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Category Archives: Oracle

Franck Pachot

A tribute to Natural Join

By | 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…

 
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Franck Pachot

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

By | 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…

 
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Jérôme Dubar

Easily manage dual backup destination with RMAN

By | 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…

 
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Franck Pachot

18c runInstaller -silent

By | 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…

 
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Franck Pachot

TRANSPORT_CONNECT_TIMEOUT and RETRY_COUNT

By | 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…

 
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Franck Pachot

ATP vs ADW – the Autonomous Database lockdown profiles

By | Cloud, Oracle | No Comments

By Franck Pachot . The Oracle database has always distinguished two types of workloads: transactional (OLTP) and datawarehouse (VLDB, DWH, DSS, BI, analytics). There is the same idea in the managed Oracle Cloud with two autonomous database services. To show how this is old, here is how they were defined in the Oracle7 Tuning Book: The definition has not changed a lot. But the technology behind DSS/DWH has improved. Now, with In-Memory Column Store, Smart…

 
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Franck Pachot
CaptureUSEMERGECARTESIAN

MERGE JOIN CARTESIAN: a join method or a join type?

By | Oracle | No Comments

By Franck Pachot . I’ll present about join methods at POUG and DOAG. I’ll show how the different join methods work in order to better understand them. The idea is to show Nested Loops, Hash Join, Sort Merge Join, Merge Join Cartesian on the same query. I’ll run a simple join between DEPT and EMP with the USE_NL, USE_HASH, USE_MERGE and USE_MERGE_CARTESIAN hints. I’ll show the execution plan, with SQL Monitoring in text mode. And…

 
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Pascal Brand

New installed Fusion Middleware Reports or Forms WebLogic Servers fails to start after configuring SSL

By | Application integration & Middleware, Oracle | No Comments

We installed a Fusion Middleware reports and Forms 12.2.1.2.0 on a Linux Server. Those are single node Reports and Forms WebLogic Servers. After disabling the Non SSL Listen Port, we got the below error in the WebLogic Servers log files while starting the Managed Server with only SSL ports enabled. ####<Aug 19, 2017 9:22:44 PM GMT+00:00> <Notice> <Security> <host01.example.com> <WLS_Reports> <[ACTIVE] ExecuteThread: ‘0’ for queue: ‘weblogic.kernel.Default (self-tuning)’> <<WLS Kernel>> <> <> <1320441764877> <BEA-090082> <Security initializing…

 
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Franck Pachot

How much free space can be reclaimed from a segment?

By | Oracle | No Comments

By Franck Pachot . You have the feeling that your table takes more blocks than it should? Here are the queries I use to quickly check the free space. The idea is to call DBMS_SPACE.SPACE_USAGE and infer the minimum space from the percentages. For example, a block in FS3 (defined as having at least 50 to 75% free space) is supposed to have at least 50% of free space. Of course it can have more,…

 
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Franck Pachot

Oracle 18c preinstall RPM on RedHat RHEL

By | Oracle | No Comments

By Franck Pachot . The Linux prerequisites for Oracle Database are all documented but using the pre-install rpm makes all things easier. Before 18c, this was easy on Oracle Enterprise Linux (OEL) but not so easy on RedHat (RHEL) where the .rpm had many dependencies on OEL and UEK. Now that 18c is there to download, there’s also the 18c preinstall rpm and the good news is that it can be run also on RHEL…

 
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