Hi, I am experimenting with C* 2.0 ( and today's java-driver 2.0 snapshot) for implementing distributed locks.
Basically, I have a table of 'states' I want to serialize access to: create table state ( id text , lock uuid , data text, primary key (id) ) (3 nodes, replication level 3) insert into state (id) values ( 'foo') I try to akquire the lock for state 'foo' like this: update state set lock = myUUID where id = 'foo' if lock = null; and check whether I got it by comparing the lock against my supplied UUID: select lock from state where id = 'foo'; ... do work on 'foo' state .... release lock: update state set lock = null where id = 'foo' if lock = myUUID; This works pretty well and if I increase the number of clients competing for the lock I start seeing timeouts on the client side. Natural so far and the lock also remains in a consistent state (it works to work around the failing clients and the uncertainty whether they got the lock or not). However, after pausing the clients for a while the timeouts do not disappear. Meaning that when I send a single request after everything calms down , I still get a timeout: Caused by: com.datastax.driver.core.exceptions.WriteTimeoutException: Cassandra timeout during write query at consistency SERIAL (-1 replica were required but only -1 acknowledged the write) I do not see any reaction in the C* logs for these follow-up requests that still time out. Any idea how to approach this problem? Jan
