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October 2015

Your Data Awakens : Delphix Express CloneAttack at OOW

Want a free version of Delphix Express installed on your computer with the assistance of Oracle and Delphix experts? We will be holding #CloneAttack again at Oracle Open World on Oct 27 from 1:30-4:30.

CloneAttack is a hands on labs to install a fully operation Delphix Express environment on your laptop.

The labs will be hosted at the Creativity Museum, which is at the corner of Howard St and 4th St above the carrousel,  on Tuesday Oct 27  1:30pm to 4:30pm.  Dell  and DBvisit will also beholding #ToadAttack and #RepAttack in the same location with us.


12c Parallel Execution New Features: Parallel FILTER Subquery Evaluation - Part 2: Distribution Methods

Picking up from the first part of this instalment I'll focus in this post on the available distribution methods for the new parallel FILTER subquery feature.In this post I won't go into the details how the optimizer selects the distribution method automatically - this will be covered in the last part.Here I merely describe the different available methods and how to control them using the new PQ_FILTER hint, which is also mentioned in the official documentation, although I find a bit hard to follow the description there.There are four different options available to the PQ_FILTER hint, and only two of them actually describe a distribution method.

Friday Philosophy – 3 months, 3 conferences

Flights are booked, hotels reserved, plans made. Don’t ask about talks prepared, just don’t :-)

This is not the usual list of “I’m going to this talk and I’m seeing that speaker” blog that people write before an event – well it is a little – it’s more about the different flavors of conference we have available to us.

I have an Oracle conference a month until the end of the year and I’m really looking forward to all of them. Each is very different. I know I am lucky to be able to do this sort of thing, that is go to so many conferences, and partly it is because of being an ACED. But fundamentally it’s come about as a result of the decision I made back in 2003 to give something back to the community that I’d learnt so much from, and even more so when a couple of years back my wife gave me permission to do less stuff that pays and more stuff that I enjoy. Oracle Community stuff.

Delphix Express: rolling a VDB back

The following is an example of rolling a virtual database (VDB) back in time with Delphix Express, the free version of Delphix. Delphix by default keeps a 2 week window of changes for virtual databases (configurable to 2 months, 2 years etc). Thus we can go back in time to any point in that time window.

Why would we want to go back in time?

Maybe something went wrong. For example VDBs are typically used by developers who aren’t as versed in databases as a DBA.  What happens when a developer accidentally drops a table yet there was other work in the database that they want to keep. In the industry, half the time, developer databases are not backed up because they are “just development databases.” With Delphix those developer databases are always backed up and we can go back in time in a few minutes, so if a developer accidentally drops a table or updates the wrong column we can recover in minutes.

New Python Pass the Pigs Game

So in honor of coaching a Python introduction class with Devoxx4Kids this weekend, I thought I would update my pass the pigs game and add in the scoring and just rewrite it a little.

If you aren’t familiar with this fun little game, here’s the gist-  It consists of two pigs that you roll like dice.  Depending on how the pigs land, you get a particular score-

Delphix Express: refreshing a virtual database with source data

What if I’m a developer or QA person using a copy of production database to do my work. What if my copy of production is now out of date and I want to refresh my data with the data as it is on production.

Below is a video of how to refresh a virtual database to the freshest data from the source database:

This example uses the free version of Delphix called “Delphix Express” and  “Landshark” demo environment consisting of two VMs a source VM with a source database and a target VM with no database originally where we provision a virtual database.

Direct path and buffered reads again.

Since the direct path feature for serial processes was discovered after it became available in Oracle (as far as I know, I haven’t checked Oracle 11.1), there have been a lot of blog posts on when this happens. A lot of these do not specify the Oracle version, which is a failure in my opinion. There are different decisions made in different versions.

The purpose of this blogpost is to show the results of my tests on when the Oracle database engine switches from buffered to direct path reads and vice versa. There probably are decisions made by the database engine for this feature based on internal kept statistics, like general activity and object usage, which means my tests might be different in your database. For that purpose I included an anonymous PL/SQL block in this post so you can replay the same test in your own database, except for the table, which you have to create yourself.

Copy Data Management for Oracle Database with EMC AppSync and XtremIO

This is a quick blog entry to invite readers to view this little demonstration video I created. The topic is Copy Data Management in an Oracle Database environment. We all know the pains involved with the number of database copies needed in today’s Oracle environment. Well, how about technology with these characteristics:

Using DevOps Jetpack (a.k.a. Jet Stream)


photo by Chase Elliott Clark

Here a video on using Jetstream which I like to call “DevOps Jetpack for Developers” (Remember you can get Delphix Express and Jet Stream for free.) See previous blog post on how to set up Jet Stream.

Little things worth knowing: automatic generation of extended statistics in 12c

When you are migrating to Oracle 12c I hope you might this post useful. I came across this feature when researching what’s new with Oracle 12c (and yes I still find lots of new ones I haven’t noticed before). This one is a bit hidden away in section Automatic Column Group Detection of the 12c New Features Guide. And it’s a lot more complex than I first thought! In this first post I’ll try and show the generation of extended statistics in 12c. I am planning on another post to explain how the rest of the adaptive optimisations that are new with 12c fit into the picture.

What is the motivation?