How to delete large amount of nodes in cypher

Question

I'm trying to delete 1 million nodes in cyphper at one query using web admin(i.e localhost:7474/browser).
These nodes is labeled as User. I ran following query, then returned Unknown error after waiting about 1minutes.

match (u:User) delete u

This query returned Unknown error every time. and I confirm my PC resources didn't lack. I'm using Neo4j version 2.0.0 RC1 community edition. and Neo4j Hosted on local.
Is My trying way for deletion nodes wrong?
Thanks

Answer 1

You should do write operations with a reasonable transaction size of ~10-50k atomic operations. Therefore you can use limit and run the statement until all users are gone:

match (u:User) with u limit 1000 delete u

Answer 2

With Neo4j 3.x and forward you can run large delete transactions using APOC too:

call apoc.periodic.iterate("MATCH (u:User) return u", "DETACH DELETE u", {batchSize:1000})
yield batches, total return batches, total