Configuring Advanced Options

You can configure advanced options to modify the behavior of the connector.

The following instructions describe how to configure advanced options in a DSN. You can specify the connection settings described below in a DSN, in a connection string, or as connector-wide settings. Settings in the connection string take precedence over settings in the DSN, and settings in the DSN take precedence over connector-wide settings.

To configure advanced options:

  1. To access advanced options, open the ODBC Data Source Administrator where you created the DSN, then select the DSN, then click Configure, and then click Advanced Options.
  2. To disable translation from ODBC SQL to Impala SQL, select the Use Native Query check box.
    3. Important:

    Important:

    • When this option is enabled, the connector cannot execute parameterized queries.
    • By default, the connector applies transformations to the queries emitted by an application to convert the queries into an equivalent form in Impala SQL. If the application is Impala-aware and already emits Impala SQL, then turning off the translation avoids the additional overhead of query transformation.
  3. To enable the connector to successfully run queries that contain transaction statements, select the Ignore Transactions check box.

    4. Note:

    The transaction statements are not executed, because ODBC does not support them. Enabling this option allows the connector to run the query without returning error messages.

  4. To enable the connector to return SQL_WVARCHAR instead of SQL_VARCHAR for STRING and VARCHAR columns, and SQL_WCHAR instead of SQL_CHAR for CHAR columns, select the Use SQL Unicode Types check box.
  5. To have the connector automatically attempt to reconnect to the server if communications are lost, select Enable Auto Reconnect.
  6. To have the connector restrict catalog queries to the current schema when no schema is specified, or when the schema is specified with the wildcard character %, select Restrict Metadata with Current Schema.
  7. In the Rows Fetched Per Block field, type the number of rows to be fetched per block.
  8. In the Socket Timeout field, type the number of seconds that the TCP socket waits for a response from the server before timing out the request and returning an error message.

    9. Note:

    Setting the Socket Timeout value to 0 disables the timeout feature.

  9. In the String Column Length field, type the maximum data length for STRING columns.
  10. In the Async Exec Poll Interval field, type the time in milliseconds between each poll for the query execution status.
  11. To handle Kerberos authentication using the SSPI plugin instead of MIT Kerberos by default, select one or both of the check boxes under the Use Only SSPI option:
    • To configure the current DSN to use the SSPI plugin by default, select Enable For This DSN.
    • To configure all DSN-less connections to use the SSPI plugin by default, select Enable For DSN-less Connections.
    • To configure all connections that use the Simba Impala ODBC Driver to use the SSPI plugin by default, select both check boxes.
  12. Optionally, if you want the connector to retry queries that fail, select the Enable Query Retry check box and then do the following:
    1. In the Max Retries field, type the maximum number of times that the connector retries each query.
    2. In the Result Set Cache Size field, type the maximum amount of memory that the result set cache can occupy. Values must be specified in: B (bytes), KB (kilobytes), MB (megabytes), or GB (gigabytes).
    3. In the Retry Interval field, type the amount of time that the connector waits between query retry attempts. Values must be specified in S (seconds) or MS (milliseconds).
  13. To save your settings and close the Advanced Options dialog box, click OK.

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