Re: request for enhancement: 2K -> 4K

Jon Vemo wrote: > }> > > }> >The disadvantage is that 4 K will be the minumum size for all > }> >allocations, resulting in more wasted space in the database... > }> >_______________________________________ > }> > }> I come from tge Informix side and I'd like things similar to > }> Informix's blobspaces. You have normal database spaces which have > }> 2K or 4K pages depending upon the specific port. within blobspaces > }> you then define how large a blobpage will be in units of either > }> 2K or 4K. Big buffers (up to, I think 32K) are using to access > }> blobspaces. > }> > }> Why can't we just define our own page sizes for each area of disk > }> we use? Say in units of 2K or 4K depending upon the machine type? > }> > } > }The paging functions in the Informix engine were complicated enough to > }understand in v5.01 with only 2K pages, and I am unaware of how much it has > }increased in the later versions, ie. 6+. I would think that this would not > }be approved on the same grounds as you described above. Developing and > }looking after this would simply be ugh! > > As I understand it, even in pre-6.x, the page size for Informix was platform > specific. Most ports were done with a 2K page, however some which showed > performance advantages with a larger page size, were ported as 4K. Sequent > is one example. > > Jon > As I replied to Jon, my comments were sent regarding David's comments of defining your own page sizes on different areas of the disk. Which I think would be very difficult for the engine to admin, and the programming would be horrendous. I pulled enough of my hair out when I was working to improve the paging and locking algorithms at the Porting Centre in West London. -- Graeme Allison Technical Support Consultant Kenan Systems Corporation