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  • 502: proxy: pass request body failed

    - by Andrei Serdeliuc
    Sometimes I get the following error (in apache's error.log) when viewing my site over https: (502)Unknown error 502: proxy: pass request body failed to xxx.xxx.xxx.xxx:443 I'm not entirely sure what this is and why it happens, it's also not consistent. The request route is: Browser Proxy server (apache with mod_proxy + mod_ssl) Load balancer (aws) Web server (apache with mod_ssl) The configuration on the proxy server is as follows: <VirtualHost *:443> ProxyRequests Off ProxyVia On ServerName www.xxx.co.uk ServerAlias xxx.co.uk <Directory proxy:*> Order deny,allow Allow from all </Directory> <Proxy *> AddDefaultCharset off Order deny,allow Allow from all </Proxy> ProxyPass / balancer://cluster:443/ lbmethod=byrequests ProxyPassReverse / balancer://cluster:443/ ProxyPreserveHost off SSLProxyEngine On SSLEngine on SSLCipherSuite ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP:+eNULL SSLCertificateFile /var/www/vhosts/xxx/ssl/www.xxx.co.uk.cert SSLCertificateKeyFile /var/www/vhosts/xxx/ssl/www.xxx.co.uk.key <Proxy balancer://cluster> BalancerMember https://xxx.eu-west-1.elb.amazonaws.com </Proxy> </VirtualHost> Any idea what the issue might be?

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  • Ubuntu Server mdadm drbd ocfs2 kvm hangs under heavy file reading

    - by Stefano Annese
    I have deployed four ubuntu 10.04 server. They are coupled two by two in a cluster scenario. on both sides we have software raid1 disks, drbd8 and OCFS2 and on top of it some kvm machines run with qcow2 disks. I followed this: Link corosync is just used for DRBD and OCFS, the kvm machines are run "manually" When it works is fine: good performances, good I/O, but at a given time one of the two cluster started hanging. Then we tried with just one server turned on and it hangs the same. It seems to happen when an heavy READ in one of the virtual machines occurs, that is during rsyn backup. When the fact occurs the virtual machines are not reachable any more and the real server responds with good delay to the ping but no screen and no ssh is available. All we can do is force shutdown (hold the button) and restart and when it turns on again the raid on which relay drbd is resyncing. All the time it hangs we see such fact. After a couple of week of pain on one side this morning also the other cluster hung, but it has different moteherboard, ram, kvm instances. What is similar is reading for rsync scenario and Western Digital RAID Edistion disks on both side. Can anybody give me some input to solve such issue?

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  • Reverse and Forward DNS set up correctly but sometimes MapReduce job fails

    - by phodamentals
    Ever since we switched over our cluster to communicate via private interfaces and created a DNS server with correct forward and reverse lookup zones, we get this message before the M/R job runs: ERROR org.apache.hadoop.hbase.mapreduce.TableInputFormatBase - Cannot resolve the host name for /192.168.3.9 because of javax.naming.NameNotFoundException: DNS name not found [response code 3]; remaining name '9.3.168.192.in-addr.arpa' A dig and nslookup both show that the reverse and forward look-ups both get good responses with no errors from within the cluster. Shortly after these messages, the job runs...but every once in awhile we get a NPE: Exception in thread "main" java.lang.NullPointerException INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.net.DNS.reverseDns(DNS.java:93) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.reverseDNS(TableInputFormatBase.java:219) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.getSplits(TableInputFormatBase.java:184) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.mapred.JobClient.writeNewSplits(JobClient.java:1063) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.mapred.JobClient.writeSplits(JobClient.java:1080) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.mapred.JobClient.access$600(JobClient.java:174) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:992) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:945) INFO app.insights.search.SearchIndexUpdater - at java.security.AccessController.doPrivileged(Native Method) INFO app.insights.search.SearchIndexUpdater - at javax.security.auth.Subject.doAs(Subject.java:415) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1408) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:945) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.mapreduce.Job.submit(Job.java:566) INFO app.insights.search.SearchIndexUpdater - at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:596) INFO app.insights.search.SearchIndexUpdater - at app.insights.search.correlator.comments.CommentCorrelator.main(CommentCorrelator.java:72 Does anyone else who has set-up a CDH Hadoop cluster on a private network w/DNS server get this? CDH 4.3.1 with MR1 2.0.0 and HBase 0.94.6

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  • install latest gcc as a non-privileged user

