Welcome!

You will be redirected in 30 seconds or close now.

ColdFusion Authors: Yakov Fain, Jeremy Geelan, Maureen O'Gara, Nancy Y. Nee, Tad Anderson

Related Topics: ColdFusion

ColdFusion: Article

Compilation and Precompilation in CFMX Templates

Compilation and Precompilation in CFMX Templates

Last month I introduced a precompile "batch" file that allowed you to manually compile CFMX templates, saving the penalty paid by the first user to browse a CFMX template after it was created or edited.

But there will be curious folks (and bit-twiddlers) among you who will want to know more - maybe lots more. How much time is this really saving? If it's compiled to disk, how and when does CFMX read it into memory to execute it? What's the cost of that? What happens with CFINCLUDEd files? Where does the compiled code go? Can I look at it? Can I just delete the generated class files instead? How do I determine which class file was generated for which CF template? Can I distribute the compiled code on other servers without the source code?

I'll address these questions and more in this conclusion.

Evaluating the Execution Time
Before going on, it may be helpful to explain something about determining the impact in terms of execution (and other startup) times for running a template. It will be very helpful to turn on the "Report Execution Times" option in the ColdFusion Administrator settings for "Debugging Settings". This will produce a display (see Table 1) at the bottom of a page when executed in a browser.

As in previous releases, you will only see this debugging information if the Administrator has enabled it. Also, if any IP addresses are listed in the "Debugging IP Addresses" page of the Administrator, then you will only see it if you are in that list. If there are no values in that list, all who execute CF templates on the server will see this info. Finally, if you still don't see this information, be sure that your template (or the application.cfm that is called before it) does not have <CFSETTING ShowDebugOutput="no">.

This particular example shows a file called test.cfm, which included a file called test.html, and also had an application.cfm that was called. It also shows a separate value for "startup, parsing, compiling, loading, & shutdown". We'll get to that in a moment. Keep an eye on this set of timing information when trying to evaluate the impact of various choices and settings.

Compilation Doesn't Eliminate All the Waits
So, after reading my previous article you now know how to precompile a template. You've paid the cost of compiling the code to its underlying Java byte code and now it should execute without any parsing/compiling delay (assuming it's not been edited). What if you restart the server? Will the first user really experience no further delay? Not exactly.

You may recall that I said that CFMX writes the compiled code to disk. Did you wonder how it gets from disk into memory, for CFMX to execute? I mentioned at the outset of the previous article that even in ColdFusion 5 and before, the first execution of a template after a server restart would cause CF to interpret the template into "pcode" and then load that into a "template cache". The code was then executed from memory all day, rather than being read from disk (unless the cache filled, in which case the least recently used template would be flushed from the cache). This was a useful solution for making code run as quickly as possible when executed.

CFMX faces the same dilemma. While the compilation of code to a Java class file eliminates the interpretation step the first time the code is executed after each restart, the fact remains that the compiled code needs to be read from disk and loaded into ColdFusion's memory - in that same template cache that existed in previous releases.

The precompile batch file from the previous release does not perform this "load" of the compiled code into CFMX's template cache, so you can't save that time. Similarly, when the server has just been restarted, it will need to be "loaded" into memory. It's just the first user to run the code after restart (or a compile or precompile) that experiences that load time. So be aware that precompiling won't eliminate the entire wait. There's still the time needed to load the code into the template cache the first time it's executed after restart.

Also, be careful in evaluating the impact of these steps. If you watch the precompile.bat file process, you may notice that compiling even a single template seems to take longer than if you simply let CF compile it automatically. The compiler process in the precompile.bat file has some load time itself on the first template it compiles. If only one template is precompiled, you see that time reflected in the time it takes to compile. If multiple files are precompiled at once, you see each individual template taking less time than if it was compiled alone.

Handling Included Files
In my example above I included a test.html file, but what if I had included a cfm file? Do you wonder if there might be an effect on compilation if code in the included file changes? Would you expect ColdFusion to have to recompile the including template?

It does not. Precompiling the including file after the included file has changed isn't necessary. Indeed, if you look at the compile time reported by the precompile tool it will be reported as 0ms. This reiterates the point that CFINCLUDE is a runtime directive, not a compile time one. Many misconstrue that. (Further proof is demonstrated by the fact that the value of the TEMPLATE attribute naming a file in CFINCLUDE can in fact be a variable. It's clearly a runtime directive.)

