The Shared Pool is a critical component of the SGA in Oracle. It is responsible for storing frequently used information to optimize performance. The Shared Pool consists of several key components that help reduce processing load and speed up SQL query execution. The main components of the Shared Pool include:
- Function: Stores SQL and PL/SQL statements that have been parsed, compiled, and executed.
- Soft Parse: When an SQL statement is sent to the database, Oracle checks if this statement already exists in the Library Cache. If it does, the system will reuse the statement without needing to parse and compile it again. This process is called a soft parse, which saves resources and time.
- Hard Parse: If the statement does not exist in the Library Cache, the system will perform a hard parse, which is more resource-intensive as it requires parsing and compiling the statement from scratch.
?? 2. Data Dictionary Cache (or Row Cache)
- Function: Stores the database's metadata, such as information about tables, columns, indexes, and access privileges.
- Benefit: This helps metadata queries to be executed more quickly without needing direct disk access. This significantly improves performance, especially for large databases.
?? 3. Server Result Cache
- Function: The Server Result Cache is a special part of the Shared Pool that stores the results of specific SQL or PL/SQL queries that have already been executed. When a query requests the same result as a previous query, Oracle can retrieve the data directly from the Server Result Cache instead of re-executing the entire query.
- Benefit: Optimizes repeated queries, reducing processing time and optimizing memory resources.
Database Developer | Database Administrator | Database Oracle #performanceturning, and #toiuucosodulieu
6 个月thanks for sharing