dbi services Blog
Welcome to the dbi services Blog! This IT blog focuses on database, middleware, and OS technologies such as Oracle, Microsoft SQL Server & SharePoint, EMC Documentum, MySQL, PostgreSQL, Sybase, Unix/Linux, etc. The dbi services blog represents the view of our consultants, not necessarily that of dbi services. Feel free to comment on our blog postings.
I'm currently following the session 'Real-World Performance of Star and Snowflake Schemas' with Michael Hallas, Andrew Holdsworth, John Clarke. It's really a good presentation. the Real Performance team tries to spread messages about how to design for performance. But today I'll not blog about what I've seen but about what I've not seen. Everybody talks about those nice 12c features that are useful in BI workloads, such as adaptive joins, adaptive parallel distribution, vector 'in-memory' aggregation, etc. Nobody talks about Adaptive Bitmap Pruning.
The basic issue is that when the delete occurs, a redo entry is generated for each row that is deleted and then Dbvisit replicate generates an update statement to do the same on the target. But when there are duplicates the first statement will affect several rows and the next statement will affect no rows.
Today, in this post I will describe some best practices I learned in several sessions. It's always good to see what is adviced by other people that are confronting to other or same challenges.
Landing on Sunday 28th, after a 13 hours' trip my colleague Franck Pachot and I had just the time to do the registration, go to the hotel, and go back to the "Welcome Reception" where we could eat something. After a night where I could feel the jet lag :-) we where ready to "participate" in this amazing event, the Oracle Open World 2014.
The new D2-Client does not correctly display the icon for some formats. This usually happens when the icon.css is not up to date based on the content format in the repository. The solution is to find these formats and update the icon.css.
A thread on OTN Forum about Exadata came to the following question: "But how can I monitor if it is effectively used or not?". This is a common question. There are 3 exclusive features coming with Exadata, and instance statistics can show their usage. Even better: two of them can even be checked on your current (non-Exadata) system. And that is good to foresee how Exadata can improve your workload.
When you learn about SQL Server, you will often hear that a commit transaction is a synchronous operation and that you can trust it. In this blog post, I will provide some details about what we mean by synchronous behavior. The reason is that sometimes, when I talk about the new delayed durability feature provided by SQL Server 2014, there are some confusions. If you want more details on this new feature, please read the blog post of my colleague Stéphane Haby here. A quick shortcut is often the following: writing to the transaction log is synchronous, while writing with the new delayed durability feature is asynchronous.