What's the difference? Say you have a template that includes another and that included file changes often during the day. You will notice a delay in loading the file. But it would have been true in CF 5 and before. Compilation isn't the cause, and precompilation is not the answer. You just need to get CF to reexecute the template so that it runs the CFINCLUDE to detect that changed file and load it into memory. Again, it's a runtime issue.

I've done this and watched the time reported in the debug output on the first execution of the calling template (after the included file has changed). In one example it went from 1000 ms (reported as execution time for the calling template) to 0ms from then on. Note that this change is in the runtime of the template, not its compile time. So it's not really a compilation issue.

What can you do, especially if some automated process is causing updates to the included file? You could add to that automated process (or create another) that simply executes the calling page once after the included file has changed. This could be kicked off via CFSCHEDULE or CFHTTP. The point isn't to save the resulting output in any way (which is an option with these tags), but merely to cause execution of (or in other words to "touch") the calling page so that it does what it needs to do to interpret the change in the included file.

Where Does the Compilation Go?
I also mentioned in the previous article that CFMX compiles your cfm (and cfc) templates into .class files, which are Java byte code files. If you're curious, the files are written to (and executed from) the cfclasses subdirectory of [cfusionmx]\wwwroot\WEB-INF\ directory where CFMX is installed. This occurs whether you are using another Web server or have located your file outside the default wwwroot location. CFMX compiles and runs the code from this cfclasses directory, regardless of the location of the source file.

This is the reason why in the previous article we needed to specify the -webinf directive in the batch file, to tell it to place compiled code there. If it's not placed there, it won't run in CFMX.

Be warned, though, that the file names for these class files may not be at all apparent. A CF template named Setsession.cfm might lead to a class file named cfsetsession2ecfm1011928409.class.

All templates from all directories end up in this one cfclasses subdirectory. They're not stored here in any subdirectories related to their original location. Instead, CF includes a hash of the directory name in that set of numbers after the file name. Keep that in mind when trying to associate a given class file with its original cfm template. The hashing process is a bit convoluted. (See my blog entry of Oct. 5 for more details, at cfmxplus.blogspot.com.)

Perhaps the easiest way to detect which class file goes with which source file is to simply edit the file and then execute (or precompile) it. Look in the cfclasses directory for the most recently created class file. Assuming your server is not too busy with many compilations taking place, it should be pretty easy to associate the classname with the CF source code name.

Saving Java Source Code Produced by CFMX
So that's where the compiled source code goes. But what about seeing the actual uncompiled Java source code that your CF template is converted into? Normally it's of no concern to CF developers what CFMX is doing under the covers in converting our CFML to Java.

For the ardently curious among you, did you know that you can ask CFMX to save the Java code it creates, in source form? You can. It's an undocumented feature, and while I've had no trouble doing it, I must warn that this is something you do at your own risk. Neither I, nor SYS-CON, nor Macromedia accept responsibility for your trying this.

The setting can only be enabled by someone with administrative control of the server, and the setting is also server-wide. It will add a slight additional time to the compile process, so it's not something you'd want to turn on in production. It probably ought not be left on in development either.

You need to edit the file web.xml in the [cfusionmx]\wwwroot\WEB-INF directory. There, if you're familiar with XML files, you'll find a parameter called "coldfusion.compiler.saveJava". Change its value from false to true. Save the file. Restart the server.

Now, whenever a new or recently edited file is compiled (whether automatically by CFMX or by our precompile.bat file), CFMX will also create a ".java" file along with the ".class" file. This ".java" file will be found in that same [cfusionmx]\wwwroot\WEB-INF\cfclasses\ directory as the ".class" files (and will be subject to that same issue of the curious file naming mentioned above).

The Idea of Deleting the Generated Class Files
Some have proposed that instead of precompiling their code they'd just as soon delete the underlying Java class file that was created when it was last compiled. That may seem like overkill, but there are times when it might be worth trying. Just note that, as the previous sections discussed, finding the class file that's associated with a given source template can be challenging. While some may simply delete all the class files, that's certainly overkill.

Don't forget that in the previous article I mentioned there is a -f directive you can pass to the compile process (by modifying the precompile.bat file). That will force a recompile of a file even if CF doesn't think it's necessary. Sometimes that solves the same problem that deleting the class file would solve.

