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Flashback Functions – One Name, different Techniques

Since version 9i there is the term “Flashback” in the Oracle Technology. However it is often hard to harmonize the different terms and corresponding technologies. Let’s start with the definitions: Flashback means, at least in the Oracle terminology, that a past state shall be restored. Might be you want to see the state of a data set one hour ago, the table before it was deleted or the change from last month. And here we are at the actual question: What have I got to do to meet requirements like these?

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By • • 4 minutes of reading
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Be careful when setting the DBTIMEZONE!

Why you should not set the DBTIMEZONE to a “Location Time Zone” format in Oracle. First of all, the DBTIMEZONE does not control at what time scheduler jobs exactly starts. When I have been taking care of my scheduler jobs recently I was wondering how do I now configure these, I came across a very simple question. After what time zone will “by hour 23” executed which I have planned here? In addition to the well known SYSDATE, I came across the DBTIMZONE parameter. What would make more sense that the database time zone controls when my >database!< scheduler jobs

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By • • 3 minutes of reading
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Second SCAN-Listener

Since Oracle 12c you create and use a second (or even more) SCAN-Listener for Load-Balancing, Failover, etc. This can be useful to separate Network traffic e.g. for Dataguard or Shareplex replication. Like the ordinary SCAN-Listener you need two additional VIP- and three additional SCAN-Addresses. In the following example I want to separate the Dataguard traffic between a RAC Database with two nodes (morrison and manzarek) and a single node (daltrey) RAC Database as standby.

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By • • 3 minutes of reading
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Prevent PDB creation in a Single Tenant environment

How do I prevent the creation of a second PDB in a Single Tenant environment? At last Oracle introduced a number of new features with 12c, but Multi Tenant is still the one outstanding innovation. But when switching to the new version my customers have one question: Do I really need this feature? Beside the not really low licensing costs for the Multi Tenant Option, there are practical use cases. But when I use one productive environment with one test environment or a consolidation into a Multi Tenant environment makes simply no sense, I still can use the Non-CDB alternative.

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By • • 2 minutes of reading
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Datapump or Flashback Database

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Do you need Datapump? At nearly every customer I’m visiting there is a need to take export dumps of the entire database every single day. But why? You probably know the answer: because the application team requested it to reset a schema or a table to an earlier time in the event due to a user failure, batch error or whatever. My next question is this: “How often did you reset a table or a schema within the last 12 months?” Answer: “Not a single time… but we had to do it some years ago with one of our databases.

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By • • 5 minutes of reading
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inMemory on Oracle RAC

In my last blog I described my first experience with inMemory at a customer side. I was really impressed about the massive performance gain and the ease of use. Now it’s time for a second trial. As stated earlier the customer was using a single instance database as test environment but the production and preproduction were running on Oracle RAC. This again shows how important it is to have the same environment for preproduction and production – or better for test as well as that whould have shown the non comparable results early enough and not just before it went

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By • • 9 minutes of reading
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Oracle inMemory – First experiences

With Oracle 12.1.0.2 the brand new database option named inMemory has been introduced. There are many blogs and articles out in the field so I don’t want to go in to much detail of the main concept. To me “inmemory” sounds a little obvious because whenever we are working with the Oracle database most of our data should be in Memory – right? But there is another naming for it: Column store. So it stores the data in columns instead of rows? Due to the Oracle documentation this isn’t true because “The columnar format exists only in memory (Concepts Guide)”.

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By • • 8 minutes of reading
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Optimized Multitentant Database Configuration

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Talking to customers about Multitenant database several of them complained that you need to install all database features regardless if you have them licensed or if you really need them. Using the Oracle Database Configuration assistant, you will find that it is not possible to deselect any of the database components. But is this a problem?

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By • • 2 minutes of reading
Oracle

Data Guard Protection Modes

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The availability and consistency of the Standby Database changed evermore throughout the last years and by that the loss of transactions decreased till 0 transactions. Originally only the archived Redolog files were transmitted to the Standby side and loaded there. By this the loss of transactions was in scale of one redolog file. With the 9i version Oracle then introduced the Standby Redologs, so transactions could now be transmitted right from the Online Redologs into the Standby Redologs and loaded immediately. So the loss of transactions was only a few transactions. With the 10g version then the LNS process was

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By • • 3 minutes of reading
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