RE: Btree Percentage

You are probably being impacted by one of the following bugs: 121515 115327 Look at Informix's TechInfo Center for more details. Before using NOLRUPRIO, check your release notes to ensue that bug# 111681 has been fixed in your release. 111681 - NOLRUPRIO DOES NOT WORK AND CAN HANG THE SYSTEM I discovered the hard way that it was not fixed in IDS 7.31.UC3-1 on AIX. Rick -----Original Message----- From: Frank Langelage [mailto:frank@lafr.de] Sent: Monday, December 11, 2000 13:09 To: informix-list@iiug.org Subject: Re: Btree Percentage hanna_shaw@my-deja.com schrieb: > > Hi, > > We have a performance problem in one of our production box for a long > time. I found the percentage of Btree in the box is really high. Here > is the tail part of output of 'onstat -P': > > Percentages: > Data 3.38 > Btree 95.41 > Other 1.21 > > Output of 'onstat -R': > ... > # f/m pair total % of length LOW MED_LOW MED_HIGH HIGH > 0 f 2477 98.7% 2446 0 229 2010 207 > 1 m 1.3% 31 0 31 0 0 > 2 f 2476 98.9% 2450 0 240 2010 200 > 3 m 1.1% 26 0 26 0 0 > ... > > Most are 'MED_HIGH' instead of 'MED_LOW'. I checked the previous > related emails in the news group and found some suggestion for this > problem. But none seems to be a solution of our problem. Our current > Informix version is 7.31.uc4. 'NOAGE' is already set to 1. > > I also found that the performance is pretty good everytime when we > recycle the Informix server. And then it will be worse and worse until > we recycle it again.(Now we recycle it once a week. We can't recycle it > everyday.) We had a batch job running every night. After recycle, it > just takes minutes. But before recycle, it even couldn't finish in 24 > hours and blocks all other jobs. > > Does anyone know how to solve the performance problem? > > Thanks in advance. I got the same problem after upgrade from 7.30.UC2 to 7.31.UC6 on SCO UnixWare 7.1.1. There are two recommended Environmentvariables (Shell-Variables) NOLRUPRIO and LRUAGE. My experience is, that setting LRUAGE=1 and not setting NOLRUPRIO gets the best result. But LRUAGE is supported only in newer releases. You can check this like this: - go to $INFORMIXDIR - do strings bin/oninit | grep LRUAGE If you get a result, the server knows about the variable. Then add LRUAGE=1; export LRUAGE to your profile (/etc/profile or .profile of user who starts the IDS-Server). If it is working, you will see a value greater than zero on the last line of onstat -R for "priority downgrades". Regards Frank