logical logs sizes

Let's clarify the issue of logical logs. (I think I've been talking apples and the poor guy I "RTFM'd" was talking oranges.) > > Can anybody tell me an easier method for changing th logfile size on > > I-Online 5.x than unloading the whole database and reloading it? > > There are several things you can do: > 1) add more logs > 2) change the size of the existing logs (without unloading/loading) > 3) move the logs on disk (the physical and logical log *files*) > 4) adjust high-water marks (are they too low?) > 5) adjust locks while you're at it (lock level and number) There are three logical log sizes: Type: Location: Tbconfig: Description: _______________________________________________________________________ Holds records of changes until Logical written to disk. Max number of Log shared LOGSBUFF these buffers stored in LOGSMAX. Buffers memory _______________________________________________________________________ Logical dbspace LOGSIZE Receives change records Log from shared memory. Files Max number of these files stored in LOGFILES. Size of each file cannot be changed w/o re-init. Additional files can be added, up to LOGFILES value. LOGFILES can be changed w/o re-init, up to a max of ~60. _______________________________________________________________________ Logical Backup copy of logical log Log tape LTAPESIZE files, used with archive Tape Device drive to restore database So. You cannot change the size of each logical log file (on disk) without re-initializing. You *can* change the max number of files, and add files up to that number (each file the original size). In order to do this, you must bring the instance down and back up (not re-initialize). All this comes from the "Informix-OnLine Admin Guide" version 5.0, chapters 2 and 3. In version 7.2, the parts of the manual that deal with logical logs have been entirely re-written. There are many more features available, such as emergency log backup, logs-full high-water marks, sizing guidelines, nifty graphics explaining what's going on, and very readable prose. For that reason alone, you should be lining up at the door, checks in hand, waiting for the upgrade. From 7.x on, you can add log files of a different size using the onparams command. You still can't change the log file size parameter (LOGSIZE) in the onconfig file, and you can't add files of a different size using onmonitor. It's a way of getting around that barrier. (Forget Murphy, if it can break--fix it.) I hope that helps. If I've mis-stated something--again--or was not clear, just let me know. <Don flame-proof gear> _______________________________________________________________ | Clem Akins clema@informix.com | | International Support formerly | | Informix Software, Inc cwakins@leia.alloys.rmc.com | | Menlo Park, California, USA Standard Disclaimers Apply | |_____________________________________________________________|