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Oracle

Franck Pachot

The myth of NoSQL (vs. RDBMS) “joins dont scale”

By | AWS, Database Administration & Monitoring, NoSQL, Oracle, Postgres, SQL Server | No Comments

By Franck Pachot . I’ll reference Alex DeBrie article “SQL, NoSQL, and Scale: How DynamoDB scales where relational databases don’t“, especially the paragraph about “Why relational databases don’t scale”. But I want to make clear that my post here is not against this article, but against a very common myth that even precedes NoSQL databases. Actually, I’m taking this article as reference because the author, in his website and book, has really good points about…

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Franck Pachot

Oracle ACFS: “du” vs. “df” and “acfsutil info”

By | Oracle | No Comments

By Franck Pachot . This is a demo about Oracle ACFS snapshots, and how to understand the used and free space, as displayed by “df”, when there are modifications in the base parent or the snapshot children. The important concept to understand is that, when you take a snapshot, any modification to the child or parent will [[email protected] ~]$ asmcmd lsdg DATAC1 State Type Rebal Sector Logical_Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files…

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Marc Wagner

POUG 2020 Workshop Day 1

By | Oracle | No Comments

I had the opportunity to participate to POUG day 1 and wanted through this blog to share some of my feedback on the interesting sessions I could follow. First of all, I would like to mention the great introduction done by the staff team and the great organization. POUG staff team could adapt to the coronavirus situation and organized excellent POUG virtual days. Well done!

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Mouhamadou Diaw

Oracle Data Guard RedoRoutes : What is Priority 8 ?

By | Database Administration & Monitoring, Oracle | No Comments

When dealing with cascading or far sync in a Data Guard environment, it is important to understand how to configure the RedoRoutes property. By default, a primary database sends redo to each transport destination that is configured in the destination. We can create more complex transport topology, depending of our environment, using the RedoRoutes property. Basically the RedoRoutes property has this format (redo_routing_rule_1) [(redo_routing_rule_n)] Where each routing rule contains a redo source field and a…

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Franck Pachot

Oracle Autonomous Linux: cron’d ksplice and yum updates

By | Cloud, Database Administration & Monitoring, Oracle | No Comments

By Franck Pachot . Oracle Enterprise Linux (OEL) is a Linux distribution which is binary compatible with Red Hat Enterprise Linux (RHEL). However, unlike RHEL, OEL is open source, free to download, free to use, free to distribute, free to update and gets free bug fixes. And there are more frequent updates in OEL than in CentOS, the free base of RHEL. You can pay a subscription for additional support and features (like Ksplice or…

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Lazhar Felahi

Oracle GoldenGate 19c: Cannot register Integrated EXTRACT due to ORA-44004

By | Application integration & Middleware, Database Administration & Monitoring, Oracle | No Comments

The global_name in an oracle database has a direct impact on the Golden Gate Extract process registration we need to do when we create an Integrated Extract. In my example below, I use Oracle GoldenGate MicroServices architecture but the same behaviour occurs with Oracle GoldenGate Classic architecture.   Let’s start with the creation of the Extract process by clicking on the plus button :   Choose Integrated Extract and click on Next button: Fulfill all…

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Jérôme Dubar

Oracle Cloud basics for beginners

By | Cloud, Database Administration & Monitoring, Database management, Hardware & Storage, Operation systems, Oracle | 2 Comments

Introduction Cloud, Cloud, Cloud. Everyone is talking about the Cloud but a lot of people are still in the fog with Cloud technologies. Let’s talk about basic features of the Oracle Cloud, called OCI for Oracle Cloud Infrastructure. What is really OCI? OCI is physically a lot of servers in datacenters all around the world. These servers are not very different from the servers you probably have in your own datacenter. Some of these servers…

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Franck Pachot

Some myths about PostgreSQL vs. Oracle

By | Oracle, Postgres | One Comment

By Franck Pachot . I originally wrote this as a comment on the following post that you may find on internet: https://www.2ndquadrant.com/en/blog/oracle-to-postgresql-reasons-to-migrate/ but my comment was not published (many links in it… I suppose it has been flagged as spam?) so I put it there. You should never take any decision on what you read on the internet without verifying. It is totally valid to consider a move to Open Source databases, but doing it…

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Franck Pachot

Oracle non-linguistic varchar2 columns to order by without sorting

By | Cloud, Oracle | No Comments

By Franck Pachot . Sorting data is an expensive operation and many queries declare an ORDER BY. To avoid the sort operation you can build an index as it maintains a sorted structure. This helps with Top-N queries as you don’t have to read all rows but only those from a range of index entries. However, indexes are sorted by binary values. For NUMBER or DATE datatypes, the internal storage ensures that the order is…

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Franck Pachot

No{Join,GroupBy}SQL – Analytic Views for BI

By | Cloud, Oracle | No Comments

By Franck Pachot . Advocates of NoSQL can query their structures without having to read a data model first. And without writing long table join clauses. They store and query a hierarchical structure without the need to follow relationships, and without the need to join tables on a foreign key name, in order to get a caption or description from a lookup table. The structure, like an XML or JSON document, provides metadata to understand…

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