Shared memory area Shared Pool
The Shared Pool is made up of two performance-related memory structures:
Row cache, discussed below.
Cache "library" examined in the second advanced tutorial on oracle architecture.
Row cache.
When a user submits an SQL query, the server process extracts, during the analysis of the query, information stored in the dictionary tables (user account data, names of data files, names of table segments and indexes , extents locations, table descriptions and user privileges…).
This information is cached in the dictionary for reuse. During subsequent parse scans, the server process searches the dictionary cache for information to resolve object names and validate access.
Caching data dictionary information reduces response time to LMD statements (SELECT, INSERT, UPDATE, DELETE). A sufficient size of this cache contributes significantly to improving performance.
If the dictionary cache is of limited size, recursive calls slower than the queries made directly in the cache, will be operated by the server process on the database dictionary (disk access).
To learn more about the components and basic concepts of the Oracle architecture, take look at our Expert DBA Team Club blog and more advance topics are available at this source.
