db file parallel read
官网解释：
This happens during recovery. It can also happen during buffer prefetching, as an optimization (rather than performing multiple single-block reads). Database blocks that need to be changed as part of recovery are read in parallel from the database.
Wait Time: Wait until all of the I/Os are completed
解释：
db file parallel read 这在恢复期间发生。 它也可能在缓冲区预取期间发生，作为优化（而不是执行多个单块读取）。 从数据库并行读取需要作为恢复一部分进行更改的数据库块。
本文出自 “Linux Oracle MariaDB” 博客，请务必保留此出处http://wangergui.blog.51cto.com/8504247/1912804
Oracle 等待事件之 db file parallel read
原文：http://wangergui.blog.51cto.com/8504247/1912804