AW-argh
This is another of the blog notes that have been sitting around for several years – in this case since May 2014, based on a script I wrote a year earlier. It makes an important point about...
View ArticleDrop Column bug
When I was a child I could get lost for hours in an encyclopedia because I’d be looking for one topic, and something in it would make me want to read another, and another, and …The same thing happens...
View ArticleRecursive WITH upgrade
There’s a notable change in the way the optimizer does cost and cardinality calculations for recursive subquery factoring that may make some of your execution plans change – with a massive impact on...
View ArticleMassive Deletes
One of the recurrent questions on the Oracle Developer Commuity forum is:What’s the best way to delete millions of rows from a table?There are an enormous number of relevant details that you need to...
View ArticleCase and Aggregate bug
The following description of a bug appeared on the Oracle Developer Community forum a little while ago – on an upgrade from 12c to 19c a query starting producing the wrong results on a simple call to...
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Upgrades : You have to do them. When are you going to learn? (TLSv1.2)
Questions:Do you remember when SSLv3 was a thing?Do you remember when everyone disabled SSLv3 on their websites?Do you remember how loads of people running Oracle database version 11.2.0.2 and lower...
View ArticleUpgrade trivia
Sometimes it’s the little things that catch you out (perhaps only briefly) on an upgrade. Here’s one that came up on Oracle’s Groundbreakers Developers Community [sic] (who knows what it will be called...
View Article19c tweak
There are times when an upgrade makes a big difference to performance because an enhancement to the optimizer code path changes the costing of a plan that was always possible, but badly costed. I...
View ArticlePivot upgrade
I’ve hardly ever touched the pivot/unpivot feature in SQL, but a recent comment by Jason Bucata on a note I’d written about Java names and the effects of newer versions of Oracle allowing longer object...
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Oracle Database Upgrades : One Size Does Not Fit All
If you follow me on Twitter, you’ll know I’ve been doing a lot of upgrades recently. Whenever I mention upgrades, someone comes back with a comment asking me to describe in detail what I’ve done. This...
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