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The taboo of ‘underscore parameters’
Oracle provides lots or parameters that can control the behavior of the software. The default values are probably the best ones most of the time. Hundreds of parameters are documented and we can set...
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Standard Edition 2 testing the 16 thread limitation
From 12.1.0.2 the Standard Edition – now called Standard Edition 2 – has a few limitations that were not there in SE and SE1. One of them is the limitation to 16 threads. Let’s see how it behaves when...
View ArticleGTT in Exadata are eligible to SmartScan
I wanted to check if Exadata predicate offloading can occur on Global Temporary Tables. Actually, I thought it did not and I was wrong. I was ready to post that as an hypothesis for...
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Easy transport of SQL Tuning Sets with OEM
When you want to transport a SQL Tuning Set between production and test for example, you have to pack it into a table, then export the table, import it into the target database, and unpack the STS....
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Resource Manager plan from OEM vs. command line
You are rather GUI or command line? Let’s compare what you can do with them when you want to create a Resource Manager plan, and what is missing in the GUI. I’m using EM13c here on a 12c database. Doc...
View ArticleAny reason to change the C## common user prefix?
In 12.1.0.1 the common user prefix was set to C## by an underscore parameter. In 12.1.0.2 it’s a documented parameter and you can change it. But is there any reason for that? I can think of a reason....
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Conversion to Flex ASM with asmca takes 5 minutes
In 12c Oracle recommands Flex ASM. You can opt for it at Grid Infrastructure installation, but it’s very easy to convert to it later from asmca. It has to configure [grid@racp1vm1 ~]$ asmcmd...
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12c multitenant: Cursor sharing in CDB
In multitenant, there are two goals: consolidation within the same container database and isolation of pluggable databases. I see multitenant consolidation as an extension of schema consolidation. What...
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12c Multitenant internals: AWR tables and views
I received a question about multitenant. AWR tables are often raised as an example of Object Links because automatic workload repository is stored only in CDB$ROOT. However, neither the views DBA_HIST…...
View ArticleThe privileges to connect to a container
In Multitenant, there are two ways to connect to a pluggable database. This means that if you want to prevent access to a pluggable database you need to revoke two privileges. Privilege Analysis Rather...
View Article12c Multitenant: PDB spfile parameters for standby database
In multitenant, the spfile parameters at pluggable database level are not stored in the spfile but in the CDB$ROOT table SYS.PDB_SPFILE$ If you open the standby database in read only for reporting,...
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RMAN 12c Push and Pull duplicate explained
Oracle Database 12c introduced the ‘restore from service’ where you can restore and recover by requesting backupsets from the source. With that feature, the duplicate from active can work in the...
View ArticleRAC to RON then RON to RAC and singleton service
You will probably never do it, but let’s imagine you have a RAC database, policy managed, with singleton service. Then you convert it to RAC One Node and you change you mind and convert it back to RAC....
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How to check Multitenant Option feature usage
Matching the Feature Usage Statistics to licensed options is not always easy. And once a feature usage is recorded, it is usually stored definitively. Let’s see how the multitenant option is recorded...
View ArticleCloning a PDB to the Oracle Cloud Service
When you create a DBaaS on the Oracle Cloud Service you have only one way to access to your database: ssh with the public rsa key you provide. Then you can open some ports to access the VM. However,...
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Lost in the Cloud? My Cloud vs. My Services
The Oracle Cloud has two interfaces that are very similar visually and it’s easy to get lost and don’t find what we are looking for in the menus. You see the difference: My Account on the left and My...
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Créer une base Oracle sur le Cloud en quelques clicks
Il n’a jamais été aussi facile de créer une base Oracle. Et ceci grâce au Database as a Service (DBaaS). C’est l’occasion de tester le cloud: Oracle Cloud Service offre une version d’essai de un mois....
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Fixed table automatic statistic gathering in 12c
Before 12c, the fixed stats statistics were not gathered automatically. In 12c this has changed: even when you have never gathered fixed objects statistics you can see that you have statistics for X$...
View ArticleSingle-Tenant vs. non-CDB: no reason to refuse it
When non-CDB has been declared deprecated, I was a bit upset because multitenant with a lone PDB just looks like an overhead of 3 containers instead of one. But with experience I changed my mind. First...
View ArticleTransparently externalize BLOB to BFILE
Storing documents within the database is the easiest, especially because you get them consistent with the metadata stored in the database. If you store them externally, then you need to manage their...
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