Chapter 1: Understanding Query Processing

This chapter provides an overview of the query processor in Adaptive Server Enterprise.

The query processor processes queries that you specify. The processor yields highly efficient query plans that execute using minimal resources and ensure that results are consistent and correct.

To process a query efficiently, the query processor uses:

To successfully process a query, the query processor must execute several steps across several modules, which are shown in Figure 1-1:

Figure 1-1: Query processor modules

Graphic showing the query process modules as stacked boxes, with the Parser, preparser, optimizer, code generator, procedural execution engine, and query execution engine as labled boxes.