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SQL Server Analysis Services Partitions €? Create And Manage [PORTABLE]



Partitions divide a table into logical parts. Each partition can then be processed (Refreshed) independent of other partitions. Partitions defined for a model during model authoring are duplicated in a deployed model. Once deployed, you can manage those partitions by using the Partitions dialog box in SQL Server Management Studio(SSMS), by using Tabular Model Scripting Language (TMSL), or programmatically with the Tabular Object Model (TOM).




SQL Server Analysis Services partitions – Create and Manage



By default, each table in a tabular model has one partition. Tasks in this section describe how to create and manage partitions in the model project's workspace database by using Partition Manager. After a model has been deployed (Azure Analysis Services, SSAS, Power BI), model database administrators can create and manage partitions in the deployed model by using SSMS or by script.


To create and manage partitions in Visual Studio, use Partition Manager. To view the Partitions Manager dialog box, click Extensions > Table > Partitions, or in Tabular Model Explorer, right-click a table, and then click Partitions.


To create and manage partitions for a deployed tabular model database, use the Partitions dialog box in SSMS. To open the Partitions dialog box, in SSMS, right-click a table, and then click Partitions.


Partitions are defined by the Partitions object in Tabular Model Scripting Language (TMSL). To create, copy, or delete partitions, execute a CreaterOrReplace, Create, Alter, or Delete command. To merge partitions, execute a MergePartitions command.


Granularity is influenced by various factors including how much data is required to be incrementally processed within an acceptable amount of time. For example, if only the last whole day needs to be processed daily, it may be beneficial to use daily granularity. Mixed granularity can be configured for scenarios such as near-real time refresh at low grain coupled with historical, static partitions at higher granularity. This results in fewer partitions, but also increases management overhead to ensure partition ranges are defined correctly.


When authoring models with the Tabular model designer in Visual Studio, you create new partitions, edit, merge, or delete partitions in the model workspace database by using Partition Manager. Depending on the compatibility level of the model you're authoring, Partition Manager provides two modes for selecting data to be included in a partition: For tabular 1400 and higher models with structured data sources, partitions are defined by using an Power Query M expression. For example, the following query defines a partition for the 2019 calendar year:


The Automated Partition Management for Analysis Services Tabular Models .pdf article, along with the accompanying AsPartitionProcessing code sample in GitHub provides both in-depth information and a solution example for the fictitious company, Advenure Works, by using the Tabular Object Model (TOM) to create and manage partitions. Concepts described in this article and project apply to all Analysis Services platforms.


A dedicated secondary database can store remote partitions for one and only one master database, but the master database can use multiple secondary databases, as long as all the secondary databases are on the same remote instance of SQL Server Analysis Services. Dimensions in a database dedicated to remote partitions are created as linked dimensions.


Two separate computers that are running an instance of SQL Server SQL Server Analysis Services are each required to create a remote partition arrangement that designates one computer as the primary server and the other computer as the secondary server.


The following procedure assumes that you have two server instances, with a cube database deployed on the primary server. For the purposes of this procedure, the cube database is referred to as db-master. The storage database containing remote partitions is referred to as db-storage.


Remote partitions can be merged only with other remote partitions. If you are using a combination of local and remote partitions, an alternative approach is to create new partitions that include the combined data, deleting the partitions you no longer use.


On the secondary server: In Solution Explorer, create a new data source pointing to the cube database, db-master. Use the provider Native OLE DB\Microsoft OLE DB Provider for Analysis Services 11.0.


On the primary server: Open the cube in Cube Designer and click Partitions tab. Expand the measure group. Click New Partition if the measure group is already configured for multiple partitions, or click the browse (. . ) button in the Source column to edit the existing partition.


Although databases dedicated to storage of remote partitions are not exposed to schema rowsets, applications that use Analysis Management Objects (AMO) can still discover a dedicated database by using the XML for Analysis Discover command. Any CREATE or DELETE command that is sent directly to a dedicated database by using a TCP or HTTP client will succeed, but the server will return a warning indicating that the action may damage this closely managed database.


