© 2008 Quest Software, Inc. ALL RIGHTS RESERVED.

Perfmon and Profiler 101

About Me: Brent Ozar

• SQL Server Expert for Quest Software

• Former SQL DBA

• Managed >80tb SAN, VMware

• Dot-com-crash experience

• Specializes in performance tuning

Today’s Agenda

• The Honda Civic and the Nissan GT-R

• Metrics, Trace, Mitigations

• A New Secret Weapon

• Resources and Q&A

If You Don’t Need to Go Fast…

From http://flickr.com/photos/stevekeys/2755142278/

But The Faster You Want To Go

The More You Have To Measure

Windows “Check Engine” Light

And If You Wanna Go Fast:

Two Approaches to Detection

• Exceptions Monitoring: Check Engine

• Proactive Monitoring: Detailed Gauges

Where Do We Start?

Capture Metrics With Perfmon

• Performance Monitor, aka Perfmon

• Ships with all Windows versions

• Polls any server from your desktop

• Pulls performance metrics

• Writes them to a file

• Requires some OS permissions

• Does not include alerts or analytics

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Memory Counters

• Memory – Available Mbytes

• Paging File - % Usage

• SQLServer:Buffer Manager – – Buffer cache hit ratio– Page life expectancy

• SQLServer:Memory Manager – Memory Grants Pending

Storage Metrics: Physical Disk

• % Disk Time

• Avg. Disk Queue Length

• Avg. Disk sec/Read

• Avg. Disk sec/Write

• Disk Reads/sec

• Disk Writes/sec

CPU Metrics

• Processor - % Processor Time

• System – Processor Queue Length

• SQLServer:General Statistics – User Connections (not CPU, just “other”)

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The Raw Output: CSV Files

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Adding Analytical Formulas

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That’s a Lot of Zeroes!

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Sorting High to Low

What To Look For, In Order

• System – Processor Queue Length

• Memory – Available Mbytes

• Lock pages in memory!

What To Look For Next

• Disk metrics on the page file drive

• Disk metrics on the log file drive

• Disk metrics on the data file drive

• Disk metrics on the TempDB drive

Got Everything on One Drive?

• Narrow it down with the DMV sys.dm_io_virtual_file_stats

What If We Could Data Mine It?

Table Analysis Tools For The Cloud

Detecting Categories of Load

Capture Queries with a Trace

Columns to Capture

What’s Going On

• Text Data• DatabaseID and/or

DatabaseName• Login Name• Host Name• Application Name

What The Impact Was

• CPU• Reads• Writes• Duration• Start Time• End Time

Profiler’s Results: A Trace Table

Order By Duration Descending

Casting and Grouping

Another Cloud Analytics Candidate

Another Way: Perf Dashboard

Correlate Metrics & Trace

• Show a cause and effect relationship

• Fields to mentally “join” on:– Date/Time ranges– CPU– Reads/Writes– Duration

Sample Problem #1

• Metrics tell us:– Very high disk queue

lengths on data drive

• Trace tells us:– Report queries doing

table scans w/o indexes– Many scheduled reports

run simultaneously

Ways We Can Mitigate It

• Add covering indexes

• Modify existing indexes

• Run reports serially, not all at once

• Add hard drives to the data file array

• Add memory to cache scanned tables

Sample Problem #2

• Metrics tell us:– Page file drive queue lengths

average >20– Page file use averages >1%– Available memory averages

<200mb– Buffer cache hit ratio and

page life expectancy are high

• Trace tells us:– No unusual queries

Memory Configuration

Ways We Can Mitigate It

• Add memory and enable AWE/PAE

• Add memory and upgrade to 64-bit

• Reduce SQL’s min/max memory sizes

• Move the app to its own server

Sample Problem #3

• Metric looks OK, but every 15 minutes:– Long drive queues on the

log file drive– Page life expectancy

drops near zero– Network traffic jumps

• Trace tells us:– Transaction log backups

are running

Ways We Can Mitigate It

• Stop doing log backups

• Put the databases in simple mode

• Add drives to the transaction log array

• Throttle the transaction log backups

Sample Problem #4

• Metrics tell us:– CPU average is high – Disk, memory look OK

• Trace tells us:– Queries are using

cursors– Operating on

individual records, not sets

How We Can Mitigate It

• Change cursor to set-based query

• Buy really fast processors

• Spend a lot on licensing

Wrapping Things Up

• Double-check the event log first

• Don’t get overwhelmed: focus with the Metric – Trace – Mitigation process

• Show a clear cause and effect

• Use cloud-based BI to get an edge

Resources On The Web

• My posts about Perfmon and analytics:www.BrentOzar.com/perfmonwww.BrentOzar.com/perfmoncloud

• Excel Table Analysis Tools for the Cloud:www.SQLServerDataMining.com/cloud

• SQL Server community:SQLServerPedia.com