Jesus Camacho Rodriguez created HIVE-18825:
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             Summary: Define ValidTxnList before starting query optimization
                 Key: HIVE-18825
                 URL: https://issues.apache.org/jira/browse/HIVE-18825
             Project: Hive
          Issue Type: Improvement
          Components: Transactions
    Affects Versions: 3.0.0
            Reporter: Jesus Camacho Rodriguez
            Assignee: Jesus Camacho Rodriguez


Consider a set of tables used by a materialized view where inserts happened 
after the materialization was created. To compute incremental view maintenance, 
we need to be able to filter only new rows from those base tables. That can be 
done by inserting a filter operator with condition e.g. {{ROW__ID.transactionId 
< highwatermark and ROW__ID.transactionId NOT IN(<open txns>)}} on top of the 
MVs query definition and triggering the rewriting (which should in turn produce 
a partial rewriting). However, to do that, we need to have a value for 
{{ValidTxnList}} during query compilation so we know the snapshot that we are 
querying.

This patch aims to generate {{ValidTxnList}} before query compilation. There 
should not be any visible changes for end user.



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