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July 2013

Cinderella

Just a little whimsy – the most famous (misquoted?) line from the fairy-tale in the title is (probably) “you shall go to the ball”.

Despite having all my abstracts rejected I will be speaking at OOW 2013, courtesy of “the Optimizer Lady”, Maria Colgan.

Oracle Optimizer Boot Camp: 10 Optimizer Tips You Can’t Do Without [CON8643]

Jonathan Lewis – Sole Proprietor, JL Computer Consultancy
Maria Colgan – Master Product Manager, Oracle

LAOTN Tour (Southern Leg) : Arrived in Santiago, Chile…

I’m now in the hotel in Santiago, Chile.

The flights were fine. I landed in Paris with just enough time to walk to the departure gate and board my next flight. The Air France boarding was a bit chaotic, and once again there was no vegetarian food. With many airlines, booking a special meal seems to be very hit or miss. It’s not like I’m going to starve though, so never mind. :)

For some reason, unknown to me, I got a Business Class flight out, so the 14.5 hour flight from Paris to Santiago wasn’t nearly as bad as it could have been. I’m cattle-class for the rest of the flights, including the 11+ hour flight home from Sao Paulo.

Oracle 12c Security - SQL Translation and Last Logins

There has been some big new security items added to 12cR1 such as SHA2 in DBMS_CRYPTO, code based security in PL/SQL, Data Redaction, unified audit or even privilege analysis but also as I hinted in some previous blogs there are....[Read More]

Posted by Pete On 31/07/13 At 11:11 AM

12c Histograms pt.2

In part 2 of this mini-series I’ll be describing the new mechanism for the simple frequency histogram and the logic of the Top-N frequency histogram. In part 3 I’ll be looking at the new hybrid histogram. You need to know about the approximate NDV before you start – but there’s a thumbnail sketch at the end of the posting if you need a quick reminder.

Simple Frequency Histograms

To allow for collection of simple frequency histogram – record the first rowid for each hash value generated and count the number of times the hash value is generated. If, by the end of the table you have no more than the requested (default 254, max 2,000) distinct hash values you can look up the actual values with a query by rowid.

How to improve VMware performance on your PC

I found very interesting post here - VMware Performance Enhancing Tweaks (Over-the-Counter Solutions). I used it on my VMware Player and Workstation and when I disabled vmem file my laptop it stopped blinking HDD led for 5 - 10 min every time it wake up from sleep mode.

regards,
Marcin

How to improve VMware performance on your PC

I found very interesting post here - VMware Performance Enhancing Tweaks (Over-the-Counter Solutions). I used it on my VMware Player and Workstation and when I disabled vmem file my laptop it stopped blinking HDD led for 5 - 10 min every time it wake up from sleep mode.

regards,
Marcin

ASSM

A couple of thoughts.

The intent of ASSM is to minimise contention when multiple small transactions are busy inserting data concurrently into the same table. As a consequence, you may be able to find a number of odd behaviour patterns if you do experiments with a single session running one transaction at a time; or when executing a single large transaction, or when experimenting with small tables.

As far as I know, no-one has written up any detailed explanation of the internal strategies of ASSM – and there are a number of strange variations that you can uncover if you start running things that you might call “unexpected” tests; but many of the anomalies disappear (or become insignificant) when you’re operating at the correct scale.

LAOTN Tour (Southern Leg) Preparation Complete…

Tomorrow is going to be a very tough day. I’ve got work as normal, including one of my fortnightly Tuesday presentations. From work I dash home, get changed, pick up my stuff and it’s off to the airport. I get a quick flight to Paris, then it’s a 14.5 hour flight to Santiago, Chile. That’s the starting point for the southern leg of the LAOTN tour this year. I can only hope I break the habit of a lifetime and actually get some sleep on the plane. If not I’m going to be like Day of the Dead when I get there.

Oracle Certified Professional (OCP) Database 12c…

I just noticed the Database 12c OCP beta exams have started to appear (see here).

Not surprisingly, the multitenant option seems to be a big factor in the content of the both the Advanced Administration and Upgrade exam.

There are a few things that see a little odd (to me) though: