[ https://issues.apache.org/jira/browse/CASSANDRA-19436?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Ariel Weisberg updated CASSANDRA-19436: --------------------------------------- Test and Documentation Plan: Updated existing tests Status: Patch Available (was: Open) > When transitioning to Accord migration it's not safe to read immediately > using Accord due to concurrent non-serial writes > ------------------------------------------------------------------------------------------------------------------------- > > Key: CASSANDRA-19436 > URL: https://issues.apache.org/jira/browse/CASSANDRA-19436 > Project: Cassandra > Issue Type: Bug > Components: Accord, Consistency/Coordination > Reporter: Ariel Weisberg > Assignee: Ariel Weisberg > Priority: Normal > Fix For: 5.x > > Time Spent: 10m > Remaining Estimate: 0h > > Concurrent writes at the same time that migration starts make it unsafe to > read from Accord because txn recovery will not be deterministic in the > presences of writes not done through Accord. > Migration to Accord needs to be split into two phases, in the first phase we > write through Accord and always respect the consistency level and do > synchronous commit. This allows Paxos and non-serial writes to continue while > Accord's metadata covers everything needed for future reads. Paxos continues > to operate as normal since it has enough metadata to allow key migration in > the second phase and we need to stay online so something needs to handle LWTs. > Then repair runs and makes it possible for Accord to read any data written > non-transactionally and we can then do key migration and route all updates > (conditional or blind) through Accord while Paxos repair runs so we can stop > doing key migration. -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org