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Re: Insert Times

From: Alan Stange <stange(at)rentec(dot)com>
To: PC Drew <drewpc(at)ibsncentral(dot)com>
Cc: "Leeuw van der, Tim" <tim(dot)leeuwvander(at)nl(dot)unisys(dot)com>,pgsql-performance(at)postgresql(dot)org
Subject: Re: Insert Times
Date: 2004-01-27 15:58:29
Message-ID: 40168AA5.6040702@rentec.com (view raw or flat)
Thread:
Lists: pgsql-performance
PC Drew wrote:

>I tested this out and saw no improvement:
>  
>
I'd still suspect some class loading issues and HotSpot compilation 
issues are polluting your numbers.    Try using a PreparedStatement to 
another table first in order to make sure that classes bytecode has been 
loaded.   There are some command line options to the JVM to have it 
print out some status info when it is loading classes and compiling 
methods; you might want to turn on those options as well.

-- Alan

>EXPLAIN ANALYZE SELECT * FROM one;
>Seq Scan on one  (cost=0.00..20.00 rows=1000 width=404) (actual time=0.04..0.50 rows=51 loops=1)
>Total runtime: 0.75 msec
>EXPLAIN ANALYZE SELECT * FROM one;
>Seq Scan on one  (cost=0.00..20.00 rows=1000 width=404) (actual time=0.06..0.50 rows=51 loops=1)
>Total runtime: 0.64 msec
>EXPLAIN ANALYZE SELECT * FROM one;
>Seq Scan on one  (cost=0.00..20.00 rows=1000 width=404) (actual time=0.04..0.40 rows=51 loops=1)
>Total runtime: 0.54 msec
>EXPLAIN ANALYZE SELECT * FROM one;
>Seq Scan on one  (cost=0.00..20.00 rows=1000 width=404) (actual time=0.04..0.41 rows=51 loops=1)
>Total runtime: 0.54 msec
>EXPLAIN ANALYZE SELECT * FROM one;
>Seq Scan on one  (cost=0.00..20.00 rows=1000 width=404) (actual time=0.04..0.41 rows=51 loops=1)
>Total runtime: 0.53 msec
>EXPLAIN ANALYZE INSERT INTO one (id, msg) VALUES (1, 'blah');
>Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.01..0.02 rows=1 loops=1)
>Total runtime: 0.85 msec
>EXPLAIN ANALYZE INSERT INTO one (id, msg) VALUES (1, 'blah');
>Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.02..0.02 rows=1 loops=1)
>Total runtime: 0.15 msec
>EXPLAIN ANALYZE INSERT INTO one (id, msg) VALUES (1, 'blah');
>Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.02..0.02 rows=1 loops=1)
>Total runtime: 0.14 msec
>EXPLAIN ANALYZE INSERT INTO one (id, msg) VALUES (1, 'blah');
>Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.02..0.02 rows=1 loops=1)
>Total runtime: 0.12 msec
>EXPLAIN ANALYZE INSERT INTO one (id, msg) VALUES (1, 'blah');
>Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.01..0.02 rows=1 loops=1)
>Total runtime: 0.12 msec
>
>
>
>-----Original Message-----
>From:	Leeuw van der, Tim [mailto:tim(dot)leeuwvander(at)nl(dot)unisys(dot)com]
>Sent:	Tue 1/27/2004 12:38 AM
>To:	PC Drew; pgsql-performance(at)postgresql(dot)org
>Cc:	
>Subject:	RE: [PERFORM] Insert Times
>
>Hi,
>
>My personal feeling on this is, that the long time taken for the first query
>is for loading all sorts of libraries, JVM startup overhead etc.
>
>What if you first do some SELECT (whatever), on a different table, to warm
>up the JVM and the database?
>
>regards,
>
>--Tim
>
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