RE: Share Mode Locking Problem...

In article <Pine.BSF.3.96.971021161609.1192C-100000@shell9.ba.best.com>, cchervit@shell9.ba.best.com says... > >>[... use temp table ...] >This seems to be the recommended strategy from many people >and makes a lot of sense given the information I gave to you >to work with. Unfortunately, the base table has 11 million records, all >interrelated. We need sub-second response times on these "scenarios". >[...] > >This solution just won't work. > Informix, we really need multiversioning! When I took a sysadmin course almost two yers ago, I was told this was in the pipe or at least being seriously looked into. > >But, then again, I came from Sybase and after all, we *are* number 3. So, >maybe Informix is right in this case? But, maybe not. *smile* > Does Sybase handle multiversioning? I have been led to believe that Informix and Sybase had similar approaches to locking/old values/rollback issues. Oracle has, and Borlands Interbase is supposed to have a different approach. > >> If you can eloquently describe a mechanism by which the engine could follow >> a locking strategy that *would* make you happy, then I invite you to register >> a feature request. It's how the world gets better. :) >> > >Well, seeing as how much I'd love to make the world a better place... >maybe I will open that request. > Here is my shot, quoting myself from an earlier post: IMHO, 'multiversioning' solves this issue without imposing read locks. It does this by a semantic that essentially says: 1 - 'Nothing is written to the database until commit is done!' 2 - 'Your queries return the result that you would have gotten if the query was instantaneous.' The implementation of (1) is of course not done so as to delay writing until commit, instead old versions of data are kept around to ensure the semantic. The implementation of (2) is rather interesting for time consuming queries, there might be times here when committed data are disregarded in favor of old versions of data! If you think about transaction consistency, this is actually desirable! Essentially this is my understanding of how Oracles multiversioning strategy works and I miss it dearly in Informix. /Johan -- ________________________________________________________________________ | >>> The opinions herein are mine and not neccessarily my employers <<< | | Johan Andersson, Msc CSE jna@carmenta.se | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~