SQL Server 2019 Cumulative Update 2: Bug Fixes and a Warning

UPDATE: Please hold on this update, as it can break the SQL Agent!!

Microsoft released SQL Server 2019 Cumulative Update 2 in February 2020, providing a range of bug fixes for the newest version of the software. While the first cumulative update for any new version of SQL Server is expected to be full of bugs, Cumulative Update 2 includes even more adventurous fixes.

The update addresses a range of issues, including corruption bugs. Accelerated Database Recovery, for example, was found to silently corrupt data. Microsoft issued a warning after the release of the update that it can break Agent, and the recommendation is to uninstall it.

Cumulative Update 2 also fixes server crashing bugs such as out-of-memory errors caused by memory accounting. There were also issues with SQL Server frequently crashing when running CHECKTABLE against a columnstore index.

Security bugs have also been addressed in the update, such as passwords appearing in clear text in audit logs and encryption failures with symmetric keys. Query crashing bugs, such as memory leaks due to scalar UDF inlining, were also resolved. The update also fixes issues with floating point exceptions when running a stored procedure, non-yielding scheduler when sorting on an NVARCHAR, and error when combining encryption with UNION queries.

Backup bugs were also addressed in the update. For example, SQL Server 2012 databases with nonclustered columnstore indexes could not be restored, and VSS backups could freeze IO and not resume it. Additionally, the log shipping agent could not log history or errors.

The update also included fixes for availability group bugs, such as Linux DAG not syncing after failover and contained AG master database deadlock. Partitioning bugs, including an error when running a query with a partition function and non-yielding scheduler if you do an online index rebuild on a non-partition-aligned index, were also addressed.

DMV bugs were also fixed in Cumulative Update 2. For example, users can now query sys.dm_exec_requests. The update also addresses issues with related services, such as the log reader not running and SSIS running slower in SQL Server 2019.

Memory-optimized TempDB also received fixes in the update, such as speeding up two more system tables. However, users cannot query TempDB DMVs after they set their isolation level.

While Microsoft has fixed many issues with SQL Server 2019 Cumulative Update 2, it’s important to note that serious bugs are still being found and fixed every 30 days. This update is a significant release for those running SQL Server 2019, even in a development environment. However, it’s important to remember why you don’t really want to jump on a brand new release within the first 60-90 days of it going live. There be serious danger here.

To download SQL 2019 CU2, visit the Microsoft website: https://support.microsoft.com/en-us/help/4548597/cumulative-update-2-for-sql-server-2019