5 amazing reasons dbas need to love extended events

5 Amazing Reasons DBAs Need to Love Extended Events

Jason Strate

e: [email protected]

e: [email protected]

b: www.jasonstrate.com

t: StrateSQL

Resources jasonstrate.com/go/xevents

Introduction

MAKING BUSINESS INTELLIGENT www.pragmaticworks.com


• Founded 2008 by MSFT MVP Brian Knight• Focused on the MSFT SQL Server Platform• Provides services, training and software• MSFT/HP “go to” partner: • Gold Certified:

o BIo Data Managemento SQL Performance

• Team led by multiple MVP’s• Offices throughout the US with Corporate

HQ in Jacksonville, FL

Pragmatic Works Company History

Extended Events

Extended Events

Dynamic, highly configurable tracing tool that provides access to events and

related information from the event.

Amazing!

Data Survivability


Data Survivability

Scenario• Weekend performance

issues expected• Configure SQL Trace to

capture statistics• You enjoy your weekend• Sysadmin/junior DBA

restarts instance on Friday night

• Monday morning… GO!


Data Survivability

Scenario• Performance issue shows

up• Start Profiler to collect

some events• Initial analysis deems

– New events are needed– New columns are needed

• Collected data is still important

• Change the trace… GO!


Data Survivability

• Solution exists with SQL Trace/Profiler

– Configure startup stored procedures

– Save off data

• Extended events

– Keep the session, restart on SQL Server startup

– Add events and columns on the fly

– Existing target unaffected


DATA SURVIVABILITY

Demo


Key Points on Data Survivability

• Extended events are highly configurable

• Active sessions

– Events can be added/removed

– Columns can be added/removed

• Sessions

– Retained on startup

– Can automatically restart

Get What You Want


Get What You Want

Mo’ Problems• Performance issue shows

up• Start Profiler to collect

some events• Initial analysis deems

– New events are needed– New columns are needed

• Collected data is still important

• Change the trace… GO!


Get What You Want

Mo’ Problems

• Textdata returns parameterized T-SQL

• Do you need BigintData1 and BigintData2?

• Aggregate data for trends


Get What You Want

Mo’ Solutions• Actions

– Plan_handle– Query_handle– Query_hash– TSQL_stack– Is_system

• Targets– Histogram/Bucketizer– Event_coutner– Event_stream


GET WHAT YOU WANT

Demo


Key Points on Get What You Want

• Extended events are highly configurable

– STILL!!

• Actions

– Add in the columns that you need

– Create actionable traces

• Targets

– More options that are useful

DMV Integration


DMV Integration

DMV Information

• Summary information

• Deeper information

DMV Columns

• Plan_handle

• Query_handle

• Query_hash

• TSQL_stack


DMV INTEGRATION

Demo


Key Points on DMV Integration

• DMVs allow expansion of trace results

– More detail

– Link other items together

• Build the complete picture

– Analyze all at once

• No intermediate levels of aggregation

Wait Stat Tracing


Waits & Queues Methodology


Wait Stat Tracing

DMVs

• Sys.dm_os_wait_stats

• Sys.dm_os_waiting_tasks

Problem

• High level

• Aggregate

• Point in time


Wait Stat Tracing

Scenario• Instance has been online for

months.• Code change deployed

recently• CPU spiked from 40% to 100% • High SOS_SCHEDULER_YIELD

waits and counts– Death by a million cuts

• High CPU items in DMVs are overnight maintenance jobs


WAIT STAT TRACING

Demo


Key Points on Wait Stat Tracing

• Waits & Queues is a popular methodology– Difficult to track waits to statement

• DBAs empowered in Waits & Queues– Truly perform root cause analysis

• Specific waits can be traced and captured– Instance

– Database

– Application

– User

Latch Tracing


Latch Tracing

Latch: Lightweight synchronization activity.

Examples: • Page allocations• Disk-to-memory transfers• In-memory transfers

DMV• Sys.dm_os_latch_stats


Latch Tracing

Scenario• New application deployed• High volume of users• High number of LATCH_EX waits

– Non-buffer latching– Exclusive

• Other applications appear to be affected

• Application is much slower than in test

• Where’s the problem… GO!


LATCH TRACING

Demo


Key Points on Latch Tracing

• Latch issues can be hard to troubleshoot

• Typically happening out of sight

• Latches can be traced and captured

– Instance

– Database

– Application

– User

Loving Extended Events

Data Survivability

Get What You Want

DMV Integration

Wait Stat Tracing

Latch Tracing

Learn More About Extended Events


ServicesSpeed development through training, and rapid development services from Pragmatic Works.

ProductsBI products to covert to a Microsoft BI platform and simplify development onthe platform.

FoundationHelping those who do not have themeans to get into information technologyachieve their dreams.

For more information…

Name: Jason Strate

Email: [email protected]

Blog: www.jasonstrate.com

Resource: jasonstrate.com/go/xevents

5 amazing reasons dbas need to love extended events

Technology

business intelligent

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data survivability demo

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latch tracing demo

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