Data Buffer (Oracle)

Data buffers have the following functions:

Table: Data buffer and their functions

Buffer	Function
Data buffer	holds Oracle blocks in shared memory (System Global Area or SGA)
Data buffer qualitycache hit ratio (CHR)	measures the number of times that a data block requested by an Oracle process is found to be already in memory.
Physical reads and physical writes	Information is also provided on the number of physical input/output (I/O) operations performed on behalf of Oracle
Busy waits	the number of times a process had to wait to acquire a data buffer in a compatible state