Repository: falcon Updated Branches: refs/heads/master 91c0a9926 -> 21cf37172
FALCON-2143 Documentation of BacklogEmitter Service Author: Praveen Adlakha <[email protected]> Reviewers: @ajayyadava Closes #282 from PraveenAdlakha/backlog_doc and squashes the following commits: bf3e31a [Praveen Adlakha] comments addressed dd5c1e1 [Praveen Adlakha] comments addressed ff78d59 [Praveen Adlakha] FALCON-2143 Documentation of BacklogEmitter Service Project: http://git-wip-us.apache.org/repos/asf/falcon/repo Commit: http://git-wip-us.apache.org/repos/asf/falcon/commit/21cf3717 Tree: http://git-wip-us.apache.org/repos/asf/falcon/tree/21cf3717 Diff: http://git-wip-us.apache.org/repos/asf/falcon/diff/21cf3717 Branch: refs/heads/master Commit: 21cf3717285c68d5cc55fdb52d5b811da5bc34b1 Parents: 91c0a99 Author: Praveen Adlakha <[email protected]> Authored: Wed Sep 14 11:58:10 2016 +0530 Committer: Pallavi Rao <[email protected]> Committed: Wed Sep 14 11:58:10 2016 +0530 ---------------------------------------------------------------------- .../twiki/BacklogMetricEmitterService.twiki | 50 ++++++++++++++++++++ 1 file changed, 50 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/falcon/blob/21cf3717/docs/src/site/twiki/BacklogMetricEmitterService.twiki ---------------------------------------------------------------------- diff --git a/docs/src/site/twiki/BacklogMetricEmitterService.twiki b/docs/src/site/twiki/BacklogMetricEmitterService.twiki new file mode 100644 index 0000000..2b10f6c --- /dev/null +++ b/docs/src/site/twiki/BacklogMetricEmitterService.twiki @@ -0,0 +1,50 @@ +---+Back Log Emitter Service + +Back Log Emitter service keeps track of all the process which have missed an SLA for a particular time and calculates backlog. Once a notification comes that process has completed, it updates the backlog. This service keeps on sending data to Graphite for each process which is missing SLA. + +The emission and calculation of backlog are controlled by the below properties in startup.properties : + +<verbatim> +*.falcon.backlog.metricservice.emit.interval.millisecs=60000 +*.falcon.backlog.metricservice.recheck.interval.millisecs=60000 +</verbatim> + +---+How Backlog is Calculated + +Back Log Emitter Service is a listener to : + + 1. EntitySLAAlertService + 1. !WorkflowExecutionListener + + +EntitySLAListeners service notifies !BacklogEmitter whenever a process misses its shouldEndIn sla. + +!WorkflowExecutionListener notifies !BacklogEmitter service whenever a process get completed. + + +*Back Log Calculation:* + +If two instances of hourly process p1 have missed SLA for 4th and 5th hour then in 6th hourbacklog for process p1 will be ((6-4) + (6-5))*60 = 180 mins. It is cumulative in nature. + +---+Dependencies : + +*Other Services :* + +Following services and listeners should be enabled for Backlog Emitter Service in startup.properties: + +<verbatim> +##Add if you want to enable BacklogMetricService +# org.apache.falcon.service.FalconJPAService,\ +# org.apache.falcon.metrics.MetricNotificationService,\ +# org.apache.falcon.service.EntitySLAMonitoringService,\ +# org.apache.falcon.service.EntitySLAAlertService,\ +# org.apache.falcon.service.BacklogMetricEmitterService + +*.entityAlert.listeners=org.apache.falcon.service.BacklogMetricEmitterService +</verbatim> + + + +*Falcon Database :* +Back Log Emitter Service maintains its state in the database. It needs one table *BACKLOG_METRIC* please have a look at [[FalconDatabase]] to know how to create it. +
