Re: Informix and Oracle in the same shop

In article <5n1dv1$2ar_at_mew.corp.sgi.com>, Pablo Sanchez <news_reader_at_mew.corp.sgi.com> writes
>
>In article <33935782.7D9610FC_at_devnull.org>, Tim Schaefer <devnull_at_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 multithreaded     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_at_pager.sgi.com
>--------------+-----------------+--------------------------------------------
>pablo_at_sgi.com ... when mailing me, place "not spam" in the Subject
 

-- 
David Williams