Working principle of ORACLE10G, oracle10g64-bit download

Working principle of ORACLE10G, oracle10g64-bit download

Internal execution of database query statements

Select * from xxx

Procedure

Analysis phase (parse)

1. Does the Shared Pool cache have this statement. If any, directly return results.

2. Check whether the SQL statement is correct in syntax analysis.

3. Check whether the table exists. (Object parsing and searching for data dictionary tables)

4. Translate * into all fields. Check whether the field is correct.

5. Get the object resolution lock and lock the table structure to prevent other users from changing the table structure.

6. Check that the user permissions are insufficient.

7. The scheduler generates the execution plan and stores it in the library cache (Binary Execution Code ).

 

Execute)

1. Check whether the database high-speed buffer exists. If so, extract it.

2. If not, read the data buffer from the data file.

 

Extraction stage (fetch)

1. read data from the database buffer cache to the user.