Hi,
But now having 12 columns and multicolumn index, wont this slow down
the search process. I mean in general retrieving 12 columns using a
multicolumn index is slower or faster compared to an index on a 12 size
array?
Thanks
Abhang
Quoting "John D. Burger" <[EMAIL PROTECTED]>:
ABHANG RANE wrote:
I have a array column which has 12 real values in it. Basically
these values represent co-ordinates in 12 dimensions for a
substance. My main need is to find substances similar to a
particular compound. Now I can do by calculating differences with
each array in the whole table. But the table has millions of rows.
So I need some kinda higher dimensional index.
Is there any particular reason you're using an array? If every row
has all twelve values, I'd just make them columns. Then I could use
a multi-column index.
I have read about the cube operation in postgre, can it be extended
to 12 dimensions or something like that.
I have no experience with CUBE, but I think it's just a kind of
summarization aggregate.
It sounds like you want the Nearest Neighbor(s) of your "particular
compound". You might to read about that:
http://en.wikipedia.org/wiki/Nearest_neighbor_search
- John Burger
G63
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