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Stefania commented on CASSANDRA-9673: ------------------------------------- The user profile is correct, I verified with a temporary debug line that SP.syncWriteToBatchlog() is executing. With progressively bigger tests it gets clearer however that the GC times improve with the patched version. I've attached the results with *n=500000*, file 004, along with the JMC screenshots of the GC times of the first node. > 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 > > Attachments: 9673_001.tar.gz, 9673_004.tar.gz, > gc_times_first_node_patched_004.png, gc_times_first_node_trunk_004.png > > > 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)