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Tuesday, February 9, 2021

Tableau Server

 88.Describe the Tableau Architecture?

 Source Tableau Server has a highly scalable, n-tier client-server architecture that serves mobile clients, web clients, and desktop-installed software. Each of the components is explained below.


 89.Data Layer:

 One of the fundamental characteristics of Tableau is that it supports your choice of data architecture. Tableau does not require your data to be stored in any single system, proprietary or otherwise. Most organizations have a heterogeneous data environment: data warehouses live alongside databases, whether on premise or in the cloud. Cubes and flat files like Excel are still very much in use. Tableau can work with all of these simultaneously. 


 90.Data Connectors:

 Tableau includes over 40 optimized data connectors for data sources such as Microsoft Excel, SQL Server, Google BigQuery, Amazon Redshift, Oracle, SAP HANA, Salesforce.com, Teradata, Vertica, Cloudera and Hadoop. There is also a generic ODBC connector for any systems without a native connector. 

Tableau provides two modes for interacting with data: live connection or in-memory. Users can switch between a live and in-memory connection as they choose.


91.Live connection:

 Tableau’s data connectors leverage your existing data infrastructure by sending dynamic SQL or MDX statements directly to the source database rather than importing all the data. This means that if you’ve invested in a fast, analytics-optimized database like Vertica, you can gain the benefits of that investment by connecting live to your data. This leaves the detail data in the source system and sends the aggregate results of queries to Tableau.


 92.In-memory: 

Tableau offers a fast, 64-bit ready, columnar in-memory Data Engine that is optimized for analytics. You can connect to your data and then, with one click, extract your data to bring it in-memory to perform queries in Tableau up to 100x faster. Tableau’s Data Engine fully utilizes your entire system to achieve fast query response on hundreds of millions of rows of data on commodity hardware. Tableau Server Main Components: The work of Tableau Server is handled with the following four server processes:


 93.Application Server: 

Application Server processes (wgserver.exe) handle content browsing, server administration and permissions for the Tableau Server web and mobile interfaces. When a user opens a view in a client device, that user starts a session (workgroup_session_id) on Tableau Server. The default timeout for this session is easily configuration by an administrator. 


94.VizQL Server:

 Once the user is authenticated via the application server, the user can open a view. The client sends a request to the VizQL process (vizqlserver.exe). The VizQL process then sends queries directly to the data source, returning a result set that is rendered as images and presented to the user. In many cases, Tableau Server leverages client-side rendering and caching to reduce the load on the server.


95.Data Server:

 Unlike traditional approaches to meta data management, the Tableau Data Server is a key component that allows IT administrators to enable monitoring, meta data management and control for IT, while enabling self-service analytics for business users. It lets you centrally manage and store Tableau data sources and provides end users with secure access to trusted data in a self-service analytics deployment. 


96.Backgrounder: 

The backgrounder refreshes scheduled extracts, delivers notifications and manages other background tasks. The backgrounder is designed to consume as much CPU as is available so as to finish the background activity as quickly as possible. 


97.Gateway/ Load Balancer: 

The Gateway routes requests to other components. Requests that come in from the client first hit an external load balancer, if one is configured, or the gateway and are routed to the appropriate process. In the absence of an external load balancer, if multiple processes are configured for any component, the Gateway will act as a load balancer and distribute the requests to the processes.


 98.Clients: Web Browsers and Mobile Apps

 Tableau Server provides interactive dashboards to users via zero-footprint HTML5 in a web or mobile browser, or natively via a mobile app.


 99.Tableau Desktop

 Tableau Desktop is the rapid-fire business analytics authoring environment used to create and publish views, reports and dashboards to Tableau Server. Using Tableau Desktop, a report author can connect to multiple data sources, explore relationships, create dashboards, modify metadata, and finally publish a completed workbook or data source to Tableau Server

 Read more from this whitepaper. 


100. What are the different data security levels?

 Tableau provides several ways for you to control which users can see which data. For data sources that connect to live databases, you can also control whether users are prompted to provide database credentials when they click a published view. The following three options works together to achieve different results:

Database login account: When you create a data source that connects to a live database, you choose between authenticating to the database through Windows NT or through the database’s built-in security mechanism.

 Authentication mode: When you publish a data source or a workbook with a live database connection, you can choose an Authentication mode. Which modes are available depends on what you choose above. 

User filters: You can set filters in a workbook or data source that control which data a person sees in a published view, based on their Tableau Server login account. Read more here


101. What is Authentication on Server?

 Authorization refers to how and what users are allowed to do with content hosted on Tableau Server (including projects, sites, workbooks, data sources) after authentication has been verified. These actions are determined by a combination of the user's site role and permissions associated with content. 


102. What are different site roles we can assign to a user?

 Site roles are permission sets that are assigned to a user, such as System Administrator, Publisher, or Viewer. The site roles define collections of capabilities (delete, save, view, and others) that can be granted to users or groups on Tableau Server. 

General capabilities allowed with each site role

  • Server Administrator: The server administrator has full access to all servers and site functionality, all content on the server, and all users.
  •  Site Administrator: Site administrators can manage groups, projects, workbooks, and data sources for the site.
  •  Publisher: Publishers can sign in, interact with published views and publish dashboards to Tableau server from the desktop. 
  •  Interactor: Interactors can sign in, browse the server, and interact with the published views, but are not allowed to publish to the server.
  •  Viewer: Viewers can sign in and see published views on the server but cannot use any interaction features like filtering and sorting
  •  Unlicensed: Unlicensed users cannot sign in to the server. Users are assigned this role when licenses are not available.
103. What are permissions and how can we set them on various resources?

