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  1. Apache Drill
  2. DRILL-4503

Schema change exception even with all_text_mode enabled

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    Details

    • Type: Bug
    • Status: Reviewable
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 1.6.0
    • Fix Version/s: Future
    • Component/s: Storage - JSON
    • Labels:
      None

      Description

      Both HashAggregate and StreamingAggregate encounter schema change error whey querying a JSON file with non-null values for column 'a' and many null values for column 'c'.

      This occurs even when all_text_mode is enabled, which seems counterintuitive since once all_text_mode is enabled, everything (including nulls) should be treated as varchar and one would expect no schema change errors.

      Here are some example queries that encounter this error:

      0: jdbc:drill:zk=local> select a, c from dfs.`mostlynulls_1.json` group by a, c;
      Error: UNSUPPORTED_OPERATION ERROR: Hash aggregate does not support schema changes
      
      0: jdbc:drill:zk=local> alter session set `store.json.all_text_mode` = true;
      +-------+------------------------------------+
      |  ok   |              summary               |
      +-------+------------------------------------+
      | true  | store.json.all_text_mode updated.  |
      +-------+------------------------------------+
      1 row selected (0.15 seconds)
      0: jdbc:drill:zk=local> select a, c from dfs.`mostlynulls_1.json` group by a, c;
      Error: UNSUPPORTED_OPERATION ERROR: Hash aggregate does not support schema changes
      
      0: jdbc:drill:zk=local> select min(a), min(c) from dfs.`mostlynulls_1.json`;
      Error: UNSUPPORTED_OPERATION ERROR: Streaming aggregate does not support schema changes
      

        Attachments

        1. mostlynulls_1.json
          128 kB
          Aman Sinha

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              • Assignee:
                amansinha100 Aman Sinha
                Reporter:
                amansinha100 Aman Sinha
                Reviewer:
                Padma Penumarthy
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                Dates

                • Created:
                  Updated: