1. Using XEvents to determine delays caused by logon triggers or resource governor
Trayce Jordan MCM, MCA, CISSP
Architect
Microsoft Corporation
@SeekWellDBA

2. SQL Saturday 734
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3. Derive it from application side
How can I use determine
how much a logon trigger or Resource Group Classifier function affects logon times?
Ring buffers
Derive it from application side
XEvents

4. Our Agenda Open forum Show how to view impact with Ring Buffers
Show how to use OSTRESS
View impact using XEvents
Open forum

5. This is what we’re looking for!

6. Using Ring Buffers SYS.dm_os_ring_buffers Limited sample size (Ring!)
Have to parse XML (yuck)
Lose info after restart
Built-in – you don’t have to configure the ring buffer for this – it’s just there.
But ring buffers (by definition have limited number of entries).
256 entries / scheduler
The data from the Ring Buffer needs to be shredded from XML into tabular form
The ring buffers are cleared upon restart.

7. select distinct ring_buffer_type from sys.dm_os_ring_buffers
Demo1
ring_buffer_type
RING_BUFFER_CLRAPPDOMAIN
RING_BUFFER_MEMORY_BROKER_CLERKS
RING_BUFFER_RESOURCE_MONITOR
RING_BUFFER_SCHEDULER_MONITOR
RING_BUFFER_SECURITY_CACHE
RING_BUFFER_MEMORY_BROKER
RING_BUFFER_SECURITY_ERROR
RING_BUFFER_XE_BUFFER_STATE
RING_BUFFER_HOBT_SCHEMAMGR
RING_BUFFER_SCHEDULER
RING_BUFFER_EXCEPTION
RING_BUFFER_QE_MEM_BUFF_POOL_RESERVE
RING_BUFFER_CONNECTIVITY
RING_BUFFER_XE_LOG
select distinct ring_buffer_type from sys.dm_os_ring_buffers
DEMO1.SQL

8. Using XEvents preconnect_completed Unlimited sample size
Histogram – easy to see quick
Can save off data to file as well
The Xevent to use is the preconnect_completed
Because it is an Xevent and not a ring buffer, you can have unlimited data points.
Using the Histogram target (even in real-time) you can see the effect without having to parse ugly XML
You can also have a file target to save for future analysis.
Only drawback that I can see is that be default you don’t get the SPID -- you have to remember to add it.

9. Demo2

10. References Histogram Target
Targets for Extended Events in SQL Server
An Xevent A Day: 31 days of Extended Events
Resource Governor

11. References Logon Triggers
Create Trigger
RML Utilities
Description of the Replay Markup Language (RML) Utilities for SQL Server
Resource Governor Classifier Function

12. Thank you! Questions? Trayce.Jordan@microsoft.com