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From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Created] (PHOENIX-4277) Use raw scans for IndexScrutinyTool
Date Wed, 04 Oct 2017 21:08:02 GMT
James Taylor created PHOENIX-4277:
-------------------------------------

             Summary: Use raw scans for IndexScrutinyTool
                 Key: PHOENIX-4277
                 URL: https://issues.apache.org/jira/browse/PHOENIX-4277
             Project: Phoenix
          Issue Type: Bug
            Reporter: James Taylor
            Assignee: Vincent Poon


The IndexScrutinyTool relies on doing point-in-time scans to determine consistency between
the index and data tables. Unfortunately, deletes to the tables cause a problem with this
approach, since delete markers take effect even if they're at a later time stamp than the
point-in-time at which the scan is being done (unless KEEP_DELETED_CELLS is true). The logic
of this is that scans should get the same results before and after a compaction take place.

Taking snapshots does not help with this since they cannot be taken at a point-in-time and
the delete markers will act the same way - there's no way to guarantee that the index and
data table snapshots have the same "logical" set of data.

Using raw scans would allow us to see the delete markers and do the correct point-in-time
filtering ourselves. We'd need to write the filters to do this correctly (see the Tephra TransactionVisibilityFilter
for an implementation of this that could be adapted). We'd also need to hook this into Phoenix
or potentially dip down to the HBase level  to do this.

Thanks for brainstorming on this with me, [~lhofhansl].



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