SQL DEBUGGINGOPRIS MONICA – DB & BI Developer

04/12/2023

SQL Debugging 2

Outline

• SQL Server Debugging

• SQL Server Profiler

• Database Engine Tuning Advisor

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Demo: SQL Server 2012 TSQL Debugger

Enhancements:

1) Conditional Hit breakpoints

2) Hit Count

3) Breakpoint Filter

4) Breakpoint Action

5) Breakpoint Location

6) Export/Import the breakpoints to an XML file.

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Keyboard shortcuts

Action StandardStart or continue debugging ALT+F5Stop debugging SHIFT+F5Step into F11Step over F10Step out SHIFT+F11Implement the Run To Cursor command

CTRL+F10

Display the QuickWatch dialog box CTRL+ALT+QToggle breakpoint F9Delete all breakpoints CTRL+SHIFT+F9Display the Breakpoints window CTRL+ALT+BBreak all CTRL+ALT+BREAKDisplay the Watch 1 window CTRL+ALT+W, 1Display the Watch 2 window CTRL+ALT+W, 2Display the Watch 3 window CTRL+ALT+W, 3Display the Watch 4 window CTRL+ALT+W, 4Display the Autos window CTRL+ALT+V, ADisplay the Locals window CTRL+ALT+V, LDisplay the Immediate window CTRL+ALT+IDisplay the Call Stack window CTRL+ALT+CDisplay the Threads window CTRL+ALT+H

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Debugging using PRINT

Declare @isdebug = 1

IF @isdebug = 1 PRINT @yourvar

IF @debug = 1 BEGIN

PRINT 'Something' --or insert into a log table if you need the rows of a temp table --or the results of a calculation

END

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SQL Server Profiler

• Monitor the performance of an instance of SQL Server

• Debug Transact-SQL statements and stored procedures

• Identify slow-executing queries

• Troubleshoot problems in SQL Server by capturing events on a production system and replaying on a test system

• Audit and review activity that occurred on an instance of SQL Server

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SQL Server Profiler terminology

• Events

• Data columns

• Filters

• Trace

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RPC:Completed,SP:StmtCompleted SQL:BatchStartingSQL:BatchCompletedShowplan XML

Duration ObjectNameTextData CPU Reads Writes IntegerData DatabaseName ApplicationName StartTime EndTime SPID LoginName EventSequence BinaryData

SQL Server Profiler

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• Which is worse, a query that runs once and takes 30 seconds to run or a query that runs 100 times and takes 1 second to run?

• Does a query run slowly every time?

SQL Server Profiler

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DTA using Profiler trace

1) RPC:Completed

2) SP:StmtCompleted

3) SQL:BatchCompleted

1) TextData2) Duration3) SPID4)DatabaseName5)LoginName:

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Conclusions

• SQL Debugger has limitations

• Profiler is not just for DBAs

• Use Profiler to learn how applications work

• Use Profiler to monitor live activity

• Collect only relevant data

• Be selective when applying DTA recommendations

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References

• http://technet.microsoft.com/en-us/library/cc293612.aspx

• http://www.sqlservercentral.com/articles/SQL+Trace/99217/

• http://download.red-gate.com/ebooks/SQL/Mastering_Profiler_eBook.pdf

• http://technet.microsoft.com/en-us/library/ms187929.aspx

• http://technet.microsoft.com/en-us/library/ms175047.aspx

• http://msdn.microsoft.com/en-us/library/ms173494(v=sql.105).aspx

• http://midnightdba.itbookworm.com/Video/Watch?VideoId=88

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Thank you