RE: [ifxmaillist] Huge checkpoint times during backup

Jay This may be a problem in large systems with Archives relating to the Informix page "timestamp" (really a counter). It occurs when some pages have not been updated for a *long* time and the "timestamp" has wrapped around negative (or something). This results in Archives of almost random duration as the archive "corrects" the "timestamp" in older pages. We have this problem on one of our clients systems. The normal archive duration is just under 2 hours. In the last 20 archive, 1 took over 6 hours, 3 took over 4 hours but most are under 2.5 hours. I understand the checkpoints are long because the pages are being updated. Either .. 1. Manually update old data (although how do you know what data to update I dont know). 2. Export all databases and import. 3. Live with it. This information is from Informix Tech Support. MW -----Original Message----- From: owner-ifxmaillist@quanta.co.nz [mailto:owner-ifxmaillist@quanta.co.nz]On Behalf Of Jay Aymond Sent: Thursday, April 20, 2000 1:16 AM To: informix-list@iiug.org Subject: [ifxmaillist] Huge checkpoint times during backup I am running Informix 7.31 on a Sun 3500 (Solaris 2.6). Starting Monday night, during the nightly level-0 backup, the checkpoint times increased from 0-1 seconds to 80-103 seconds. The backup which normally runs 1 hour ran in 4 hours. Initally I thought the backups were competing with another job, but that was not the case. On Tuesday night, I set up some cron jobs to watch the Informix engine during the backups. The same thing happened --- extreamly high checkpoints. The backup ran for 6 hours. My cron jobs verified that the backups were not competing with anything else. I did notice that the number of dirty buffers was extreamly high --- 20,000 to 40,000 dirty. The database is set to start flushing at 1% and stop and 0%. There are no other complaints about the system being slow. Nothing has changed .... prior to Monday, we had no problems. Any clues?