 Permissions determine whether a given user is allowed or denied to perform a specific action on a specific resource. 

There are six areas where permissions can be set:

 Site: Sites are at the top of the content hierarchy and provide a way to partition your server into separate environments for users. Each site is administered separately and has its own Groups, Users, Projects, Workbooks and Data Sources.

 Project: Projects exist within Sites, and are also used to separate content in the server and typically used to split content into logical groupings, for example around department or function etc.

 Group: Groups are collections of Users within a site. They help to organize and manage sets of users for administration purposes.

 User: Users are the individual named users accessing a Site. Every user added to Tableau Server must have an associated site role. The site role determines the levels of permissions allowed for a user, including whether a user can publish, interact with, or only view content published to the server. 

Workbook: Workbooks use the default permissions from their project. Unless permissions are locked, the publisher of the dashboard has final control over who sees their data when it is published. 

Data Source: Similar to Workbooks, Data Source permissions can be determined by either the Publisher, if publishing to an unlocked project, or by the project permissions, if publishing a data source to a locked project. 

104. Why do you publish a data sources and workbooks? 

Suppose you create a view that exposes a new range of questions in the data you’re using, and you want to share this analysis with other people using this data. Or maybe you are your team’s Data Steward, in charge of building the data models approved for use by analysts, and meeting your organization’s requirements for security, compliance, performance, and so on.
 You can share your work with the rest of your team by publishing it to Tableau Server or Tableau Online. After it’s published, you and your team can access it through your web browser or the Tableau mobile app. Publishing data sources can also help you to centralize data management.

 105. What are the Best Practices for Published Data Sources

 Publishing data sources to Tableau Online or Tableau Server is integral to maintaining a single source for your data. Publishing also enables sharing data among colleagues; including those who don’t use Tableau Desktop but have permission to edit workbooks in the web editing environment. 
Updates to a published data source flow to all connected workbooks, whether the workbooks themselves are published or not. Read more he

106. What makes up a published data source 

The data connection information that describes what data you want to bring in to Tableau for analysis. When you connect to the data in Tableau Desktop, you can create joins, including joins between tables from different data types. You can rename fields on the Data Source page to be more descriptive for the people who work with your published data source.

 An extract, if you decide to create one. Guidelines for when to create an extract are included below, as well as in the additional resources. 

Information about how to access or refresh the data. The connection also includes access information. 

107. How can you schedule the Reports in tableau? 

When you publish workbooks that connect to extracts you can schedule the extracts to be refreshed automatically. That way you don't have to republish the workbook every time the underlying data is updated and you can still get the performance of a data extract.
 This increases performance and avoids queries to the live database. Then you can add that workbook to a schedule so that the extract is refreshed at regular intervals with updated data from the data warehouse. 
Schedules are created and managed on the server by an administrator. However, an administrator can allow you to add a workbook to a schedule when you are publishing from Tableau Desktop.
 
1. As you are publishing a workbook, in the Publish Workbook to Tableau Server dialog box, click Scheduling & Authentication.

 2. In the Scheduling & Authentication dialog box, select a schedule for the workbook: All data sources that require authentication must have an embedded password so that the extract can be refreshed. This includes data sources that are not extracts 

108. What is Hyper?

 Hyper is a high-performance in-memory data engine technology that helps customers analyze large or complex data sets faster, by efficiently evaluating analytical queries directly in the transactional database. A core Tableau platform technology, Hyper uses proprietary dynamic code generation and cutting-edge parallelism techniques to achieve fast performance for extract creation and query execution. 

With Hyper, transactions and analytical queries are processed on the same column store, with no postprocessing needed after data ingestion. This reduces stale data and minimizes the connection gap between specialized systems. Hyper's unique approach allows a true combination of read-and write-heavy workloads in a single system. This means you can have fast extract creation without sacrificing fast query performance. 

109. What are the performance benefits of Hyper?

 Starting in 10.5, Hyper technology is integrated with Tableau Data Engine to give you the following key benefits:

 Faster extract creation: With Hyper technology, extracts are generated almost as fast as the source system can deliver data, no sorting needed. 

Support for larger extracts: Prior to this release, you might have not been able to get all your data into a single extract.With the new Hyper technology, much larger amounts of data can be included in a single extract. 

Faster analysis of extracts: In many cases you will see faster querying of data for larger extracts, or workbooks with complex calculations.

 Hyper technology is memory-optimized. This means that when needed, all data lives in memory. This results in fast data access times.

 Hyper is a compiling query engine. Queries are either interpreted or compiled to the machine code for maximum performance and allowing the Data Engine to get most performance out of modern hardware (CPU, large main-memory capacities). Read more here.

110. What is VizQL?

 At the heart of Tableau is a proprietary technology that makes interactive data visualization an integral part of understanding data. A traditional analysis tool forces you to analyze data in rows and columns, choose a subset of your data to present, organize that data into a table, then create a chart from that table.

 VizQL skips those steps and creates a visual representation of your data right away, giving you visual feedback as you analyze. As a result, you get a much deeper understanding of your data and can work much faster than conventional methods–up to 100 times faster.

 111. Where can we find Tableau Repository?

 Tableau Repository will be found under the “Documents” It contains number of folders. It will be automatically created while we install Tableau in our system. Those folders contain logs, where every hit of Tableau will be recorded in the form of logs in the notepad files also it contains some of the information like map sources, Bookmarks, etc. 

112. What is an increment refresh and full refresh? 

Incremental refresh and Full refresh are the classification of scheduling. Incremental refresh will refresh only the incremental records of data during refresh in scheduling whereas the full refresh will refresh the full data during refresh in scheduling.