How InterSystems IRIS Processes SQL Statements

InterSystems IRIS processes SQL statements through a multi-step pipeline: preparsing, normalization, compilation, query plan generation, and ObjectScript execution code creation. This pipeline standardizes whitespace and literals to optimize performance.

SQL statement preparsing in InterSystems IRIS normalizes keywords, whitespace, and literals before compilation. This standardization step enables literal substitution and query caching within the Universal Query Cache to accelerate repeated DML statement execution.

You can optimize SQL query performance in InterSystems IRIS by leveraging literal substitution, Universal Query Cache, and generated query plans. Understanding the compilation pipeline reveals bottlenecks and helps developers execute DML statements efficiently.

Query caching in InterSystems IRIS uses the Universal Query Cache to store normalized and compiled execution code. When identical SQL statements resubmit, the system retrieves cached ObjectScript execution code, bypassing compilation and accelerating performance.

SQL compilation in InterSystems IRIS generates optimized query plans and creates ObjectScript execution code to run them. This compilation step follows preparsing and processes DML statements for efficient database execution.