"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 NOVEMBER 27, 2019
Applies to:Oracle Database - Enterprise Edition - Version 18.104.22.168 and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Information in this document applies to any platform.
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.
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