[jira] [Updated] (LENS-777) Query remains in queue even when driver is free

["Akshay Goyal (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/LENS-777?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Akshay Goyal updated LENS-777:
------------------------------
    Attachment: LENS-777.01.patch

> Query remains in queue even when driver is free 
> ------------------------------------------------
>
>                 Key: LENS-777
>                 URL: https://issues.apache.org/jira/browse/LENS-777
>             Project: Apache Lens
>          Issue Type: Bug
>            Reporter: Arshad Matin
>            Assignee: Akshay Goyal
>         Attachments: LENS-777.01.patch
>
>
> Scenario:
> Config
> {noformat}
>   <property>
>     <name>driver.max.concurrent.launched.queries</name>
>     <value>1</value>
>     <description>Maximum queries which can be launched simultaneously on this driver. This should be equal to
>       lens.driver.jdbc.pool.max.size. This configuration value is only useful when MaxConcurrentDriverQueriesConstraint
>       is enabled by using org.apache.lens.server.api.query.constraint.MaxConcurrentDriverQueriesConstraintFactory as
>       one of the factories in lens.driver.jdbc.query.constraint.factories property.</description>
>   </property>
> <property>
>     <name>lens.driver.jdbc.pool.max.size</name>
>     <value>1</value>
>     <description>Maximum number of concurrent connections allowed in pool</description>
>   </property>
> {noformat}
> Launched 1st query with user U1
> Launched 2nd query with user U2
> Launched 3rd query with user U1
> Launched 4th query with user U2
> Query Status
> ==========
> Q1 -> Running
> Q2 -> Queued(queue number = 1)
> Q3 -> Queued(queue number = 2)
> Q4 -> Queued(queue number = 3)
> When Q1 completes, Query Status
> ==========================
> Q1 -> Successful
> Q2 -> Queued(queue number = 1)
> Q3 -> Running
> Q4 -> Queued(queue number = 2)
> When Q2 completes, Query Status
> ==========================
> Q1 -> Successful
> Q2 -> Queued(queue number = 1)
> Q3 -> Successful
> Q4 -> Queued(queue number = 2)
> user "U2" query will never get picked. Another query launched by user "U1" will be answered.



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