Oracle wait event buffer busy waits

Buffer busy waits (Hot block contention)

Website Explanation:

This wait indicates that there is some buffers in the buffer cache that multiple processes is attempting to access C oncurrently. Query V$waitstat for the wait statistics for each class of buffer. Common buffer classes that has buffer busy waits include data block, segment Header, undo header and undo block.

Check the following v$session_wait parameter columns:

• P1: File ID

• P2: Block ID

• P3: Class ID

Explain:

This wait represents a buffer in the buffer cache where multiple processes are attempting to access simultaneously. Query V$waitstat for the wait statistics for each type of buffer. Public buffers with buffer busy wait include data blocks, segment headers, undo headers, and undo blocks.

This wait event only shows that a session is waiting for a Buffer (data block)

There are two scenarios:
(1) When a session tries to modify a buffer, but the buffer is being modified by another session.
Hot block is a typical resource contention, analysis of the cause of the hot block to the right remedy: The following is the location of the hot block:
(2) when a session needs to read a buffer while the buffer is being read from disk to memory by another session.
read by other session naming wait events.
buffer busy waits wait events are common when hot blocks exist in the database, This wait event occurs when multiple users frequently read or modify the same block of data.

This article is from the "Linux Oracle MariaDB" blog, so be sure to keep this source http://wangergui.blog.51cto.com/8504247/1912944

Oracle wait event buffer busy waits