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12c Multitenant internals: AWR tables and views

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(…)

12c multitenant: Cursor sharing in CDB

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(…)

Conversion to Flex ASM with asmca takes 5 minutes

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(…)

Pre-warming the buffer cache in PostgreSQL

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(…)

Any reason to change the C## common user prefix?

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?(…)

Resource Manager plan from OEM vs. command line

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.

Transactional DDL

When you are working on Oracle you probably learned that each DDL does an implicit commit in the background. There is no way to have DDLs wrapped in a real transaction (with the exception of the “create schema” command which(…)

Easy transport of SQL Tuning Sets with OEM

By Franck Pachot . 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(…)

Install PL/JAVA in Postgres Plus Advanced Server 9.5

While doing a project at a customer we came to a point where we needed to install pl/java into Postgres Plus Advanced Server 9.5. If you follow the official documentation you will probably fail(…)

GTT in Exadata are eligible to SmartScan

By Franck Pachot . 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(…)