Informatica handles incremental data loading by focusing on processing only the data that has changed or been newly added since the last load, rather than processing the entire dataset each time. This significantly improves performance and reduces resource consumption. Here's how Informatica facilitates incremental loading:
Key Techniques :
- Timestamp-based Incremental Loading :
- This is a common method where a timestamp field (e.g., "modified_date," "created_date") in the source data is used to identify new or updated records.
- Informatica can store the latest timestamp value from the previous load and then use it to filter the source data, retrieving only records with timestamps greater than that value.
- Mapping variables are very useful for this.
- Change Data Capture (CDC) :
- CDC involves capturing changes made to source data in real-time or near real-time.
- Informatica can integrate with CDC mechanisms provided by databases to identify and extract changed data.
- This approach is particularly useful for applications requiring low latency and up-to-date data.
- Using Mapping Variables :
- Informatica's mapping variables play a crucial role in tracking the state of incremental loads.
- For example, a mapping variable can store the last successful load timestamp or a sequence number.
- This variable's value is updated after each successful load, ensuring that the next load picks up from where the previous one left off.
- SQL Override :
- Within the Source Qualifier transformation, SQL override can be used to add "WHERE" clauses that filter data based on the stored timestamp or other relevant criteria.
- Lookup Transformations :
- Lookup transformations can be used to compare source data with target data and identify records that have been updated or inserted.
Benefits of Incremental Loading :
- Improved Performance: Processing only changed data significantly reduces processing time.
- Reduced Resource Consumption: Less data processing means lower utilization of CPU, memory, and network resources.
- Enhanced Data Consistency: Incremental loading ensures that the target data is consistently updated with the latest changes.
Informatica's flexibility and robust transformation capabilities enable developers to implement various incremental loading strategies tailored to specific data sources and business requirements.
