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Stefania commented on CASSANDRA-9673: ------------------------------------- [~iamaleksey] do we also need a BATCH_RESPONSE verb or should we just keep on using REQUEST_RESPONSE? I've added BATCH_RESPONSE but it is functionally identical to REQUEST_RESPONSE. The same goes for the handler, WriteResponseHandler, which I have not duplicated instead. Another question is whether we need to introduce a new stage or is it OK to keep on using Stage.MUTATION? I started writing dtest to check that we can still support older nodes, e.g. 2.2, but things are quite broken at the moment, for example in ReadCommand serializer: {code} if (version < MessagingService.VERSION_30) throw new UnsupportedOperationException(); {code} cc [~slebresne] - do we already have a ticket or plan for fixing compatibility with older nodes? > Improve batchlog write path > --------------------------- > > Key: CASSANDRA-9673 > URL: https://issues.apache.org/jira/browse/CASSANDRA-9673 > Project: Cassandra > Issue Type: Improvement > Reporter: Aleksey Yeschenko > Assignee: Stefania > Fix For: 3.0.0 rc1 > > > Currently we allocate an on-heap {{ByteBuffer}} to serialize the batched > mutations into, before sending it to a distant node, generating unnecessary > garbage (potentially a lot of it). > With materialized views using the batchlog, it would be nice to optimise the > write path: > - introduce a new verb ({{Batch}}) > - introduce a new message ({{BatchMessage}}) that would encapsulate the > mutations, expiration, and creation time (similar to {{HintMessage}} in > CASSANDRA-6230) > - have MS serialize it directly instead of relying on an intermediate buffer > To avoid merely shifting the temp buffer to the receiving side(s) we should > change the structure of the batchlog table to use a list or a map of > individual mutations. -- This message was sent by Atlassian JIRA (v6.3.4#6332)