    - by voth
    I want to compile a program on a cluster (as a non-privileged user), which requires gcc-4.6, but the cluster has only gcc-4.1.2. I don't want to tell the administrator to update gcc, because 1) he is busy and would do it only after several days. 2) He probably wouldn't update it anyway, since other users may need the older gcc version (gcc is not backward compatible) I tried to compile gcc from source, which seems more difficult that it sounds, since it requires several other packages to be installed (GMP, MPFR, MPC, ...), and when I did it, after several hours I got a message like checking for __gmpz_init in -lgmp... no configure: error: libgmp not found or uses a different ABI (including static vs shared). at which point a got stuck. My question is: what is the easiest way to install the latest version of gcc as a non-privileged user? (something like apt-get install XXXXX, with an option to not install as root for example) The setup of the cluster is the following: CentOS release 5.4 (Final) Rocks release 5.3 (Rolled Tacos) If there are no other options than compiling from source, do you have any ideas how to handle the above error?

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  • SQL Server performance on VSphere 4.0

    - by Charles
    We are having a performance issue that we cannot explain with our VMWare environment and I am hoping someone here may be able to help. We have a web application that uses a databases backend. We have an SQL 2005 Cluster setup on Windows 2003 R2 between a physical node and a virtual node. Both physical servers are identical 2950's with 2x Xeaon x5460 Quad Core CPUs and 64GB of memory, 16GB allocated to the OS. We are utilizing an iSCSI San for all cluster disks. The problem is this, when utilizing the application under a repeated stress testing that adds CPUs to the cluster nodes, the Physical node scales from 1 pCPU to 8 pCPUs, meaning we see continued performance increases. When testing the node running Vsphere, we have the expected 12% performance hit for being virtual but we still scale from 1 vCPU to 4 vCPUs like the physical but beyond this performance drops off, by the time we get to 8 vCPUs we are seeing performance numbers worse than at 4 vCPUs. Again, both nodes are configured identically in terms of hardware, Guest OS, SQL Configurations etc and there is no traffic other than the testing on the system. There are no other VMs on the virtual server so there should be no competition for resources. We have contacted VMWare for help but they have not really been any suggesting things like setting SQL Processor Affinity which, while being helpful would have the same net effect on each box and should not change our results in the least. We have looked at all of VMWare's SQL Tuning guides with regards to VSphere with no benefit, please help!

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  • Upgrade SQLServer 2008 hardware

    - by John
    Forgive me if I'm not able to be totally clear here. It is not intentional, I'm a senior level developer in a very small company having to act like a manager at the moment. Anyway, the story is that we have 2 older dell servers with SQL Server 2008 Standard in a "cluster". I put that in quotes because I'm still not 100% clear what that means. We have 2 brand new blade servers and want to move the existing databases to the new hardware. Ok, so here is the gotcha. We need to do this with little or no down time. I'm being told that we can evict the passive node, then pull in one of the new servers. But I'm also being told that this is a dangerous step because something could go wrong that would cause the cluster to fail and then we would be left with nothing because the active server would not be able to come back up. Does anyone have any thoughts on how to handle this? I'm being told that the only way to ensure success is to have at least a day of down time where we bring up a new cluster on the new hardware and then migrate the databases 1 by 1.

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  • Hadoop streaming job on EC2 stays in "pending" state

    - by liamf
    Trying to experiment with Hadoop and Streaming using cloudera distribution CDH3 on Ubuntu. Have valid data in hdfs:// ready for processing. Wrote little streaming mapper in python. When I launch a mapper only job using: hadoop jar /usr/lib/hadoop/contrib/streaming/hadoop-streaming*.jar -file /usr/src/mystuff/mapper.py -mapper /usr/src/mystuff/mapper.py -input /incoming/STBFlow/* -output testOP hadoop duly decides it will use 66 mappers on the cluster to process the data. The testOP directory is created on HDFS. A job_conf.xml file is created. But the job tracker UI at port 50030 never shows the job moving out of "pending" state and nothing else happens. CPU usage stays at zero. (the job is created though) If I give it a single file (instead of the entire directory) as input, same result (except Hadoop decides it needs 2 mappers instead of 66). I also tried using the "dumbo" Python utility and launching jobs using that: same result: permanently pending. So I am missing something basic: could someone help me out with what I should look for? The cluster is on Amazon EC2. Firewall issues maybe: ports are enabled explicitly, case by case, in the cluster security group.

