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Franck Pachot

Efficiently query DBA_EXTENTS for FILE_ID / BLOCK_ID

By | Oracle | No Comments

By Franck Pachot . This was initially posted to CERN Database blog on Thursday, 27 September 2018 where it seems to be lost. Here is a copy thanks to web.archive.org Did you ever try to query DBA_EXTENTS on a very large database with LMT tablespaces? I had to, in the past, in order to find which segment a corrupt block belonged to. The information about extent allocation is stored in the datafiles headers, visible though…

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Franck Pachot

Oracle write consistency bug and multi-thread de-queuing

By | Oracle | 3 Comments

By Franck Pachot . This was initially posted on CERN Database blog where it seems to be lost. Here is a copy thanks to web.archive.org Additional notes: – I’ve tested and got the same behaviour in Oracle 21c – you will probably enjoy reading Hatem Mahmoud going further on Write consistency and DML restart Posted by Franck Pachot on Thursday, 27 September 2018 Here is a quick test I did after encountering an abnormal behavior…

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Christian Weinfurtner

Upgrade to Oracle 19c – performance issue

By | Database Administration & Monitoring, Database management, Oracle | One Comment

In this blog I want to introduce you to a workaround for a performance issue which randomly appeared during the upgrades of several Oracle 12c databases to 19c I performed for a financial services provider. During the upgrades we ran into a severe performance issue after the upgrades of more than 40 databases had worked just fine. While most of them finished in less than one hour, we run into one which would have taken…

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Franck Pachot

CLUSTER

By | Oracle | No Comments

By Franck Pachot . Statistically, my blog posts starting with a single SQL keyword (like COMMIT and ROLLBACK) in the title are not fully technical ones, but about moves. Same here. It is more about community engagement, people sharing. And about a friend. And clusters of course… In 2020 because of this COVID virus, we try to avoid clusters of people. And everybody suffers from that in the community because we have no, or very…

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Franck Pachot

Oracle ADB from a Jupyter Notebook

By | Database Administration & Monitoring, Oracle | No Comments

By Franck Pachot . My first attempt to connect to an Oracle database from a Jupyter Notebook on Google Colab was about one year ago: https://medium.com/@FranckPachot/a-jupyter-notebook-on-google-collab-to-connect-to-the-oracle-cloud-atp-5e88b12282b0 I’m currently preparing a notebook as a handout from my coming SQL101 presentation where I start with some NoSQL to discover the benefits of RDBMS and SQL. I’m running everything on the Oracle Database because it provides all APIs (NoSQL-like key-value, with SODA, documents with OSON, and of course…

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Marc Wagner

How to synchronize the appliance registry metadata on an ODA?

By | Database Administration & Monitoring, Oracle | No Comments

Databases administration on a Bare Metal ODA will be done as root user by running odacli commands : odacli create-database to create a database odacli upgrade-database to upgrade a database between major releases odacli move-database to move databases from one Oracle home to another of the same database version odacli update-dbhome to update a specific RDBMS home to the latest patch bundle version etc… The odacli commands will do the needful and at the end…

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Clemens Bleile

Oracle DML (DELETE) and the Index Clustering Factor

By | Oracle | No Comments

As a consultant working for customers, I’m often in the situation that I have an answer to a problem, but the recommended solution cannot be implemented due to some restrictions. E.g. the recommendation would be to adjust the code, but that is not feasible. In such cases you are forced to try to help without code changes. Recently I was confronted with the following issue: A process takes too long. Digging deeper I could see…

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Franck Pachot

Troubleshooting performance on Autonomous Database

By | Oracle | No Comments

By Franck Pachot . On my Oracle Cloud Free Tier Autonomous Transaction Processing service, a database that can be used for free with no time limit, I have seen this strange activity. As I’m running nothing scheduled, I was surprised by this pattern and looked at it by curiosity. And I got the idea to take some screenshot to show you how I look at those things. The easiest performance tool available in the Autonomous…

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