Re: [Dbbalancer-users] Preliminary performance statistics

[Andrew M. <an...@ca...>]

On Tue, 2001-11-06 at 11:56, Daniel Varela Santoalla wrote:
> Hello Andrew
> 
> I would like to know a little more about your setup.
> Are you comparing DBBalancer with PHP "persistent", pconnect()?
> When you use DBBalancer, do you use also pconnect() or connect()?

I was using pg_pconnect() before, and when I switched to the DBBalancer
connection pool I switched to pg_connect().


> My very informal tests gave several different results, ranging from a 700% 
> gain in very short querys to an actual loss of performance in the case of the 
> ones that returned a very large result set. I tested C programs (libpq) and 

My live application does a single "SELECT myfunction(parameters);" and
that function (which is written in PL/PgSQL) will return a single TEXT
value of less than 100 bytes.

Internally the PL/PgSQL function does two SELECTs, the first will return
no rows, and the second will return a single row.  It will then do a
single INSERT into a table which is cleaned periodically by a background
process.

As you might guess from my description, this particular process has been
carefully put together for maximum performance, and I want it to be able
to survive extreme loads, hopefully one or two orders of magnitude
greater than current.

This isn't really a benchmark, it's a real-world measurement of 
application performance.  As such it is perhaps lesss applicable to
other people, but it certainly applies to me :-)

Cheers,
					Andrew.


> On Mon 05 Nov 2001 12:09, you wrote:
> > Hi All,
> >
> > This is way preliminary, but it looks so positive I just had to put it
> > up here...
> >
> > |----------+------+-------+-------+---------+--------+--------+
> > |
> > |          | Avg  | StDev |  Max  |   Min   | Median | Sample |
> > |
> > |----------+------+-------+-------+---------+--------+--------+
> > |Persistent| 0.056|  0.081| 12.674| 0.000361|  0.051 |  74371 |
> > |----------+------+-------+-------+---------+--------+--------+
> > |DBBalancer| 0.020|  0.011|  0.758| 0.000417|  0.019 |  14684 |
> >
> > +-------------------------------------------------------------+
> >
> >
> > The application in question is fairly tuned for performance, managing to
> > get this particular component (the bit that gets a reasonable number of
> > hits) down to around three simple queries.
> >
> > The performance statistics are measured by wrapping each query, so do
> > not include any component of execution time for the script (or even the
> > connection startup time) - just the queries themselves.
> 
> This doesn't make much sense. How can execution times be faster without 
> counting the connection startup time.... Here is where the gain is supposed 
> to be. Did you try also counting this time?
> 
> >
> > Regards,
> > 				Andrew.
> 
> It is good to start seeing some real world results. And it is better to see 
> that they're good :-))
> 
> Regards
> 
> -- 
> 
> ----------------------------------
> Regards from Spain.  Daniel Varela
> ----------------------------------
> 
> If you think education is expensive, try ignorance.
>            -Derek Bok (Former Harvard President)
> 
-- 
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