Category: Oracle
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Parse Error Warnings in database alert.log file
SQL syntax errors and parse errors can impact database performance. The 12.2 release records failing SQLs in alert.log if called excessively, as seen with the “select dual” statement failing 100 times in 4 minutes. The default setting for recording parse errors in alert log is every 100 errors within a 60-minute period, but this can be adjusted.
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Resolving CRS Startup Error: Fixing ASM Disk Group Credentials
The post discusses the challenges faced in restoring a mirrored disk failure, including errors with CRS and missing internal users. It outlines steps taken to resolve issues and successfully start CRS. Later, backup location changes are made.
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ASM Disk Failure: Restoring OCR Config and amdu command
The post describes a recovery process after a Mirrored Disk Failure in Normal Redundancy Mode, causing CRS downtime. The team restored OCR config, changed VOTING disk location, and employed Oracle support documentation for ASM-based OCR restoration. The process involved reconfiguring and relocating files and resolving issues with missing disks, leading to successful recovery.
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ASM Disk Failure Recovery: Detailed Diagnostics
The DR site faced dual disk failure, causing database and cluster failures. ASM issue triggered rebalancing, leading to additional disk failures. Recovery attempts failed, resulting in loss of standby databases and DATA disk group.
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Troubleshooting Exadata Storage Server Disk Failures
On a typically busy Monday at the office, a storage server experienced multiple disk failures, causing a reboot and loss of grid disks. Investigation revealed cacheContentLost status due to a flashdisk failure and import failure. The team resolved the issue by recreating the grid disks and replacing the faulty disks. To prevent future occurrences, they updated the Exadata server image. The problem has not recurred since.
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Dropping unused MDRT tables in Oracle database
The MDRT_$ tables in Oracle Spatial are crucial for spatial indexes and should not be moved, altered, or replicated. It’s possible to drop unrelated tables if using Oracle DB version 12cR2 or later. While MDXT_# tables, which supported spatial index statistics, can be dropped after use, changes to the tablespace for MDRT_# tables are permitted. Queries are provided to identify and clean up unnecessary tables, resulting in a significant reduction in table count.
Osman’s DBlog 