Everything our consultants learn while running databases for customers: Oracle, PostgreSQL, SQL Server, MySQL, MariaDB, MongoDB and Delphix. Expect hands-on posts about installation, day-to-day administration, backup and recovery, performance tuning, replication and upgrades.
By Franck Pachot . 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, which is one reason to get Active Data Guard option, you may want different optimizer settings suited for reporting. In non-CDB it’s easy: the…
By Franck Pachot . 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 than trying with different combination of privileges there is a clever way to do it in 12c with privilege analysis (remember it’s…
Some weeks ago, I did a general presentation about Windows Server 2016 and the new Container feature (here). Today, I will go through the installation and utilization of Windows Containers. I will use a Virtual Machine, under Hyper-V, during this blog. First of all, I have to set the environment to be able to use Windows Containers as it requires…
Did you miss aggregate pushdown capability shipped with columnstore index? Well, I remember the first time I heard about it is was when I read the very interesting blog post of Niko Neugebauer here with a very good covering of the topic (principle, advantages and limitations). So why to write a new blog post here? Well because since the last…
I write this article because it is very interesting to see that the upgrade advisor has evolved… Recently (February 11, 2016), a new version is available: Microsoft® SQL Server 2016® Upgrade Advisor Preview 1.4 The msi package is 10 MB and is named SqlAdvisor. Run the msi and follow the steps like every time… After the installation, it is easy…
There are many foreign data wrappers available for PostgreSQL. One of them can be used to query rss feeds. In this post I’ll show you how you can feed summary information of a blog into your PostgreSQL database. The foreign data wrapper you’ll need to download and install is called multicorn. This foreign data wrapper in fact brings more than…
By Franck Pachot . 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$ROOT. However, neither the views DBA_HIST… nor the tables WRH$_… are defined as Object Link. Let’s explain on an example: DBA_HIST_SYSSTAT I’ll talk about all those multitenant internals in DOAG 2016…
By Franck Pachot . 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 is not possible in schema consolidation, such as public objects name collision, is now possible with pluggable databases. 10 years ago I administrated on a database with high…
By Franck Pachot . 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 showclustermode ASM cluster: Flex mode disabled In ASMCA if you are not in Flex ASM then you have the button to convert to…
When a database gets shutdown for patching, operating system maintenance or other reasons you completely lose the contents of the buffer cache. No surprise. Memory is not persistent. Wouldn’t it be nice to load the most important tables to the cache when the instance starts automatically? This would reduce the time for the most important queries to return the results…
By Franck Pachot . 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. Let’s say I want to use external authentication for my common users SQL> show parameter prefix NAME…
By Franck Pachot . 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 for command line API is here. I’ll explain what you can set in the GUI and…
