Author Archives

Easy – Oops.

A question came up on OTN today asking for suggestions on how to enforce uniqueness on a pair of columns only when the second column was not null. There’s an easy and obvious solution – but I decided to clone the OP’s example and check that I’d typed my definition up before posting it; and the […]

Tweaking

The following question came up on OTN recently: Which one gives better performance? Could please explain. 1) nvl( my_column, ‘N’) <> ‘Y’ 2) nvl( my_column, ‘N’) = ‘N’ It’s a question that can lead to a good 20 minute discussion – if you were in some sort of development environment and had a fairly free hand […]

Tweaking

The following question came up on OTN recently: Which one gives better performance? Could please explain. 1) nvl( my_column, ‘N’) <> ‘Y’ 2) nvl( my_column, ‘N’) = ‘N’ It’s a question that can lead to a good 20 minute discussion – if you were in some sort of development environment and had a fairly free hand […]

Juggernaut

One of the problems of “knowing” so much about Oracle is that the more you know the more you have to check on each new release of the software. An incoming ping on my posting “Lock Horror” reminded me that I was writing about 11.2.0.1, and the terminal release is 11.2.0.4, and the whole thing may have […]

Juggernaut

One of the problems of “knowing” so much about Oracle is that the more you know the more you have to check on each new release of the software. An incoming ping on my posting “Lock Horror” reminded me that I was writing about 11.2.0.1, and the terminal release is 11.2.0.4, and the whole thing may have […]

Diagnostics

Here’s a little test you might want to try. Examine the following script, and decide what sort of symptoms you would see in the AWR report. I don’t need anyone to tell me their results – but if your predictions and the actual results match then you can give yourself a pat on the head. […]

Diagnostics

Here’s a little test you might want to try. Examine the following script, and decide what sort of symptoms you would see in the AWR report. I don’t need anyone to tell me their results – but if your predictions and the actual results match then you can give yourself a pat on the head. […]