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From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Created] (PHOENIX-3744) Support snapshot scanners
Date Fri, 17 Mar 2017 22:44:41 GMT
James Taylor created PHOENIX-3744:
-------------------------------------

             Summary: Support snapshot scanners
                 Key: PHOENIX-3744
                 URL: https://issues.apache.org/jira/browse/PHOENIX-3744
             Project: Phoenix
          Issue Type: Bug
            Reporter: James Taylor


HBase support scanning over snapshots, with a SnapshotScanner that accesses the region directly
in HDFS. We should make sure that Phoenix can support that.

Not sure how we'd want to decide when to run a query over a snapshot. Some ideas:
- if there's an SCN set (i.e. the query is running at a point in time in the past)
- if the memstore is empty
- if the query is being run at a timestamp earlier than any memstore data
- as a config option on the table
- as a query hint
- based on some kind of optimizer rule (i.e. based on estimated # of bytes that will be scanned)

Phoenix typically runs a query at the timestamp at which it was compiled. Any data committed
after this time should not be seen while a query is running.



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