Introduction

One important aspect of database management is auditing, which involves logging and tracking user activities. In the context of ETL (Extract, Transform, Load) processes, auditing becomes even more crucial. In this article, we will explore a method to effectively audit ETL processes in SQL Server.

SSIS Logging

SQL Server Integration Services (SSIS) provides a built-in logging mechanism that can be configured to capture technical information about ETL processes. While this logging is useful, it can become overwhelming if not properly configured. To complement the technical logging, a business logging approach can be implemented to answer specific questions related to the ETL processes.

Key Questions

By implementing auditing in ETL processes, we can answer the following questions:

• Which package ran, when, and for how long?
• Who started the package and on which server?
• What kind of errors occurred and how many?
• What was the development version of the package?
• What data was written or changed by which ETL process?

Principle of Auditing

Every SSIS package contains valuable information that can be logged for auditing purposes. By saving this information, we can track and analyze the ETL processes. The specific information to be logged depends on the project requirements.

Audit Table

The core of the auditing process is the audit table. This table stores all the relevant information about the ETL processes. Here is an example of an audit table:

CREATE TABLE Audit (
    PackageName VARCHAR(255),
    StartTime DATETIME,
    EndTime DATETIME,
    UserID VARCHAR(255),
    ServerName VARCHAR(255),
    ExecutionGUID VARCHAR(255),
    ErrorCount INT,
    VersionBuild INT,
    ProcessID INT
);

Implementing Auditing

To implement auditing, we need to perform the following steps:

1. Open an audit record at the beginning of each package execution.
2. Capture the necessary information such as package name, start time, user ID, server name, and execution GUID.
3. Assign a unique process ID to the audit record.
4. Carry the audit ID along to the target tables as metadata.
5. At the end of the package execution, update the audit record with additional information such as end time, error count, and version build.

Handling Errors

In case of technical errors, SSIS logging can provide information. However, for business errors, it is recommended to log them to custom tables. This allows for better tracking and analysis of business-related issues.

Conclusion

Implementing auditing in ETL processes is essential for tracking and analyzing the execution of packages. By logging relevant information, such as package details, start and end times, user IDs, and error counts, we can gain valuable insights into the ETL processes. The audit table serves as a central repository for this information, enabling us to answer important questions about the execution and quality of the ETL processes.