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Oracle

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 | No 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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Jérôme Dubar

Should I go for ODA 19.5 or should I wait until 19.6?

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

Introduction As you may know, Oracle Database 19c is available for new (X8-2) or older Oracle Database Appliances since several weeks. Current version is 19.5. But when you go to the official ODA documentation , it still first proposes version 18.7 not compatible with 19c databases. Here is why. 19c database is the final 12.2 First of all, 19c is an important release because it’s the terminal release of the 12.2, as 11.2.0.4 was for…

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Franck Pachot

ROLLBACK TO SAVEPOINT;

By | Oracle | No Comments

By Franck Pachot . I love databases and, rather than trying to compare and rank them, I like to understand their difference. Sometimes, you make a mistake and encounter an error. Let’s take the following example: create table DEMO (n int); begin transaction; insert into DEMO values (0); select n “after insert” from DEMO; update DEMO set n=1/n; select n “after error” from DEMO; commit; select n “after commit” from DEMO; The “begin transaction” is…

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Jérôme Dubar

Make Oracle database simple again!

By | Database Administration & Monitoring, Database management, Development & Performance, Hardware & Storage, Operation systems, Oracle | 6 Comments

Introduction Let’s have a look at how to make Oracle database as simple as it was before. Oracle database is a great piece of software, yes it’s quite expensive, but it’s still the reference and most of the companies can find a configuration that fits their needs according to a budget. Another complain about Oracle is the complexity: nothing is really simple, and you’ll need skillful DBA(s) to deploy, manage, upgrade, troubleshoot your databases. But…

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Mouhamadou Diaw

Dbvisit 9: Adding datafiles and or tempfiles

By | Database Administration & Monitoring, Oracle | No Comments

One question I was asking is if the standby_file_management parameter is relevant in a Dbvisit environment with Oracle Standard Edition. I did some tests and I show here what I did. We suppose that the Dbvisit is already set and that the replication is fine [[email protected] trace]$ /u01/app/dbvisit/standby/dbvctl -d dbstd -i ============================================================= Dbvisit Standby Database Technology (9.0.08_0_g99a272b) (pid 19567) dbvctl started on dbvisit1: Fri Jan 17 16:48:16 2020 ============================================================= Dbvisit Standby log gap report for…

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