Hi, About the number of relationships per node and how that affects things: it affects the load performance of a node the first time its relationships are touched after the node being freshly loaded into memory (either first time, or after eviction from cache). Iterating over all of a certain type, as in your case, requires all relationships to be loaded for that node. In 2.1 there will be a store format change where only relationships of the requested type and direction are loaded. Nodes that go over a certain threshold number of relationships will take advantage of such a representation on disk, so in your case where a worst case is 4 relationships, or more specifically 1 relationship of each type, there will no gain by that store format change.
The geo estimate evaluator in neo4j takes into consideration the fact that the earth aint flat, but if a simpler version works, then by all means :) I think it's safe to say that the TraversalAStar isn't really experimental anymore, it's probably a notice left in there by mistake. On Mon, May 19, 2014 at 2:30 PM, Angelo Immediata <[email protected]>wrote: > Hi Michael > > For hot dataset do you mean a dataset stored in memory? Well we tried both > for in memory dataset and for dataset on the disk > Well I don't know exactly how many relationships can have a node....the > worst case is the each node contains 4 relationship each one with direction > BOTH > > > 2014-05-19 13:22 GMT+02:00 Michael Hunger < > [email protected]>: > >> Is this for a hot dataset, or one that has to be fetched from disk? >> How many rels do you usually have per node? >> >> >> On Mon, May 19, 2014 at 9:04 AM, Angelo Immediata <[email protected]>wrote: >> >>> Hi there >>> >>> With my colleague, we are are buillding a route system by using neo4j >>> 2.0.3; so we are suing A* and Dijkstra algorithms in order to calculate the >>> shortest path, >>> I was wondering if the relationships number can affect the algorithm >>> perfomance. I mean, we have a graph with around 1 million (or more) of >>> nodes and 50 million of relationships. We have several types of >>> relationship; specifically we have: >>> >>> - relationships for cars: the most of relationships are of this type >>> - relationships for bikes >>> - relationships for pedestrian >>> - relationships for public transports >>> >>> When we execute Dijkstra and/or A* we can specify, in our PathExpander, >>> the type of the relationships we want to consider during the traverser, so, >>> my sensation is that the relationships number should not affect algorithm >>> performance since we will sparsely (almost never) consider all the >>> relationships types. Am I right? >>> >>> Thak you >>> Angelo >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Neo4j" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "Neo4j" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/neo4j/YtOt_rNy9sA/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> >> For more options, visit https://groups.google.com/d/optout. >> > > -- > You received this message because you are subscribed to the Google Groups > "Neo4j" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- Mattias Persson Neo4j Hacker at Neo Technology -- You received this message because you are subscribed to the Google Groups "Neo4j" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
