Re: ***SPAM*** Re: same question little different test MSSQL

I've tested in a relation of mine, with about 20 attributes, and here
are the results:

test=# select count(*) from gestionestareas;
count
--------
447681
(1 row)

test=# explain analyze select * from gestionestareas where agrupable;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------
Seq Scan on gestionestareas (cost=0.00..12334.81 rows=155495
width=372) (actual time=0.603..1176.177 rows=153530 loops=1)
Filter: agrupable
Total runtime: 1380.113 ms
(3 rows)

So, doing a seq scan on a 450,000 rows table and fetching 150,000 rows
takes only 1.3 secs. This a 900Mhz PIII, 1GB mem (133 Mhz), 7200RPM ide
disk, running freebsd. This machine is also a webserver (apache &
tomcat), mail server, file server (smb & nfs), ldap server, etc.

I don't use pgadmin, I use psql (postgresql console client). It took 2
minutes to display the results of the above query (without the EXPLAIN
ANALIZE).... this makes me think, couldn't be the problem that pgadmin,
psql, etc. takes too much time to display all the rows? It seems a
client software problem, not a server problem.

My advice is, use EXPLAIN ANALYZE to test both servers performance. If
you want to know which the final results will be, you test both
databases from a self programmed application (java, php, C++, etc.).

Hope this helped.

Joel Fradkin wrote:

>Well last evening (did not try it this morning) it was taking the extra
>time.
>
>I have made some adjustmenNots to the config file per a few web sites that you
>all recommended my looking at.
>
>It is now using 137 of 756 meg avail.
>it is now taking 8 secs to return 22,000 rows (using pgadminIII in a sql
>edit window).
>
>The EXPLAIN ANALYSE still shows the same as below, but the table has 344,000
>recs of which only 22636 are clientnum = 'SAKS'
>
>I am still doing a seq search (this applies to the view question where if it
>is a small result set it used a index search but on a larger return set it
>did a seq search) in my view, but with the adjustments to the kernel I get a
>result in 140 secs (MSSQL was 135 secs).
>
>This is not production, I am still very worried that I have to do all this
>tweeking to use this, MSSQL worked out of the box as it does (not saying its
>great, but I never had to adjust a kernel setting etc). Since we cannot
>afford the 70,000 dollars they want to license it I am not implying I can
>use MSSQL, but I could look at other DB's like MYSQL, or Firebird, etc.
>
>I have a lot of time now (two weeks) in this conversion and do not wish to
>give up, I will see if I can learn what is needed to get the maximum
>performance. I have seen much information available and this list has been a
>huge resource. I really appreciate all the help.
>
>
>Joel Fradkin
>
>Wazagua, Inc.
>2520 Trailmate Dr
>Sarasota, Florida 34243
>Tel. 941-753-7111 ext 305
>
>
>
>>QUERY PLAN
>>"Seq Scan on tblcase (cost=0.00..30066.21 rows=37401 width=996) (actual
>>time=0.344..962.260 rows=22636 loops=1)"
>>" Filter: ((clientnum)::text = 'SAKS'::text)"
>>"Total runtime: 1034.434 ms"
>>
>>
>
>That's only 1 second - to return 22,636 rows. Not 27 seconds, as in the
>original post. You'll never persuade PG to use the index when some 75%
>of your rows match the filter - it just doesn't make sense.
>
>--
> Richard Huxton
> Archonet Ltd
>
>
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