[jira] [Commented] (CALCITE-872) Add support for aborting the query optimization process

["Julian Hyde (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-872?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15359437#comment-15359437 ] 

Julian Hyde commented on CALCITE-872:
-------------------------------------

This is related to CALCITE-1227, because the cancel flag for the planner should be of the same type as the cancel flag for execution.

I believe that the flag should either be an {{AtomicBoolean}} or a {{volatile boolean}}. {{CancelFlag}} contains a regular {{boolean}}, so may not propagate on some CPU architectures.

So, I propose to change {{RelOptPlanner.setCancelFlag(CancelFlag cancelFlag)}} to {{{{RelOptPlanner.setCancelFlag(AtomicBoolean cancelFlag)}}. [~amansinha100], [~dsbos], any comments from you, since you're involved in DRILL-4355 and DRILL-2884?

> Add support for aborting the query optimization process
> -------------------------------------------------------
>
>                 Key: CALCITE-872
>                 URL: https://issues.apache.org/jira/browse/CALCITE-872
>             Project: Calcite
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 1.4.0-incubating
>            Reporter: Aman Sinha
>            Assignee: Julian Hyde
>
> We should have the facility to abort the query optimization process.  There are several motivations for having this: 
> 1. The optimizer's join planning may take too long (order of minutes) when 
>  working with larger number of tables. 
> 2. Certain sequence of rule applications may cause a cycle. 
> 3. Operations related to metadata could potentially introduce a dependency 
>     cycle. 



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