Large datasets normally require table partitioning to accelerate and optimize the data-load process. Partitioning enables incremental loads, increases parallelization, and reduces memory consumption. The Tabular Object Model (TOM) serves as an API to create and manage partitions.


Partitions make it possible for you to create extremely large cubes. You can effectively create small, medium-sized, and even remarkably large cubes without using partitions. But partitions are useful when you need to create very large, enterprise-wide applications. For that reason, the ability to manage multiple partitions is available only with Microsoft SQL Server 2008 Enterprise Edition.


In this section, you will create three partitions in the AdventureWorks cube Reseller Sales measure group. One partition will contain data for CY 2011, another for CY 2010, and a final partition will contain data for all prior years. In the first procedure, you will modify the existing partition so that it contains the most current data, and then in the following procedure you will create two partitions to contain data from prior years.


Click Finish. The Reseller Sales measure group now contains two partitions. Notice that both partitions are using the 30 Percent AggregationDesign. In the next step, you will create one more partition that will contain the data from all prior years. Because this historical data will be queried less frequently than the more recent data, you can choose to have fewer aggregations. With fewer aggregations, the partition can be processed more quickly and will use less storage space.


Because the partitions have been merged in SQL Server Management Studio, the AdventureWorks SSAS database that is deployed on the Analysis Services server is no longer synchronized with the solution that is currently open in BIDS. Whenever changes are made to an Analysis Services database in SSMS, you should import those design changes into a new project in BIDS. Then use the new project for any future design changes that will be deployed back to the Analysis Services server.


In this chapter, you learned that Analysis Services has three storage modes: ROLAP, HOLAP, and MOLAP. ROLAP mode leaves dimension, detail, and aggregate data in the source relational database; MOLAP stores dimension, detail, and aggregate data in proprietary data structures on the Analysis Services server; and HOLAP leaves detail data in the source relational database and stores aggregate data on the Analysis Services server. Cube data is stored in measure group partitions. A measure group can have multiple partitions. Partitions in a measure group can have different storage modes and can use different aggregation designs. You can add, delete, or merge the partitions in a measure group.


By following these specifications, anyone can create a model and communicate with the backend server without using an existing tool. There is nothing stopping someone from creating an application that runs on operating systems other than Windows. However, creating the communication stack that implements the technical specifications is a large investment.


If you create a model in Power BI Desktop, the only way to manage partitions is through the Incremental Refresh feature. Power BI Desktop does not provide any control over the partitions. Once the model is published, it is possible to manage partitions using SQL Server Management Studio (SSMS) or by creating a PowerShell script using the TOM libraries.


Thus, though Microsoft is going to address the lack of tools for entreprise-level models, it is a long-term plan that does not affect developers who manage large and complex Power BI and Analysis Services models in 2021 and 2022. However, Microsoft provides the support (libraries and documentation) required to create third-party tools that fill the gap.


I've managed to create an automated script that generates the XMLA query of creating the partitions in SSMS, I'm executing it and I can see the partitions being created, However when returning to SSDT and opening the solution these partitions are not reflected there. is there a way to "force" SSDT to read the meta data from the analysis services instance upon opening the solution again?


As userfl89 already pointed out, any partitions that you create in SSMS need to be "backported" into your SSDT project, for example by using the "Import From Server (Tabular)" option when creating a new project. Otherwise, you risk losing the partitions (and the data contained in them) when deploying from SSDT.


The database that you're accessing in SSDT is your workspace database. The workspace database is essentially a local copy of the tabular model. The partitions you added to the model in SSMS were created, the workspace database is just out of sync. Your can overwrite your workspace database with the current version of the model by deleting/moving the files used in your local SSAS project, then creating a new Analysis Services project in SSDT and using the "Import From Server (Tabular)" option, then selecting the current version of the tabular model. This will create a new workspace database using the current version of the model. When doing this, make sure that when you delete or move the files from your local SSAS project, the files you move are for your local project, not the actual model. If you need to verify the location of the files used by the model, the DataDir property of the SSAS instance in SSMS will show this file path.


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