Re: storing large graphs in postgres

On Wed, 5 Sep 2001, 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?

You could probably write functions to do your operations
and then just use those from the sql queries.
If you use the C interface to make the functions the code
in contrib/array is probably a reasonable starting point to
look at.