So for upgrading Paxos to v2, the non-serial consistency level should be set to ANY or LOCAL_QUORUM, and the serial consistency level should still be SERIAL or LOCAL_SERIAL. Got it, thanks!
From: Laxmikant Upadhyay <laxmikant....@gmail.com> Date: Tuesday, 12 March 2024 at 7:33 am To: user@cassandra.apache.org <user@cassandra.apache.org> Cc: Weng, Justin <justin.w...@netapp.com> Subject: Re: Question about commit consistency level for Lightweight Transactions in Paxos v2 You don't often get email from laxmikant....@gmail.com. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification> EXTERNAL EMAIL - USE CAUTION when clicking links or attachments You need to set both in case of lwt. your regular non -serial consistency level will only applied during commit phase of lwt. On Wed, 6 Mar, 2024, 03:30 Weng, Justin via user, <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> wrote: Hi Cassandra Community, I’ve been investigating Cassandra Paxos v2 (as implemented in CEP-14<https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-14%3A+Paxos+Improvements>) which improves the performance of lightweight transaction (LWT). But I’ve got a question about setting the commit consistency level for LWT after upgrading Paxos. In cqlsh<https://docs.datastax.com/en/cql-oss/3.3/cql/cql_reference/cqlshSerialConsistency.html>, gocql<https://github.com/gocql/gocql/blob/master/session.go#L1247> and Python driver<https://docs.datastax.com/en/developer/python-driver/3.29/api/cassandra/query/#cassandra.query.Statement.serial_consistency_level>, there are two settings for consistency levels: normal Consistency Level and Serial Consistency Level. As mentioned in the cqlsh documentation<https://docs.datastax.com/en/cql-oss/3.3/cql/cql_reference/cqlshSerialConsistency.html>, Serial Consistency Level is only used for LWT and can only be set to either SERIAL or LOCAL_SERIAL. However, the Steps for Upgrading Paxos<https://github.com/apache/cassandra/blob/trunk/NEWS.txt#L532> and CEP-14<https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-14%3A+Paxos+Improvements> mention that ANY or LOCAL_QUOROM can be used as the commit consistency level for LWT after upgrading Paxos to v2. Therefore, I have a question about how to correctly set the commit consistency level to ANY or LOCAL_QUORUM for LWT. Namely, which consistency level should I set, the normal Consistency Level or Serial Consistency Level? Any help would be really appreciated. Thanks, Justin