The Dream of Distributing Compiled Code Without Source
Finally, all this talk of creating compiled Java code has excited some. They wonder if they might finally be able to distribute the compiled code without the associated source files. From an intellectual property protection standpoint, this makes sense. Being able to do so is important to those who sell ColdFusion applications. They want their clients to be able to use the code, without them (or their competitors) seeing the actual source code.

Unfortunately, this is not going to happen with the current release of CFMX (if at all). Macromedia has designed the process so that the source code must be present for the file to be loaded. That's an interesting key point. Some were excited by a demo by Ben Forta at last year's DevCon where he was able to delete a source code file and the template continued to run. Some have even noticed that that can still work. Not always, though. Only if the trusted cache setting is enabled.

With what you know from our previous discussion of loading templates and using the trusted cache setting, you may be able to figure out what's happening. If you run a CF template, it's loaded into memory (after being compiled if it changed). Once it's in memory, that's where CF runs it from. And if the trusted cache setting is enabled, then CFMX no longer looks to the source code file to determine if it's changed. Indeed, it also doesn't look to see if it's been deleted.

But if you restart the server, then CF will try to load the template from disk and even with the trusted cache enabled, the first time the template is run, it will look to see if the CF source template has changed since it was last compiled to disk. Only if they disabled that would we be able to truly distribute the source code.

Macromedia folks have further asserted that they won't enable that feature because it's inappropriate to assume that code compiled on one machine would necessarily work on another machine. It's important to note that your ColdFusion code is more than just the underlying Java byte code it's been compiled into. There are libraries that come with CFMX that are called when your code is run. You would at least need to distribute those as well. Whether Macromedia will address this problem for commercial solution developers is still unclear.

Conclusion
The process of compiling and understanding the compilation process for CFMX templates is something that's not well documented. I don't even want to claim to fully understand it. I've encountered some things in preparing this article that still confound me, and since it's undocumented, maybe we can't expect to fully understand it. I just hope that the information shared here will help you, and that it may also motivate Macromedia to decide what aspects of the process they want to make more public.

You could argue that an Admin interface would be a useful addition in doing the compilation process. Perhaps someone has already started working on that. I welcome comments, questions, and concerns you may have about this compilation process. Feel free to e-mail me or post comments below the online version of this article at the www.sys-con.com site.

SIDEBAR
Trusted Cache Still Applies
I mentioned in the previous article that ColdFusion automatically detects any new or newly edited templates and then automatically compiles them (in CFMX, or interprets them in CF 5 and before). It does this by checking to see if a CF template about to be executed is new or newly updated. And it does this before each invocation of a template, by every user.

That's a rather costly operation, but it's the cost of being able to freely make code changes and see them reflected immediately. If your production environment is designed so that you don't make changes to your code except on a scheduled basis (perhaps overnight), you should enable the "Trusted Cache" setting in the ColdFusion Administrator.

By enabling "Trusted Cache", you're telling ColdFusion that once it loads a program into memory, it should no longer check to see if its underlying source code template has been updated. This will remain in effect until the server is restarted. Sadly, disabling it and re-enabling it does not cause the template cache to be flushed.

One thing that has changed about the "trusted cache" is the specification of its size. Prior to CFMX, the size setting (on the same page in the Administrator) was set in bytes, and it was difficult to calculate an accurate size. Now, the setting is the total number of templates to cache, rather than their size. It still defaults to 1,024.

More Stories By Charlie Arehart

A veteran ColdFusion developer since 1997, Charlie Arehart is a long-time contributor to the community and a recognized Adobe Community Expert. He's a certified Advanced CF Developer and Instructor for CF 4/5/6/7 and served as tech editor of CFDJ until 2003. Now an independent contractor (carehart.org) living in Alpharetta, GA, Charlie provides high-level troubleshooting/tuning assistance and training/mentoring for CF teams. He helps run the Online ColdFusion Meetup (coldfusionmeetup.com, an online CF user group), is a contributor to the CF8 WACK books by Ben Forta, and is frequently invited to speak at developer conferences and user groups worldwide.

