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  1. Calcite
  2. CALCITE-2928

Make UDF lookup default to case insensitive

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    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 1.19.0
    • Fix Version/s: 1.20.0
    • Component/s: core

      Description

      Now for Calcite, we make default parser config unquotedCasing to Lex.ORACLE.unquotedCasing(to uppercase)[1], and caseSensitive to Lex.ORACLE.caseSensitive(case sensitive true).

      So if we have a UDAF named my_func and query with sql like:

      select f0, my_func(f1) from table1 group by f0;
      

      We would got a unparsed sql:

      SELECT F0, MY_FUNC(F1) FROM TABLE1 GROUP BY F0;
      

      For CalciteCatalogReader we hard code the function look up to case sensitive true[2],

      For ListSqlOperatorTable we make the operator name lookup case sensitive true[3].

      For ReflectiveSqlOperatorTable, we make built-in operators case-insensitively[4].

      For most of the cases, we use ListSqlOperatorTable to register our UDFs[5] chained with SqlStdOperatorTable(which composite a ChainedSqlOperatorTable), which finally passed to CalciteCatalogReader for validation.

      So there are some questions i have:

      1. Why we make built-in operators look up case-insensitively while ListSqlOperatorTable(for UDFs) case-sensitively, with default unquotedCasing of TO_UPPERCASE.
      2. What is the usage of CalciteCatalogReader#lookupOperatorOverloads i only saw it used in a unit test LookupOperatorOverloadsTest.

      It seems that make UDF look up case-sensitively does not make any sense, users will never distinguish their function with just word cases. And i checked also MYSQL, ORACLE, POSTGRES, their UDFs are all registered case-insensitively.

      [1] https://github.com/apache/calcite/blob/ffca956be03a99cd11e440d652b09674aaa727e6/core/src/main/java/org/apache/calcite/sql/parser/SqlParser.java#L231
      [2] https://github.com/apache/calcite/blob/ffca956be03a99cd11e440d652b09674aaa727e6/core/src/main/java/org/apache/calcite/prepare/CalciteCatalogReader.java#L166
      [3] https://github.com/apache/calcite/blob/ffca956be03a99cd11e440d652b09674aaa727e6/core/src/main/java/org/apache/calcite/sql/util/ListSqlOperatorTable.java#L63
      [4] https://github.com/apache/calcite/blob/ffca956be03a99cd11e440d652b09674aaa727e6/core/src/main/java/org/apache/calcite/sql/util/ReflectiveSqlOperatorTable.java#L103
      [5] https://github.com/apache/calcite/blob/ffca956be03a99cd11e440d652b09674aaa727e6/core/src/test/java/org/apache/calcite/test/MockSqlOperatorTable.java#L46

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              • Assignee:
                danny0405 Danny Chen
                Reporter:
                danny0405 Danny Chen
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