RE: Fuzzy checkpoints.

The information at the following Web site may alleviate your concerns. http://members.tripod.com/markscranton/informix/monthly_topic.htm#Fuzzy Checkpoints The Monthly topic for April 2000 describes fuzzy checkpoints in more detail. -----Original Message----- From: William Rice [mailto:ricew@operamail.com] Sent: Tuesday, May 02, 2000 11:53 To: informix list Subject: Fuzzy checkpoints. I have concerns about whether or not 9.2 is as robust in bad situations as 7.x was. My concerns center around the fact that fuzzy operations(updates, inserts, and deletes) are not physically logged To me, this means if I unplug my machine in the middle of a write to disk initiated by a fuzzy operation I am now going to a backup and rolling forward logical logs. Example: Begin work; Insert record; Commit work; ... Cleaner starts writing page to disk; SA unplugs machine before write completes. When machine comes back up there is no Physical log of the before image from the last checkpoint. DBA has to find most recent backup. Considering that many of our machines are continuously doing I/O due to low LRU_MAX_DIRTY values I would imagine that the probability of being in the middle of a write when power was lost would not be low enough for my taste. I do make the assumption that 7.x was able to determine that a page had not been fully written to the physical log. Considering that the last thing in a page is the current timestamp, this seems to be a reasonable assumption. Am I missing something, or misunderstanding the current implementation? Will ------------------------------------------------------------ This e-mail has been sent to you courtesy of OperaMail, as a free service from Opera Software, makers of the award-winning Web Browser, Opera. Visit us at http://www.opera.com/ or our portal at: http://www.myopera.com/ Your free e-mail account is waiting at: http://www.operamail.com/ ------------------------------------------------------------