apache/beam · error · UnsupportedOperationException

Converting %s to Beam schema type is not supported

Error message

Converting %s to Beam schema type is not supported

What it means

SingleStoreDefaultRowMapper's ResultSetFieldConverter.of(...) maps each SingleStore column type to a Beam Schema.FieldType converter. Column types not covered by the switch (anything outside the supported VARCHAR/CHAR/numeric/date/NULL set) hit the default branch and throw UnsupportedOperationException, because there is no defined Beam schema representation for them.

Source

Thrown at sdks/java/io/singlestore/src/main/java/org/apache/beam/sdk/io/singlestore/SingleStoreDefaultRowMapper.java:176

              Schema.FieldType.DECIMAL, ResultSet::getBigDecimal);
        case TIMESTAMP:
          return new TimestampResultSetFieldConverter();
        case DATE:
          return new DateResultSetFieldConverter();
        case TIME:
          return new TimeResultSetFieldConverter();
        case LONGVARBINARY:
        case VARBINARY:
        case BINARY:
          return new BinaryResultSetFieldConverter();
        case LONGVARCHAR:
        case VARCHAR:
        case CHAR:
          return new CharResultSetFieldConverter();
        case NULL:
          return new DirectResultSetFieldConverter(STRING, ResultSet::getString);
        default:
          throw new UnsupportedOperationException(
              "Converting " + columnType + " to Beam schema type is not supported");
      }
    }
  }

  static class DirectResultSetFieldConverter extends ResultSetFieldConverter {
    Schema.FieldType fieldType;
    ResultSetFieldExtractor extractor;

    public DirectResultSetFieldConverter(
        Schema.FieldType fieldType, ResultSetFieldExtractor extractor) {
      this.fieldType = fieldType;
      this.extractor = extractor;
    }

    @Override
    @Nullable Object getValue(ResultSet rs, Integer index) throws SQLException {
      return extractor.extract(rs, index);

View on GitHub (pinned to 12126d8942)

Solutions

Exclude the unsupported column from the read query (select only supported columns)
Implement a custom UserDataMapper/row mapper that converts the column to a supported Beam type (e.g. read as STRING)
Cast the column to a supported type in the SQL query (e.g. CAST(col AS CHAR))
File/patch the IO to add a converter case for the column type

Example fix

// before
statement.apply("SELECT * FROM t"); // table has JSON column -> throws
// after
statement.apply("SELECT id, name, CAST(extra AS CHAR) AS extra FROM t");

Defensive patterns

Strategy: validation

Validate before calling

Set<String> unsupported = tableColumns.stream().map(c -> c.getType()).filter(t -> !SUPPORTED_TYPES.contains(t)).collect(toSet()); if (!unsupported.isEmpty()) { /* exclude or cast these columns */ }

Try / catch

try { pipeline.apply(SingleStoreIO.read()...); } catch (UnsupportedOperationException e) { if (e.getMessage().contains("to Beam schema type is not supported")) { /* narrow SELECT column list */ } throw e; }

Prevention

Inspect table DDL (SHOW COLUMNS) before building reads; avoid SELECT * on tables with JSON/GEOMETRY/BIT columns
Cast unsupported columns to CHAR in SQL
Keep the Beam SingleStore IO dependency current so newly added server types are mapped

When it happens

Trigger: Reading from a SingleStore table containing a column whose java.sql.Type/SingleStore type falls through the switch in of(), e.g. exotic or JSON/GEOMETRY/BIT types not handled, during schema inference in SingleStoreIO.read().

Common situations: Tables with JSON, GEOMETRY, or other semi-structured SingleStore column types; newer SingleStore server versions introducing types the connector/IO doesn't map yet; schema drift after a table ALTER adds an unsupported column.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/aa0e462e44d62d7a. Report an issue: GitHub.