Oracle Archives - Blog dbi services

Oct 12 2018

How to migrate Grid Infrastructure from release 12c to release 18c

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

Oracle Clusterware 18c builds on this innovative technology by further enhancing support for larger multi-cluster environments and improving the overall ease of use. Oracle Clusterware is leveraged in the cloud in order to provide enterprise-class resiliency where required and dynamic as well as online allocation of compute resources where needed, when needed. Oracle Grid Infrastructure provides the necessary components to manage high availability (HA) for any business critical application. HA in consolidated environments is no…

Sep 24 2018

SQL Plan stability in 11G using stored outlines

By Petre Radut | Database Administration & Monitoring, Database management, Development & Performance, Oracle | No Comments

Plan stability preserves execution plans in stored outlines. An outline is implemented as a set of optimizer hints that are associated with the SQL statement. If the use of the outline is enabled for the statement, then Oracle Database automatically considers the stored hints and tries to generate an execution plan in accordance with those hints (Oracle documentation). Oracle Database can create a public or private stored outline for one or all SQL statements. The…

Aug 29 2018

COMMIT

By Oracle Team | Oracle | 4 Comments

By Franck Pachot . COMMIT is the SQL statement that ends a transaction, with two goals: persistence (changes are durable) and sharing (changes are visible to others). That’s a weird title and introduction for the 499th blog post I write on the dbi-services blog. 499 posts in nearly 5 years- roughly two blog posts per week. This activity was mainly motivated by the will to persist and share what I learn every day.

Aug 21 2018

Restoring a database without having any controlfile backup

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

It should never happen but sometimes it happens. You just lost your datafiles as well as your fast recovery area (probably because most of the time these areas are on the same disks despite the recommendations). Normal restore operations with RMAN are quite easy and secure as far as you have backupsets for database, archivelogs, and spfile/controlfile: Step 1 – restore the spfile and start the instance Step 2 – restore the controlfile and mount…

Aug 20 2018

A tribute to Natural Join

By Oracle Team | Oracle | No Comments

By Franck Pachot . I know that lot of people are against the ANSI join syntax in Oracle. And this goes beyond the limits when talking about NATURAL JOIN. But I like them and use them quite often. Why is Natural Join bad? Natural join is bad because it relies on column names, and, at the time of writing the query, you don’t know which columns will be added or removed later. Here is an…

Aug 16 2018

The size of Oracle Home: from 9GB to 600MB

By Oracle Team | Oracle | No Comments

By Franck Pachot . This is research only and totally unsupported. When building docker images to run Oracle Database in a container, we try to get the smallest image possible. One way is to remove some subdirectories that we know will not be used. For example, the patch history is not used anymore once we have the required version. The dbca templates can be removed as soon as we have created the database… In this…

Aug 15 2018

Easily manage dual backup destination with RMAN

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

Backup on disk with RMAN is great. It’s fast, you can set as many channels as your platform can handle for faster backups. And you can restore as fast as you can read and write files on disk with these multiple channels. As far as you’re using Enterprise Edition because Standard Edition is stuck to a single channel. Disk space is very often limited and you’ll probably have to find another solution to keep backups…

Aug 12 2018

18c runInstaller -silent

By Oracle Team | Oracle | No Comments

By Franck Pachot . You find two different ‘runInstaller’ under an Oracle Home. The old one, the Oracle Universal Installer, in $ORACLE_HOME/oui/bin. And the new one, in $ORACLE_HOME directly. They have the same name but are completely different. The old one was used to install an Oracle Home from the installation media. But in 18c you don’t use it. It has been used by Oracle to build the Oracle Home image. Then you download and…

Aug 10 2018

TRANSPORT_CONNECT_TIMEOUT and RETRY_COUNT

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

By Franck Pachot . When you have a Data Guard configuration, you want the application to connect to the right server, where the primary is, without taking too much time. The default TCP timeout is 1 minute which is too long. When you don’t want to configure a virtual IP address (VIP) you can simply list all the addresses in the client connection string. But then you need to reduce the timeout. A short duration…

Category Archives: Oracle

How to migrate Grid Infrastructure from release 12c to release 18c

SQL Plan stability in 11G using stored outlines

COMMIT

Restoring a database without having any controlfile backup

A tribute to Natural Join

The size of Oracle Home: from 9GB to 600MB

Easily manage dual backup destination with RMAN

18c runInstaller -silent

TRANSPORT_CONNECT_TIMEOUT and RETRY_COUNT

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