Re: SELECT's take a long time compared to other DBMS

Relaxin kirjutas N, 04.09.2003 kell 17:35:
> So after you did that, where able to position to ANY record within the
> resultset?
>
> Ex. Position 100,000; then to Position 5; then to position 50,000, etc...

not in the case of :
time psql test100k -c 'select * from test' > /dev/null
as the whole result would be written to dev null (i.e discarded)

Yes in case of python: after doing

res = con.query('select * from test') # 3 sec - perform query
list = res.getresult() # 1 sec - construct list of tuples

the whole 128k records are in a python list ,
so that i can immediately access any record by python list syntax,
ie list[5], list[50000] etc.

> If you are able to do that and have your positioned row available to you
> immediately, then I'll believe that it's the ODBC driver.

It can also be the Cygwin port, which is known to have several problems,
and if you run both your client and server on the same machine, then it
can also be an interaction of the two processes (cygwin/pgsql server and
native win32 ODBC client) not playing together very well.

> "Hannu Krosing" <hannu(at)tm(dot)ee> wrote in message
> news:1062673303(dot)5200(dot)135(dot)camel(at)fuji(dot)krosing(dot)net(dot)(dot)(dot)
> > Relaxin kirjutas N, 04.09.2003 kell 03:28:
> > > I have a table with 102,384 records in it, each record is 934 bytes.
> >
> > I created a test database on my Linux (RH9) laptop with 30GB/4200RPM ide
> > drive and P3-1133Mhz, 768MB, populated it with 128000 rows of 930 bytes
> > each and did
> >
> > [hannu(at)fuji hannu]$ time psql test100k -c 'select * from test' >
> > /dev/null
> >
> > real 0m3.970s
> > user 0m0.980s
> > sys 0m0.570s
> >
> > so it seems definitely not a problem with postgres as such, but perhaps
> > with Cygwin and/or ODBC driver
> >
> > I also ran the same query using the "standard" pg adapter:
> >
> > >>> import pg, time
> > >>>
> > >>> con = pg.connect('test100k')
> > >>>
> > >>> def getall():
> > ... t1 = time.time()
> > ... res = con.query('select * from test')
> > ... t2 = time.time()
> > ... list = res.getresult()
> > ... t3 = time.time()
> > ... print t2 - t1, t3-t2
> > ...
> > >>> getall()
> > 3.27637195587 1.10105705261
> > >>> getall()
> > 3.07413101196 0.996125936508
> > >>> getall()
> > 3.03377199173 1.07322502136
> >
> > which gave similar results
-------------------
Hannu