[jira] [Created] (DRILL-2222) For Parquet data check for schema change when we read footers the first time

["Aman Sinha (JIRA)" <ji...@apache.org>]

Aman Sinha created DRILL-2222:
---------------------------------

             Summary: For Parquet data check for schema change when we read footers the first time
                 Key: DRILL-2222
                 URL: https://issues.apache.org/jira/browse/DRILL-2222
             Project: Apache Drill
          Issue Type: Improvement
          Components: Query Planning & Optimization
    Affects Versions: 0.7.0
            Reporter: Aman Sinha
            Assignee: Jinfeng Ni


For parquet data, we are already reading the footers for row count information during the planning phase.  It would make sense to also check for schema change as we read each file's footer and throw an error early, otherwise we could fail in unexpected ways later during execution.  For example, here's a run-time error:  
{code}
 "java.lang.IllegalStateException: Failure while reading vector.  Expected vector class of org.apache.drill.exec.vector.NullableDecimal18Vector but was holding vector class org.apache.drill.exec.vector.NullableDecimal28SparseVector."
{code}

The reason for this error is that some data files have the column defined as decimal(15, 6) while others have decimal(19, 6).  



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)