i'm going to specify at apache now :)
Sunday, April 15, 2001, 8:52:59 PM, you wrote:
> But my point is that the communication overhead is still gained by process
> based systems. True they don't have the same pooling ability, as does a
> threaded process management. Overhead saved using pconnect is that which is
> being debated here.
that is only the case for *optimal* configured system.
Just for those who don't know, Apache is configured by utilising
"MinClients" (number of min. worker processes), "MaxClients" (max. number of worker
processes),
"MinSpareServers" (min. number of unused worker processes) and "MaxSpareServers"
(max. number of unused worker processes).
Now let's compare multi-thread and multi-process based systems :)
Threads: the max number of pconnects is valid for *all* threads of the
parent process, also *every* persistent connections made by
*every* thread is shared.
Process: the max number of pconnects is only valid for *one* working
process, the connections can't be shared amongst the working processes
in the worst case you'll have (pconnects * (user/password combinations) * MaxClients)
If one worker process already made a connection to the db, short time
after another worker process making a pconnect using the same
user/password combination, they still will use different connections.
While in the thread based the next thread simply reuses the connection
made by the other thread.
Another big disadvantage is that if "MaxSpareServers" is reached, the
manager process wil begin the shutdown the unused worker processes
until "MinSpareServers" is reached. Surely the persistent
connections by those unused processes are closed as well.
So if you're using a process based system there *has* to be alot
of more connectivity to be done when compared to a thread based system under the same
load.
daniel
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daniel beulshausen - [EMAIL PROTECTED]
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