Overview

SQL Processing is one of the biggest problems with any database because it is the hearth of performance tuning. In that chapter I will try to summarize, how Oracle processes an SQL. Firstly the statement has to be processed and there are several steps which should be executed.

Parse:

Open Cursor

Syntax Check

Semmantic Check

Shared Pool check

Binding

*Optimization

*Row source generation

Execute:

Execution

Fetch:

Fetch results

Close Cursor

*-Optional steps in case of hard parse

Below you can check a brief picture of Cursor Processing:

Parsing

Execute

Fetching