how NOT to design (more...)
Oracle Database Gateways 11g R2 (11.2) Installation and Configuration for heterogeneous connection from Oracle to Microsoft SQL database
Install the Oracle Database Gateways 11g R2 (11.2). See the screen snapshots of the installation here.
- During the installation, the following default initialization parameter file is created:
dg4msql = Database gateway for Microsoft SQL Server. If you choose a different database option, (more...)
When to consider sharding a MySQL database
Why should you not just design your applications from the start to account for data sharding? Sharding a database, that is horizontally partitioning tables among multiple databases, creates an added level of complexity that is not desirable in an application. However, there are times when sharding is required to maintain acceptable performance. So when is the right time to shard your database?
When to consider sharding a MySQL database Why should you not just design your applications from the start to account for data sharding? Sharding a database, that is horizontally partitioning tables among multiple databases, creates an added level of complexity that is not desirable in an application. However, there are times when sharding is […] -->
Schemas and users are frequently used interchangeably as if they were the same thing. For the most part, that's ok. In Oracle the concepts are so tightly coupled that thinking of them as the same thing is not really that far wrong.
In reality, a user is a database account that is given a password and permissions. A schema is a container, or namespace, for containing schema objects. Schema objects are things like tables, views and indexes.
In Oracle, when a us
The LAST_REFRESH_DATE column of the DBA_MVIEWS or the LAST_REFRESH column of the DBA_MVIEW_REFRESH_TIMES indicates the start refresh time. But what if we’d like to find out how long the refresh of the materialized view really takes. Well, we can query the DBA_MVIEW_ANALYSIS.
For Complete Refresh, the refresh duration will be in the FULLREFRESHTIM column of the DBA_MVIEW_ANALYSIS. For Fast Refresh duration, it will be in the INCREFRESHTIM column.
Both values are in seconds.
SELECT mview_name, last_refresh_date, fullrefreshtim, increfreshtim FROM dba_mview_analysis WHERE owner='JOHN'; MVIEW_NAME LAST_REFRESH_DATE FULLREFRESHTIM INCREFRESHTIM ------------------------ ---------------------- -------------- ------------- MV_CHANGE_HISTORY 07-JAN-13 04.36.58 PM 0 (more...)
Given the incredible number of comments I received on my last blog post, and the content of those comments, it is very obvious that folks are extremely confused by what I meant by that post, as well as the comments by Mr. Garsthagen (Oracle Director Level Employee), referenced in that post.
The confusion is typified by the following comment, the most recent I have received:
Oracle does not recognize either (Vmware/DRS Affinity) as a hard partition
First, to be completely clear, I have never stated, nor do I believe, that VMware (or any other software hypervisor for that matter) (more...)
As all of my readers know, I have been a strong proponent of VMware virtualization of Oracle Database servers for license cost savings purposes. Predictably, Oracle has pushed back on this issue in the past. Well, they have now thrown in the towel.
In an online video, Richard Garsthagen, Director of Cloud Business Development EMEA for Oracle, has stated publicly that VMware host affinity rules (when combined with vMotion logging) work just fine, thank you very much, for purposes of establishing where Oracle software is "installed and/or running" for purposes of the Oracle Software License Agreement (OSLA).
As many of you have heard by now, Paul Mauritz is out as CEO of VMware, and Pat Gelsinger (formerly COO of EMC, reporting directly to Joe Tucci) is replacing him.
The relevant question for those of us who care passionately about Oracle virtualization using VMware vSphere is:
What does this mean for VMware's BCA (Business Critical Applications: stuff like Oracle) strategy (which under Maritz was somewhat lacking)?
In my view, this is very, very good news indeed. The reason is simple: Paul Maritz was former Microsoft, and thus very Microsoft-centric. Under Maritz, VMware very successfully penetrated the Microsoft (more...)
I thought it worth republishing Dave Welch's (of House of Brick) comments to my discussion on the Everything Oracle at EMC online community on the subject of Oracle licensing costs on VMware vSphere configurations. Here are Dave's comments:
Let me start by bringing all of you into the courtroom. There are three issues that you will observe me as counsel provide to the jury as part of my allowed instruction (I am not an attorney in real life).
I offer the definitions in this paragraph only to make this post as self-sufficient as possible and not with intent (more...)
VMware has put a stake in the ground with respect to Oracle licensing of VMware VMs running Oracle. The gist of this statement regarding certification, support, and licensing is that DRS host affinity rules, combined with vCenter audit trails showing where VMs have actually run, are sufficient for Oracle licensing purposes. The summary of the document states:
DRS Host Affinity rules can be used to run Oracle on a subset of the hosts within a cluster. In many cases, customers can use vSphere to achieve substantial licensing savings.
vCenter VMotion Logging
Concerning vCenter VMotion logging, the (more...)
I have received a fair number of responses to my previous post on this subject (some via comments and some via email). I thought the discussion worthwhile enough to punch it up a bit more here.
As I pointed out in the previous post, EMC can easily match NetApp's play to back up ExaData with the following:
As Geoff Rosser so correctly pointed out, this answer is incomplete. Yes, Data Domain is an awesome Oracle backup solution. Yes, it provides incredible deduplication rates for Oracle database environments. (Thanks, dynamox.) However, it is not the only viable solution from (more...)
There has been lots of material on the web recently concerning NetApp being able to backup ExaData. The purpose of this blog is to respond to that content, and state why NetApp's offering is rather lame, and actually offers nothing new.
The items on the web produced by NetApp are easy to find. I will not increase their Google hit rate by linking to them here. Suffice it to say, Neil Gerren's blog contains the principle content to which I will respond here. There is also NetApp technical report TR 4022, a 34 page tome, which I have read thoroughly. (more...)
Appliances such as microwave ovens, refrigerators, iPods, iPads and TVs are excellent examples of the ease-of-use approach. Bringing the inherently complex world of Oracle databases together with the ease-of-use approach of appliances is challenging. By definition if Oracle Exadata is an appliance then its use should be simple, require relatively little maintenance and like a refrigerator do its job which in this case is run databases at extreme performance levels. If Oracle Exadata isn’t an appliance than what is it?
I found this question (more...)
Book Review: Oracle 11g R1/R2 Real Application Clusters Essentials by Ben Prusinski and Syed Jaffer Hussain (Packt Publishing)
Oracle Real Application Cluster (RAC) becomes the technology of choice for highly available and highly scalable deployment of enterprise Oracle database environment. With its innovative technology it comes with no surprise its complexity. The complexity is not only with the underlying database technology itself, but also how well you design and implement it to work with other components including operating system, storage subsystem, etc. In order to setup and maintain a successful RAC environment, it not only requires technical knowledge of database administrator (DBA), but also well collaboration and extended planning between all IT and business partners.
Few years (more...)