Buffer Pool

Hi, We are running informix 9.4 FC5xs with SAP. Our SAP admin recently advised that the INFORMIX buffers were set to low. Based on some SAP recommendation, we increased the buffers parameter from 301049 to 501049 (about 600Mb to a little les than 1Gb. 2 days later I found the following WARNING message in our online log about the Buffer pool. 05:15:22 Checkpoint Completed: duration was 0 seconds. 05:15:22 Checkpoint loguniq 152127, logpos 0x539b018, timestamp: 0xefde1d37 05:15:22 Maximum server connections 43 05:41:21 WARNING: Buffer pool size is too small for read ahead operation 05:45:40 Checkpoint Completed: duration was 0 seconds. 05:45:40 Checkpoint loguniq 152127, logpos 0x5ec5018, timestamp: 0xefdee8f1 I could not find any information in the oneline docs. Any help would be appreciated?

You did not include what your "read ahead" settings were/are in onconfig. If you were not getting these "read ahead" warnings before you increased your buffers, it seems strange you should be getting them now. Did you also adjust "read ahead" parameters based on SAP recommendation? Maybe SAP recommended increased buffers because of a few greedy programs and those same programs are causing the 'read ahead' issues. Perhaps the programs need adjusting or the read ahead settings need to be lowered? Did the recommendation come from one of those SAP "go-live" reports that you can order after a big SAP project/support pack implementation? Don't necessarily take SAP's word for it or your SAP Basis admin's word... Your best bet is to put in an SAP ticket and question them in detail. By being specific and detailed in your SAP ticket, you will get past the front-line support to the folks who know Informix.... then you will get the real answer. The informix support folks at SAP are extremely good (well, they were for as long as I communicated with them before ours migrated off informix). Norma Jean Sebastian -----Original Message----- From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of ANTONIO VARRICCHIO Sent: Tuesday, February 10, 2009 11:25 AM To: ids@iiug.org Subject: Buffer Pool [14822] Hi, We are running informix 9.4 FC5xs with SAP. Our SAP admin recently advised that the INFORMIX buffers were set to low. Based on some SAP recommendation, we increased the buffers parameter from 301049 to 501049 (about 600Mb to a little les than 1Gb. 2 days later I found the following WARNING message in our online log about the Buffer pool. 05:15:22 Checkpoint Completed: duration was 0 seconds. 05:15:22 Checkpoint loguniq 152127, logpos 0x539b018, timestamp: 0xefde1d37 05:15:22 Maximum server connections 43 05:41:21 WARNING: Buffer pool size is too small for read ahead operation 05:45:40 Checkpoint Completed: duration was 0 seconds. 05:45:40 Checkpoint loguniq 152127, logpos 0x5ec5018, timestamp: 0xefdee8f1 I could not find any information in the oneline docs. Any help would be appreciated? ************************************************************************ ******* Forum Note: Use "Reply" to post a response in the discussion forum.

Antonio, Copy the output of this two commands here: # to get how much of overhead of Read Ahead your IDS are doing . onstat -p# get the config of read ahead onstat -c | grep RA_ # this command, don't need to copy here, is just for you check what table have # more sequencial scan. onstat -g ppf | awk '/^partnum/ || $12 > 0' | sort -nk12 big tables with sequencial scan + misconfiguration of read ahead can be the problem ... --- Em ter, 10/2/09, ANTONIO VARRICCHIO <antonio.varricchio@domtar.com> escreveu: De: ANTONIO VARRICCHIO <antonio.varricchio@domtar.com> Assunto: Buffer Pool [14822] Para: ids@iiug.org Data: Terça-feira, 10 de Fevereiro de 2009, 15:25 Hi, We are running informix 9.4 FC5xs with SAP. Our SAP admin recently advised that the INFORMIX buffers were set to low. Based on some SAP recommendation, we increased the buffers parameter from 301049 to 501049 (about 600Mb to a little les than 1Gb. 2 days later I found the following WARNING message in our online log about the Buffer pool. 05:15:22 Checkpoint Completed: duration was 0 seconds. 05:15:22 Checkpoint loguniq 152127, logpos 0x539b018, timestamp: 0xefde1d37 05:15:22 Maximum server connections 43 05:41:21 WARNING: Buffer pool size is too small for read ahead operation 05:45:40 Checkpoint Completed: duration was 0 seconds. 05:45:40 Checkpoint loguniq 152127, logpos 0x5ec5018, timestamp: 0xefdee8f1 I could not find any information in the oneline docs. Any help would be appreciated? ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum. Veja quais são os assuntos do momento no Yahoo! +Buscados http://br.maisbuscados.yahoo.com

What are your Readahead parameters (RA_PAGES, RA_THRESHOLD) set to in the ONCONFIG file? Art On Tue, Feb 10, 2009 at 12:25 PM, ANTONIO VARRICCHIO < antonio.varricchio@domtar.com> wrote: > Hi, > > We are running informix 9.4 FC5xs with SAP. Our SAP admin recently advised > that the INFORMIX buffers were set to low. Based on some SAP > recommendation, > we increased the buffers parameter from 301049 to 501049 (about 600Mb to a > little les than 1Gb. 2 days later I found the following WARNING message in > our > online log about the Buffer pool. > > 05:15:22 Checkpoint Completed: duration was 0 seconds. > 05:15:22 Checkpoint loguniq 152127, logpos 0x539b018, timestamp: 0xefde1d37 > > 05:15:22 Maximum server connections 43 > 05:41:21 WARNING: Buffer pool size is too small for read ahead operation > > 05:45:40 Checkpoint Completed: duration was 0 seconds. > 05:45:40 Checkpoint loguniq 152127, logpos 0x5ec5018, timestamp: 0xefdee8f1 > > I could not find any information in the oneline docs. Any help would be > appreciated? > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > -- Art S. Kagel Oninit (www.oninit.com) IIUG Board of Directors (art@iiug.org) Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Oninit, the IIUG, nor any other organization with which I am associated either explicitly or implicitly. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. --0016369891bd67ac6c046295bf69