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Library Cache in Oracle
The Library Cache is a piece of memory within the SGA that Oracle uses in order to store SQL Statements. Whenever a Process issues an SQL Statement, the text of the Statement goes into the Library Cache where the statement is parsed an validated. If for example I do a
In a similar way, the Library Cache also caches PL/SQL Statements and Objects.
The Library Cache was introduced because parsing (and validating and checking privileges) is expensive in terms of CPU cycles.
Library Cache Namespaces
The Library Cache is divided into Namespaces (or Libraries). These can be found through v$librarycache
select namespace from v$librarycache
NAMESPACE --------------- SQL AREA TABLE/PROCEDURE BODY TRIGGER INDEX CLUSTER OBJECT PIPE JAVA SOURCE JAVA RESOURCE JAVA DATA