SQLScript is SAP HANA’s powerful extension of SQL designed for complex data processing and procedural logic inside the database. It enables developers to write stored procedures, functions, and anonymous blocks that leverage the full capabilities of SAP HANA’s in-memory engine. However, to fully exploit the performance potential of SQLScript, advanced optimization techniques and best practices are essential. This article explores how to optimize SQLScript code and shares practical tips for writing efficient and maintainable procedures.
Unlike standard SQL, SQLScript supports procedural programming constructs such as loops, conditions, variables, and cursors. While this increases flexibility, it can also introduce performance pitfalls if not handled correctly. The goal of optimization is to minimize expensive data movement between the database engine and the procedural code, maximize parallelism, and leverage SAP HANA’s set-based processing.
SAP HANA is optimized for set-based operations that process entire data sets at once. Avoid using cursors or loops to process data row by row whenever possible. Replace loops with single SQL statements or use FOR loops only for small control logic.
Example:
Instead of:
FOR rec AS cur1 CURSOR FOR SELECT * FROM sales LOOP
-- process each row
END LOOP;
Use:
UPDATE sales SET discount = price * 0.1 WHERE category = 'Electronics';
Avoid unnecessary SELECT statements inside loops or procedural blocks that fetch large data repeatedly. Wherever possible, retrieve and process data in a single operation to reduce round trips and context switches.
SQLScript supports table variables to hold intermediate results. Use them carefully by:
SAP HANA provides many optimized functions for string manipulation, mathematical operations, and analytical calculations. Also, Core Engine (CE) functions provide highly optimized operators for joins, aggregation, and filtering.
Use these functions instead of manual implementations whenever possible.
Design your SQLScript code to allow SAP HANA to execute operations in parallel. Avoid sequential dependencies and break down large tasks into set operations that can be parallelized.
Use EXCEPTION blocks to handle errors gracefully but avoid overusing them in performance-critical loops, as exception handling can add overhead.
Each procedure call introduces overhead. Where possible, consolidate logic into fewer procedures or inline code segments.
Use SAP HANA tools like PlanViz, SQL Trace, and the Performance Monitor to analyze SQLScript execution plans, identify bottlenecks, and tune queries.
CREATE PROCEDURE Calculate_Discounts()
LANGUAGE SQLSCRIPT
AS
BEGIN
-- Update discounts for electronics category in a single statement
UPDATE sales
SET discount = price * 0.1
WHERE category = 'Electronics';
END;
This simple example illustrates set-based processing rather than procedural looping.
Advanced SQLScript optimization is key to unleashing the full power of SAP HANA’s in-memory computing. By adopting set-based processing, minimizing data movement, leveraging built-in functions, and using profiling tools, developers can create fast, scalable, and maintainable database logic. Following these best practices will help ensure your SAP HANA applications perform efficiently and reliably under demanding workloads.