Category Archives: Oracle Internals

This category list all articles about internal functionnalites of oracle, optimizer, statistics, internal components of the Oracle database

Information Lifecycle Management

Presentation of Information Lifecycle Management (ILM)

With data volume growing, finding adapted storage solutions to storage costs and performance objectives is a real challenge for IT department in large companies.
Information Lifecycle management is about managing the data all along its useful life while offering the best performance and storage cost.
The concept is simple, data is spread into multiple storage tiers, each one with specific properties. According to this, you can keep active data on fast storage devices and inactive or less active data compressed or into cheap storage devices or offline storage (tape for example).

Information LifeCycle Management


As you can see in previous diagram, storage tiers are classed by usage, these data classes are definied in the database using partitions. The only thing missing here is the way to manage where and when to move the data.

Oracle 12c offers a new tool to achieve this objective. Continue reading Information Lifecycle Management

Result Cache concept and benefits

This feature was first introduced in Oracle 11g and was meant to increase performance of repetitive queries returning the same data.
The Result Cache feature is interesting if your application always look for static data, or data that is rarely updated, for these reasons, it is firstly destinated to Data Warehouses databases (OLAP) as many users will look for the same data via reporting tools.
This is particularly useful when you query a large amount of data to return only a few rows, for example, the last month sales aggregated by week.
Oracle will have to look for a large amount of data to retrieve all sales and make the aggregate, but the result will be only 4 rows.
For the first query execution, the runtime will be standard but for the subsequent queries, it will be very fast.
This cache is part of the shared pool.

Result Cache
Continue reading Result Cache concept and benefits