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May 2015

OT: Get your next job through Twitter?

From Gwen Shapira’s interview in the May 2015 issue of the NoCOUG Journal :
“I got my current job at Cloudera through Twitter.
At the time, I was working with a retailer in Japan, as a consultant through Pythian. I was there to help them migrate to Exadata, but their data warehouse system was tightly integrated with Hadoop, and I got to work on this integration too. I got a lot of exposure to Cloudera’s distribution—indispensible tools for integrating Hadoop with data...(read more)

Friday Philosophy – Make a Team by Letting Them Burn

The title of today’s Friday Philosophy sounds extreme, but it’s true.

Sir John Harvey-JOnes

Sir John Harvey-Jones

Temp Table Transformation Cardinality Estimates - 2

Continuing from the previous part - which was about the Temp Table Transformation and join cardinality estimates - using the same simple table setup here is a slight variation of the previously used query to demonstrate the potential impact on single table cardinality estimates:

explain plan for
cte as (
select /* inline */ id from t1 t
where 1 = 1
select /*+
no_merge(a) no_merge(b)
*/ * from cte a, cte b
where =
and > 990 and > 990

-- 11.2.0.x Plan with TEMP transformation

Writing Tips

writingIn this series of posts I’ve been discussing my opinion on various aspects of writing, including blogging, writing articles and whitepapers, or just writing documentation in your company. If anything more comes to mind I’ll write it and link it from this post.

Here are the posts that made up this series.

SLOB 2.3 Is Getting Close!

SLOB 2.3 is soon to be released. This version has a lot of new, important features but also a significant amount of tuning in the data loading kit. Before sharing where the progress is on that front, I’ll quickly list some of the new important features that will be in SLOB 2.3:

DHCP: Virtualbox vs VMware on laptops

I’ve been using VMware Fusion on my Mac but it costs about $60. Not that much but Virtualbox is free, so I also have Virtualbox as well.

For my VMs I use DHCP and this has caused some problems but mainly on Virtualbox. With VMware Fusion (and VMware Workstation) everything works fine.


With VMware, under “Edit Hardware Settings” then “Network Adaptor” I just set the network

  • Mac:  “Share with MAC”
  • PC:  NAT

This causes the system to act as a router, isolating the VM’s on their own network, while allowing internet connectivity outbound as well as being able to connect to the VMs from my laptop and being able to connect from one VM to another.


Oracle : Do you even internet? (broken links again)

Broken-LinkI mentioned in a recent post that Oracle are often guilty of changing URLs, which breaks all the documentation links in your site. Someone replied with this link. I knew I had a lot of clean-up to do, but I expected most of it to be old URLs, like stuff pointing to 8i, 9i etc.

I’ve just been looking and vast swathes of links have been changed in the 12.1 docs. In some cases, articles I wrote a couple of weeks ago are screwed. The reference manual is guilty of this big time!

Writing Tips : Copyright Theft

writingIf you’ve followed my blog you will know people try to steal my articles all the time. It happens to all bloggers, unless they are unpopular or rubbish. You don’t really have to look for it, because your readers will spot it and tell you. :)

Some things to remember about this stuff…

All material published on the internet has an implicit copyright, even if there is no explicit copyright notice on the site. This means, unless the copyright owner gives you explicit permission, republishing their content is an act of theft. When you are writing, make sure you are doing the work, not stealing other people’s work.

One year at Delphix

It’s been over a year since I leapt into the void.

OK, more than a little melodramatic.  In many respects, I was leaping from the void by joining a promising and exciting startup company like Delphix.

With Modern Storage the Oracle Buffer Cache is Not So Important.

With Oracle’s move towards engineered systems we all know that “more” is being done down at the storage layer and modern storage arrays have hundreds of spindles and massive caches. Does it really matter if data is kept in the Database Buffer Cache anymore?

Yes. Yes it does.

Time for a cool beer

Time for a cool beer

With much larger data sets and the still-real issue of less disk spindles per GB of data, the Oracle database buffer cache is not so important as it was. It is even more important.