资料简介：

These events need to be analyzed and presented as reports to decision makers. Consider a

typical use case of generating aggregate information. For example:

• What were the sales of a product at various intervals (every 5 minutes, 15 minutes, 30

minutes, 1 hour, 24 hours, etc.)?

• Did the sales for a product increase in the day following the introduction of a promotion

scheme?

• How many hits did the page generate in the first 1 hour of being published?

• What are the key words associated with the user activity on our news website in the

last 5 seconds? Which ads do we show to this user based on this information?

The most common method of implementing such solutions is to collect the daily transactions

in a staging database and perform aggregations and other analytics operations in a batch

processing mode. The output of this batch processing system is then collected in a Data