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Performance Tuning Tips for Informix.

Posted in 2006

Summary

fun-do reported an oninit process using 100% CPU on IDS 9.40.FC5W2 under HP-UX 11.11 and asked for tuning steps. Gene Sais suggested checking OS memory and swapping. Art S. Kagel said PA-RISC thrashes its four shared-memory registers with more than 2 or 3 segments (check onstat -g seg) and advised RESIDENT -1. Superboer suggested identifying the CPU VP, then checking sequential scans via onstat -p and sysptprof. Unresolved.

Auto-generated by Claude from the posts below — may be imperfect; read the full thread.

Topics: Performance & Tuning

fun-do — — source: Usenet: comp.databases.informix

Hi, I would like to know some Performance Tips for Informix IDS. I am trying to debug an issue with the oninit process blocking 100% CPU utilisation. how do I tackle this issue? OS is HPUX 11.11 & database IDS ver 9.40.FC5W2 Any step by step processes to narrow down to the root cause of this issue? Thanks. Prashant

↪ replying to fun-do
Gene Sais — — source: Usenet: comp.databases.informix

I would start looking at your OS, probably was never set up to run a db, common problem. Memory management and swapping are usually the first items to look at. >>> "fun-do" <prashatt@gmail.com> 10/17/06 10:03 AM >>> Hi, I would like to know some Performance Tips for Informix IDS. I am trying to debug an issue with the oninit process blocking 100% CPU utilisation. how do I tackle this issue? OS is HPUX 11.11 & database IDS ver 9.40.FC5W2 Any step by step processes to narrow down to the root cause of this issue? Thanks. Prashant _______________________________________________ Informix-list mailing list Informix-list@iiug.org http://www.iiug.org/mailman/listinfo/informix-list

↪ replying to fun-do
Art S. Kagel — — source: Usenet: comp.databases.informix

fun-do wrote: > Hi, I would like to know some Performance Tips for Informix IDS. I am > trying to debug an issue with the oninit process blocking 100% CPU > utilisation. how do I tackle this issue? > OS is HPUX 11.11 & database IDS ver 9.40.FC5W2 > Any step by step processes to narrow down to the root cause of this > issue? > > Thanks. > Prashant Is the HPUX on Itanium or PA_RISC? On PA-RISC there is a common problem related to the PA-RISC architecture. The CPU has 4 special purpose registers used to access shared memory segments. If an application, like Informix IDS, needs access to more than 4 segments that will cause those registers to thrash and drive CPU usage up. How many shared memory segments does the IDS instance have configured right now (onstat -g seg)? If it's more than 2 or 3 that's the problem. On HP/PA-RISC you have to set RESIDENT -1 and the engine will try to combine as many segments as possible into one. Art S. Kagel

↪ replying to fun-do
Superboer — — source: Usenet: comp.databases.informix

First check what oninit proc it is; most likely a cpu vp. (onstat -g glo gives the pid.) then i would check for seq scans -->> onstat -p -->> if TBLSPACE_STATS is 1 on $ONCONFIG goto sysmaster and select * from sysptprof-->> secscans. check for the tread(s) which are a lot active.. trace them back to the session and review the sql, maybe one does something really expensive like comparing chars with ints etc Superboer. fun-do schreef: > Hi, I would like to know some Performance Tips for Informix IDS. I am > trying to debug an issue with the oninit process blocking 100% CPU > utilisation. how do I tackle this issue? > OS is HPUX 11.11 & database IDS ver 9.40.FC5W2 > Any step by step processes to narrow down to the root cause of this > issue? > > Thanks. > Prashant

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