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September 2015

Longer strings in 12c

Most people are now aware that in 12c, a VARCHAR2 has been extended from a maximum size of 4000 to 32767 bytes.

Similarly, there’s many a note/blog post etc about needing to set the following parameter to enable it:


SQL> alter system set max_string_size = EXTENDED scope=spfile;

System altered.

and then bounce the database. But its important note that its NOT just as simple as that. Here’s what will happen if you only do that

Oracle OpenWorld : It’s just around the corner…

The total insanity that is Oracle OpenWorld 2015 is just around the corner. I’ve got my flights and hotels booked, so I think I’m good to go!

The first couple of days will be ACE Director briefings. The big announcement this year will be the Oracle Games Cloud (#OGC), but as a beta program participant I’m under NDA so I’m not allowed to talk about it. It will be interesting to see what else is coming down the pipeline. I expect lots of hardware refreshes and standard stuff like that, but there is always something unexpected that makes you sit back…

VirtualBox 5.0.4

virtualboxVirtualBox 5.0.4 has been released.

It’s a maintenance release, with a whole bunch of bug fixes. Downloads and changelog in the usual places.

The “Check for Updates…” link from the menu hasn’t noticed the upgrade yet, so if you are keen you will have to download it manually. :)

Happy upgrading…

Cheers

Tim…

 

SQL and the Art of Problem Solving

What would you do if you were lost in a labyrinth of underground caves? In the dark. With no food. Mark Twain tells the story of how Tom Sawyer and Becky Thatcher got separated from their picnic group and got lost in a labyrinth of underground caves. What’s that got to do with problem solving? I think that the first rule of problem solving is “If at first you don’t succeed, try, try, again.” Of course, there’s more to problem solving than determination. In his 1945 book “Solve It!”, one of the 20th century’s most notable mathematicians, George Polya, said: “If you cannot solve the proposed problem try to find first some related problem. Could you imagine a more accessible related problem? A more general problem? A more special problem?

Viewing Figures

I’ve just realised that I haven’t been paying any attention to the number of visitors I’ve had over the last few months, so I missed the moment when I reached the next half million.  The count has now reached 4,571,856 – probably hitting 4,500,000 around July 6th – so it’s time to do another of my little summary pages to see if new topics have become important and old topics have faded to insignificance.

In fact, the top five remain virtually unchanged, though 4th and 5th places have swapped over.

#Oracle Learning Streams – Have a look!

Oracle University has introduced a new format that suits the way many learn today: Oracle Learning Streams

Oracle Learning Streams

Although I do not expect that this format will replace classroom training, I consider it a great enhancement – coming with a price like most good things…

As you can see, I’m happy to contribute to it in my area of expertise: You can find me here in the Database Stream.

Friday Philosophy – On “Being the Expert”

Working as a recognised expert at something is a little…strange, I find.

I had an assignment this week to go visit a client, have a look at a performance issue and find out the root cause. I was also to at least come up with suggested resolutions with the ideal aim of giving them a proven fix they could implement. All to be done in two to three days. This is pretty standard fayre when you are putting yourself forward as some sort of expert in something. And it is not always an easy thing to do – for more reasons than you might expect.

Measuring Tuxedo Queuing in the PeopleSoft Application Server

Why Should I Care About Queuing?

Queuing in the application server is usually an indicator of a performance problem, rather than a problem in its own right.  Requests will back up on the inbound queue because the application server cannot process them as fast as they arrive.  This is usually seen on the APPQ which is serviced by the PSAPPSRV process, but applies to other server processes too.  Common causes include (but are not limited to):

SQL for Beginners : Videos and Articles

love-sqlI’ve been saying for some time I should do some more entry level content, but it’s been kind-of hard to motivate myself. I mostly write about things I’m learning or actively using, so going back and writing entry level content is not something that usually springs to mind.

Recently I’ve got involved in a number of “grumpy old man” conversations about the lack of SQL knowledge out there. That, combined with a few people at work getting re-skilled, prompted me to get off my ass and give it a go. It’s actually quite difficult trying to get yourself into the head-space of someone who is coming fresh to the subject. You don’t want to pitch it too low and sound patronizing, but then pitching it too high makes you sounds like an elitist dick.

Histogram Tip

I’ve just responded to the call for items for the “IOUG Quick Tips” booklet for 2015 – so it’s probably about time to post the quick tip that I put into the 2014 issue. It’s probably nothing new to most readers of the blog, but sometimes an old thing presented in a new way offers fresh insights or better comprehension.

Histogram Tips

A histogram, created in the right way, at the right time, and supported by the correct client-side code, can be a huge benefit to the optimizer; but if you don’t create and use them wisely they can easily become a source of inconsistent performance, and the automatic statistics gathering can introduce an undesirable overhead during the overnight batch. This note explains how you can create histograms very cheaply on the few columns where they are most likely to have a beneficial effect.