What is library cache hit ratio in Oracle?
The Oracle docs note: “The Library Hit Ratio Oracle metric is also known as the library cache hit ratio. The ratio indicates the number of pin requests which result in pin hits. A pin hit occurs when the SQL or PL/SQL code you wish to execute is already in the library cache and is valid…
The Oracle docs note: “The Library Hit Ratio Oracle metric is also known as the library cache hit ratio. The ratio indicates the number of pin requests which result in pin hits. A pin hit occurs when the SQL or PL/SQL code you wish to execute is already in the library cache and is valid to execute.Click to see full answer. Hereof, what is 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.Similarly, what is Data Dictionary cache in Oracle? Dictionary Cache The data dictionary is a collection of database tables and views containing reference information about the database, its structures, and its users. Oracle accesses the data dictionary frequently during SQL statement parsing. The other area in memory to hold dictionary data is the library cache. One may also ask, what is library cache lock in Oracle? Description. The library cache lock controls the concurrency between clients of the library cache by acquiring a lock on the object handle so that one client can prevent other clients from accessing the same object or the client can maintain a dependency for a long time (no other client can change the object).What is SGA memory?The System Global Area (SGA) is a group of shared memory structures, known as SGA components, that contain data and control information for one Oracle Database instance. The SGA is shared by all server and background processes. Examples of data stored in the SGA include cached data blocks and shared SQL areas.
