Re: Problem with Long Checkpoints

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