Max PDBs in Standard Edition
Here is a small warning. In Standard Edition, you may expect that the features that are not available for your edition are blocked, but in 12.2 you can create more than one PDB in Standard Edition, and...
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Multitenant internals: INT$ and INT$INT$ views
This month, I’ll talk – with lot of demos – about multitenant internals at DOAG conference. The multitenant dictionary architecture starts with a simple idea: system metadata and data are in CDB$ROOT...
View ArticleDynamic Sampling vs. Extended Statistics
On datawarehouse databases, I frequently recommend increasing the level of dynamic sampling because: Queries have complex predicates with AND, OR, IN(), ranges and correlated values for which the...
View ArticleCBO, FIRST_ROWS and VIEW misestimate
There are several bugs with the optimizer in FIRST_ROWS mode. Here is one I encountered during a 10.2.0.4 to 12.2.0.1 migration when a view had an ‘order by’ in its definition. Here is the test case...
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12c Multitenant Internals: compiling system package from PDB
When I explain the multitenant internals, I show that all metadata about system procedures and packages are stored only in CDB$ROOT and are accessed from the PDBs through metadata links. I take an...
View Articleimpdp logtime=all metrics=y and 12cR2 parallel metadata
A quick post to show why you should always use LOGTIME=ALL METRICS=Y when using Data Pump. Just look at an example showing the timestamp in front of each line and a message about each task completed by...
View ArticleNaming of archivelog files with non existing top level archivelog directory
In Oracle 12.2 an archive log directory is accepted, if top level directory does not exist: oracle@localhost:/u01/app/oracle/product/12.2.0/dbhome_1/dbs/ [DMK] ls -l /u02/oradata/DMK/ total 2267920...
View Article12cR2 Subquery Elimination
More and more we can see crazy queries generated by ORM frameworks or BI query generators. They are build to be easily generated rather than being optimal. Then, the optimizer has to implement more and...
View ArticleDrop PDB including datafiles may keep files open
I like that Oracle drops the datafiles from the operating system when we remove them from the database (with drop tablespace or drop pluggable database) because I don’t like to have orphean files...
View Article12c Multitenant internals: PDB replay DDL for common users
In multitenant, you can create common Users, Roles, and Profiles. You create them in CDB$ROOT, with the CONTAINER=ALL clause (which is optional because it is the only possible value when connected to...
View Article12c Multitenant internals: PDB_PLUG_IN_VIOLATIONS
In the previous post https://blog.dbi-services.com/12c-multitenant-internals-pdb-replay-ddl-for-common-users I’ve done some DDL on a common user to show how this is replayed later for PDBs that were...
View ArticleKeep your orapw password file secure
This is a small demo I did when I’ve found a database password file (orapw) lying around in /tmp with -rw-rw-rw- permissions, to show how this is a bad idea. People think that the orapw file only...
View ArticleAutomatic Data Optimization Part I : Compression Tiering
Nowadays data are increasing more and more. And some challenges we can face can be how to reduce storage costs and how to improve performance. With Oracle 12c, the feature Automatic Data Optimization...
View ArticleORACLE 11g to 12c RMAN catalog migration
This is a small migration demo of a 11g catalog (RCAT11G) to a new 12c catalog (RCAT12c). Demo databases environments have been easily managed thanks to DBI DMK tool. oracle@vmreforadg01:/home/oracle/...
View ArticleUnplug an Encrypted PDB (ORA-46680: master keys of the container database...
In the Oracle Database Cloud DBaaS you provision a multitenant database where tablespaces are encrypted. This means that when you unplug/plug the pluggable databases, you also need to export /import...
View ArticleMultitenant, PDB, ‘save state’, services and standby databases
Creating – and using – your own services has always been the recommendation. You can connect to a database without a service name, though the instance SID, but this is not what you should do. Each...
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One command database upgrade on ODA
The 12.2 finally arrived on ODA and is now available on all generations. Modern ODAs are now supporting 11.2.0.4, 12.1.0.2 and 12.2.0.1 database engines, and these 3 versions can work together without...
View ArticleDatabase Vault : Rules, Rule Sets and Command Rules
In a previous blog I talked about protecting data using Realms. With Database Vault we can also protect our database against some SQL statements. These statements can include SELECT, ALTER SYSTEM,...
View ArticleNew features and known issues with RMAN tool on Oracle database 12.1.0.2
Oracle Database 12c has new enhancements and additions in Recovery Manager (RMAN). The RMAN tool continues to enhance and extend the reliability, efficiency, and availability of Oracle Database Backup...
View ArticleUsing Oratcptest
Last day I did some tests with Oratcptest. This a command line tool which can be used to measure network bandwidth and network latency between client and server. In this blog I am going to show how to...
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