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https://issues.apache.org/jira/browse/LENS-619?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Himanshu Gahlaut updated LENS-619:
----------------------------------
Component/s: server
driver-jdbc
driver-hive
api
> Applying Query Launching Constraints before allowing a query to be launched
> ---------------------------------------------------------------------------
>
> Key: LENS-619
> URL: https://issues.apache.org/jira/browse/LENS-619
> Project: Apache Lens
> Issue Type: New Feature
> Components: api, driver-hive, driver-jdbc, server
> Reporter: Himanshu Gahlaut
> Assignee: Himanshu Gahlaut
> Fix For: 2.3
>
> Attachments: LENS-619.01.patch
>
>
> Lens will always accept a new query from a user and put it in a scheduling
> queue for processing.
> Next candidate query picked up from scheduling queue for processing will be
> launched only if all query constraints evaluated on candidate query and
> launched queries allows the candidate query to be launched, otherwise the
> candidate query will be added to waiting queries.
> When any launched query is finished, a waiting query selector will select
> waiting queries for rescheduling using a list of waiting queries selection
> policy. Every waiting query selection policy will return a list of eligible
> waiting queries to be rescheduled. Query Selector will calculate intersection
> of multiple list of eligible waiting queries and add the result of
> intersection to scheduling queue for reprocessing.
> At initialization, Query Constraints and Waiting Query Selection Policies
> will be configured using configuration values.
> New Query Constraints and Waiting Query Selection Policies can be added at
> runtime, without rebuilding and deploying lens module. Drivers should be
> allowed to add more Query Constraints and Waiting Queries Selection policies.
> Waiting Queries will be persisted across server restarts.
> Query Constraint 1: Allow a candidate query to be launched, only if,
> cumulative query cost of all current queries launched by the user, who
> submitted candidate query, is less than a cumulative query cost ceiling for
> launching a new query.
> Waiting Query Selection Policy 1: Select all waiting queries of the user
> whose query has finished.
> Query Constraint 2: Allow a candidate query to be launched, only if, current
> concurrent queries launched on the selected driver are less than max
> concurrent queries allowed on the driver.
> Waiting Query Selection Policy 2: Select all waiting queries of the driver
> whose query has finished.
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