Big data (big data), is a collection of data that cannot be captured, managed, and processed with conventional tools within an affordable time frame. Its 4 basic characteristics are:

Large data volumes, terabytes, petabytes, and even petabytes of data need to be analyzed and processed.

2. Requirements for rapid response, the market is changing rapidly, requiring a timely and rapid response to changes, that the analysis of data should also be fast, there are higher requirements in the performance, so the amount of data appears to be some of the speed of the requirements of the "big".

3. Data diversity: different data sources, more and more unstructured data, the need for cleaning, organizing, screening and other operations, into structured data.

4. Low value density, due to untimely data collection, incomplete data samples, data may not be continuous, etc., the data may be distorted, but when the amount of data reaches a certain size, more data can be used to achieve a more realistic and comprehensive feedback.