Network analysis performance issue

Question

Hello,
I am starting working on a Project
on Oracle Network data model.
The network I will manage will have about 5.000.000 of links
(all Italian Streets).
I am working with oracle database 10g R2
Until now I only did some tests:
I loaded only one zone (about 130.000 links) and I tried
to do some network analysis like find the shortest path between
2 nodes.
I used plsql and a client java, using java api, to do the network analysis
and I obtained the following results:
In a plsql script:
1) execute SDO_TOPO_MAP.SET_MAX_MEMORY_SIZE(1000000000) procedure;
2)execute sdo_net_mem.network_manager.read_network('NETWORK_1') procedure to
load all the network in memory.
It takes about 22 seconds
3) execute sdo_net_mem.network_manager.SHORTEST_PATH('NETWORK_1', start_node_id, end_node_id) function
to find the shortest path.
It takes about 1.8 sec
In java Client StandAlone
1)invoke the NetworkManager.readNetwork(connection, networkName) java API
to load all the network in memory.
It takes about 11 seconds.
2) invoke NetworkManager.shortestPath(network,startNodeID,endNodeID) java API
to find the shortest path. It takes about 140 milliseconds
My question are:
1) How can I improve the plsql api performance?
2) When I'll have loaded all the network links and nodes
(about 5.000.000 of links ) into database,
the step to load the entire network will take very
long time (in java enviroment too)...
So it should be unthinkable (response time too high) to load
the network at runtime...
It means that the system have to hold always the network object in memory?
This solution is not scalable, and it need a lot system resources....
I will be very grateful if someone who faced the same problem can
help me and give me some suggestions.
Thank you
Paola

Answer 1

hi K,
did u have a look at this post?
Re: Network Memory Object (PL/SQL)
The oracle documentation seems to be wrong for the procedure SDO_TOPO_MAP.SET_MAX_MEMORY_SIZE (you can also try this SDO_NET_MEM.SET_MAX_MEMORY_SIZE which seems to do the same!!!): "Number of bytes for the Java maximum heap size. The default value is 262144 (256MB)."
It is wrong : for 1GB you should use this value 1073741824 and not 1048576 !!!
With my network which has about 10.000 nodes / 10.000 links, it has no effect to load the network : 7min... I will try again to create a network which has 700000 links...
hope this help...