Re: FAQ

johnl@informix.com (Jonathan Leffler) wrote: >With a reasonable log configuration (say more than 4 logs), the 70/80 limit >is very unlikely to run you into trouble. Unless you are mass inserting or >deleting extremely small records (say 1-8 bytes, though I'm tempted to >suggest 1-4 bytes), it is very difficult to run into problems. I do not >recall seeing systems run into trouble with 80/90 figures which are the >default in tbconfig.std.... >I consider that you have to be trying quite hard to run into trouble with >LTXHWM = 70, LTXEHWM = 80.... Long transactions and completely locked up Informix systems have been the bane of my existence for the last two years. I strongly recommend that the defaults be revised to lower values. We gradually reduced them to their current levels (LTXHWM=65, LTXEHWM=75) and I am tempted to take them to 60,70 to feel safer. We have 8 logs and definitely ran into trouble at 70, 80. Change the defaults. The consequence of not doing so is an extended period of downtime. Either you must get through to Menlo Park, have them dial in to your system, and do some bit twiddling or you initialize the system and do an archive restore being careful when applying the logs not to go so far as to re-create the long transaction. The trade-offs are that the former takes 3-4 hours under the best of circumstances but results in minimal data loss while the latter gets you back up in less than an hour with some data loss. The curious may wonder why I continued to experience problems. Politics is the short answer. Living in a less than ideal world, my systems group has little control over the programmers who write the applications. I consider it a great success that they no longer surround SELECT statements in their query and report programs with BEGIN WORK and COMMIT WORK statements and that they understand that logging should be turned off for temporary tables. -Jim Frison