satisfy your technical curiosity profiling and optimizing.net applications ingo rammer

Satisfy Your Technical Curiosity

Profiling and OptimizingProfiling and Optimizing.NET Applications.NET Applications

Ingo RammerIngo Rammer

http://www.thinktecture.comhttp://www.thinktecture.com

Satisfy Your Technical CuriositySatisfy Your Technical Curiosity

Ingo Rammer and Ingo Rammer and Support and consulting for software architects and Support and consulting for software architects and developersdevelopers

Application Optimization and TuningApplication Optimization and TuningDeveloper-Coaching and -MentoringDeveloper-Coaching and -MentoringArchitecture and Code ReviewsArchitecture and Code ReviewsPrototyping and Architectural ConsultingPrototyping and Architectural Consulting

http://www.thinktecture.com [email protected]


Scenario IScenario I

ArchitectureDesignInitial Coding and Load Testing


Load Testing PitfallsLoad Testing Pitfalls

It’s important to test It’s important to test the right thingthe right thingDouble-check that network link and client CPUs Double-check that network link and client CPUs are not overloadedare not overloadedRun test clients in the same LAN as the serversRun test clients in the same LAN as the servers

Two ways of testing with very different resultsTwo ways of testing with very different resultsSimulated user load (including think times, etc.)Simulated user load (including think times, etc.)Maximum Request Load (no think time, just load)Maximum Request Load (no think time, just load)

Include ramp-up time (“step user load”)Include ramp-up time (“step user load”)


Load Testing in PracticeLoad Testing in Practice

Track counters of multiple serversTrack counters of multiple serversTest clients, Web servers, DB serversTest clients, Web servers, DB servers

Liebig’s Law of the MinimumLiebig’s Law of the Minimum is applicable here is applicable here as wellas well

““The scarcest resource will limit growth”The scarcest resource will limit growth”

After the resource is identified, take actionAfter the resource is identified, take action


Scenario IIScenario II

ArchitectureDesignCodingTestDeployment


UsersUsers


Don‘t assume Don‘t assume anythinganything


11stst - Trace the Network Interactions - Trace the Network InteractionsThe wire never liesThe wire never lies

Wireshark/Ethereal (Sniffing)Wireshark/Ethereal (Sniffing)TcpTrace (Explicit Port-Forwarding)TcpTrace (Explicit Port-Forwarding)Fiddler, ProxyTrace (HTTP Proxies)Fiddler, ProxyTrace (HTTP Proxies)

Caution: Some companies do not allow sniffing! Caution: Some companies do not allow sniffing!


Things you might find outThings you might find outOverhead you didn’t expectOverhead you didn’t expect

Authentication, sub-optimal bindings, …Authentication, sub-optimal bindings, …

Roundtrips you didn’t expectRoundtrips you didn’t expectCookiesCookiesImages Images (check your IE settings!)(check your IE settings!)MarshalByRefObject-roundtripsMarshalByRefObject-roundtrips

General: Too many roundtrips, or too bigGeneral: Too many roundtrips, or too bigLatency vs. BandwidthLatency vs. Bandwidth


22ndnd - Trace your SQL - Trace your SQLMost SQL today is generatedMost SQL today is generated

DataSets and AdaptersDataSets and AdaptersO/R MappersO/R Mappers

Suboptimal SQL: main reason for scalability probsSuboptimal SQL: main reason for scalability probsToday's databases are Today's databases are (unfortunately?)(unfortunately?) very good: very good:

Hide a lot of problems in single-user access during DEVHide a lot of problems in single-user access during DEV


Invoicing Application SubsetInvoicing Application Subset

Invoice

InvoiceIdInvoiceDateCustomerIdStatus

InvoiceItems

InvoiceIdItemldProductIdProductNameQuantityPriceStatus

SerialNumbers

InvoiceIDItemIdSerialNumberStatus

SerialNumberAudit

AuditIdEntryDateUsernameSerialNumberDescription


Invoicing - RequirementsInvoicing - Requirements

Cancel (Status=2)Cancel (Status=2)CopyCopy


Lessons Learned from SQL ProfilingLessons Learned from SQL ProfilingDataSets, DataAdapters and O/R Mappers are great DataSets, DataAdapters and O/R Mappers are great toolstoolsCan simplify more than 80% - 90% of your generic Can simplify more than 80% - 90% of your generic database access codedatabase access codeBUT: Please avoidBUT: Please avoid them in high-load / them in high-load / high-throughput parts of your applicationhigh-throughput parts of your application


Optimize Your SQL for TransactionsOptimize Your SQL for Transactions

““UPDATE” with Foreign KeysUPDATE” with Foreign Keys““INSERT INTO ... SELECT”INSERT INTO ... SELECT”

In the high-load areas of your application. Not In the high-load areas of your application. Not everywhereeverywhere!!


Database LocksDatabase Locks

Minimize Minimize durationduration and and numbernumber of locks of locksDynamic SQL (with parameters) vs. Stored ProceduresDynamic SQL (with parameters) vs. Stored Procedures

UPDATE only changed rows if possibleUPDATE only changed rows if possibleSELECT only the rows you need, join only tables you needSELECT only the rows you need, join only tables you need

Possibility: changed isolation level (snapshot isolation Possibility: changed isolation level (snapshot isolation or or NOLOCKNOLOCK) in statistics if you have to report from OLTP ) in statistics if you have to report from OLTP datadataDon‘t use “Sequence-Tables” (better go for Don‘t use “Sequence-Tables” (better go for Autoincrement/Identity/Guid columns!)Autoincrement/Identity/Guid columns!)


