[CASSANDRA-4718] More-efficient ExecutorService for improved throughput

• Type: Improvement
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 2.1 rc1
• Labels: performance
• Assignee: Benedict Elliott Smith
• Reporter: Jonathan Ellis

Authors

Benedict Elliott Smith

Reviewers

Jason Brown

• Created: 25/Sep/12 18:11
• Updated: 16/Apr/19 09:32
• Resolved: 29/May/14 21:29

Description

Currently all our execution stages dequeue tasks one at a time. This can result in contention between producers and consumers (although we do our best to minimize this by using LinkedBlockingQueue).

One approach to mitigating this would be to make consumer threads do more work in "bulk" instead of just one task per dequeue. (Producer threads tend to be single-task oriented by nature, so I don't see an equivalent opportunity there.)

BlockingQueue has a drainTo(collection, int) method that would be perfect for this. However, no ExecutorService in the jdk supports using drainTo, nor could I google one.

What I would like to do here is create just such a beast and wire it into (at least) the write and read stages. (Other possible candidates for such an optimization, such as the CommitLog and OutboundTCPConnection, are not ExecutorService-based and will need to be one-offs.)

AbstractExecutorService may be useful. The implementations of ICommitLogExecutorService may also be useful. (Despite the name these are not actual ExecutorServices, although they share the most important properties of one.)

Issue Links

• is duplicated by: CASSANDRA-6995 Execute local ONE/LOCAL_ONE reads on request thread instead of dispatching to read stage
• is related to: CASSANDRA-1632 Thread workflow and cpu affinity
• supercedes: CASSANDRA-7045 Investigate changes to threading model for network consumers to improve performance for small messages
• supercedes: CASSANDRA-6995 Execute local ONE/LOCAL_ONE reads on request thread instead of dispatching to read stage