Full Table Scans Slower after Upgrade to 12.1.0.2 Due to an Increase in Disk Reads and Consequently Higher Waits on 'db file sequential read'
(Doc ID 2084790.1)
Last updated on NOVEMBER 07, 2023
Applies to:
Oracle Database - Enterprise Edition - Version 12.1.0.2 to 12.1.0.2 [Release 12.1]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 Backup Service - Version N/A and later
Information in this document applies to any platform.
Symptoms
- After upgrading to Rel. 12.1.0.2 from Rel. 11.2.0.4, a full table scan takes much longer, due to a higher number of disk reads.
The number of buffer gets (query column) has not changed, but the disk reads (disk column) have increased by approximately fifty percent. The execution plan is the same in each release.
11.2.0.4
Changes
Upgraded database from Rel. 11.2.0.4 to Rel. 12.1.0.2.
Cause
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In this Document
| Symptoms |
| Changes |
| Cause |
| Solution |
| References |