KB5033688: Cumulative update for SQL Server 2019, CU branch, February 2024. Availability databases return in SSMS; parallel SESSION_CONTEXT remains risky

For: Windows SQL Server users

• Processing additions no longer cause the described performance degradation, increased CPU use, and longer execution time.¹
  Fixes performance degradation during execution of the ProcessAdd command.

For: Windows SQL Server users

• Recursive hierarchies can load all levels instead of failing to load some levels.²
  Fixes an issue that might prevent a recursive hierarchy from loading all levels.
• Model upgrades no longer fail for the described inappropriate entity name.³
  Fixes model upgrade failures when an inappropriate entity name, such as "Entity", is set.

For: Windows SQL Server users

• A VSS restore using Restore with Move no longer restores the wrong file or fails when the .mdf file path ends with a space.⁴
  Fixes the Restore with Move behavior when the .mdf file path includes a trailing space.

• A cloned database is less likely to associate a database file with the wrong filegroup.⁵
  Fixes incorrect filegroup association in a clone database created by using DBCC CLONEDATABASE.

For: Windows SQL Server users

• The Availability Databases folder in SSMS shows databases in read-scale availability groups again.⁶
  Fixes the sys.dm_hadr_database_replica_cluster_states issue affecting read-scale availability groups after SQL Server 2019 CU24 or later.

• Creating or updating statistics no longer causes the described deadlock. Query plans or execution times might differ because query compilation is no longer blocked by statistics collection.⁷
  Fixes a deadlock by turning off the blocking Auto Stats feature, which is turned on when using PolyBase.

• The Distributor agent in peer-to-peer replication no longer encounters the described truncation error when the conflicting table's column count changes.⁸
  Fixes the _$update_bitmap column size not updating with changes to the original conflicting table's column count.
• Conflict detection and the Replication Merge Agent no longer encounter the described conversion error.⁹
  Fixes the error converting bigint to int when converting the generation to int.
• After an in-place Publisher upgrade to SQL Server 2019, sp_helpsubscription returns results so you can reinitialize the subscription without the described error.¹⁰
  Fixes sp_helpsubscription returning no results after the in-place upgrade, which prevents subscription reinitialization.

For: Windows SQL Server users

• Creating a read-scale availability group with a large number of databases is prevented to avoid a subsequent assertion failure.¹¹
  Prevents creation of read-scale availability groups with a large number of databases to avoid the assertion failure at ucsconnectionsend.cpp:103.

• A mitigation reduces the chance of an assertion failure during some complex queries using large-value data types; it does not apply in every situation.¹²
  Adds mitigation for the lobss.cpp:707 assertion failure when running a complex query that uses large value data types such as varchar(max).

For: Windows SQL Server users

• Compressed memory dumps use I/O more efficiently, limit excessive file-cache growth, and can make better use of available CPU cores.¹³
  Adds FILE_FLAG_NO_BUFFERING and dynamic auto-tuning parallelism to the compressed memory dump feature.

• The error 824 message includes a link to help with troubleshooting.¹⁴
  Adds a link to MSSQLSERVER_824 for error 824.