Overview
Reverse Polling is a specialized data retrieval pattern in UnifyApps Data Pipelines when working with API-based data sources that return results in chronological order (oldest records first). This approach requires specific handling techniques to efficiently process and extract the most recent or relevant data.
What is Reverse Polling?
When consuming data from external APIs, some services return data in chronological order by default (oldest to newest). In Reverse Polling, the system must traverse through the entire list to find the most recent records, which are positioned at the end rather than the beginning of the result set.
Why It Matters?
Understanding Reverse Polling helps data engineers and developers:
Efficiently retrieve the most recent data when APIs present oldest records first
Optimize data retrieval when only recent records are needed
Implement proper pagination strategies for chronologically ordered APIs
Reduce unnecessary data processing when only certain timeframes are relevant
Technical Details
When an API returns data in chronological order (oldest first), the system must:
Process the entire list to reach the newest records
Implement efficient lookup mechanisms to find specific timestamps or IDs
Use appropriate pagination parameters to navigate forward in time
Optimize queries to potentially skip earlier pages when only recent data is needed
Implementation Considerations
The UnifyApps platform handles these complexities behind the scenes by:
Detecting API response ordering patterns
Implementing optimized pagination strategies based on data ordering
Using markers and indices to efficiently locate relevant data points
Maintaining state information to optimize subsequent polling cycles
Common API Examples
APIs that commonly return data in oldest-first order include:
Certain legacy database systems
Some financial transaction APIs
Log management systems
Historical data services
This knowledge article serves as background information for those interested in understanding the underlying concepts of API data retrieval patterns in UnifyApps Data Pipelines.
