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https://issues.apache.org/jira/browse/LENS-619?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14607597#comment-14607597
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Himanshu Gahlaut commented on LENS-619:
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Due to further development, this ticket now appears to be blocked on LENS-630
for QueryCost interface. Hence creating the relationship.
> 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
> Reporter: Himanshu Gahlaut
> Assignee: Himanshu Gahlaut
>
> 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 launching 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 Launching Constraints and Waiting Query Selection
> Policies will be configured using configuration values.
> New Query Launching Constraints and Waiting Query Selection Policies can be
> added at runtime, without rebuilding and deploying lens module.
> Waiting Queries will be persisted across server restarts.
> Query Launching 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 and submit the selected user queries for scheduling.
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