STEP by STEP : Qlik Sense Architecture

 

Qlik Sense Architecture Diagram

+---------------------------------------------------+
|                    User Layer                    |
|                                                   |
|    +-----------+    +-----------------------+     |
|    | Qlik Sense |<-->| Web Browser / Qlik Hub|     |
|    | Hub (UI)   |    | (Client-Side Interaction)|
|    +-----------+    +-----------------------+     |
|                                                   |
+---------------------------------------------------+
            |             |
            | REST APIs    |   (For Authentication, Session, Data, etc.)
            |             |
            v             v
+---------------------------------------------------+
|                Proxy Server (QPS)                |
|   - Handles user authentication and sessions     |
|   - Manages load balancing between Qlik nodes     |
+---------------------------------------------------+
            |
            v
+---------------------------------------------------+
|                Repository Service (QRS)           |
|   - Stores app metadata, configurations, and     |
|     security rules.                              |
|   - Responsible for app management.              |
+---------------------------------------------------+
            |
            v
+---------------------------------------------------+
|                Engine (QES - Qlik Engine)         |
|   - In-memory calculations (Associative Model)   |
|   - Processes selections and updates on-the-fly  |
|   - Loads data (QVDs) and manages data models     |
+---------------------------------------------------+
            |
            v
+---------------------------------------------------+
|               Data Layer (QVDs)                  |
|   - Optimized Qlik Data files for fast reloads   |
|   - Stores processed, transformed data           |
+---------------------------------------------------+
            |
            v
+---------------------------------------------------+
|              External Data Sources               |
|   - Databases, APIs, Excel, Web Connectors        |
|   - Extracted, transformed, and loaded into Qlik  |
|     via the Data Load Script                     |
+---------------------------------------------------+

---

Explanation of the Components:

1. User Layer (Qlik Hub)

   • This is where the user interacts with Qlik Sense. Users access apps, interact with visualizations, and make selections.

   • Everything in the Hub happens client-side (browser).

2. Proxy Server (QPS)

   • The proxy is responsible for authentication and session handling. It manages communication between the User Layer (Qlik Sense Hub) and the Engine.

   • It also load-balances user requests if multiple Qlik nodes are available.

3. Repository Service (QRS)

   • The Qlik Repository Service stores metadata about apps, security rules, and other configuration data.

   • It also handles tasks like user permissions and app management.

4. Qlik Engine (QES)

   • The Qlik Engine is the brain of the Qlik Sense platform. It handles:

     • In-memory calculations (e.g., aggregations, filtering).

     • Data modeling based on the Associative Model.

     • Selection evaluations (green-white-grey logic).

   • It is the core engine that performs operations when users make selections or interact with the app.

5. Data Layer (QVDs)

   • QVD (Qlik View Data) files are optimized data files used for fast data reloads. These files store data that has been pre-processed by the ETL (Extract, Transform, Load) scripts.

   • Qlik Sense uses QVDs to quickly load and use data in-memory.

6. External Data Sources

   • Qlik pulls data from various external sources (e.g., databases, flat files, APIs).

   • The data is loaded, transformed, and stored in QVDs via Data Load Scripts.

---

How Data Flows:

1. User Request: A user makes a request via the Qlik Sense Hub (e.g., opening an app, making a selection).

2. Authentication: The request passes through the Proxy Server, which authenticates the user.

3. App Data: The Qlik Engine retrieves data from the QVDs or directly from external data sources if required.

4. In-Memory Calculation: The Qlik Engine performs any necessary calculations (using the Associative Model).

5. Data Update: The results are sent back to the Hub and presented to the user in real-time.