Re: Informix and Oracle in the same shop

In article <5n1dv1$2ar@mew.corp.sgi.com>, Pablo Sanchez <news_reader@mew.corp.sgi.com> writes > >In article <33935782.7D9610FC@devnull.org>, Tim Schaefer <devnull@devnull.org> >writes: >> Pablo Sanchez wrote: >> > >> > No vendor, that I know of, is truly multi-threaded... at least in the >> > sense of user threads and the like. >> > -- >> >> whoa! >> >> Finally somebody mentioned the threads thing, and you shoot it down >> so quickly! tsk tsk.... :-) > >:-)!!!! Well they'll all claim it if it's the soup of the day kinda >thing... > >> Yes, as much as I hammer on Informix, they are truly and independently >> verified to have multi-threading--unless it's all bs... But Oracle >> last I heard was multi-process not multi-threaded... > >I know that you're statement of "hammer"ing informix is more in jest >than anything else... I'm not trying to hammer >informix/sybase/oracle. If you look closely enough, you can find >enough to hammer any one of them... for that matter, you can find >something in each to glee over... so with *that* outta da way.... > >o Sybase isn't threaded in the sense of user threads as it conducts > its own type of thread management. IMHO, I believe that the > threads are too coarse to allow for a true multi-thread execution. > I'm not sure about Sybase. >o Informix isn't threaded because you have all 'em VP's running out > there. They aren't in the same execution space. They have their > own and thus there is *some* context switching. Of course Oracle > has a process for *everything* so that's taking context switching > to the max. So how do you get >1 CPU used simulatanously if you one have one UNIX process. Remember UNIX controls **EVERYTHING** even virtualising memory and I/O port usage. UNIX schedules PROCESSES to run NOT THREADS. In order to get >1 physical CPU used you must have >1 process acitve. Hence Informix recommed 1 less CPU VP less than the number of physical CPUs (to allow other things apart from Informix to run). When doing I/O which is not kernel asychronous I/O than the PROCESS doing the I/O will be blocked. You don't want all your threads within that process to stop hence put the I/O thread into it's own process (AIO VPs). AIO VPs can be only 1 (to write to the online.log message file which must be a normal UNIX file... This is the least number of processes you can run i.e. most multi- threaded you can get under UNIX. I have seen 130 informix users with ~10-12 UNIX processes handling all their connections. Proof that Informix is truely mutli-threadeded..... > >With enough CPU's, though, the context switching isn't as much as an >issue... IMHO. You can always bind a process to a processor. >-- >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 -- David Williams