Re: 7.31 performance problem ✓ Answered: green (solid confidence) — Andrew Hamm questioned whether LBU_PRESERVE only matters for onarchive; David Williams corrects this (they hit it with ontape too) and Doug McAllister explains the mechanism (archiving a log requires logging that fact, so the last log must be preserved); asker accepts and keeps the setting.

Advisory only.

David Williams wrote in message ... > >>LBU_PRESERVE 0 # Preserve last log for log backup > > Set to 1! Emmm, excuse me for going sydwayz here, but isn't this parameter only relevant if you are foolish enough to use onarchive for backups? I understand that onarchive writes to sysutils database leading to a potential log deadlock, but ontape and onbar don't have this problem. I must confess to having your opinion too, but recently when reading the fine print, it sounded like it was only relevant for onarchive.

In article <3a5274df$1@news.iprimus.com.au>, Andrew Hamm <ahamm@sanderson.net.au> writes >David Williams wrote in message ... >> >>>LBU_PRESERVE 0 # Preserve last log for log backup >> >> Set to 1! > >Emmm, excuse me for going sydwayz here, but isn't this parameter only >relevant if you are foolish enough to use onarchive for backups? I >understand that onarchive writes to sysutils database leading to a potential >log deadlock, but ontape and onbar don't have this problem. > >I must confess to having your opinion too, but recently when reading the >fine print, it sounded like it was only relevant for onarchive. > > It is used when the logical logs are filling up and is not specific to the tool used to back them up. We have hit this using ontape. > -- David Williams

David Williams wrote in message ... > > It is used when the logical logs are filling up and is not specific > to the tool used to back them up. We have hit this using ontape. > I started setting it 'cos I was involved in the recovery of a few deadlocked long transaction problems (don't ask, I'm still crying years later) and I figured it sounded like a little bit of a safety valve. So I'll just just keep that fella in there, hey? Cheers

When you archive a log file to tape, Informix needs to log that fact. If the logs are already full, you cannot log the log archive. Therefore, by preserving the last log, the archive of all of the other log files can be logged. Sounds like a tongue-twister doesn't it? :) Andrew Hamm wrote: > > David Williams wrote in message ... > > > > It is used when the logical logs are filling up and is not specific > > to the tool used to back them up. We have hit this using ontape. > > > I started setting it 'cos I was involved in the recovery of a few deadlocked > long transaction problems (don't ask, I'm still crying years later) and I > figured it sounded like a little bit of a safety valve. > > So I'll just just keep that fella in there, hey? > > Cheers