John Watson's blog

12.2 upgrade - it can break all your outgoing https calls

Do you know about multiple domain certificates? If not you may have to learn quickly, because Oracle has changed the way they are handled in release 12.2. This is going to break a lot of applications.

Upgrading to 12.2 ? Make sure you won't break JSON


Will upgrade from 12.1 to 12.2 break your applications? It may if your developers are using JSON.

Tuning with equivalent SQLs - a little challenge


I am fascinated by what I call "equal SQL": statements that are equivalent, in that they deliver the same result but may have hugely different performance characteristics. Here's a little case study.

Compression test, 12cR2


Just how effective is Hybrid Columnar Compression? This test shows that HCC is impressive, but that thought needs to be put into choice of compression algorithm.

12cR2 lots of new instance parameters


Comparing database 12cR1 release to 12cR2 release, I see these new parameters:

12cR2 new feature: online table move


Move a table without locks and without breaking indexes. That's pretty cool.

Is row-by-row processing really slow-by-slow? Emphatically: YES


Developers who come to Oracle with a background in procedural languages sometimes do not understand how efficient SQL's set oriented processing can be. This little demonstration should convince them: never use PL/SQL when SQL will do.

How to change column order when using SELECT *


We all know that using SELECT * is bad programming. One reason is that you cannot control the order in which columns are returned. Well, you can in release 12c.

Oracle 12cR2 - the next release, cloud only?


We are all waiting for database release 12.2 - but you won't get it on your own hardware.

How indexes can degrade performance


Indexes may improve the performance of SELECT statements, but what about DML? This simple demo shows how bad they can be.


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