Re: High Water Mark Question

Hi, LTXHWM - When the total number of filled logs reaches this amount, any transactions that started in the oldest logfile are marked as long transactions and are forced to roll back LTXEHWM - When the total number of filled logs reaches this amount, all processes except long transactions that are rolling back are prevented from logging to the logfiles. These processes are effectively frozen [Definitions from Informix Database Administrators Survival Guide, Joe Lumbley; Informix Press] The figures you quote should give plenty of log space to enable any transaction to be rolled back [and seem VERY low, default is 80 & 90, recommended is more like 60-70 & 75-80] Did the db recover after rollback, how long did you give for the rollback to occur John --------------------------------------------------- John Blance - UNIX Systems Engineer SHL Systemhouse (London, Waterloo) jblance@shl.com --------------------------------------------------- Bill Ennis <ennis@ssax.com> wrote in article <66h401$t1a@cssun.mathcs.emory.edu>... > Hi, > > The definition of these paramaters is as follows: > > LTXHWM - this is the percentage of logical log space that an individual > transaction can span before the database stops it and begins > to roll it back. > LTXEHWM - this is the percentage of logical log space that can be spanned > before ALL transactions get rolled back. > > So it's a combination of the offending transaction with all other transactions > on the system that is doing you in. > > In short, these are ettings that control when the database will say > "hold everything - to much is going on and I need to step in because > this DBA guy has told me to!". Now - question for you: Did your > database shutdown completely or did it come back after the rollback? > How much logical log space do you have? You have two things to > consider at this point: > 1) Should you add more logical log space? This may allow your transaction > to complete. This is quick, dirty, and incomplete but may buy you some > time while you fix the problem. > 2) Unless you have exteremely small logical logs you really need to find > out why your transactions are doing so much. Strip the transactions > down to the bare minimum. When you have done so you can use the > onlog utiility to track them. One of the attributes given from > onlog is the amount of space taken by each logical log record. > > > -Bill > > > > Hi > > > > Our database was hung recently due to a long transaction. Our LTXHWM = 20 and > > LTXHWM = 30 , which are pretty low. I am not sure why the database couldn't > > rollback and recover from this long transaction. Anyone has any idea ? > > > > Thanks. > > Keith > > > > > -- > Bill Ennis Voice: 312-474-7516 > SSA Fax: 312-474-7460 > 500 W. Madison email: ennis@ssax.com ennis@accesschicago.net >