When writing a query with order by, we can use the column position instead of its name. This order by”trick” is easy to use, but should be handled carefully as it affects the order of rows if the column list changes.
The internet is full of information about indexes, and for a reason. Indexes in a database is probably the most important performance related topic. There are so many cases, properties, and different ways to use indexes that there is simply a lot to write about. In this post I’d like to talk about a specific use case that I’ve seen a few times, and is related to index scans and performance.
When user A creates a procedure and grants execute permissions to user B, user B can execute the procedure (obviously), but he can also see the code (in ALL_SOURCE view).
Databases are designed to hold data and retrieve it, so they are optimized to run queries. Over the years I’ve seen quite a few cases where the developers did things on the application side that could be easily done on the database side, and almost every time moving it to the database improved the performance. And I’m not talking about the business logic or the “application layer”, but the data access, which is the thing that the database is build for.
If you’ve read my post about 12.2 new features and liked it, you will like this one as well. I’ve recently looked at presentations from OOW16, and found one by Keith Laker from Oracle. Keith, as principal PM for analytic SQL, talked about DWH features in 12.2, and they are great.
I’d like to thanks Keith for uploading the presentation. I will review some of the feature from the presentation, and will only mention the them without a deep explanation. There is a link to the original presentation below.
Lately I wrote a post about 12.2 new features. In the post I didn’t list sharding (probably one of the biggest features in this version), as I wanted to dedicate an entire post for it. In this post I will cover this option , but please note, as 12.2 is only released for the cloud and no one can install it and play with it, all the information is based on presentations I’ve seen at OOW and a chat I had with one of the developers in the demo ground. There might be some inaccuracies or mistakes in the post.
As you know, Oracle Open World is over (for me at least), and one of the major topics there was Oracle 12cR2 (or 12.2). It looks like a really cool version, the downside is that is currently available on Oracle cloud only. We are all waiting for the on-premise release so we can install and play with it.