Transcript ColdFusion Performance Tuning and Testing

ColdFusion
Performance
Tuning
Keen Haynes
Certified ColdFusion Developer
Overview
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Application Environments
Testing Techniques
Tuning Techniques
Coding Tips
Variable Locking
Databases and Queries
Thread Processing
Debugging
Application Environment
 Goals
 Provide separate, autonomous areas for
Development, Testing/Staging and Production
 Provide the Developer Community with an
environment that maximizes
 Productivity
 Effectiveness
Application Environment, cont.
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Provide a Testing/Staging environment that facilitates
 Automated application staging
 Testing
 Load/Scalability testing
 Production readiness (data migration, etc)
Provide a Production environment that is
 Scalable
 Manageable
 Makes efficient use of resources
 Designed for High-Availability and end-user
responsiveness
Testing Techniques
 Perform “Critical Path” or “Strategic Strike”
Analysis
 Stress User vs. Real User
 Build a “Real-World” load generator test script
 Load Test & Perform Bottleneck Analysis
 Do Manual Timings in a browser (no load vs
under load)
 Perform Endurance Testing
 Examine log files during testing
Testing Techniques, cont.
 Principle elements involved in template response time:
 Total Execution Time (i.e. 203ms)
 Query Time (i.e. 156ms)
 Processing/Response Time: Total - Query (i.e. 46ms)
Tuning Techniques
 Establish your max user base line
 Manually walk through test and capture
explode bench marking – identify
bottlenecks
 Test with new general CF admin settings
 Test with changes to simultaneous request
settings changes – normally the biggest
bang for your buck.
Managing Performance, cont.
 Query Time:
 Can be significantly reduced by proper DB Design,
Configuration, Tuning and Administration
 Use a professional Database Administrator (DBA)
 Ensure/verify updated/proper version of ODBC (i.e.
MDAC v 2.6) and/or DB client libraries on CF Server
 In CF Server, try “Maintain DB Connections”
 (Very) generally, queries taking longer than > 150ms
execution time w/no load MUST be examined closely
Coding Tips
 Use CF built-in functions wherever possible
 Avoid complex logic inside CFQUERY (build
outside)
 Fully scope variables
 Lock all Session, Application, and Server variable
access
 MDAC update
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ComCheck
 Overuse of #
Coding Tips
 Carefully load test and analyze CFX calls response
times
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C++, Java
Be careful using CFHTTP, CFFTP
Scalability of CFFILE
CFMAIL in mass mailings
Avoid redundant queries and looping queries
Use Stored Procedures where appropriate
Avoid redundant code
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Use of CFINCLUDE versus Custom Tags
 Blank space
Coding Tips
 Caching strategies
 Queries
 Administrator
 CACHEDWITHIN
 Selection of content
 Templates
 Administrator
 CFCACHE
 SUPERCACHE
Variable Locking
 Server, Application, and Session
vars must be locked using
<CFLOCK>!
 Or random memory corruption
occurs.
 Consider Client and Request scopes
 Symptoms: PCode errors, Unknown
Exception errors
 Use “Full Checking” in Dev and
Staging environments
Variable Locking
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Levels: Exclusive, ReadOnly
Exclusive: does not allow any operations on a
given variable scope until the current process
within the lock is complete.
 ReadOnly: allows multiple reads within the
scope but no write access.
 If an Exclusive lock is processed at the same
time as a ReadOnly lock, the ReadOnly lock
will wait for the Exclusive lock to finish before
proceeding.
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Variable Locking
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Locking methods
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As a general rule of practice locking should be done in the code
using CFLOCK.
ReadOnly locking can be applied globally to SERVER,
APPLICATION, and SESSION variables using the "Automatic
Read Locking" option on the Locking page of the ColdFusion
Administrator.
There is no method to write-lock variables globally in the CF
Administrator when using multi-threaded sessions. One could
single-thread sessions using the "Single Threaded Sessions"
option, thereby eliminating the need for locking SESSION
variables, but this results in severe performance degradation and
is not recommended for scalable applications.
Variable Locking
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CFLOCK Syntax
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Typical usage
<cflock SCOPE="Application", "Session", or "Server"
TIMEOUT=#seconds TYPE="Exclusive", or "ReadOnly">
[process]
</cflock>
Variable Locking
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NAME Locks
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Nesting Locks
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May be used in place of locking by scope.
The NAME argument is used in place of the SCOPE
argument.
As a general rule of thumb, nested locks should be avoided
as they can result in deadlocks. Please refer to the CFML
Language Reference Documentation if nested locks are
considered absolutely necessary.
