根据文档，这个事件的解释如下：
This event occurs when a session requests a buffer that is currently being read into the buffer cache
by another session. Prior to release 10.1, waits for this event were grouped with the other reasons for
waiting for buffers under the 'buffer busy wait' event
这个等待也就是说明数据库存在读的竞争，所以该等待事件通常和db file sequential read或db file scattered read 同时出现。
下面是AWR报告中的事件
read by other session.jpg