Handling errors effectively in Informatica is crucial for ensuring data quality and maintaining a robust ETL process. Informatica provides several mechanisms to detect, manage, and respond to errors. Here's a comprehensive overview:
1. Session-Level Error Handling :
- Session Logs:
- Informatica generates detailed session logs that record all events during session execution, including errors.
- These logs are essential for diagnosing and troubleshooting issues.
- Error Handling Options:
- Stop on Errors: You can configure sessions to stop when a certain number of errors occur.
- Treat Source Errors: You can configure how the integration service treats source errors. For example, you can have the session stop, or continue.
- Error Thresholds: Set thresholds for specific error types, and configure actions to take when those thresholds are exceeded.
- Reject Files:
- Informatica can generate reject files that contain rows that failed to be written to the target.
- These files can be used for data analysis and error correction.
2. Transformation-Level Error Handling :
- Error Functions:
- Informatica provides functions like
ISNULL, IS_NUMBER, and ERROR that can be used within transformations to detect and handle data quality issues.
- Router Transformation:
- The Router transformation can be used to separate valid and invalid data based on specific conditions.
- This allows you to handle errors in a controlled manner.
- Update Strategy Transformation:
- The
DD_REJECT option in the Update Strategy transformation can be used to reject rows that do not meet data quality criteria.
- Lookup Transformation:
- You can configure the lookup transformation to manage rows that do not match the lookup condition. You can set a default value, or send the row to an error flow.
3. Workflow-Level Error Handling :
- Workflow Variables:
- Workflow variables can be used to store error codes, messages, and other error-related information.
- Email Tasks:
- Email tasks can be used to send notifications when errors occur.
- Command Tasks:
- Command tasks can be used to execute scripts or programs to handle errors.
- Decision Tasks:
- Decision tasks can be used to create conditional logic within workflows, to handle error conditions.
- Error Handling within tasks:
- Tasks within a workflow have error handling properties, that allow the workflow to continue, or fail, based on the task result.
- Event Waits:
- Event waits can be used to pause a workflow until an error condition is resolved.
4. Data Quality Tools :
- Informatica Data Quality (IDQ):
- IDQ provides advanced data profiling, cleansing, and standardization capabilities.
- It can be used to identify and correct data quality issues before they reach the data warehouse.
Best Practices :
- Implement Comprehensive Logging:
- Enable detailed session logs and workflow logs.
- Monitor Session and Workflow Execution:
- Regularly monitor session and workflow execution to identify and address errors promptly.
- Design for Error Handling:
- Incorporate error handling logic into your mapping and workflow designs.
- Use Data Profiling:
- Use data profiling to identify data quality issues before they cause errors.
- Establish Error Handling Procedures:
- Define clear procedures for handling different types of errors.
- Use try catch logic:
- When using informatica scripting, try catch logic can be used to catch errors.
By implementing these error handling strategies, you can improve the reliability and accuracy of your Informatica data integration processes.
