> Am 07.06.2015 um 20:57 schrieb Dan R <nice...@gmail.com>: > > Hello, I am attempting to implement a specific object model that has a lot of > inheritance (Up to 12 or 13 levels in some cases). I was wondering if there > are any performance penalties associated with having a large number of labels > on a node. Here's an example: > > CREATE (n:Label1:Label2:Label3:Label4:Label5:Label6..) > > But in most cases we'd just be querying with > > MATCH (n:Label1) > > but have the freedom to match further up the chain if we want.
Yes there is some penalty, if you have more labels than fit into the node-record (5-bytes) they are stored in a separate indirection file which costs additional accesses if you accesses on of those nodes as it has to deserialize all labels. I think that's something that will be more efficient in 2.3 Perhaps for the time being it might be easier to separate the additional hierarchy either into a separate node or just into node-properties? So you have a basic "entity" label and the main labels on your nodes and for higher level queries you'd use the entity label and check in the property? But best is to just test it how it fares for your use-case. > > So is there anything wrong with this? Just wanted to check since I'm not sure > about the underlying file structures of the graph. > > I was also planning on doing something similar with properties: > > CREATE (n)-[r:REL1]-(p) > > MATCH (n)-[r:REL1|REL2|REL3|REL4|REL5|REL6|REL7]-(p) > > I'd assume this one would have more of a penalty in the match clause since > it's probably just a for loop underneath searching for each relationship but > I'm not sure of how bad of a penalty it would be. For properties the same indirection as mentioned above will kick in, even more so if you have longer strings as properties. So you either encode you additional hierarchies as numbers or as short strings, which are stored more efficiently only one indirection away. Alternatively you might also be able to just create a different relationship-type that includes the other hierarchy levels or additional rels for the other hierarchies? HTH Michael > > Thanks for any insights, > Dan > > -- > 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 neo4j+unsubscr...@googlegroups.com > <mailto:neo4j+unsubscr...@googlegroups.com>. > For more options, visit https://groups.google.com/d/optout > <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 neo4j+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
