This is an old revision of the document!
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:
The SQL processing like any other processing of code. It comes from a human and needs to go back to a human :) The problem is, through how many stops it will pass. Below you can see a basic representation on the possible wait times for any query:
