With the trend to consolidate more and more databases on a single server the question arises how to limit the resource consumption of a single database. Memory can easily be limited because most of the memory is going to be allocated either for the SGA or the PGA. But what about the CPU? By default all processes from all instances are balanced across all CPUs of the server.
How to limit CPU-Consumption of a database Blogbeitrag lesen »
CloneDB Feature Oracle has quietly and secretly provided a new method to duplicate databases with Version 11.2.0.2 (yes, the patchset). CloneDB makes it possible to build up several databases on the basis of a RMAN image copy. Foundation for that is Direct NFS support in the database, introduced with version 11.1.0.6. With that it is possible to run an Oracle database on NFS storage over a special driver (dNFS). With CloneDB a new I/O layer will be implemented, so that reading access will be provided by a RMAN backup and writing access creates own unique files. In the view of the database
CloneDB – Quick ‘n Easy Blogbeitrag lesen »
Clone Wars When we’re hearing „Clone“, most people will associate it with Star Wars the Clone Wars … something like that, The main idea behind the clones was that they are identically as possible with identical functions, that means that they have the same power, strength and what else. When we think about cloning databases, it’s not really different. Target is to create a copy of the production environment which is preferably as much identical as we can get it, for testing and development purposes. In most cases it will not stop with only one copy. Over the time different
Database virtualization and instant cloning … and 12c Blogbeitrag lesen »
Multitenant Database Multitenant or pluggable database is probably the most discussed feature in Oracle 12c. For many of us DBAs or Developers in can be a dramatic shift as it requires different thinking of how the “database” is working or how we define a database from now on. Many articles are available in the web and on ToadWorld there are already several blogs discussing this feature. In one of my previous blogs I already mentioned the ability of managing Pluggable Databases in Toad 12. But Toad 12.1 brings some major enhancements and it’s unbelievable how easy the management of PDBs
Pluggable Database Management with Toad 12.1 Blogbeitrag lesen »
Invisible Indexes With Version 11g Oracle introduced invisible Indexes and I had several discussions with customers why it makes sense to create Indexes which are not used but maintained – because that’s what an invisible index is. Let’s have a closer look at the creation of indexes and why an invisible index might fit.
My Database becomes invisible Blogbeitrag lesen »
1. Migration Scenarios Over the past years I’ve done several Oracle database migrations to a different platform (e.g. HP/UX to Linux) to a different edition (e.g. Enterprise Edition to Standard Edition) or to Unicode. The most easiest one nowadays is the platform migration as Oracle offers some nice features like cross platform transportable tablespaces or RMAN cross platform backups or if you want to migrate from Windows to Linux vice versa you can simply setup a data guard environment. Of course there are still some pitfalls like the downtime but in general it’s straight forward and well tested.
Unicode Migration to Oracle 12c Blogbeitrag lesen »
Is it by chance that within an interval of a few days both Oracle announced Oracle 12c and Dell Software announced Toad for Oracle v12? When I first saw Toad 12 (which was the first one), I was wondering about the features. As I generally don’t like reading documents I tried myself and immediately found a new feature named “Jump”. This helps a lot finding useful tools like the various compare options but is able to scan your directories and even the entire internet for additional information. So if you are new to Toad use it to find the tools;
Toad 12 and Oracle 12 Blogbeitrag lesen »
Maximum Columnsize for VARCHAR2 is now 32k! With Oracle12c you can define a column of data type VARCHAR2, NVARCHAR2 or RAW with a maximum length of 32767 Byte (but not CHAR!). But why is that useful? Datatype CLOB or NCLOB are fit better for pure text fields of a certain size. They can be handled in chunks instead of manipulating the entire text at once and with the SecureFile option which is now default for CLOB and BLOB in Oracle12c the storage is much more efficient.
VARCHAR2(32767) – Sense or Nonsense? Blogbeitrag lesen »
Multi-Process Multi-Threaded Oracle If you are running Oracle databases on Unix or Linux you probably know that there are many processes even if no user is connected. But if you run Oracle on Microsoft Windows you only see one processes and all Actions are connected to it as threads. With Oracle 12c it’s now possibe to run an instance with very few processes and all tasks are running as threads. This is named “Multi-Threaded Oracle“.
Oracle 12c – Where have all the processes gone …? Blogbeitrag lesen »
Creating an Oracle database with character set U7ASCII should be an exception nowadays. So if you try dbca (database configuration assistant) in Oracle 11g you don’t even have the choice by default. But it’s still possible – in all current Oracle versions. If that’s what you really wanted – I don’t know!
Using Umlaute in US7ASCII – doesn’t work, does it? Blogbeitrag lesen »
