SQL Server 2017 CU17 Released

On October 8, 2019, Microsoft released SQL Server 2017 CU17, which is Build 14.0.3238.1. There are 34 public hot fixes in the cumulative update. Starting with SQL Server 2017, Microsoft is not using Service Packs as a servicing mechanism for SQL Server, only Cumulative Updates.

Microsoft has fixed hundreds of bugs since SQL Server 2017 RTM, and they have also added a significant number of product improvements and new features since the RTM release. I’ve already updated my blog post that highlights the more important hotfixes (in my opinion) for each SQL Server 2017 CU that has been released.

Performance and Stability Fixes in SQL Server 2017 CU Builds

You really are better off trying to stay as current as possible on your SQL Server builds. I still believe this despite some recent problems Microsoft has had with SQL Server Cumulative Updates.

Here is Microsoft’s official guidance:

Microsoft recommends ongoing, proactive installation of CUs as they become available

  • SQL Server CUs are certified to the same levels as Service Packs, and should be installed at the same level of confidence.
  • Historical data shows that a significant number of support cases involve an issue that has already been addressed in a released CU.
  • CUs may contain added value over and above hotfixes. This includes supportability, manageability, and reliability updates.



SQL Server 2016 SP2 CU9 Released

Update: 10/9/2019

Microsoft has now released SQL Server 2016 SP2 CU10 as a replacement for SP2 CU9 (and they have removed SP2 CU9 from the build list). This happened not because of any problems with the actual SP2 CU9 payload (the binaries), but because of a problem if you tried to uninstall SP2 CU9. Here is the Microsoft statement about the issue:

SQL Server 2016 SP2 CU10 is a replacement for SQL Server 2016 SP2 CU9. CU9 had an uninstall issue that is resolved in the CU10 package. If you previously installed CU9, we recommend that you install CU10.

In my experience, it is not that common to want to (or have to) uninstall a SQL Server CU, but it does occasionally happen. Even so, the uninstall process should work as advertised, and it is unfortunate that this issue wasn’t caught before it was released.

Original Post:

Microsoft has released SQL Server 2016 SP2 CU9, which is Build 13.0.5470.0. This cumulative update has 21 public hotfixes. Keep in mind that both the SQL Server 2016 RTM and SQL Server 2016 SP1 branches are out of support, so there won’t be any more cumulative updates for those branches.

This is one of the more interesting fixes:

FIX: Poor query performance due to low cardinality estimation in SQL Server 2016 when you use default CE and column is covered by both single and multi column statistics

If you haven’t done it already, you should be making plans to get on the SP2 branch of SQL Server 2016. The Microsoft SQL Server 2016 build versions list is here.




Performance and Stability Related Fixes in Post-SQL Server 2014 SP3 Builds

As of July 29, 2019, there have been four Cumulative Updates (CU) for the Service Pack 3 branch of SQL Server 2014. There were a relatively large number of hotfixes in this last cumulative update. SP3 CU4 is the final Cumulative Update for SQL Server 2014 SP3, since SQL Server 2014 fell out of Mainstream Support on July 9, 2019.

If you are running on the SQL Server 2014 SP3 branch, I really think you should be running the latest SQL Server 2014 SP3 Cumulative Update. 

Table 1 shows the SQL Server 2014 SP3 CU builds that have been released.

Build Description Release Date
12.0.6205 SP3 CU1 December 12, 2018
12.0.6214 SP3 CU2 February 19, 2019
12.0.6259 SP3 CU3 April 16, 2019
12.0.6329 SP3 CU4 July 29, 2019
     

Table 1: SQL Server 2014 SP3 CU Builds

You can follow the KB article link below to see all of the CU builds for the SQL Server 2014 RTM, SQL Server 2014 SP1, SQL Server 2014 SP2, and SQL Server 2014 SP3 branches.

SQL Server 2014 Build Versions

Like I have done for other versions and branches of SQL Server, I decided to scan the hotfix list for all of the Cumulative Updates in the SP3 branch, looking for performance and general reliability-related fixes for the SQL Server Database Engine. I came up with the list below, but this listing is completely arbitrary on my part. You may come up with a completely different list, based on what specific SQL Server 2014 features you are using.

