Re: storing large graphs in postgres

You could try one row per node, and a series of integer columns that
store adjacency at the bit-level.  (A function for extracting individual
bits would help here.)  Actually, I would probably go with the edge-list
layout in the end; storage is cheap.  BTW, isn't INT8 a tad small for
20GB of data?

T.

Taher H. Haveliwala wrote:

>I need to store very large graphs structures in
>postgres.  The graphs are close to 20GB when in
>flatfile format.  I first tried using an adjacency
>list representation, i.e.,
>
>  graph (source INT8 PRIMARY KEY, dest INT8[]);
>
>but operating on the array type seems a bit
>inflexible. I took a look at the contrib/array stuff
>as suggested in a previous post, but it seems like
>that only allows for boolean predicates on the array.
>I.e., I would like to be able to say 'return all nodes
>within distance two from x' using purely sql.  Of
>course I could use an edge-list format:
>
>  graph (source INT8, dest INT8);
>
>but this takes up almost double the space (which is
>painful, given that the original input is close to
>20GB).
>
>Any way to get richer queries on array types, or some
>other efficient way to store large graphs?
>
>I suppose some python glue, making multiple db calls,
>would do the trick, but it would be nicer if postgres
>could take care of it all.
>
>Thanks
>Taher
>
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--
Timothy H. Keitt
Department of Ecology and Evolution
State University of New York at Stony Brook
Stony Brook, New York 11794 USA
Phone: 631-632-1101, FAX: 631-632-7626
http://life.bio.sunysb.edu/ee/keitt/