Josef, Yes, N1 is locked during the creation of the relationship. Different than a table, Neo4j actually stor direct links between the nodes as relationships, making data-local traversals without index lookups possible. This means both nodes will be locked during the TX1 .
HTH /Peter On Tuesday, January 10, 2012, Josef Holy <josef.h...@gmail.com> wrote: > Hello neo4j-ers, > > I have question - when 2 threads (in embedded neo4j mode) want to concurrently create the following RELs A and B (each within their own transaction, nodes N1, N2 and N3 existed before): > > Thread 1 - tx1 - N1--RELA-->N2 > Thread 2 - tx2 - N1--RELB-->N3 > > does the node N1 represent critical section? I mean - if Thread 2's tx2 starts later, does it have to wait till Thread 1's tx1 finishes and thus releases node N1? > > Sorry for asking, but I don't know the neo4j internals and I would expect, that the creation of relationship wouldn't lock the 2 nodes - similarly to the relational (SQL) db, where adding rows to M:N 'relationship' table also doesn't lock records in the entity table(s)... > > Please advise... > > > Thanks a lot! > > -Josef. > > _______________________________________________ > NOTICE: THIS MAILING LIST IS BEING SWITCHED TO GOOGLE GROUPS, please register and consider posting at https://groups.google.com/forum/#!forum/neo4j > > Neo4j mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > -- Cheers, /peter neubauer Google: neubauer.peter Skype: peter.neubauer Phone: +46 704 106975 LinkedIn: http://www.linkedin.com/in/neubauer Twitter: @peterneubauer Tungle: tungle.me/peterneubauer brew install neo4j && neo4j start heroku addons:add neo4j _______________________________________________ NOTICE: THIS MAILING LIST IS BEING SWITCHED TO GOOGLE GROUPS, please register and consider posting at https://groups.google.com/forum/#!forum/neo4j Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
