Re: [igraph] graphs too large for RAM

[Tamas Nepusz]

Hi Richard,

> It doesn't look like igraph has support for the graph>RAM problem,  
> though, but I thought I'd ask around to see how others deal with the  
> problem (buying more RAM won't work for this machine).
We have a branch in igraph's Launchpad repository (maintained by  
Emmanuel Navarro) that replaces igraph's lowest in-memory graph  
storage layer with another one that stores the graph in an SQL  
database. Actually, there are two branches, one is based on the  
development tree, the other one is on the stable 0.5 tree:

https://code.launchpad.net/~enavarro222/igraph/0.5.1-db
https://code.launchpad.net/~enavarro222/igraph/0.6-db

I have never tried these branches myself, and I remember that Manu  
told that although it works, a caching layer on top the database layer  
would be desirable to make the thing efficient. There's another: some  
igraph functions start by converting whatever graph representation  
they get into an in-memory adjacency list, so at this point the graph  
must fit into the memory again (but of course one can rewrite these  
functions to use the original representation).

The relevant threads in the igraph-help mailing list archive are as  
follows (I think):

http://lists.gnu.org/archive/html/igraph-help/2009-03/msg00183.html
http://lists.gnu.org/archive/html/igraph-help/2008-12/msg00009.html
http://lists.gnu.org/archive/html/igraph-help/2008-12/msg00001.html

--
Tamas