Can pgRouting work more efficiently？

Question

I use a river network on which has a lot of nodes to test pgRouting,

and I run the SQL, searching for the shortest path between nodes.

SELECT * FROM shortest_path('
            SELECT gid as id,
                     start_id::int4 AS source, 
                     end_id::int4 AS target,
                     shape_leng::double precision as cost
                    FROM network',
            10, 20, false, false)

But if I want to search for the distance between node#10 and node#21, I need to type the code again and run the SQL.

The result below is parts of distance from node#10 to node#20, but I want is the total distance from starting node to ending node.

In my case, I have 159 nodes and I want to know if there are more efficient way using pgRouting？(like type the SQL code once and I can get all total distance between all nodes)

Answer 1

With the "Driving Distance" function (the one that returns the "raw" list of points and not the polygon), you can query the cost from a start node to all nodes within a maximum cost.

So if you define your cost as distance and set the limit high enough to reach all nodes in your river network, then it will return the distance from your start node to all other nodes. So you get a 1:n distance matrix, which should be already better, right?