'Log File Sync' problem on a Sun Server: Discussion of a Potential Source for LOGFILE SYNC Performance Problems plus references
(Doc ID 1205673.1)
Last updated on MAY 27, 2023
Applies to:
Oracle Database - Standard Edition - Version 10.2.0.1 to 11.2.0.2.0 [Release 10.2 to 11.2]Oracle Database Cloud Schema Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database 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.
RDBMS
Performance
Log File Sync
Symptoms
Comment:
As is often the case the source and solution depends on factors too numerous and unique to mention in a single note.
For more excellent information regarding high resolutions timeouts please see Steve Sistare's Oracle Blog regarding High Resolution Timeouts
For more excellent information regarding high resolutions timeouts please see Steve Sistare's Oracle Blog regarding High Resolution Timeouts
Reference: High Resolution Timeout - blogs.oracle.com/sistare/entry/high_resolution_timeouts
General Description
- You have recently upgraded your database on a Sun Server and now you are finding very poor performance, including notable Log File Sync (LFS) problems as reported in the AWR reports
- The Logfile Syncs are seen on the same server that did not have problems with Log File Syncs as the top of the Top 5 Wait Event
- IO performance appears to be within normal ranges
- Background and Foreground Waits also appear to confirm the Logfile Sync performance as a serious performance problem
Specific Example
- Customer has a 10.2.0.4 database and an 11.2.0.1 database
- The same import is run on each database. However the time to complete the import varies greatly.
- 10.2.0.4 => 55 minutes
- 11.2.0.1 => 5 hours
- Furthermore: the problem was seen on the SAME server where the 10.2x performance was normal
Changes
- You have recently changed the database version on the Sun Server to a newer database version such as 11gR2
- No other changes are known
Cause
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In this Document
| Symptoms |
| Changes |
| Cause |
| Solution |
| References |