The _ActPrivBuffer VST displays the activity of a private buffer cache, such as the number of OS and logical reads.
Field name Data type Description
_PrivBuf-Id INT64 Index of entry
_PrivBuf-LogicRds INT64 Number of client requests for database block read operations for private buffers
_PrivBuf-OSRds INT64 Number of database block reads from disk for private buffers
Note: The _ActPrivBuffer VST contains only one record. Therefore, _PrivBuf-Id is always 1.

A buffer hit count occurs when a client requests a database block that is already in the database buffer cache rather than having to retrieve the database block from the disk. The buffer hit ratio is the percentage of reads that do not require retrieving a database block from the disk. The PROMON Buffer Cache Activity display shows the private buffer pool hit ratio percentage. For a sample PROMON Buffer Cache Activity display showing the private buffer pool hit ratio, see Buffer Cache.