Avoid use of locks in queries
Database Issues
 Use latest stable release
 Look for PCode errors including “SQL” or
“Query”
 Queries that never return; apparent CF
Server hang
 Troubleshoot by setting max DB
connections to 1
SQL
 Ensure appropriate indexes are available
for all common queries
 Clustered Indexes in SQL Server
 Avoid calling queries in loops
 Use joins instead of looping around
queries if possible
Query Caching
 Appropriate for queries with
few permutations
 Limits to number and size of
queries
 No easy way to “flush” cached
queries
 Caching for only one minute at
10 queries per second reduces
load on the database (for that
query) by 600x
Query Caching
 Example: Cache statecodes query for 10 minutes:
<CFQUERY Name=“qStateCodes”
DataSource=“#Request.DSN#”
CachedWithin=“#CreateTimeSpan(0,0,10,0)#”>
SELECT *
FROM States
ORDER BY StateCode
<CFQUERY>
Thread Processing
 A .cfm page is requested by a web
browser
 The .cfm request passed to the CF Web
server stub
 The stub sends the request to the
ColdFusion Application Server for
processing.
Thread Processing (cont)
 A listener thread receives the request,
sends it to one of the waiting active
simultaneous threads to process the
request.
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If all of simultaneous threads are busy, the listener
thread places the request on a waiting list.
When one of the simultaneous request slots
becomes available, listener thread sends the waiting
request to the active slot.
Thread Processing (cont)
 The ColdFusion server
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Processes all of the CFML tags in the page
Converts the results to HTML and sends them back
to the web server to be sent to the browser.
Thread Processing (cont)
 The thread is put back into the active pool
to be reused.
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Much less resource intensive than the thread
create/destroy scenario.
3rd Party Calls
 If 3rd party call never returns a result set
or error message, thread will continue to
wait and will NOT timeout
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If many .cfm page requests with blocking third party
requests
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Simultaneous Request limit will be reached
ColdFusion server will appear to hang
BUT: ColdFusion is not failing to process, it simply is
waiting for a response from a third party resource
call.
ColdFusion Debugging
 Performance or stability problems more often than not
are caused by processing of a third party request
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Pinpointing these third party problems can be difficult
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The following steps should be taken to help determine the source of
the issue
ColdFusion Debugging
 STEP 1
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Examine logs
ColdFusion Debugging
 STEP 2
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Verify the source of the unresponsiveness of the ColdFusion
server
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Try opening up ColdFusion Administrator or other simple
.CFM page
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If this fails, try to open a .html or .html page
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If web server returns the .html page, the web server is
functioning properly, go to Step 2
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If .html page does not return, web server is causing the
problem, stop and restart the web server
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If after stopping and starting the web server ColdFusion
pages still do not return, go to step 2.
ColdFusion Debugging
 STEP 3
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Open up the NT Performance Monitor or run cfstat and add the
CF "Queued Requests", and "Running Requests" counters,
along with %CPU usage for the CFSERVER instance.
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If third party request is suspected, at time of the hang:
%CPU usage will be approx. zero, Running Requests will be
approx. at Simultaneous Request limit and Queued
Requests should be rising
ColdFusion Debugging
 STEP 4 - At the time of the unresponsive period, try
running a query through MSQuery using SQLPlus or
ISQL.
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These do not connect to the database through ODBC and will
verify the ODBC connection to the database
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Run the same SQL statement that you believe is causing the
problem
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SQL Profiler
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Deadlocking
ColdFusion Debugging
 STEP 5 - Turn on "logging of slow pages" in the
debugger section.
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At the very least it will list the templates that are active for n
seconds.
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This will give your users a place to start looking for long running
queries
ColdFusion Debugging
 STEP 6 - Non-functioning, or slow functioning CFX tags, or
CFML code called in your ColdFusion templates can also be the
cause of ColdFusion performance/stability issues.
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Determining that a CFX tag or piece of CFML code is causing
the problem is not an easy task
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Use the CF function GetTickCount() around CFX tag call (or any
suspected piece of slow performing code)
ColdFusion Debugging
 Example:
<CFSET tickBegin = GetTickCount()>
(code to be timed here...)
<CFSET tickEnd = GetTickCount()>
<CFSET totalTime = tickEnd - tickBegin>
<CFOUTPUT>Time to Complete:
#totalTime#</CFOUTPUT>
ColdFusion Debugging
 Versions:
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Be certain all patch revisions are current
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OS
 Kernal
 C++
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DB
WWW
CFAS
ColdFusion Debugging
 Poorly written SQL statements
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Full table scans (not, like)
 No database indexing
 No use of stored procedures
 Deadlocking
ColdFusion Debugging
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CFMAIL as mass-mailer
CFX tags that lose thread control
CFHTTP - incorrect URLs
No CFLOCK around client, application
variables
 Poorly written logic
 Liberal use of CFLOCATION
 Disk I/O
ColdFusion Debugging
 Logs
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Overuse (CFAS)
Fill disk (DB, WWW, CFAS)
 Client variable storage in registry
 Debug settings on
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IP specific
 Third party application servers sharing box
 Extraneous services
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ScreenSaver, etc.