Advanced Tuning:
Unconventional Solutions to
Everyday Problems
Robert L Davis
Who am I?
Advanced Tuning: What is Tuning?
 Finding poor performance and making it
better.
 Ensuring that the server is configured for
optimal performance.
 Making use of the tools available to you find
hidden problems and resolve them.
Advanced Tuning: Tools
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SQL Trace/Profiler (please don’t use Profiler in production)
Performance Monitor
SQLDiag/PSSDiag
SQLNexus
RML Utilities
PAL Tool
Database Engine Tuning Advisor (DTA)
SQLIO
DMV’s
SQL Error Log
Your creativity
Advanced Tuning: Tools
 SQL Trace/Profiler – Captures SQL activity
 Find out what is occurring internally in SQL Server
 Output to a trace file
 Profiler can correlate a trace file and a Performance
Monitor file by time
 http://msdn.microsoft.com/en-us/library/ms191152.aspx
 Performance Monitor – Captures server activity
 Find out what is occurring at the server level
 Output to a file
 SQL counters can be captured via
sys.dm_os_performance_counters
Advanced Tuning: Tools
 SQLDiag/PSSDiag – Collects a variety of diagnostic data
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Windows Performance Logs
Windows Event Logs
SQL Traces
SQL blocking info
SQL Configuration info
 http://msdn.microsoft.com/en-us/library/ms162833.aspx
 SQLNexus – Analyzes SQLDiag/PSSDiag data
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Creates easy to interpret reports and graphs
Finds most expensive queries in trace files
Provides details on resource waits statistics
http://sqlnexus.codeplex.com/
Advanced Tuning: Unconventional
Solutions to Everyday Problems
Advanced Tuning: Tools
 RML Utilities – Diagnoses SQL Server Performance data
 ReadTrace – consumes trace files
 Reporter – provides easy to understand reports on trace data
consumed using Readtrace
 OStress – replays and stress tests queries
 ORCA – Ostress replay control agent
 http://blogs.msdn.com/b/psssql/archive/tags/rml+utilities/
 PAL Tool – Performance Analysis of Logs
 Creates easy to read and understand graphs from Performance
Monitor files
 Color codes graphs based on known thresholds to easily identify
possible bottlenecks
 Requires Microsoft Chart Controls for .NET Framework 3.5
 http://pal.codeplex.com/
Advanced Tuning: Unconventional
Solutions to Everyday Problems
Advanced Tuning: Tools
 Database Engine Tuning Advisor (DTA)
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Formerly Index Tuning Wizard
Performs in-depth index analysis
Can be based on a single query or a full trace file or work file
Can perform “What if?” analysis to verify recommendations
Limited in scope
 SQLIO – Determines I/O capacity of storage
 Should be used to verify I/O capabilities before deploying SQL to
the storage
 Validates storage I/O capabilities through stress testing
 Not the simplest tool to learn
 Great tutorial by Brent Ozar (@BrentO) on SQL Server Pedia:
http://sqlserverpedia.com/wiki/SAN_Performance_Tuning_with_SQLIO
Advanced Tuning: Tools
 DMV’s – provides insight into the internal statistics and structures of
SQL Server
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Developed to make troubleshooting easier
SQL Team developers were challenged to try to fix bugs by only using data readily available to
administrators
DMV’s for troubleshooting everyone should know:
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sys.dm_os_wait_stats – overall wait statistics for the server. Most are cumulative
sys.dm_os_waiting_tasks – wait statistics for active tasks currently executing
sys.dm_os_performance_counters – all SQL Server performance counters available to Performance Monitor
also found here
sys.dm_db_index_usage_stats – statistics on how your indexes are being used
sys.dm_exec_cached_plans – query plans in the plan cache
sys.dm_exec_sql_text – text of a query based on the sql handle. Joined to other DMV’s to get the exact text to
which they are referring
sys.dm_os_buffer_descriptors – statistics on how the memory areas in the buffer pool are allocated
sys.dm_exec_query_memory_grants – statistics on how much memory is allocated to individual queries or
what memory grants are pending
sys.dm_exec_requests – the current requests on the server
sys.dm_exec_sessions – the current sessions on the server
Glenn Berry’s DMV a day series:
http://www.sqlservercentral.com/blogs/glennberry/archive/2010/05/03/recap-of-april-2010dmv-a-day-series.aspx
Advanced Tuning: Tools
 SQL Error Log – error and other important information
 Wealth of information about alerts and errors occurring in
SQL Server that may not be reported through any other
means
 Very useful for capturing deadlock information via trace
flags 1204 and 1222
 Reports I/O freezing and excessive waits for I/O requests
 Reports when a torn page is recovered from a mirroring
partner
 Your creativity – don’t be afraid to think out of the box
Unconventional Solution
to Everyday Problems
 Scenario: CPU utilization spikes
 No pattern to when they occur
 Are short term (< 10 min.) and disappear before
operations personnel can react
 Performance critical production server
 Users are affected by the CPU spikes
 Solution: run a custom SQL trace automatically as
soon as a CPU spike is detected and capture top
50 CPU consuming queries.
 This solution can be adapted to respond to any
performance criteria that you can measure
Advanced Tuning: Unconventional
Solutions to Everyday Problems
Unconventional Solution
to Everyday Problems
 Scenario: How to measure replication latency
without tracer tokens
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Replication latency can spike to high latency at times
Tracer tokens not effective when latency is high
Data freshness critical replication servers
Monetary decisions based on replicated data
 Solution: query the Replication Monitor tracking
tables and the replication system tables to
determine current latency
Advanced Tuning: Unconventional
Solutions to Everyday Problems
Advanced Tuning: Unconventional
Solutions to Everyday Problems
Q&A
Advanced Tuning: Unconventional
Solutions to Everyday Problems
Thank You!
The PowerPoint slide-deck and the SQL code
will be posted on my blog tonight:
http://www.sqlsoldier.com