A Fine Slice Of SQL Server
With sp_BlitzFirst & sp_WhoIsActive in a SQL Agent job with scheduled execution for every 10-15 minutes, you can look back in time in terms of What was running, its execution stats, file stats, wait stats and Perfmon counters. This would help you to answer anybody as why your server was slow at a particular point in time.
Click through for the post and check out the GitHub repo as well. Baselining is extremely important for proper administration.
Comments closedSolomon Rutzky is a month early with this:
In the event shown directly above, towards the bottom, in the final “<Data>” element that starts with “
\\?\C:\ProgramData...“, that entry does point to a folder containing a Report.wer file. It is a plain text containing a bunch of error dump info, but nothing that would seem to indicate where to even start looking to fix this. And, nothing useful for searching on, at least not as far as my searching around revealed.Conclusion
There you have it: a nearly untraceable way to prevent SQL Server from starting.
Read on to see how what Solomon did.
Comments closedThe next piece of code helps fix orphaned users by reconnecting them to logins that have precisely the same name, but a differing SID. This code is a variant of the above code that dynamically creates
ALTER USERstatements. A statement is created for each orphaned user where there is a match-by-name in the list of server logins. Once the list of dynamically createdALTER USERstatements are compiled, the commands to fix orphaned users are automatically executed.
Click through for the scripts.
Comments closedRandolph West wants you to disable priority boost if you have it turned on:
It turns out that on one of the benchmarks, Microsoft was able to achieve higher throughput by setting the SQL Server process to
HIGH_PRIORITY_CLASS, and the thread priority level over and above that toTHREAD_PRIORITY_HIGHEST. While it was extremely helpful to beat artificial benchmarks, it came at the cost of giving SQL Server higher execution context on the CPU than almost every other process on Windows.
And that’s the only good use of priority boost ever. If you’ve never heard of priority boost, just keep on ignoring it.
Comments closedAndy Levy explains why he wants script update mode to run in parallel:
When you have 8000+ databases on an instance, this is a huge deal. You’re looking at over two and a half hours just to bring SQL Server online after installing an SP or CU. While the instance is in script update mode, incoming connections are locked down and the service remains in the Starting status. Only the Dedicated Administrator Connection can be used to connect to the instance remotely.
Taking advantage of having a Failover Cluster Instance to patch the passive node in advance is great for minimizing downtime for Windows updates. But whether you have an FCI or not, SQL Server will remain in the “Starting” state until all of your databases have been through this process after installing an update. What was once a 10-minute failover is now a multi-hour ordeal, and maintenance windows become a lot harder to negotiate.
Andy’s pretty far over on the right-hand side of that Bell curve, but I like his SQL Server suggestion because even with just a few hundred or a couple thousand databases, you’re still talking real time savings.
Comments closedSQL Server does have a fairly useful dynamic management view, or DMV, which provides insight that can be leveraged in this area. The DMV I’m talking about is the set of DMVs around missing indexes, consisting of
sys.dm_db_missing_index_groups,sys.dm_db_missing_index_details, etc. I’m not saying the missing indexes DMVs are a panacea that will enable you to fix every performance situation you run into, but they can be useful if you know where to look. This post doesn’t go into a lot of depth about how to use those DMVs for the purpose of actually creating indexes, however I will show you how you can create multi-column stats objects as an interim performance booster while evaluating the need for those indexes.
I’ve never had great luck with multi-column stats versus simply creating indexes but that could simply be a case of me doing it wrong.
1 CommentThe good news is that it is not an unreasonable requirement and it has been done before. The solution is to use Group Managed Service Accounts (gMSA) and Credential Spec Files. A number of people have already documented their efforts. Some were more successful than others.
Click through for a detailed guide to getting this working.
Comments closedLonny Niederstadt tracked down an ugly bug in SQL Server 2016 SP2 CU4:
When I started investigating, the error was known only as an access violation, preventing some operations related to data cleansing or fact table versioning.
It occurred deep within a series of stored procedures. The execution environment included cross-database DELETE statements, cross-database synonyms, lots of SELECT statements against system views, scalar UDFs, and lots and lots of dynamic SQL.
And… I don’t have access to the four systems where the access violation occurred.
I was able to have some investigation performed on those systems – we learned that by disabling ‘auto stats update’ for the duration of the sensitive operations, the error was avoided. We also learned that reverting a system from SQL Server 2016 SP2 CU4 to SP2 CU2 avoided the errors. On those systems, reverting to SP2 CU2 or temporarily disabling ‘auto stats update’ were sufficient temporary mitigations.
Very interesting sleuthing work. It also appears the issue might have been limited to SP2 CU4, as SP2 CU3 and SP2 CU5 return different results in Lonny’s repro.
Comments closedMax Trinidad shares some tools you can use to automate SQL Server processes with Powershell:
For script automation we could install either or both version of PowerShell Core: (As of February 19th, 2019)
PowerShell Core GA version 6.1.3
PowerShell Core Preview 6.2.0 Preview 4Here are some important PowerShell Modules to use for SQL Server management scripting:
*SQLServer – This module currently can be use on SQL Server 2017 and greater.
*DBATools – This a community supported module that will work with SQL Server 2000 and greater.
DBAReports – Supports for Windows SQL Server.
DBCheck – Support for Windows SQL Server.
Automation is a great DBA’s best weapon. Knowing the tools which help you automate your tasks is critical.
Comments closedEduardo Pivaral shows that you should clear out some of the bigger SSIS tables occasionally:
If you have SQL Server Integration Services installed on your server, and you left the default configurations a table named sysssislog is created on MSDB database, it contains logging entries for packages executed on that instance.
If you are not careful enough, this table can grow uncontrollably over time and can make subsequent insertions very slow.
This kind of batched delete works for more than just the Integration Services tables; it’s a good plan wherever you have a large table and need to delete a fairly significant number of records from it.
Comments closed