Re: Update table performance - Mailing list pgsql-performance

From Piotr Kołaczkowski
Subject Re: Update table performance
Date
Msg-id 200708071544.17399.P.Kolaczkowski@elka.pw.edu.pl
Whole thread Raw
In response to Update table performance  (Mark Makarowsky <bedrockconstruction@yahoo.com>)
List pgsql-performance
Hi,

update valley set test='this is a test'

Such query updates ALL of your records in the table.
5 million records * 47 fields - that can be several gigabytes of data.
The system has to scan that gigabytes to change every record. This is a huge
task. Try vacuuming and see if it helps. It can help a lot, if you perform
such 'whole table updates' often.

Best regards,
Piotr Kolaczkowski

pgsql-performance by date:

Previous
From: runic
Date:
Subject: select count(*) performance
Next
From: Enrico Weigelt
Date:
Subject: Implementing an regex filter