Managing Errors During Oracle Communications Data Model Intra-ETL Execution

This topic discusses how you can identify and manage errors during intra-ETL execution.

Monitoring the Execution of the Intra-ETL Process

Three ocdm_sys schema control tables, DWC_INTRA_ETL_PROCESS, DWC_INTRA_ETL_ACTIVITY, DWC_OLAP_ACTIVITY monitor the execution of the intra-ETL process. These tables are documented in Oracle Communications Data Model Reference. You can access these three tables from ocdm_user user.

Each normal run (as opposed to an error-recovery run) of a separate intra-ETL execution performs the following steps:

  1. Inserts a record into the DWC_INTRA_ETL_PROCESS table with a monotonically increasing system generated unique process key, SYSDATE as process start time, RUNNING as the process status, and an input date range in the FROM_DATE_ETL and TO_DATE_ETL columns.
  2. Invokes each of the individual intra-ETL programs in the appropriate order of dependency. Before the invocation of each program, the procedure inserts a record into the intra-ETL Activity detail table, DWC_INTRA_ETL_ACTIVITY, with values for:
  3. ACTIVITY_KEY, a system generated unique activity key.PROCESS_KEY, the process key value corresponding to the intra-ETL process.ACTIVITY_NAME, an individual program name.ACTIVITY_DESC, a suitable activity description.ACTIVITY_START_TIME, the value of SYSDATE.ACTIVITY_STATUS, the value of RUNNING.
  4. Updates the corresponding record in the DWC_INTRA_ETL_ACTIVITY table for the activity end time and activity status after the completion of each individual ETL program (either successfully or with errors). For successful completion of the activity, the procedure updates the status as 'COMPLETED-SUCCESS'. When an error occurs, the procedure updates the activity status as 'COMPLETED-ERROR', and also updates the corresponding error detail in the ERROR_DTL column.
  5. Updates the record corresponding to the process in the DWC_INTRA_ETL_ PROCESS table for the process end time and status, after the completion of all individual intra-ETL programs. When all the individual programs succeed, the procedure updates the status to 'COMPLETED-SUCCESS'; otherwise it updates the status to 'COMPLETED-ERROR'.
  6. For OLAP cubes loading, a record is inserted into DWC_OLAP_ACTIVITY table with CUBENAME as cube name, status as 'RUNNING', and LOAD_START_DT as SYSDATE for each cube. It updates the record upon the completion of cube loading. It updates STATUS column to 'COMPLETED-SUCCESS' if cube loading is successful, otherwise 'COMPLETE-ERROR' and updates LOAD_END_DT column to SYSDATE. In case of 'COMPLETED-ERROR' cubes, it also updates ERROR_DTL column with error details.

You can monitor the execution state of the intra-ETL, including current process progress, time taken by individual programs, or the complete process, by viewing the contents of the DWC_INTRA_ETL_PROCESS, DWC_INTRA_ETL_ACTIVITY, and DWC_OLAP_ACTIVITY tables. In DWC_INTRA_ETL_ACTIVITY table, see the records of currently running process. Monitoring can be done both during and after the execution of the intra-ETL procedure.

Recovering an Intra ETL Process

To recover an intra-ETL process

  1. Identify the errors by looking at the corresponding error details that are tracked against the individual programs in the DWC_INTRA_ETL_ACTIVITY table.
  2. Identify errors of OLAP cubes loading for individual cubes in DWC_OLAP_ACTIVITY table.
  3. Correct the causes of the errors.
  4. Re-invoke the intra-ETL process.

The intra-ETL workflow process identifies whether it is a normal run or recovery run by referring the DWC_INTRA_ETL_ACTIVITY table. During a recovery run, the intra-ETL workflow executes only the necessary programs. For example, for a derived population error as a part of the previous run, this recovery run executes the individual derived population programs which produced errors in the previous run. After their successful completion, the run refreshes aggregate materialized views in the appropriate order.

In this way, the intra-ETL error recovery is almost transparent, without involving the data warehouse or ETL administrator. The administrator must only correct the causes of the errors and re-invoke the intra-ETL process. The intra-ETL process identifies and executes the programs that generated errors.