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

Graeme, The first DBMS I used was IBM's IMS I was using version 1.3 which was written sometime in the early 80's or late 70's. You could use any page size you wanted. Surely if the problem was solved once it could be solved again. Regards David Ashby ______________________________ Reply Separator _________________________________ Subject: Re: request for enhancement: 2K -> 4K Author: <gallison@kenan.com> at WCA-INET Date: 18/12/97 10:45 AM 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