Re: Informix vs. Sybase vs. Oracle vs. (gasp) MS SQL Server

In article <frLQBCADmlVzEwN4@smooth1.demon.co.uk>, David Williams <djw@smooth1.demon.co.uk> writes: > In article <5j39eg$2sj@mew.corp.sgi.com>, Pablo Sanchez > <pablo@mew.corp.sgi.com> writes > > > >In article <0v8awLAcPRVzEwpS@smooth1.demon.co.uk>, David Williams > ><djw@smooth1.demon.co.uk> writes: > >A big ++++ for Sybase that Informix currently does not have is > >that the buffer cache can be partitioned and tables/indexes... can > >be found to portions of the cache. Rather than treating the cache > >as an unknown, the DBA is allowed to micro manage it. They can > >change the wash section, I/O pool size (for reading/writing).... > >quite nifty. > > Surely this will reduce performance for unbound cache entries? Absolutely! Of course typical DBA action would be (atomically): 1) create the named partition (Sybase lingo) 2) create the I/O pools within the named partition 3) bind one or more objects to the pool. 4) run a bench and monitoring tool to ensure that it's being used. A neat idea (well, okay, IMHO) is that you can have a configuration for "normal" operation and a configuration for "crunching" operation. Cool eh? > I would have thought that binding objects into the cache only > helps in limits cicumstances?? Most applications benefit from it because minimally you can create a named partition for your database log(s) and bind them to it. The high turnover rate of dirty buffers is now restricted to a small area in memory. Neat eh? And of course, if you have a mixed workload on your RDBMS, you can bind frequently scanned tables to a named cache so that they don't flush out the working set established in the "default cache." > Informix has a logical log buffer - up to one logical log can > be buffered at a time - I'm not sure what the I/O size is that > is used for writing logical log buffers to disk... This is *my* weakness because we didn't go into this in class like I thought we would (no fault of the instructor... he had a lot to cover) and next thing ya know, the class was over! :-(... I really want to learn more about how connections send their transactions to the logical log and how the physical log relates to the logical log. Any reading you recommend? and/or websites with info? -- Pablo Sanchez | wk: 415.933.3812| pg: 800.930.5635 -or- pablo_p@pager.sgi.com --------------+-----------------+-------------------------------------------- pablo@sgi.com ... when mailing me, place "not spam" in the Subject