[GENERAL] Store derived data or use view?

gvimrc

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Jul 3, 2009, 1:08:17 PM7/3/09

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I have a table which stores the absolute longitude of a planetary position, eg:

MERCURY
---------------
157.65

SATURN
-------------
247.65

When 2 planets are a certain distance apart there is an 'aspect', eg. 90 degrees is a "square" aspect

I wish to record these aspects for different user profiles and eventually do searches for users who have the same aspect(s). Would it be better, in terms of search speed/efficiency, to calculate and store the aspect data, eg. Mercury/Saturn square, or should I just store the longitude data and create a view with the calculated aspects? I anticipate a large dataset of users so search speed/efficiency is very important.

gvim

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Hartman, Matthew

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Jul 3, 2009, 1:46:30 PM7/3/09

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If it's static (i.e. the planets don't move too much, hah), calculate
and store. No sense in re-calculating it each and every time.

Matthew Hartman
Programmer/Analyst
Information Management, ICP
Kingston General Hospital
(613) 549-6666 x4294

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Martin Gainty

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Jul 3, 2009, 3:46:50 PM7/3/09

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i just asked NASA the same question
I'll post the answer back to the list..

Martin Gainty
We can lick gravity, but sometimes the paperwork is overwhelming. - Wehrner Von Braun
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> Date: Fri, 3 Jul 2009 18:08:17 +0100
> From: gvi...@googlemail.com
> To: pgsql-...@postgresql.org

> Subject: [GENERAL] Store derived data or use view?
>

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Michael Black

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Jul 3, 2009, 6:23:55 PM7/3/09

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In addition to the amount of data that will be captured, you will need take in to consideration how often each user will be accessing this data as well as the number of users. For example, if you have 10 users running the query once an hour every hour of the day, you might get away with calculating the aspect each time the data data is requested. But if you have 100 users wanting the data every 15 minutes, you may find it faster to perform the calculations on the insert of the planetary data. Personally, and since you indicated that there will a large amount of data, I would do the calculations on insert.

I am not associated with NASA.

From: mga...@hotmail.com
To: gvi...@googlemail.com; pgsql-...@postgresql.org
Subject: Re: [GENERAL] Store derived data or use view?
Date: Fri, 3 Jul 2009 15:46:50 -0400