Here are the fixes in the SP3 branch:

SQL Server 2014 SP3 Cumulative Update 1 (Build 12.0.6205), 13 total public hot fixes

FIX: Change Tracking cleanup message 22123 is unexpectedly recorded in the error log file in SQL Server

FIX: Incorrect results occur when you convert “pollinginterval” parameter from seconds to hours in sys.sp_cdc_scan in SQL Server

FIX: Access violation when you run a query that uses the XML data type in SQL Server 2014

FIX: Overestimations when using default Cardinality Estimator to query table with many null values

FIX: Access violation for query that uses INSERT INTO … SELECT to insert data into clustered columnstore index

FIX: “ran out of memory” error when executing a query on a table that has a large full-text index in SQL Server 2014 and 2016

FIX: I/O errors on a BPE file causes buffer time out in SQL Server

FIX: Assertion error occurs during restore of compressed backups in SQL Server 2016

FIX: Internal error messages when you update a FILESTREAM tombstone system table in SQL Server

FIX: ObjectPropertyEx does not return correct row count when there are partitions in a database object

FIX: SQL Server service crashes when DBCC CHECKDB runs against a database that has a corrupted partition in SQL Server

 

 SQL Server 2014 SP3 Cumulative Update 2 (Build 12.0.6214), 5 total public hot fixes

FIX: High CPU use when large index is used in a query on a memory-optimized table in SQL Server

FIX: “Non-yielding” error occurs when there is a heavy use of prepared statements in SQL Server 2014 and 2016

FIX: Assertion occurs when a parallel query deletes from a Filestream table

 

 SQL Server 2014 SP3 Cumulative Update 3 (Build 12.0.6259), 4 total public hot fixes

FIX: Query plans are different on clone database created by DBCC CLONEDATABASE and its original database in SQL Server 2016 and 2017

FIX: Columnstore filter pushdown may return wrong results when there is an overflow in filter expressions in SQL Server 2014

FIX: Log reader agent may fail after AG failover with TF 1448 enabled in SQL Server 2014

 

 SQL Server 2014 SP3 Cumulative Update 4 (Build 12.0.6329), 19 total public hot fixes

FIX: Access violation occurs and server stops unexpectedly when you use XEvent session with sqlos.wait_info event in SQL Server

FIX: Filtered index may be corrupted when you rebuild index in parallel in SQL Server 2014 and 2016

FIX: Stack Dump occurs in the change tracking cleanup process in SQL Server 2014, 2016 and 2017

FIX: Fail to join the secondary replica if the database has a defunct filegroup in SQL Server 2014, 2016 and 2017

FIX: Columnstore filter pushdown may return wrong results when there is an overflow in filter expressions in SQL Server 2014, 2016 and 2017

FIX: Tlog grows quickly when you run auto cleanup procedure in SQL Server 2014, 2016 and 2017

FIX: SQL Server 2014 and 2016 do not perform the requested pre-row assignments when you use MERGE statement that performs assignments of local variables for each row

FIX: Prolonged non-transactional usage of FileTable without instance restart may cause non-yielding scheduler error or server hang in SQL Server 2014

FIX: Full-text search fails to remove files from \FTDATA\FilterData subfolder in SQL Server 2014

FIX: High CPU usage on Primary when SQL Service on Readable Secondary is turned off in Availability Group in SQL Server 2014

FIX: SQL batch performance drops when you enable “Force Encryption” in SQL Server 2014

FIX: Full text search auto populate stops when Availability Group goes offline in SQL Server 2014

FIX: Error 409 occurs when you back up databases by using BackuptoURL

FIX: Fix prefast warnings (62100) in Sql\Sqlrepl\xpreplclr.net\ReplCmdDataReader.cs to prevent SQL injection attacks

FIX: Syscommittab cleanup causes a lock escalation that will block the syscommittab flush in SQL Server 2014

 

The reason that I put these lists together is that I want to convince more people to try to keep their SQL Server instances up to date with Cumulative Updates. If you do the proper testing, planning and preparation, I think the risks from installing a SQL Server Cumulative Update are quite low (despite the occasional issues that people run into).

If you install a Cumulative Update or Service Pack on a Production system the day it is released, after doing no testing whatsoever, and then run into problems (and don’t have a plan on how to recover), then I don’t have that much sympathy for you.

On the other hand, if you go through a thoughtful and thorough testing process, and you have a plan for how you will install the CU, and how you would recover if there were any problems, then you are much less likely to have any problems. You are also much more likely to avoid the issues that are fixed by all of the included fixes in the new build of SQL Server. You have done your job as a good DBA.

Finally, Microsoft has changed their official guidance about whether you should install SQL Server Cumulative Updates. As they say, “we now recommend ongoing, proactive installation of CU’s as they become available”.