В Вт., 27/09/2011 в 10:54 +0200, Thomas Steinmaurer пишет:

>
> > В Вт., 27/09/2011 в 10:23 +0200, Dimitry Sibiryakov пишет:
> >> 27.09.2011 10:18, Thomas Steinmaurer wrote:
> >>>> Records are already compressed as delta + RLE. Page level
> compression is pointless
> >>>> because page of variable size is a headache.
> >>>
> >>> Still fixed page size on disk with compressed data.
> >>
> >> And this is exactly why page compression is pointless: you are
> writing to disk full
> >> page size anyway, no difference between page with uncompressed data
> and page with
> >> compressed data + some filling zeros.
> >>
> >
> > Must say that for example NTFS supports writing compressed pages to
> disk
> > and does not fill it with 0, instead puts more data to the page. We
> > probably can do something like this - when adding new record/version
> to
> > the page compress it and when result does not fit, use another page
> for
> > that record/version.
>
> I don't know what algorith is used here, but AFAIK it decompress
> stuff
> before going over the network etc ...

I do not see how is compression in database _file_ related with what is
travelling over network.