Re: [GENERAL] Hardware optimising - Mailing list pgsql-general

From Bruce Momjian
Subject Re: [GENERAL] Hardware optimising
Date
Msg-id 199908270333.XAA08164@candle.pha.pa.us
Whole thread Raw
List pgsql-general
> > P.S. From previous posts, I'm starting to think that
> > there is a VAST misconception that a single-threaded
> > database engine (which is what Oracle was until some
> > version 7 releases, I believe, called Oracle MTS
> > appeared) can only handle ONE query at a time, and
> > does
> > not exec() a child process for each connection.
> > Someone ought to start the propoganda of claiming
> > multi-threaded DBMS as "single process" servers.
>
> Yes, I am totally unsure how this gets confused by people.  I am going
> to put it int the FAQ.
>
> Yes, and I agree that most multi-threaded DBMS are "single process",
> which can't make use if multiple cpus, except on some very special OS's
> that allow threads to move between cpus, sometimes called kernel
> threads, I think, but I am not sure on that.

I have added this to the FAQ:

We handle each user connection by creating a Unix process. Backend
processes share data buffers and locking information. With multiple
CPU's, multiple backends can easily run on different CPU's. Unlike
PostgreSQL, databases that use process threads have multiple users
connections running in the same Unix process. This makes it difficult
for them to utlilize multiple CPU's.


--
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