Excessive Random read Bursts on Storage Array due to Excessive Fragmentation
(Doc ID 1070465.1)
Last updated on JULY 15, 2022
Applies to:
Oracle Database - Enterprise Edition - Version 11.1.0.7 and laterInformation in this document applies to any platform.
Symptoms
- Excessive random read bursts are seen on storage array
- Top wait event is 'direct path read'
- Information from the storage array itself indicates that this is performing ok.
- From AWR reports the i/o time on disks are high.
- High levels of throughput from large queries doing Full Table Scans (important).
- No individual query is particularly slow compared to others
- Comparison between Test and Production show similar load
Changes
Database files were cloned at the operating system level from one machine to another with files being copied simultaneously.
Cause
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In this Document
Symptoms |
Changes |
Cause |
Solution |