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Benedict commented on CASSANDRA-15241: -------------------------------------- The patch looks good, thanks. It's a low cost, low risk and valuable insight into what the system is doing, so I think it will be really helpful. I've pushed some minor suggestions [here|https://github.com/belliottsmith/cassandra/tree/15241-suggest]. One problem was that the {{task}} field was not guaranteed under the JMM to ever see modifications to its contents. It may be that we typically would see them, but we may have to incur the cost of a lazySet to absolutely guarantee it. Unfortunately I don't know of another mechanism for guaranteeing a write is made visible eventually from within a loop. There was also a visibility issue with {{nowNanos}} in {{LocalMutationRunnable}}, since the task can be assigned to a worker before it runs, at which time the nowNanos will be zero and the running time would look absurd. Finally, there remains an issue with the semantics of the start time - in some cases it's when the task starts running, in others when the task was created, so including any time spent queued. If we want, we could quite easily expose _both_ of these items, and perhaps we might like to. But otherwise we should pick one and stick to it for all of the implementations. I would presume we are slightly _more_ interested in actual running time, as otherwise tasks queued up behind long running tasks might appear long running themselves - though this would require the executor to be entirely saturated. We might also want to put a bit of time into improving the descriptions, to include e.g. the CQL being executed. Right now, for executing a prepared statement, we only get the statementId and the options it is invoked with. > Virtual table to expose current running queries > ----------------------------------------------- > > Key: CASSANDRA-15241 > URL: https://issues.apache.org/jira/browse/CASSANDRA-15241 > Project: Cassandra > Issue Type: New Feature > Components: Feature/Virtual Tables > Reporter: Chris Lohfink > Assignee: Chris Lohfink > Priority: Normal > > Expose current running queries and their duration. > {code}cqlsh> select * from system_views.queries; > thread_id | duration_micros | task > ------------------------------+-----------------+--------------------------------------------------------------------------------- > Native-Transport-Requests-17 | 6325 | QUERY > select * from system_views.queries; [pageSize = 100] > Native-Transport-Requests-4 | 14681 | EXECUTE > f4115f91190d4acf09e452637f1f2444 with 0 values at consistency LOCAL_ONE > Native-Transport-Requests-6 | 14678 | EXECUTE > f4115f91190d4acf09e452637f1f2444 with 0 values at consistency LOCAL_ONE > ReadStage-10 | 16535 | > SELECT * FROM basic.wide1 LIMIT 5000 > ReadStage-13 | 16535 | > SELECT * FROM basic.wide1 LIMIT 5000 > ReadStage-14 | 16535 | > SELECT * FROM basic.wide1 LIMIT 5000 > ReadStage-19 | 11861 | > SELECT * FROM basic.wide1 LIMIT 5000 > ReadStage-20 | 11861 | > SELECT * FROM basic.wide1 LIMIT 5000 > ReadStage-22 | 7279 | > SELECT * FROM basic.wide1 LIMIT 5000 > ReadStage-23 | 4716 | > SELECT * FROM basic.wide1 LIMIT 5000 > ReadStage-5 | 16535 | > SELECT * FROM basic.wide1 LIMIT 5000 > ReadStage-7 | 16535 | > SELECT * FROM basic.wide1 LIMIT 5000 > ReadStage-8 | 16535 | > SELECT * FROM basic.wide1 LIMIT 5000{code} -- This message was sent by Atlassian JIRA (v7.6.14#76016) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org