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As a SQL Server Reporting Services (SSRS) developer or administrator, one of your challenges could be optimizing report performance. Two useful features to help with this are report caching and snapshots. Both aim to minimize the time it takes to generate a report, but they achieve it in different ways. Report caching generates and stores a temporary copy of a processed report, while snapshots save a report's layout and query results at a specific point in time.

Report caching in SSRS is a feature that can be used to improve the performance of your reports. Once a report is executed, the results are stored in a cache on the report server. The next time the report is requested, SSRS retrieves the cached copy, rather than re-executing the report's query against the database. This is particularly beneficial when you have reports that deal with large amounts of data and are frequently accessed by users.

-- T-SQL code to enable caching

USE ReportServer

GO

EXEC SetCacheOptions @ReportPath = '/AdventureWorks Sample Reports/Sales Order Detail',

@CacheOptions = 1, -- 1 for Cache, 0 for Do Not Cache

@CacheExpirationMinutes = 30 -- Cache duration

Snapshots, on the other hand, store a report's layout and data at a specific point in time. This is useful for reports that take a long time to process due to complex calculations or large data volumes. With snapshots, you do not need to rerun the report for each new viewer; instead, all users see the same data. Snapshots also help you manage report server resources by scheduling large reports to run during off-peak hours.

-- T-SQL code to create a snapshot

USE ReportServer

GO

EXEC CreateSnapshot @ReportPath = '/AdventureWorks Sample Reports/Sales Order Detail'

These features are not exclusive to SQL Server 2019. If you are working with MySQL 8.0, DB2 11.5, Azure SQL, or Azure Synapse, similar functionality can be achieved. In MySQL, query caching can be enabled to store the result of a SELECT statement in the cache, so subsequent identical SELECTs can be retrieved faster. For DB2, the equivalent of snapshots is known as materialized query tables, which store the results of a query and can be refreshed at specific intervals.

In the Azure ecosystem, Azure SQL Database provides an automatic tuning feature that includes the intelligent query processing capabilities of SQL Server 2019. In Azure Synapse Analytics, you can use materialized views, which are similar to snapshots, to store the results of complex queries and hence improve the performance of analytic workloads.

In conclusion, SSRS report caching and snapshots are powerful tools for optimizing report performance. By understanding when and how to use each feature, you can provide a better experience for your report users and more efficiently use your server resources. Whether you are using SQL Server, MySQL, DB2, or Azure-based databases, these features or their equivalents can help you deliver fast, consistent, and reliable reports.