RE: Logical logs

It will hang the server with one logical log reserved for admin tasks. In this case the admin task is add more logical logs so the rollbackcan complete. Will >===== Original Message From "Vinod Bhansali" <iiug@hotmail.com> ===== >Girish, > >Why is it difficult to manage more no. of logs from admin point? > >If I increase the size of each log to 8 MB, in case of database failure I >will be loosing 8 MB of data(transactions) in case failure occured before it >was backed up. > >As you suggest to increase LTXHWM & LTXEHWM are 80 and 90, what will happen >if there is a long transaction and the engine doesn't have enough space to >roll back the transaction even though we have LBU_PRESERVE set to 1? Will it >crash the server? or will it freeze all activity? > >I do agree that tunning the application is the best solution to avoid long >trx, but its a long process. > >Thanks >Vinod Bhansali > > >>From: Girish Punjabi <girishpunjabi@my-deja.com> >>Reply-To: Girish Punjabi <girishpunjabi@my-deja.com> >>To: informix-list@iiug.org >>Subject: RE: Logical logs >>Date: Tue, 23 May 2000 23:51:17 GMT >> >>HI Vinodh, >> >>Nothing wrong with more logical logs except that is is inefficient from >>an administrative point of view. >>Instead of having 120 logical logs of 2MB each you can have 30 logs of >>8MB each.You can also set LTXHWM & LTXEHWM are 80 and 90 >>respectively.We have overcome the long transaction problem here by >>deviating from Informix suggested values of 50 and 60. >>Also , as William suggested, you need to have a look at the code as >>well , as no amount of tuning can help if the code is inefficient. >> >> >>In article <8ge25v$s64$1@news.xmission.com>, >> William Rice <ricew@operamail.com> wrote: >> > >> > I do not feel their is anything wrong with having that many logical >>logs. >> > One thing you might want to establish is why you are having long >>transactions >> > and whether or not what is being done is required to be one >>transaction. >> > >> > If the cause is a process which is required to be updated in one >>transaction >> > you have no choice but to increase the number of logs. >> > >> > If the cause of the long transactions is a purge or something of that >>nature, >> > which can be done in smaller increments without effecting the >>validity of the >> > data, you might want to look into making the purge use a select cursor >> > and deleting each record and committing periodically.(If their is a >>better way >> > to do this I would love to hear it.) If you just increase the number >>of logs, >> > as >> > the amount of data purged grows, the likelihood of hitting a long >>transaction >> > again grows. A program which commits at regular intervals bypasses >> > these emergencies. >> > >> > If the cause of the long transactions is a lock held for an >>inordinate period >> > of time, it might be worth implementing some sort of timing mechanism >> > to cause the user to abort after holding a lock for some period of >>time, >> > or rewriting the application to not hold locks while waiting for user >>input. >> > >> > Hope this helps, >> > Will >> > >===== Original Message From "Vinod Bhansali" <iiug@hotmail.com> ===== >> > >In our system, I am noticing Long Transactions being caused >>sometimes. We >> > >have 80 log files, each of size 2048. LTXHWM & LTXEHWM are 50 & 60. >>I don't >> > >want to increase them. I am planning to increase the no. of log >>files to 120 >> > >or to 160. Are there any pros and cons of having more no. of logical >>log >> > >files. We have continuous logical log backup running and we take >>zero level >> > >db backup daily using ontape. >> > > >> > >Thanks in advance >> > >Vinod Bhansali >> > >> >_______________________________________________________________________ >>_ >> > >Get Your Private, Free E-mail from MSN Hotmail at >>http://www.hotmail.com >> > >> > ------------------------------------------------------------ >> > 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/ >> > ------------------------------------------------------------ >> > >> > >> >> >>Sent via Deja.com http://www.deja.com/ >>Before you buy. > >________________________________________________________________________ >Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com ------------------------------------------------------------ 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/ ------------------------------------------------------------