Wrong JDBC type. Expected '{}' but got '{}'. Overriding with

Error message

Wrong JDBC type. Expected '{}' but got '{}'. Overriding with '{}'.

What it means

Warning logged by the SQL Server write SchemaTransform provider when the configuration's jdbcType differs from the provider's jdbcType(). The value is overridden with the provider's own type and the write proceeds against SQL Server. It indicates a misconfigured database type in the write path.

Source

Thrown at sdks/java/io/jdbc/src/main/java/org/apache/beam/sdk/io/jdbc/providers/WriteToSqlServerSchemaTransformProvider.java:62

    return getUrn(ExternalTransforms.ManagedTransforms.Urns.SQL_SERVER_WRITE);
  }

  @Override
  public String description() {
    return inheritedDescription("SQL Server", "WriteToSqlServer", "sqlserver", 1433);
  }

  @Override
  protected String jdbcType() {
    return MSSQL;
  }

  @Override
  public @UnknownKeyFor @NonNull @Initialized SchemaTransform from(
      JdbcWriteSchemaTransformConfiguration configuration) {
    String jdbcType = configuration.getJdbcType();
    if (jdbcType != null && !jdbcType.isEmpty() && !jdbcType.equals(jdbcType())) {
      LOG.warn(
          "Wrong JDBC type. Expected '{}' but got '{}'. Overriding with '{}'.",
          jdbcType(),
          jdbcType,
          jdbcType());
      configuration = configuration.toBuilder().setJdbcType(jdbcType()).build();
    }

    List<@org.checkerframework.checker.nullness.qual.Nullable String> connectionInitSql =
        configuration.getConnectionInitSql();
    if (connectionInitSql != null && !connectionInitSql.isEmpty()) {
      throw new IllegalArgumentException("SQL Server does not support connectionInitSql.");
    }

    // Override "connectionInitSql" for sqlserver
    configuration = configuration.toBuilder().setConnectionInitSql(Collections.emptyList()).build();
    return new SqlServerWriteSchemaTransform(configuration);
  }

View on GitHub (pinned to 12126d8942)

Solutions

Remove jdbcType from the write configuration so the SQL Server default is used.
Set jdbcType to the SQL Server provider's jdbcType() value.
Use the matching provider class for the actual target database.
Confirm the JDBC URL (jdbc:sqlserver://...) matches SQL Server.

Example fix

// before
JdbcWriteSchemaTransformConfiguration cfg = JdbcWriteSchemaTransformConfiguration.builder()
    .setJdbcType("oracle")
    .setUrl("jdbc:sqlserver://host;databaseName=db")
    .build();
// after
JdbcWriteSchemaTransformConfiguration cfg = JdbcWriteSchemaTransformConfiguration.builder()
    .setUrl("jdbc:sqlserver://host;databaseName=db")
    .build();

Defensive patterns

Strategy: validation

Validate before calling

if (config.getJdbcType() != null && !config.getJdbcType().isEmpty()
    && !"sqlserver".equalsIgnoreCase(config.getJdbcType())) {
  throw new IllegalArgumentException("jdbcType must match the SQL Server provider");
}

Prevention

Omit jdbcType when using the SQL Server write provider.
Match provider class and JDBC URL to the same database.
Add a config smoke test that builds the transform and inspects the resolved configuration.

When it happens

Trigger: Calling from() on WriteToSqlServerSchemaTransformProvider with a JdbcWriteSchemaTransformConfiguration whose jdbcType is non-null, non-empty, and unequal to jdbcType().

Common situations: Reusing a Postgres/MySQL write configuration for a SQL Server sink, or an expansion-service config carrying a stale jdbcType after switching databases.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/cbe2a9fc79c06aae. Report an issue: GitHub.