What's New in SQL Server Analysis Services

APPLIES TO: yesSQL Server Analysis Services (2016 and later) noAzure Analysis Services noPower BI Premium

This article summarizes new features and improvements in the most recent versions of SQL Server Analysis Services (SSAS). New features and improvements are cumulative.

SQL Server 2019 Analysis Services

Tabular model compatibility level

This release introduces the 1500 compatibility level for tabular models.

Query interleaving

Query interleaving is a tabular mode system configuration that can improve user query response times in high-concurrency scenarios. Query interleaving with short query bias allows concurrent queries to share CPU resources. To learn more, see Query interleaving.

Calculation groups in tabular models

Calculation groups can significantly reduce the number of redundant measures by grouping common measure expressions as calculation items. Calculation groups are shown in reporting clients as a table with a single column. Each value in the column represents a reusable calculation, or calculation item, that can be applied to any of the measures. A calculation group can have any number of calculation items. Each calculation item is defined by a DAX expression. To learn more, see Calculation groups.

Governance setting for Power BI cache refreshes

The ClientCacheRefreshPolicy property setting is now supported in SSAS 2019 and later. This property setting is already available for Azure Analysis Services. The Power BI service caches dashboard tile data and report data for initial load of Live Connect report, causing an excessive number of cache queries being submitted to the engine, and in extreme cases overload the server. The ClientCacheRefreshPolicyproperty allows you to override this behavior at the server level. To learn more, see General Properties.

Online attach

This feature provides the ability to attach a tabular model as an online operation. Online attach can be used for synchronization of read-only replicas in on-premises query scale-out environments. To perform an online-attach operation, use the AllowOverwrite option of the Attach XMLA command.

xml
<Attach xmlns="http://schemas.microsoft.com/analysisservices/2003/engine"> 
  <Folder>C:\Program Files\Microsoft SQL Server\MSAS15\OLAP\Data\AdventureWorks.0.db\</Folder> 
  <AllowOverwrite>True</AllowOverwrite> 
</Attach>

This operation may require double the model memory to keep the old version online while loading the new version.

A typical usage pattern could be as follows:

  1. DB1 (version 1) is already attached on read-only server B.

  2. DB1 (version 2) is processed on the write server A.

  3. DB1 (version 2) is detached and placed on a location accessible to server B (either via a shared location, or using robocopy, etc.).

  4. The command with AllowOverwrite=True is executed on server B with the new location of DB1 (version 2).