"Db file sequential read" and "Db file scattered read" Does Not Perform ASYNC I/O Even Though ASYNC I/O is Enabled (Doc ID 2144394.1)

Last updated on JUNE 02, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 12.1.0.2 and later
Information in this document applies to any platform.

Goal

Why is "db file sequential read" and "db file scattered read" not doing async I/O reads even though Async I/O related database parameters (disk_asynch_io and filesystemio_options) are set at database level? The database files reside on ext4 file system and   Async I/O is also enabled at OS and filesystem level. But still "db file sequential read" and "db file scattered read" are reading the datafiles using "pread" OS calls (i.e.) synchronous read I/O instead of async I/O reads. 

Solution

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