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Loading XML documents into an Oracle database (1)

Very often people want to load XML documents into an Oracle database so, for example, they can shred the needed values from those XML documents...
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When Storage is REALLY Fast Even Zero-Second Wait Events are Top 5. Disk File Operations I/O: The Mystery Wait Event.

The SLOB code that is generally available here differs significantly from what I often test with in labs. Recently I was contorting SLOB to hammer an EMC XtremIO All-Flash Array in a rather interesting way. Those of you in the ranks of the hundreds of SLOB experts out there will notice two things quickly in the following AWR snippet:

1)   Physical single block reads are being timed by the Oracle wait interface at 601 microseconds (3604/5995141 == .000601) and this is, naturally for SLOB, the top wait event.

2)   Disk file operations I/O is ranking as a top 5 timed event. This is not typical for SLOB.



AWR Warehouse Webinar from ODTUG

The webinar is over, but you haven’t missed out on everything I presented on the console feature, under the hood and behind the scenes!

Delivering DBaaS using EM

One of the jobs I’m currently working on is writing a technical whitepaper on Delivering DBaaS using EM12c. I realized as I was starting it that a technical whitepaper really isn’t the place for a step-by-step how-to sort of description, so I thought I’d better blog about it instead. Actually, I’m going to write a whole series of blog posts since, much like the series of blogs Kellyn and I wrote on the EM release, the area is so damn big it’s impossible to cover in a single blog post! So this post will be the introduction, and I will add links to the additional areas as they get covered. If you’re already following this blog, you’ll be informed of each one as it gets posted, so don’t forget to follow the blog to get the whole series!

VirtualBox 4.3.14

Oracle have given birth to VirtualBox 4.3.14. Mother and baby are doing well, with the downloads and changelog in the usual places.

Happy upgrading…



PS. Looks like the baby might be still-born. Fails pretty badly on Windows 7 at the moment…

PPS. Seems to work fine on Mac and Linux (Fedora 20)…

Using Database In-Memory Column Store with Complex Datatypes (1)

The Oracle database version, with the In-Memory option, isn’t yet released, but a lot of detail is already out there since it’s announcement by...
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Oracle Midlands : Event #4 – Summary

What a cracking Oracle Midlands event!

The evening started with a session on “Designing Efficient SQL” by Jonathan Lewis. The first few slides prompted this tweet.


When someone asks me a question about SQL tuning my heart sinks. It’s part of my job and I can do it, but I find it really hard to communicate what I’m doing. Jonathan’s explanation during this session was probably the best one I’ve ever heard. Rather than trying to explain a million and one optimizer features, it’s very much focussed on a “What are you actually trying to achieve?” approach. It should be mandatory viewing for all Oracle folks.

After the break, where I stuffed myself with samosas, it was on to the lightning talks (10 mins each).

What books by what authors should I read?

I’ve been asked the same question by multiple people, around what books by what authors are good to have, so let me answer it once here. :)

The answer is easy – it depends! Are you interested in database administration? Application development against an Oracle database? Technical apps? Functional apps? High Availability? Enterprise Manager? No single author covers all of those – unless you count the Oracle documentation set as a single author.

Deferrable RI – 2

A question came up on Oracle-L recently about possible locking anomalies with deferrable referential integrity constraints.

Exadata storage indexes and DML

Last week I’ve gotten a question on how storage indexes (SI) behave when the table for which the SI is holding data is changed. Based on logical reasoning, it can be two things: the SI is invalidated because the data it’s holding is changed, or the SI is updated to reflect the change. Think about this for yourself, and pick a choice. I would love to hear if you did choose the correct one.

First let’s do a step back and lay some groundwork first. The tests done in this blogpost are done on an actual Exadata (V2 hardware), with Oracle version (meaning bundle patch 6). The Exadata “cellos” (Cell O/S) version is on both the compute nodes and the storage nodes.