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ASF GitHub Bot commented on PHOENIX-5998: ----------------------------------------- ChinmaySKulkarni commented on pull request #936: URL: https://github.com/apache/phoenix/pull/936#issuecomment-716908659 @kadirozde The changes are substantial and I will need some heads-down time to review them. If it is urgent, please feel free to rely on other's reviews and don't wait for me ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org > Paged server side ungrouped aggregate operations > ------------------------------------------------- > > Key: PHOENIX-5998 > URL: https://issues.apache.org/jira/browse/PHOENIX-5998 > Project: Phoenix > Issue Type: Improvement > Reporter: Kadir OZDEMIR > Assignee: Kadir OZDEMIR > Priority: Major > Fix For: 4.x > > Attachments: PHOENIX-5998.4.x.001.patch, PHOENIX-5998.4.x.002.patch, > PHOENIX-5998.4.x.003.patch > > > Phoenix provides the option of performing upsert select and delete 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 (upsert select/delete query) is parallelized such that > multiple table regions are scanned and the mutations derived from these scans > can also be executed in parallel on the server side. However, currently there > is no paging capability and the server side operation can take long enough > lead to HBase client timeouts. When this happens, Phoenix can return failure > to its applications and the rest of the parallel scans and mutations on the > server side can still continue since Phoenix has no mechanism in place to > stop these operations before returning failure to applications. This can > create unexpected race conditions between these left-over operations and the > new operations issued by applications. 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 > and a required step to prevent the possible race conditions. This paging > mechanism has been already implemented for index rebuild and verification > operations and proven to be effective to prevent timeouts. This paging can be > implemented for all server side operations including aggregates, upsert > selects, delete queries and so on. -- This message was sent by Atlassian Jira (v8.3.4#803005)