Comments (1) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
Sven 11/14/02 04:59:00 AM EST
@ThingsExpo Stories
Big Data, cloud, analytics, contextual information, wearable tech, sensors, mobility, and WebRTC: together, these advances have created a perfect storm of technologies that are disrupting and transforming classic communications models and ecosystems. In his session at @ThingsExpo, Erik Perotti, Senior Manager of New Ventures on Plantronics’ Innovation team, provided an overview of this technological shift, including associated business and consumer communications impacts, and opportunities it ...
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
SYS-CON Events announced today that LeaseWeb USA, a cloud Infrastructure-as-a-Service (IaaS) provider, will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LeaseWeb is one of the world's largest hosting brands. The company helps customers define, develop and deploy IT infrastructure tailored to their exact business needs, by combining various kinds cloud solutions.
Manufacturers are embracing the Industrial Internet the same way consumers are leveraging Fitbits – to improve overall health and wellness. Both can provide consistent measurement, visibility, and suggest performance improvements customized to help reach goals. Fitbit users can view real-time data and make adjustments to increase their activity. In his session at @ThingsExpo, Mark Bernardo Professional Services Leader, Americas, at GE Digital, discussed how leveraging the Industrial Internet a...
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
The best-practices for building IoT applications with Go Code that attendees can use to build their own IoT applications. In his session at @ThingsExpo, Indraneel Mitra, Senior Solutions Architect & Technology Evangelist at Cognizant, provided valuable information and resources for both novice and experienced developers on how to get started with IoT and Golang in a day. He also provided information on how to use Intel Arduino Kit, Go Robotics API and AWS IoT stack to build an application tha...
Amazon has gradually rolled out parts of its IoT offerings in the last year, but these are just the tip of the iceberg. In addition to optimizing their back-end AWS offerings, Amazon is laying the ground work to be a major force in IoT – especially in the connected home and office. Amazon is extending its reach by building on its dominant Cloud IoT platform, its Dash Button strategy, recently announced Replenishment Services, the Echo/Alexa voice recognition control platform, the 6-7 strategic...
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
IoT generates lots of temporal data. But how do you unlock its value? You need to discover patterns that are repeatable in vast quantities of data, understand their meaning, and implement scalable monitoring across multiple data streams in order to monetize the discoveries and insights. Motif discovery and deep learning platforms are emerging to visualize sensor data, to search for patterns and to build application that can monitor real time streams efficiently. In his session at @ThingsExpo, ...
Verizon Communications Inc. (NYSE, Nasdaq: VZ) and Yahoo! Inc. (Nasdaq: YHOO) have entered into a definitive agreement under which Verizon will acquire Yahoo's operating business for approximately $4.83 billion in cash, subject to customary closing adjustments. Yahoo informs, connects and entertains a global audience of more than 1 billion monthly active users** -- including 600 million monthly active mobile users*** through its search, communications and digital content products. Yahoo also co...
There will be new vendors providing applications, middleware, and connected devices to support the thriving IoT ecosystem. This essentially means that electronic device manufacturers will also be in the software business. Many will be new to building embedded software or robust software. This creates an increased importance on software quality, particularly within the Industrial Internet of Things where business-critical applications are becoming dependent on products controlled by software. Qua...
In addition to all the benefits, IoT is also bringing new kind of customer experience challenges - cars that unlock themselves, thermostats turning houses into saunas and baby video monitors broadcasting over the internet. This list can only increase because while IoT services should be intuitive and simple to use, the delivery ecosystem is a myriad of potential problems as IoT explodes complexity. So finding a performance issue is like finding the proverbial needle in the haystack.
Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, discussed how research has demonstrated the value of Machine Learning in delivering next generation analytics to imp...
Large scale deployments present unique planning challenges, system commissioning hurdles between IT and OT and demand careful system hand-off orchestration. In his session at @ThingsExpo, Jeff Smith, Senior Director and a founding member of Incenergy, will discuss some of the key tactics to ensure delivery success based on his experience of the last two years deploying Industrial IoT systems across four continents.
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportuni...
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develo...
Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 19th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world and ThingsExpo Silicon Valley Call for Papers is now open.
IoT is rapidly changing the way enterprises are using data to improve business decision-making. In order to derive business value, organizations must unlock insights from the data gathered and then act on these. In their session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, and Peter Shashkin, Head of Development Department at EastBanc Technologies, discussed how one organization leveraged IoT, cloud technology and data analysis to improve customer experiences and effi...