Re: Problem with Long Checkpoints

"Art S. Kagel" wrote: > > Gabor Heppes wrote: > > > > In article <Om_43.6822$Hm1.8930@news.chello.at>, > > "nicole kofler" <nikis.atelier@teleweb.at> wrote: > > > > [... snip ...] > > > > > The 62% usage of physlog in your listing means that you write 6250+ > > > pages during the next checkpoint - a lot of pages for a 5400 rpm > > > > spindle. > > > > As I understand, the flushing of the physical log does not involve > > reading the blocks from it and writing them to somewhere else (it > > contains only before-image pages), *unless* you crash and have to do a > > fast recovery. At checkpoint time it's just marked empty. > > You are correct. The physical log plays no part in the duration of a > checkpoint its data are written to disk as each physical log buffer is > filled and only the partial physical log buffer is written out at the > beginning of the checkpoint after all current latch points are released. > So only the size of the physical log buffer has even a minor effect on > the checkpoint duration. > > Art S. Kagel Thank you for this correction. I definitely got it wrong. Sorry for that. If somebody else wants to RTFM: admin guide 11-57 ff. is all about checkpoints -- Richard Kofler debis Systemhaus EDVg - Vienna on a private account