Re: [PERFORM] I could not get postgres to utilizy indexes

2004-08-20 Thread Manfred Koizar 
On Thu, 19 Aug 2004 09:54:47 +0200, Leeuw van der, Tim
[EMAIL PROTECTED] wrote:
You asked the very same question yesterday, and I believe you got some useful 
answers. Why do you post the question again?

Tim, no need to be rude here.  We see this effect from time to time when
a new user sends a message to a mailing list while not subscribed.  The
sender gets an automated reply from majordomo, subscribes to the list
and sends his mail again.  One or two days later the original message is
approved (by Marc, AFAIK) and forwarded to the list.  Look at the
timestamps in these header lines:
|Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
|   by svr4.postgresql.org (Postfix) with ESMTP id 32B1F5B04F4;
|   Wed, 18 Aug 2004 15:54:13 + (GMT)
|Received: from localhost (unknown [200.46.204.144])
|   by svr1.postgresql.org (Postfix) with ESMTP id E6B2B5E4701
|   for [EMAIL PROTECTED]; Tue, 17 Aug 2004 11:23:07 -0300 (ADT)

[more instructions]

And while we are teaching netiquette, could you please stop top-posting
and full-quoting.

Igor, welcome to the list!  Did the suggestions you got solve your
problem?

Servus
 Manfred

---(end of broadcast)---
TIP 2: you can get off all lists at once with the unregister command
(send unregister YourEmailAddressHere to [EMAIL PROTECTED])

Re: [PERFORM] I could not get postgres to utilizy indexes

2004-08-19 Thread Leeuw van der, Tim 
Hi,

You asked the very same question yesterday, and I believe you got some useful answers. 
Why do you post the question again?

You don't even mention your previous post, and you didn't continue the thread which 
you started yesterday.

Did you try out any of the suggestions which you got yesterday? Do you have further 
questions about, for instance, how to do casting of values? If so, please continue 
posting with the previous thread, rather than reposting the same question with a 
different subject.

regards,

--Tim


-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Igor
Artimenko
Sent: dinsdag 17 augustus 2004 16:23
To: [EMAIL PROTECTED]
Subject: [PERFORM] I could not get postgres to utilizy indexes


Hi verybody!

I can't make use of indexes even I tried the same test by changing different settings 
in postgres.conf like geqo to off/on  geqo related parameters, enable_seqscan off/on 
 so on. Result is the same. 

Here is test itself:

I've created simplest table test and executed the same statement explain analyze 
select id from test where id = 5; Few times I added 100,000 records, applied 
vacuum full; and issued above explain command. 
Postgres uses sequential scan instead of index one. 
Of cause Time to execute the same statement constantly grows. In my mind index should 
not allow time to grow so much.  

Why Postgres does not utilizes primary unique index?
What I'm missing? It continue growing even there are 1,200,000 records. It should at 
least start using index at some point.


Details are below:
100,000 records:
QUERY PLAN

 Seq Scan on test  (cost=0.00..2427.00 rows=2 width=8) (actual time=99.626..199.835 
rows=1 loops=1)
   Filter: (id = 5)
 Total runtime: 199.990 ms

200,000 records:
QUERY PLAN
-
 Seq Scan on test  (cost=0.00..4853.00 rows=2 width=8) (actual time=100.389..402.770 
rows=1 loops=1)
   Filter: (id = 5)
 Total runtime: 402.926 ms


300,000 records:
QUERY PLAN
-
 Seq Scan on test  (cost=0.00..7280.00 rows=1 width=8) (actual time=100.563..616.064 
rows=1 loops=1)
   Filter: (id = 5)
 Total runtime: 616.224 ms
(3 rows)

I've created test table by script:

CREATE TABLE test
(
  id int8 NOT NULL DEFAULT nextval('next_id_seq'::text) INIQUE,
  description char(50),
  CONSTRAINT users_pkey PRIMARY KEY (id)
);

CREATE SEQUENCE next_id_seq
  INCREMENT 1
  MINVALUE 1
  MAXVALUE 100
  START 1
  CACHE 5
  CYCLE;

I use postgres 7.4.2




---(end of broadcast)---
TIP 6: Have you searched our list archives?

   http://archives.postgresql.org

---(end of broadcast)---
TIP 4: Don't 'kill -9' the postmaster

Re: [PERFORM] I could not get postgres to utilizy indexes

2004-08-18 Thread Thomas Swan 
Igor Artimenko wrote:
Hi verybody!
I can't make use of indexes even I tried the same test by changing different settings in postgres.conf like geqo to off/on  geqo related parameters, enable_seqscan off/on  so on. Result is the same. 

Here is test itself:
I've created simplest table test and executed the same statement explain analyze select id from test where id = 5; Few times I added 100,000 records, applied vacuum full; and issued above explain command. 
Postgres uses sequential scan instead of index one. 
Of cause Time to execute the same statement constantly grows. In my mind index should not allow time to grow so much.  

Why Postgres does not utilizes primary unique index?
What I'm missing? It continue growing even there are 1,200,000 records. It should at 
least start using index at some point.
 

Igor, you may want to run vacuum analyze and see if your results change.
Thomas
---(end of broadcast)---
TIP 5: Have you checked our extensive FAQ?
  http://www.postgresql.org/docs/faqs/FAQ.html

Re: [PERFORM] I could not get postgres to utilizy indexes

2004-08-18 Thread gnari 
I (gnari [EMAIL PROTECTED]) miswrote:

 Actually, I think it was determined that the problem was due to the
 int index

of course, i meant int8 index

gnari




---(end of broadcast)---
TIP 8: explain analyze is your friend