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https://issues.apache.org/jira/browse/PHOENIX-5795?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kadir OZDEMIR updated PHOENIX-5795:
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Attachment: (was: PHOENIX-5795.4.x.001.patch)
> Supporting selective queries for index rows updated concurrently
> ----------------------------------------------------------------
>
> Key: PHOENIX-5795
> URL: https://issues.apache.org/jira/browse/PHOENIX-5795
> Project: Phoenix
> Issue Type: Sub-task
> Reporter: Kadir OZDEMIR
> Assignee: Kadir OZDEMIR
> Priority: Critical
> Time Spent: 1h 40m
> Remaining Estimate: 0h
>
> From the consistent indexing design (PHOENIX-5156) perspective, two or more
> pending updates from different batches on the same data row are concurrent if
> and only if for all of these updates the data table row state is read from
> HBase under the row lock and for none of them the row lock has been acquired
> the second time for updating the data table. In other words, all of them are
> in the first update phase concurrently. For concurrent updates, the first two
> update phases are done but the last update phase is skipped. This means the
> data table row will be updated by these updates but the corresponding index
> table rows will be left with the unverified status. Then, the read repair
> process will repair these unverified index rows during scans.
> In addition to leaving index rows unverified, the concurrent updates may
> generate index row with incorrect row keys. For example, consider that an
> application issues the verify first two upserts on the same row concurrently
> and the second update does not include one or more of the indexed columns.
> When these updates arrive concurrently to IndexRegionObserver, the existing
> row state would be null for both of these updates. This mean the index
> updates will be generated solely from the pending updates. The partial upsert
> with missing indexed columns will generate an index row by assuming missing
> indexed columns have null value, and this assumption may not true as the
> other concurrent upsert may have non-null values for indexed columns. After
> issuing the concurrent update, if the application attempts to read back the
> row using a selective query on the index table and this selective query maps
> to an HBase scan that does not scan these unverified rows due to incorrect
> row keys on these rows, the application will not get the row content back
> correctly.
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