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Oracle

Franck Pachot

Oracle recovery concepts

By | Oracle | No Comments

I’ve published a while ago a twitter thead on some Oracle recovery concepts. For those who are not following twitter, I’m putting the whole thread here:   🔴⏬ Here I start a thread about some Oracle Database concepts. We will see how far it goes - all questions/comments welcome. 🔴⏬ A database (or DBMS - database management system) stores (for short and long term) and manipulates (from many concurrent users/devices) your #data. 🔴⏬ #data is logically structured (tablespaces, schemas, tables, columns, datatypes,…

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Franck Pachot

Oracle disables your multitenant option when you run on EC2

By | Cloud, Oracle | 3 Comments

I have installed Oracle 19.6 on an EC2 for our Multitenant Workshop training. And of course, during the workshop we create a lot of PDBs. If you don’t have paid for the Enterprise Edition plus the Multitenant Option you can create at most 3 pluggable database. But with this option you can create up to 252 pluggable databases. Does it worth the price, which according to the public price list is USD 47,500 + 17,500…

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Franck Pachot

Oracle 20c SQL Macros: a scalar example to join agility and performance

By | Cloud, DevOps, Oracle | One Comment

By Franck Pachot . Let’s say you have a PEOPLE table with FIRST_NAME and LAST_NAME and you want, in many places of your application, to display the full name. Usually my name will be displayed as ‘Franck Pachot’ and I can simply add a virtual column to my table, or view, as: initcap(FIRST_NAME)||’ ‘||initcap(LAST_NAME). Those are simple SQL functions. No need for procedural code there, right? But, one day, the business will come with new…

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Jérôme Dubar

Speed up datapump export for migrating big databases

By | Database Administration & Monitoring, Database management, Hardware & Storage, Oracle | 3 Comments

Introduction Big Oracle databases (several TB) are still tough to migrate to another version on a new server. For most of them, you’ll probably use RMAN restore or Data Guard, but datapump is always a cleaner way to migrate. With datapump, you can easily migrate to a new filesystem (ASM for example), rethink your tablespace organization, reorganize all the segments, exclude unneeded components, etc. All of these tasks in one operation. But datapump export can…

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Mouhamadou Diaw

Oracle 20c Data Guard : Validating a Fast Start Failover Configuration

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

In Oracle 20c, we can now validate a Fast Start Failover configuration with the new command VALIDATE FAST_START FAILOVER. This command will help identifying issues in the configuration. I tested this new feature. The Fast Start Failover is configured and the observer is running fine as we can see below. DGMGRL> show configuration verbose Configuration – prod20 Protection Mode: MaxPerformance Members: prod20_site1 – Primary database prod20_site2 – (*) Physical standby database (*) Fast-Start Failover target…

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Mouhamadou Diaw

Oracle 20c : The new PREPARE DATABASE FOR DATA GUARD

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

As you may know, Oracle 20c is in the cloud with new features. The one I have tested is the PREPARE DATABASE FOR DATA GUARD. This command configures a database for use as a primary database in a Data Guard broker configuration. Database initialization parameters are set to recommended values. Let’s see what this command will do for us The db_unique_name of the primary database is prod20 and in the Data Guard I will build,…

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Jérôme Dubar

odacli create-database extremely slow on ODA X8-2 with 19.5

By | Database Administration & Monitoring, Database management, Hardware & Storage, Operation systems, Oracle | No Comments

Introduction ODA X8-2, in the S, M or HA flavour, is the new database appliance from Oracle. But as a brand new product, you can experience troubles due to the lack of maturity. This time, it concerns database creation that can be extremely slow on these servers if you are using ODA 19.5. Deployment, appliance creation and core configuration X8-2 reimaging is fine, and appliance creation is done without any problem on X8-2. Don’t hesitate…

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Franck Pachot

How SQL Server MVCC compares to Oracle and PostgreSQL

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

By Franck Pachot . Microsoft SQL Server has implemented MVCC in 2005, which has been proven to be the best approach for transaction isolation (the I in ACID) in OLTP. But are you sure that writers do not block readers with READ_COMMITTED_SNAPSHOT? I’ll show here that some reads are still blocked by locked rows, contrary to the precursors of MVCC like PostgreSQL and Oracle.

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Franck Pachot

Running SQL Server on the Oracle Free tier

By | Cloud, Oracle, SQL Server | 2 Comments

By Franck Pachot The Oracle Cloud is not only for Oracle Database. You can create a VM running Oracle Linux with full root access to it, even in the free tier: a free VM that will be always up, never expires, with full ssh connectivity to a sudoer user, where you are able to tunnel any port. Of course, there are some limits that I’ve detailed in a previous post. But that is sufficient to…

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