2X the work of the other two. I am able to confirm this by running > glance- as the oninit processes are using only 20 -40% of the CPU, while > the rest sit idle. Informix technical support says this is normal, but > that just doesn't seem right. > > Thanks for any help you can give. Here is the info: > > onstat -p : > > Informix Dynamic Server Version 7.30.UC5   -- On-Line --

↪ replying to Willem Roos

Art S. Kagel — Wed, 29 Sep 1999 10:36:43 -0400 — source: Informix-list mailing list archive (1991-1998)

Willem Roos wrote: > > Does this buffer management funniness hold for all releases prior to > 7.30.UC7? > Like 7.30.UC2 which i'm running (no BaaN/SAP/etc) Yes. The bug has two parts. It seems that the new buffer priority code depends on the pagetype flags on each index page to indicate whether the page is a node or leaf. If not set properly then all index pages are given MED-HIGH priority which eventually starves out data pages which are MEDIUM priority. IDS 7.2x was sloppy about setting this flag properly so if you upgraded from 7.2x to 7.3x you need to rebuild all active (or perhaps all) indexes to relieve the problem. HOWEVER, it does not stop there. In 7.3x the index compression code, which cleans up empty index pages and merges mostly empty ones after deletes, still does not properly set the flag so your indexes will become problematic after a very short time on any tables where rows are deleted often. Vers 7.31 alleviates the problem somewhat because it implements priority aging so the priority of older pages is reduced over time. There is also a patched version of 7.30 and 7.31 with a fix to the bug (don't remember the PTS bug # right now) and the latest versions have the fix in them. Art S. Kagel > T > > -----Original Message----- > From: Greg [mailto:greg@fastlane.net] > Sent: Wednesday, September 29, 1999 2:06 AM > To: informix-list@iiug.org > Subject: Re: IDS/BaaN performance issues > > Russ - keep in mind I can barely spell BaaN, but SAP has gotten bit hard by > 7.30 releases prior to 7.30.UC7XK. There's a bug in the new buffer > management that eventually leaves you all but unable to keep a data page in > memory, producing low buffer hit ratios like you have. The XK release > essentially turns it off, reverting to the 7.2x style. Your BUFFERS > probably do need to be higher, but as long as you have this bug, it won't > help. Actually, it will probably hurt. And UC5 was particularly bad - > there were customers who switched within (2) days to another release looking > for relief. > > Greg > > russ_kahler@andersonsinc.com wrote: > > > Greetings, > > > > We are running IDS version 7.30.uc5 on a 4-way HP 9000 K-250 with 2.25 > > GB of memory, and HP-UX 10.20. We are also a BaaN installation running > > b40c4 with about 20 production users, and 25 test users. > > > > We have been experiencing performance difficulties with BaaN, and I have > > modified our onconfig to try to adjust for this. I recently added memory > > to bring it up to 2.25 GB, and also adjusted the SHMVIRTSIZE,BUFFERS,and > > CLEANERS to try and make better use of the added memory. What I saw > > however in onstat -p was a decline in both read cache % and write cache > > %. Are buffers still an issue here? > > > > Also, where I do an onstat -g glo, it seems as if the virtual processors > > are not balancing the loads between them, as one processor seems to be > > doing 2X the work of the other two. I am able to confirm this by running > > glance- as the oninit processes are using only 20 -40% of the CPU, while > > the rest sit idle. Informix technical support says this is normal, but > > that just doesn't seem right. > > > > Thanks for any help you can give. Here is the info: > > > > onstat -p :> > > > Informix Dynamic Server Version 7.30.UC5 -- On-Line -- Up 14:20:53 -- > > 421160 K > > bytes > > > > Profile > > dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached > > 7536503 12194535 78503378 90.40 111959 163941 661937 83.09 > > > > isamtot open start read write rewrite delete commit > > rollbk > > 36612289 443031 1916363 29251116 68550 113615 19749 51768 > > 0 > > > > gp_read gp_write gp_rewrt gp_del gp_alloc gp_free gp_curs > > 0 0 0 0 0 0 0 > > > > ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes > > 0 0 0 6499.98 1867.23 69 344 > > > > bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans > > 526588 0 30721288 0 0 15 8138 13609 > > > > ixda-RA idx-RA da-RA RA-pgsused lchwaits > > 4436892 11 1311 4423770 3720 > > > > onstat -g glo> > > > Informix Dynamic Server Version 7.30.UC5 -- On-Line -- Up 14:22:21 -- > > 421160 K > > bytes > > > > > > ------_=_NextPart_001_01BF0A57.D17E5254 > Content-Type: text/html; > charset="iso-8859-1" > > <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> > <HTML> > <HEAD> > <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> > <META NAME="Generator" CONTENT="MS Exchange Server version 5.5.2448.0"> > <TITLE>RE: IDS/BaaN performance issues</TITLE> > </HEAD> > <BODY> > > Does this buffer management funniness hold for all releases prior to 7.30.UC7? > Like 7.30.UC2 which i'm running (no BaaN/SAP/etc) > > > T > > > -----Original Message----- > From: Greg [<A HREF="mailto:greg@fastlane.net">mailto:greg@fastlane.net</A>] > Sent: Wednesday, September 29, 1999 2:06 AM > To: informix-list@iiug.org > Subject: Re: IDS/BaaN performance issues > > > > Russ - keep in mind I can barely spell BaaN, but SAP has gotten bit hard by > 7.30 releases prior to 7.30.UC7XK.  There's a bug in the new buffer > management that eventually leaves you all but unable to keep a data page in > memory, producing low buffer hit ratios like you have.  The XK release > essentially turns it off, reverting to the 7.2x style.  Your BUFFERS > probably do need to be higher, but as long as you have this bug, it won't > help.   Actually, it will probably hurt.   And UC5 was particularly bad - > there were customers who switched within (2) days to another release looking > for relief. > > > Greg > > > russ_kahler@andersonsinc.com wrote: > > > > Greetings, > > > > We are running IDS version 7.30.uc5 on a 4-way HP 9000 K-250 with 2.25 > > GB of memory, and HP-UX 10.20. We are also a BaaN installation running > > b40c4 with about 20 production users, and 25 test users. > > > > We have been experiencing performance difficulties with BaaN, and I have > > modified our onconfig to try to adjust for this. I recently added memory > > to bring it up to 2.25 GB, and also adjusted the SHMVIRTSIZE,BUFFERS,and > > CLEANER

RE: IDS/BaaN performance issues

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