Skip site navigation (1) Skip section navigation (2)

query execution time

From: preetika tyagi <preetikatyagi(at)gmail(dot)com>
To: pgsql-students(at)postgresql(dot)org
Subject: query execution time
Date: 2011-03-21 04:59:33
Message-ID: AANLkTi=FhaO5mX_YdqqsF1Yh0YNEHW8H1f0AUdpE0Fmo@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-students
Hi,

I am wondering if someone can help me understand the following query
execution behavior:

I have two similar tables and table2 consists of 5000000 records.

Query: INSERT INTO table1 SELECT * FROM table2.
Execution Time: A ms.

Query: INSERT INTO table1 SELECT * FROM table2.
Execution Time: B ms.

Sometimes B >> A (B is very larger than A). Both queries are same and run
twice. What could be the reason that the same query is taking very long
sometime?

Thanks a lot!

Responses

pgsql-students by date

Next:From: Selena DeckelmannDate: 2011-03-21 05:09:17
Subject: Re: query execution time
Previous:From: preetika tyagiDate: 2011-03-15 19:49:46
Subject: Slow INSERT as compared to UPDATE

pgsql-general by date

Next:From: Selena DeckelmannDate: 2011-03-21 05:09:17
Subject: Re: query execution time
Previous:From: Andy ColsonDate: 2011-03-21 03:26:16
Subject: Re: Database Design for Components and Interconnections

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group