Обсуждение: Re: [HACKERS] All things equal, we are still alot slower then MySQL?

Tom Lane <tgl@sss.pgh.pa.us>  writes:
>>>> MySQL: 0.498u 0.150s 0:02.50 25.6%     10+1652k 0+0io 0pf+0w
>>>> PgSQL: 0.494u 0.061s 0:19.78 2.7%      10+1532k 0+0io 0pf+0w
>
>> No --- if he were, it'd be all CPU time, not 2.7% CPU usage.
>
>Er, wait a second.  Are we measuring backend-process runtime here,
>or is that the result of 'time' applied to a *client* ?

Yeah, that would explain a lot.  When I first saw the numbers, I was so
excited because they showed that PostgreSQL is *faster* than MySQL (with
more memory, and better I/O).

That didn't make any sense, though.  MySQL is faster than every real DBMS,
because it doesn't have transactions, triggers, locking, or any other sort
of useful features to slow it down.

The question should always be, is PostgreSQL faster than Oracle, Informix,
or Sybase?
-Michael

> Tom Lane <tgl@sss.pgh.pa.us>  writes:
> >>>> MySQL: 0.498u 0.150s 0:02.50 25.6%     10+1652k 0+0io 0pf+0w
> >>>> PgSQL: 0.494u 0.061s 0:19.78 2.7%      10+1532k 0+0io 0pf+0w
> >
> >> No --- if he were, it'd be all CPU time, not 2.7% CPU usage.
> >
> >Er, wait a second.  Are we measuring backend-process runtime here,
> >or is that the result of 'time' applied to a *client* ?
> 
> Yeah, that would explain a lot.  When I first saw the numbers, I was so
> excited because they showed that PostgreSQL is *faster* than MySQL (with
> more memory, and better I/O).
> 
> That didn't make any sense, though.  MySQL is faster than every real DBMS,
> because it doesn't have transactions, triggers, locking, or any other sort
> of useful features to slow it down.
> 
> The question should always be, is PostgreSQL faster than Oracle, Informix,
> or Sybase?

I am told we are the same as Ingres, and slower than Oracle with no -F,
and faster than Oracle with -F.

--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 

> I am told we are the same as Ingres, and slower than Oracle with no -F,
> and faster than Oracle with -F.

What is "-F"?

-- 
Chris Bitmead
mailto:chris@tech.com.au

> 
> > I am told we are the same as Ingres, and slower than Oracle with no -F,
> > and faster than Oracle with -F.
> 
> What is "-F"?
> 

-F is postgres option for no-fsync.
--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 

Chris Bitmead ha scritto:

> > I am told we are the same as Ingres, and slower than Oracle with no -F,
> > and faster than Oracle with -F.
>
> What is "-F"?
>

from man postgres:
   -F     Disable an automatic fsync() call after each trans­             action.   This  option improves performance,
butan             operating system crash while a  transaction  is  in             progress  may  cause  the loss of the
mostrecently             entered data. Without the fsync() call the data  is             buffered  by  the  operating
system,and written to             disk sometime later.
 


José

In article <199909201327.JAA18590@candle.pha.pa.us>,
Bruce Momjian <maillist@candle.pha.pa.us> wrote:
>> 
>> > I am told we are the same as Ingres, and slower than Oracle with no -F,
>> > and faster than Oracle with -F.
>> 
>> What is "-F"?
>> 
>
>-F is postgres option for no-fsync.

Does that matter on read-only selects?

Might some future version of postgresql have an option to turn
off transaction support to match mysql speed for the situations
where that is more important than the ability to roll back?
 Les Mikesell  les@mcs.com