The #1 Reason for DeadlocksThe #1 Reason for DeadlocksTableName NextValue

Customer 1234

Employee 34

Invoice 445896

InvoiceDetail 2598999

Order 523456

OrderDetail 3347875

SerialNumber 23454355

Inventory 45543


Indexes help a bit...Indexes help a bit...

Use: Index (TableName)Use: Index (TableName)Not: Index (TableName, NextValue)Not: Index (TableName, NextValue)

SQL Server: An index is only locked when one or SQL Server: An index is only locked when one or more of the contained fields are locked! more of the contained fields are locked! Even snapshot isolation won’t help you here Even snapshot isolation won’t help you here Please note: Oracle Please note: Oracle sequencessequences behave differently. behave differently. They They alwaysalways run without transaction locks. run without transaction locks.


33rdrd - Memory Profiling - Memory Profiling

CLR Profiler 2.0 (free tool)CLR Profiler 2.0 (free tool)

Shows how much memory each method allocatesShows how much memory each method allocatesNot leaks, just allocationsNot leaks, just allocations


Memory UsageMemory Usage

Important for multi-user applicationsImportant for multi-user applicationsIssue: Multiple GC-cycles during one requestIssue: Multiple GC-cycles during one requestGenerative GCGenerative GCShort-lived objects end up in generation 2Short-lived objects end up in generation 2You can quickly check this in PerfMon, too!You can quickly check this in PerfMon, too!

.NET CLR Memory/Gen #0 Collections, #1, #2.NET CLR Memory/Gen #0 Collections, #1, #2

2,5 GB practical maximum for ASP.NET apps on 32 bit 2,5 GB practical maximum for ASP.NET apps on 32 bit systemssystems


In-Process ProfilingIn-Process ProfilingOften as a last stepOften as a last step

Reason: In-Proc affects “only” performanceReason: In-Proc affects “only” performanceReason 2: After eliminating memory hogs, code will Reason 2: After eliminating memory hogs, code will usually be faster anywayusually be faster anyway

ProfilerProfilerJetbrains’ DotTraceJetbrains’ DotTraceRedgate ANTSRedgate ANTSAutomated QA AQTimeAutomated QA AQTimeCompuware DevPartnerCompuware DevPartner


I code well, so where’s the scary part?I code well, so where’s the scary part?


The Scary FactsThe Scary FactsSqlDataSourceSqlDataSource

Grid AGrid A 23,926,450 Bytes23,926,450 BytesGrid BGrid B 17,147,255 Bytes17,147,255 BytesGrid C Grid C 3,325,839 Bytes3,325,839 BytesGridViewGridView 2,583,207 Bytes2,583,207 Bytes

ObjectDataSourceObjectDataSourceGridView GridView 169,551 Bytes169,551 BytesGrid CGrid C 916,769 Bytes916,769 Bytes

ManualManualHTML TablesHTML Tables 51,237 Bytes51,237 Bytesw/o ViewStatew/o ViewState 43,897 Bytes43,897 Bytes


SummarySummaryDon‘t assume anythingDon‘t assume anything

Network – the wire never lies (auth overhead, Network – the wire never lies (auth overhead, roundtrips, …)roundtrips, …)Database – generated SQLDatabase – generated SQLMemory – multiple GCs for one request? Memory – multiple GCs for one request? In-Proc Performance – as the last step In-Proc Performance – as the last step (scale up)(scale up)

Don‘t trust anyoneDon‘t trust anyoneIt might not be your code, but it could be your job!It might not be your code, but it could be your job!


ResourcesResources

Wireshark/Ethereal: Wireshark/Ethereal: http://www.wireshark.com

Fiddler: Fiddler: http://www.fiddlertool.com

TcpTrace, ProxyTrace: TcpTrace, ProxyTrace: http://www.pocketsoap.com

SQL Profiler: out of the boxSQL Profiler: out of the box

CLR Profiler 2.0: cryptic link, please googleCLR Profiler 2.0: cryptic link, please google


20062006

DSL, WLAN, MBits, …DSL, WLAN, MBits, …Ping to New York: 800 msecPing to New York: 800 msecDownload of 3,6 GB (Visual Studio):Download of 3,6 GB (Visual Studio):

6 Hours6 Hours


Early 90sEarly 90s

1200 baud acoustic coupler1200 baud acoustic coupler„„Ping“ to New York: 1200 msecPing“ to New York: 1200 msecDownload of 3,6 GB (Visual Studio):Download of 3,6 GB (Visual Studio):

347 Days347 Days


Early 90sEarly 90sDownload347 Days

Walking20.000 km5 km per hour12 hours per day

333 Days


20062006

Latency (Ping): 33% improvementLatency (Ping): 33% improvementBandwidth: 138 800 % improvementBandwidth: 138 800 % improvement

satisfy your technical curiosity profiling and optimizing.net applications ingo rammer

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