[jira] [Comment Edited] (PHOENIX-6207) Paged server side grouped aggregate operations

["chenglei (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/PHOENIX-6207?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17230391#comment-17230391 ] 

chenglei edited comment on PHOENIX-6207 at 11/12/20, 6:59 AM:
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[~kozdemir],  {{GroupedAggregateRegionObserver}} and {{ScanRegionObserver}} both already supported limit push down, why we did not  reuse the pushed down limit to implement PHOENIX-6207  and PHOENIX-6211?  Re-implementing the same similar functions make the code more complex and harder to understand.

Futhermore, I am not very understanding why we need PHOENIX-6207  and PHOENIX-6211 ? Seems that we could also putting a limit on the number of rows to be processed by
{{Scan.setCaching}} or {{hbase.client.scanner.caching}} in configuration file.


was (Author: comnetwork):
[~kozdemir],  {{GroupedAggregateRegionObserver}} and {{ScanRegionObserver}} both already support limit push down, why we did not  reuse the pushed down limit to implement PHOENIX-6207  and PHOENIX-6211?  Re-implementing the same similar functions make the code more complex and harder to understand.

Futhermore, I am not very understanding why we need PHOENIX-6207  and PHOENIX-6211 ? Seems that we could also putting a limit on the number of rows to be processed by
{{Scan.setCaching}} or {{hbase.client.scanner.caching}}

> Paged server side grouped aggregate operations
> ----------------------------------------------
>
>                 Key: PHOENIX-6207
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-6207
>             Project: Phoenix
>          Issue Type: Improvement
>    Affects Versions: 5.0.0, 4.14.3
>            Reporter: Kadir OZDEMIR
>            Assignee: Kadir OZDEMIR
>            Priority: Major
>             Fix For: 4.16.0
>
>         Attachments: PHOENIX-6207.4.x.001.patch, PHOENIX-6207.4.x.002.patch, PHOENIX-6207.4.x.003.patch
>
>
> Phoenix provides the option of performing query operations on the client or server side. This is decided by the Phoenix optimizer based on configuration parameters. For the server side option, the table operation is parallelized such that multiple table regions are scanned. However, currently there is no paging capability and the server side operation can take long enough lead to HBase client timeouts. Putting a limit on the number of rows to be processed within a single RPC call (i.e., the next operation on the scanner) on the server side using a Phoenix level paging is highly desirable. This paging mechanism has been already implemented for index rebuild and verification operations and proven to be effective to prevent timeouts. This Jira is for implementing this paging for the server side grouped aggregate operations. 



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