Click here to close now.

Welcome!

You will be redirected in 30 seconds or close now.

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

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
SYS-CON Events announced today that GENBAND, a leading developer of real time communications software solutions, has been named “Silver Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. The GENBAND team will be on hand to demonstrate their newest product, Kandy. Kandy is a communications Platform-as-a-Service (PaaS) that enables companies to seamlessly integrate more human communications into their Web and mobile applications - creating more engaging experiences for their customers and boosting collaboration and productiv...
SYS-CON Events announced today that BroadSoft, the leading global provider of Unified Communications and Collaboration (UCC) services to operators worldwide, has been named “Gold Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. BroadSoft is the leading provider of software and services that enable mobile, fixed-line and cable service providers to offer Unified Communications over their Internet Protocol networks. The Company’s core communications platform enables the delivery of a range of enterprise and consumer calling...
So I guess we’ve officially entered a new era of lean and mean. I say this with the announcement of Ubuntu Snappy Core, “designed for lightweight cloud container hosts running Docker and for smart devices,” according to Canonical. “Snappy Ubuntu Core is the smallest Ubuntu available, designed for security and efficiency in devices or on the cloud.” This first version of Snappy Ubuntu Core features secure app containment and Docker 1.6 (1.5 in main release), is available on public clouds, and for ARM and x86 devices on several IoT boards. It’s a Trend! This announcement comes just as...
What exactly is a cognitive application? In her session at 16th Cloud Expo, Ashley Hathaway, Product Manager at IBM Watson, will look at the services being offered by the IBM Watson Developer Cloud and what that means for developers and Big Data. She'll explore how IBM Watson and its partnerships will continue to grow and help define what it means to be a cognitive service, as well as take a look at the offerings on Bluemix. She will also check out how Watson and the Alchemy API team up to offer disruptive APIs to developers.
The IoT Bootcamp is coming to Cloud Expo | @ThingsExpo on June 9-10 at the Javits Center in New York. Instructor. Registration is now available at http://iotbootcamp.sys-con.com/ Instructor Janakiram MSV previously taught the famously successful Multi-Cloud Bootcamp at Cloud Expo | @ThingsExpo in November in Santa Clara. Now he is expanding the focus to Janakiram is the founder and CTO of Get Cloud Ready Consulting, a niche Cloud Migration and Cloud Operations firm that recently got acquired by Aditi Technologies. He is a Microsoft Regional Director for Hyderabad, India, and one of the f...
The 17th International Cloud Expo has announced that its Call for Papers is open. 17th International Cloud Expo, to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, APM, APIs, Microservices, Security, Big Data, Internet of Things, DevOps 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 opportunity. Submit your speaking proposal today!
In 2015, 4.9 billion connected "things" will be in use. By 2020, Gartner forecasts this amount to be 25 billion, a 410 percent increase in just five years. How will businesses handle this rapid growth of data? Hadoop will continue to improve its technology to meet business demands, by enabling businesses to access/analyze data in real time, when and where they need it. Cloudera's Chief Technologist, Eli Collins, will discuss how Big Data is keeping up with today's data demands and how in the future, data and analytics will be pervasive, embedded into every workflow, application and infra...
As Marc Andreessen says software is eating the world. Everything is rapidly moving toward being software-defined – from our phones and cars through our washing machines to the datacenter. However, there are larger challenges when implementing software defined on a larger scale - when building software defined infrastructure. In his session at 16th Cloud Expo, Boyan Ivanov, CEO of StorPool, will provide some practical insights on what, how and why when implementing "software-defined" in the datacenter.
SYS-CON Media announced today that @ThingsExpo Blog launched with 7,788 original stories. @ThingsExpo Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. @ThingsExpo Blog can be bookmarked. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago.
The world's leading Cloud event, Cloud Expo has launched Microservices Journal on the SYS-CON.com portal, featuring over 19,000 original articles, news stories, features, and blog entries. DevOps Journal is focused on this critical enterprise IT topic in the world of cloud computing. Microservices Journal offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. Follow new article posts on Twitter at @MicroservicesE
