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Category Archives: Oracle

Mehdi Bada

Introduction to Oracle Big Data Services

By | Big Data, Oracle | No Comments

Since few years, Oracle decided to move forward in the Big Data area, as their main competitor. The goal of this blog post is to explain you, how the Oracle Big Data offering is composed. As the Oracle Big Data offering is continuously improving, I’m always open to your feedback Oracle Big Data offering is split in 2 parts: On-Premise Public Cloud Note: It’s important to know, that the 2 main Big Data distribution on…

 
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Franck Pachot

When deterministic function is not

By | Oracle | No Comments

When you declare a function-based index, the function is deterministic, which means that calling it with same arguments will always return the same result. This is required because the indexed values, which are the result of the function, are stored in the index. But what happens if you declare a function deterministic when it is not?  

 
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Pascal Brand

Using WebLogic 12C RESTful management for monitoring WebLogic Domains

By | Application integration & Middleware, Oracle | No Comments

WebLogic 12.2.1 provides a new RESTful management interface with full accesses to all WebLogic Server resources. This interface offers an alternative to the WLST scripting or JMX developments for the management and the monitoring of WebLogic Domains. The following of this blog provides a few examples demonstrating the simplicity and the efficiency of the REST requests. WebLogic Server State When checking a WebLogic Server state, we are interested in the state and in the “ActivationTime”…

 
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Franck Pachot

Am I a DBA 3.0 or just an SQL*DBA?

By | Oracle | 2 Comments

There are currently a lot of new buzz words and re-namings which suggest that our DBA role is changing, most of them escorted with a #cloud hashtag. Oracle Technology Network is now called Oracle Developer Community. Larry Ellison announced the database that does not need to be operated by humans. And people talking about the death of DBA, about the future of DBA, about DBA 3.0,… Those are all generalizations and universal statements, and I…

 
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Franck Pachot

Wrong result with multitenant, dba_contraints and current_schema

By | Oracle | No Comments

Multitenant architecture is not such a big change and this is why I recommend it when you start a project in 12c or if you upgrade to 12.2 – of course after thoroughly testing your application. However, there is a point where you may encounter problems on dictionary queries, because it is really a big change internally. The dictionary separation has several side effects. You should test carefully the queries you do on the dictionary…

 
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Franck Pachot

Active Data Guard services in Multitenant

By | Oracle | No Comments

A database (or the CDB in multitenant) registers its name as the default service. When a standby database is on the same server, or same cluster, you have no problem because this database name is the db_unique_name which is different between the primary and the standby(s). In multitenant, in addition to that, each PDB registers its name as a service. But the PDB name is the same in the primary and the standby database. This…

 
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Franck Pachot

impdp content=metadata_only locks the stats

By | Oracle | No Comments

With Oracle you can learn something every day. Today, preparing a migration to 12.2, I found all tables had locked statistics. I learned that it is the expected behavior since 10.2 when importing metadata_only including statistics, to avoid that the automatic job gathering comes and replaces the stats by ‘0 rows’.  

 
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Franck Pachot

12c dbms_stats.gather_table_stats on GTT do not commit

By | Oracle | No Comments

In my UKOUG OracleScene article on 12c online statistics and GTT I mentioned the following: A final note about those 12c changes in statistics gathering on GTT. In 11g the dbms_stats did a commit at the start. So if you did gather stats after the load, you had to set the GTT as ON COMMIT PRESERVE ROWS. Or you just vacuum what you’ve loaded. That has changed in 12c. If you now choose to do…

 
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