oracle compilation process

Oracle compilation process

Overview

The Oracle compilation process is an important function in the Oracle database system. It is the process of converting SQL statements into executable code. In the Oracle database, the compilation process consists of multiple steps such as SQL statement parsing, syntax checking, semantic checking, execution plan generation and code generation.

SQL statement parsing

SQL statement parsing is the first step in the Oracle compilation process. Its main purpose is to convert SQL statements into internal data structures. During this process, Oracle will parse the SQL statement, analyze its basic syntax structure, and translate the statement into an internal data structure.

Syntax check

Syntax check is the second step of the Oracle compilation process. Its main purpose is to check whether the syntax of the SQL statement is correct. During this process, Oracle will conduct a comprehensive syntax check on the SQL statement and ensure that the SQL statement complies with the syntax rules of the Oracle database system.

Semantic Check

Semantic check is the third step of the Oracle compilation process. Its main purpose is to check whether there are illegal operations or operation objects in the SQL statement. During this process, Oracle will conduct a comprehensive semantic check on the SQL statement and ensure that the operators, operands, objects, etc. of the statement are legal.

Generate execution plan

Generate execution plan is the fourth step of the Oracle compilation process. Its main purpose is to generate the execution plan of the SQL statement. During this process, Oracle will optimize the SQL statement, select the optimal execution plan, and generate information about the execution plan.

Code generation

Code generation is the last step of the Oracle compilation process. Its main purpose is to convert SQL statements into executable code. During this process, Oracle will generate executable code from the generated execution plan and put it into memory waiting for execution.

Performance adjustment

In the Oracle compilation process, performance adjustment is an essential task. Optimization for Oracle performance tuning needs to be completed at each stage.

For SQL statement parsing, the complexity of the statement should be minimized so that Oracle can quickly parse the SQL statement.

During syntax checking, try to avoid syntax errors and avoid additional syntax checking and recompilation work.

During the semantic check stage, direct operations on the database should be minimized to avoid reducing database performance.

In the execution plan generation stage, the optimal execution plan should be selected as much as possible, and methods that support performance optimization should be used to obtain better query performance.

In code generation, the complexity of the generated code should be reduced as much as possible to obtain better query performance.

Conclusion

The Oracle compilation process is a very important function in the Oracle database system. Its main function is to convert SQL statements into executable code and provide efficient and reliable query operations for database users. In the Oracle compilation process, performance adjustment is a very important task. Through reasonable performance adjustments, database query efficiency can be maximized, thereby improving the overall performance of the database.

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