Author Archives: Valter

Managing Oracle on Linux Certified Expert

I’m very happy to share that I’m now an OCE, besides the long standing OCP titles. The full certification title is Oracle Database 10g Managing Oracle on Linux Certified Expert. To achieve it, I passed exam 1Z0-046 Oracle Database 10g: Managing … Continue reading

Posted in Certification, Oracle, Personal | Tagged , | 1 Comment

Eventual bad performance for a query with a good plan

The user calls complaining that a recurrent report, which usually completes in 15-20 minutes, is running for a few hours now. You request some more information from the user about the report and its database session, and start troubleshooting: Servers … Continue reading

Posted in Oracle, Performance | Tagged , , , , , , , | 2 Comments

Predicting Oracle Transaction Rollback Time

While waiting for a large transaction to roll back, I’ve cooked this spreadsheet which can, to some extent (not precise, just estimated – use at your own risk) predict how long it will take for the rollback to complete. The … Continue reading

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11g: handling error ORA-00752 – lost write of a data block in the PRIMARY database

With the recent (11gR1) addition of lost write detection techniques, Oracle has one more tool to help avoid data losses. Prerequisites to it are having a physical standby database applying logs and the parameters enabled in both the primary and … Continue reading

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ASM MEMBER disks showing as CANDIDATE

Some time ago I spent a few hours troubleshooting an issue where some 20 ASM member disks went all to either CANDIDATE or PROVISIONED status after the servers were rebooted. That’s odd because if the disks were really removed from … Continue reading

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