SYS-CON Events announced today that robomq.io will exhibit at SYS-CON's @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. robomq.io is an interoperable and composable platform that connects any device to any application. It helps systems integrators and the solution providers build new and innovative products and service for industries requiring monitoring or intelligence from devices and sensors.
Wearable technology was dominant at this year’s International Consumer Electronics Show (CES) , and MWC was no exception to this trend. New versions of favorites, such as the Samsung Gear (three new products were released: the Gear 2, the Gear 2 Neo and the Gear Fit), shared the limelight with new wearables like Pebble Time Steel (the new premium version of the company’s previously released smartwatch) and the LG Watch Urbane. The most dramatic difference at MWC was an emphasis on presenting wearables as fashion accessories and moving away from the original clunky technology associated with t...
SYS-CON Events announced today that Litmus Automation will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Litmus Automation’s vision is to provide a solution for companies that are in a rush to embrace the disruptive Internet of Things technology and leverage it for real business challenges. Litmus Automation simplifies the complexity of connected devices applications with Loop, a secure and scalable cloud platform.
SYS-CON Events announced today that Vicom Computer Services, Inc., a provider of technology and service solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. They are located at booth #427. Vicom Computer Services, Inc. is a progressive leader in the technology industry for over 30 years. Headquartered in the NY Metropolitan area. Vicom provides products and services based on today’s requirements around Unified Networks, Cloud Computing strategies, Virtualization around Software defined Data Ce...
SYS-CON Events announced today the IoT Bootcamp – Jumpstart Your IoT Strategy, being held June 9–10, 2015, in conjunction with 16th Cloud Expo and Internet of @ThingsExpo at the Javits Center in New York City. This is your chance to jumpstart your IoT strategy. Combined with real-world scenarios and use cases, the IoT Bootcamp is not just based on presentations but includes hands-on demos and walkthroughs. We will introduce you to a variety of Do-It-Yourself IoT platforms including Arduino, Raspberry Pi, BeagleBone, Spark and Intel Edison. You will also get an overview of cloud technologies s...
IoT is still a vague buzzword for many people. In his session at @ThingsExpo, Mike Kavis, Vice President & Principal Cloud Architect at Cloud Technology Partners, discussed the business value of IoT that goes far beyond the general public's perception that IoT is all about wearables and home consumer services. He also discussed how IoT is perceived by investors and how venture capitalist access this space. Other topics discussed were barriers to success, what is new, what is old, and what the future may hold. Mike Kavis is Vice President & Principal Cloud Architect at Cloud Technology Pa...
@ThingsExpo has been named the Top 5 Most Influential Internet of Things Brand by Onalytica in the ‘The Internet of Things Landscape 2015: Top 100 Individuals and Brands.' Onalytica analyzed Twitter conversations around the #IoT debate to uncover the most influential brands and individuals driving the conversation. Onalytica captured data from 56,224 users. The PageRank based methodology they use to extract influencers on a particular topic (tweets mentioning #InternetofThings or #IoT in this case) takes into account the number and quality of contextual references that a user receives.
Buzzword alert: Microservices and IoT at a DevOps conference? What could possibly go wrong? Join this panel of experts as they peel away the buzz and discuss the important architectural principles behind implementing IoT solutions for the enterprise. As remote IoT devices and sensors become increasingly intelligent, they become part of our distributed cloud environment, and we must architect and code accordingly. At the very least, you’ll have no problem filling in your buzzword bingo cards.
SYS-CON Events announced today that AIC, a leading provider of OEM/ODM server and storage solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. AIC is a leading provider of both standard OTS, off-the-shelf, and OEM/ODM server and storage solutions. With expert in-house design capabilities, validation, manufacturing and production, AIC's broad selection of products are highly flexible and are configurable to any form factor or custom configuration. AIC leads the industry with nearly 20 years of ...
Containers and microservices have become topics of intense interest throughout the cloud developer and enterprise IT communities. Accordingly, attendees at the upcoming 16th Cloud Expo at the Javits Center in New York June 9-11 will find fresh new content in a new track called PaaS | Containers & Microservices Containers are not being considered for the first time by the cloud community, but a current era of re-consideration has pushed them to the top of the cloud agenda. With the launch of Docker's initial release in March of 2013, interest was revved up several notches. Then late last...