Why do you need the unique constraint?
On Mon, Feb 10, 2014 at 9:52 PM, Michael Hunger < [email protected]> wrote: > I think you have to change it to use merge which takes a schema index lock. > > ie. > > create constraint on (h:HEAD) assert h.list is unique; > > MERGE (headNode:HEAD {list:"mylist"}) > > MATCH (headNode)-[old:LINK]->after > > DELETE old > CREATE headNode-[:LINK]->(newNode:LINKNODE { number : {nodeNumber} > })-[:LINK]->after > > > > HTH > > Michael > > Am 10.02.2014 um 11:30 schrieb Aran Mulholland <[email protected]>: > > I've got some real headaches inserting into linked lists. > > If I create a node as such: > > CREATE (headNode:HEAD)-[:LINK]->(headNode) > > then insert like so > > MATCH (headNode:HEAD)-[old:LINK]->after > DELETE old > CREATE headNode-[:LINK]->(newNode:LINKNODE { number : {nodeNumber} > })-[:LINK]->after > > then everything is fine and dandy. But when I try to run the insertion > code in parallel, then I get some real issues. I either get an error like > "Relationship 325457 not found" or I get two or more lists coming off the > headNode. The first error I can deal with as I can rerun the query, the > second is totally unacceptable as my other queries get very messed up > results. > > I am writing for a twitter like service and am using the linked lists so I > can have a news feed. There is a high possibility that the list will need > to be added to by more than one user at once, and this chance will grow the > more users the system has. > > What I want to be able to do is put a lock around the insertion so that > this does not happen. > > How can I better craft my queries so that parallel insertion via cypher > over REST is sustainable? > > -- > 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/groups/opt_out. > > > -- > 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/groups/opt_out. > -- 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/groups/opt_out.
