Re: Do Views execute underlying query everytime ?? - Mailing list pgsql-performance

From Amit V Shah
Subject Re: Do Views execute underlying query everytime ??
Date
Msg-id 0C072E7CC947D511AC9600A0CC7341200256CF52@vpn.tagaudit.com
Whole thread Raw
In response to Do Views execute underlying query everytime ??  (Amit V Shah <ashah@tagaudit.com>)
Responses Re: Do Views execute underlying query everytime ??  (John A Meinel <john@arbash-meinel.com>)
List pgsql-performance
After I sent out this email, I found this article from google

http://jonathangardner.net/PostgreSQL/materialized_views/matviews.html

Looks like we can control as to when the views refresh... I am still kind of
confused, and would appreciate help !!

The create/drop table does sound a solution that can work, but the thing is
I want to get manual intervention out, and besides, my work flow is very
complex so this might not be an option for me :-(

Thanks,
Amit

-----Original Message-----
From: Matthew Nuzum [mailto:mattnuzum@gmail.com]
Sent: Tuesday, June 21, 2005 10:45 AM
To: Amit V Shah
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Do Views execute underlying query everytime ??


On 6/21/05, Amit V Shah <ashah@tagaudit.com> wrote:
> Hi all,
...
> I am thinking of having a solution where I create views for each screen,
> which are just read only.
>
> However, I donot know if the query that creates the view is executed
> everytime I select something from the view. Because if that is the case,
> then I think my queries will again be slow. But if that is the way views
> work, then what would be the point in creating them ..
>
> Any suggestions, helps --

They do get executed every time. I have a similar issue, but my data
does not change very frequently, so instead of using a view, I create
lookup tables to hold the data. So once a day I do something like
this:
drop lookup_table_1;
create table lookup_table_1 as SELECT ...;

In my case, rows are not deleted or updated, so I don't actually do a
"drop table..." I merely add new records to the existing table, but if
your data changes, the drop table technique can be faster than doing a
delete or update.

--
Matthew Nuzum
www.bearfruit.org


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