Sitecore 9 Data flow – Part 2 – Collect and Store

In this post you will find a useful information about sitecore process of gathering information and storing it, all the details you need, the tracker, contact, interactions and the different servers roles involved in this process.

Before you start reading this post I recommend you to check the following first:

• Sitecore 9 Data flow – Part 1– Introduction

Image Courtesy to jammykam

The process of collecting information starts on CD website, where the tracker sub system exist, once a visit occur to the website a session will be created, this session will contains a contact and interactions, the tracker will keep track of visitor actions on the website and store these actions into the session.

The contact and interaction in the session has facets which is the information that the system want to store about the current visit, notice that the ability of adding custom facets is possible, facets could be email address, physical address, position or any other information you want the system to collect about the visits you get.

The tracker will use the reference data database to enrich the facets by using the meta data that the reference database store, a good question here will be:

What is the Reference data Database and Reference Data Service?

Reference data database is used to store the meta data or definition for the data items that been used by Sitecore experience platform, as example Goals, events and outcomes. While the Reference data service give you the ability to use the reference data client API to create or retrieve reference data.

Following is a list of the tables in the reference data database:

1. DefinitionCultures
2. DefinitionMonikers
3. Definitions
4. DefinitionTypes

Following is a screenshot:

OK, The data in the session, When the data will be saved to Database?

On the session end the data will be sent to xDB collection role which in turns store the data into xDB collection database, Following are two important information that you need to know:

1. because of the high traffic that can exist against the xDB collection role, Sitecore made this service role scale-able to handle the increase of read/write operation.
2. Sitecore made the xDB collection database scale-able by using Database Sharding,  which handle the following limitation:
1. Storage Space
2. computing resources 
3. Network Bandwidth
4. Geography

If you want to know more about Sharding, click here

Sitecore installation is defaulted into 2 shards as you can see from the following screenshot, this of course can be configured from within the xConnect .json configuration for xp0 installation.

I hope the above will help you understand how sitecore collect and store data in start of the data low process. let me know by comments if you have any questions. next will talk about processing and aggregation, stay tuned!