coldfusion performance tuning keen haynes certified coldfusion developer
Post on 27-Dec-2015
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Overview 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. 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
ComCheck
Overuse of #
Coding Tips Carefully load test and analyze CFX calls response
times 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
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
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.
Variable Locking Locking methods
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 CFLOCK Syntax
Typical usage
<cflock SCOPE="Application", "Session", or "Server" TIMEOUT=#seconds TYPE="Exclusive", or "ReadOnly">
[process] </cflock>
Variable Locking NAME Locks
May be used in place of locking by scope. The NAME argument is used in place of the SCOPE
argument.
Nesting Locks 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>
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
Thread Processing (cont)
A listener thread receives the request, sends it to one of the waiting active simultaneous threads to process the request. 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 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. 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 If many .cfm page requests with blocking third party
requests 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 Pinpointing these third party problems can be difficult
The following steps should be taken to help determine the source of the issue
ColdFusion Debugging STEP 2
Verify the source of the unresponsiveness of the ColdFusion server
Try opening up ColdFusion Administrator or other simple .CFM page
If this fails, try to open a .html or .html page If web server returns the .html page, the web server is
functioning properly, go to Step 2 If .html page does not return, web server is causing the
problem, stop and restart the web server If after stopping and starting the web server ColdFusion
pages still do not return, go to step 2.
ColdFusion Debugging STEP 3
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.
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. These do not connect to the database through ODBC and will
verify the ODBC connection to the database
Run the same SQL statement that you believe is causing the problem
SQL Profiler
Deadlocking
ColdFusion Debugging
STEP 5 - Turn on "logging of slow pages" in the debugger section. At the very least it will list the templates that are active for n
seconds.
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.
Determining that a CFX tag or piece of CFML code is causing the problem is not an easy task
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
Poorly written SQL statements Full table scans (not, like)
No database indexing No use of stored procedures Deadlocking
ColdFusion Debugging
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
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