Tag Archives: Database
Over the last few years there has been a rapid surge in the adoption of smart devices. Everything from phones and tablets, to smart meters and fitness devices, can connect to the Internet and share data. You only have to … Continue reading
If you are on Exadata or taking advantage of Database In-Memory it’s possible your queries will benefit for the automatically created and maintained Storage Indexes.
But what exactly are Storage Indexes and why don’t I always see a benefit from them?
Let me start by describing what Storage Indexes are in relation to Database In-Memory but remember they behavior in exactly the same way on the Exadata storage cell.
A Storage Index keeps track of minimum and maximum values for each column in an In-Memory Compression Unit (IMCU) or 1MB chunk on the Exadata storage cells. When a query specifies a WHERE clause predicate, the In-Memory Storage Index on the referenced column(s) is examined to determine if any entries with the specified value exist. Continue reading
A little over a year ago Connor McDonald and Chris Saxon took over answering questions posted on AskTom, which covers many topics related to building applications on top of the Oracle Database. Connor and Chris have done an amazing job of keeping up with the constant influx of questions, … Continue reading
Although there have been a number of significant changes to the Oracle Database in 12c, some of my favorite new features are actually the small enhancements, designed to make your life a little easier. So, I decided to spend some time this year sharing the details on these small but extremely useful features.
One such enhancement is Online Statistics Gathering.
Whenever an index is created, Oracle automatically gathers optimizer statistics for that index. The database piggybacks the statistics gather on the full data scan and sort operation necessary for the index creation. This approach has worked so well since it was introduced in 9i, few people even realize it’s happening. Continue reading