Great! I was just about to ask for some test code. You can either send it directly to me or here to the list. Another option is to upload it to http://trac.neo4j.org if you create a ticket for the problem.
-Johan On Thu, Nov 12, 2009 at 1:40 PM, Daniel Martínez <[email protected]> wrote: > Hello, > > I have created a small test in java demonstrating this use case. If it > is useful for you, please tell me where to upload/send it. > > Regards, > -- > Daniel Martínez > > El mié, 11-11-2009 a las 17:10 +0100, Daniel Martínez escribió: > >> Hi and thanks for the answer, >> >> By close transaction I mean commit. The code as it is does not share >> transactions. >> >> The problematic use case is: >> >> T1 begin >> create rel 0 -> 1 >> T1 commit >> T1 begin >> create rel 1 -> 2 >> T2 begin >> create rel 0 -> 3 <<<<<< deadlock >> set property 3 >> T2 commit >> T1 set property 2 >> T1 commit >> >> The case that works (with 0 -> 1 and 0 -> 3 already created): >> >> T1 begin >> obtain 0 -> 1 >> obtain 1 >> T1 commit >> T1 begin >> create rel 1 -> 2 >> T2 begin >> obtain 0 -> 3 >> set property 3 >> T2 commit >> T1 set property 2 >> T1 commit >> >> The goal is having 0 -> 1 -> 2 and 0 -> 3 created. I suspect the problem >> lies within node 0. Is it possible that T1 locks 0 when creating 1 -> 2? >> >> Regards, >> -- >> Daniel Martínez >> >> >> El mié, 11-11-2009 a las 14:13 +0100, Johan Svensson escribió: >> >> > Hi, >> > >> > There is no global lock in Neo4j. We lock on a relationship and node level >> > so: >> > >> > create node - write lock on created node (so other tx can't see until >> > it exist for real) >> > set/remove property - write lock on either the node or relationship >> > create / delete relationship - write lock on the relationship and both >> > nodes it is connected to >> > >> > There is however a special case during relationship create/delete. For >> > a short period of time (during commit) a write lock may be grabbed on >> > some other relationship (connected to the same node) while updating >> > the "dual interleaved linked list" storing the relationships. >> > >> > I could not quite understand the use case you describe. By close you >> > mean commit/rollback or suspend of transaction? If close means commit >> > I get: >> > >> > T1 begin >> > create rel 0 -> 1 >> > T1 commit >> > T1 begin >> > create rel 1->2 >> > T2 begin >> > setProperty 2 // this will block since other open tx has created >> > relationship to node 2 >> > >> > When T1 commits T2 can continue. >> > >> > Regards, >> > -Johan _______________________________________________ Neo mailing list [email protected] https://lists.neo4j.org/mailman/listinfo/user