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  • Re-packaging commercial software into RPM packages

    - by gac
    The situation is this - I have a small CentOS 5 "cluster" (currently 7 machines, but potential for more) which run a commercially available software package that's distributed essentially in tarball format (it's actually a zip file with a mixture of Windows/Linux binaries and an installation shell script with no potential for automation). I'd like to re-package this somehow into an RPM package (ideally that I can throw onto a self-hosted yum repository) in order to keep these "cluster" machines both up to date and consistent. I could do 7 manual installations, but there's scope for error. As I understand it, I'll need to accomplish the following tasks: add a non-privileged user to the target system for running the daemon without unnecessary root privileges package the binary files themselves up from the final installation location on a separate build machine (probably under /opt/package for sanity's sake). No source is available. add a firewall hole in order for the end-users to be able to communicate with the "cluster" nodes add a cron task which can start the daemon on @reboot I'm coming up with plenty of good packaging resources so far, but all are based on the traditional method (i.e. if I were the vendor packaging up my source files), rather than re-packaging a ton of binary files from an already-installed instance of the application, which is the only option available to me. Anyone have any good resources they can share for achieving this goal? Thanks!

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  • vSphere education - What are the downsides of configuring virtual machines with *too* much RAM?

    - by ewwhite
    VMware memory management seems to be a tricky balancing act. With cluster RAM, Resource Pools, VMware's management techniques (TPS, ballooning, host swapping), in-guest RAM utilization, swapping, reservations, shares and limits, there are a lot of variables. I'm in a situation where clients are using dedicated vSphere cluster resources. However, they are configuring the virtual machines as though they were on physical hardware. In turn, this means a standard VM build may have 4 vCPUs and 16GB or more of RAM. I come from the school of starting small (1 vCPU, minimal RAM), checking real-world use and adjusting up as necessary. Some examples from a "problem" cluster. Resource pool summary - Looks almost 4:1 overcommitted. Note the high amount of ballooned RAM. Resource allocation - The Worst Case Allocation column shows that these VMs would have access to less than 50% of their configured RAM under constrained conditions. The real-time memory utilization graph of the top VM in the listing above. 4 vCPU and 64GB RAM allocated. It averages under 9GB use. Summary of the same VM What are the downsides of overcommitting and overconfiguring resources (specifically RAM) in vSphere environments? Assuming that the VMs can run in less RAM, is it fair to say that there's overhead to configuring virtual machines with more RAM than they need? What is the counter-argument to: "if a VM has 16GB of RAM allocated, but only uses 4GB, what's the problem??"? E.g. do customers need to be educated? What specific metric should be used to meter RAM usage. Tracking the peaks of "Active" versus time?

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  • How to keep multiple servers in sync file wise?

    - by GForceSys
    I'm currently managing a cluster of PHP-FPM servers, all of which tend to get out of sync with each other. The application that I'm using on top of the app servers (Magento) allows for admins to modify various files on the system, but now that the site is in a clustered set up modifying a file only modifies it on a single instance (on one of the app servers) of the various machines in the cluster. Is there an open-source application for Linux that may allow me to keep all of these servers in sync? I have no problem with creating a small VM instance that can listen for changes from machines to sync. In theory, the perfect application would have small clients that run on each machine to be synced, which would talk to the master server which would then decide how/what to sync from each machine. I have already examined the possibilities of running a centralized file server, but unfortunately my app servers are spread out between EC2 and physical machines, which makes this unfeasible. As there are multiple app servers (some of which are dynamically created depending on the load of the site), simply setting up a rsync cron job is not efficient as the cron job would have to be modified on each machine to send files to every other machine in the cluster, and that would just be a whole bunch of unnecessary data transfers/ssh connections.

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  • Redirect without changing URL

    - by Coobadivin
    Here's the setup. We have a hardware load balancer with an http virtual cluster. Let's call this virtual cluster example1.com. This virtual cluster load balances between two squid reverse proxies which are also on the same physical servers as the web servers. Squid listens on 80 and points to itself as the cache_peer web server which listens on 81. We also have a standalone web server which we will call example2.com. What we are trying to do is create a subdirectory on example1.com called example1.com/example2. This will point to example2.com, but we want our users to stay at example1.com/example2 in their browser. So, it's like a redirect without actually being a redirect. How the hell do I go about doing this? Is this even possible? I'm looking at squid docs in the meantime. example1.com is running a proprietary web server - not Apache :( We can't host example2.com's content in example1.com's file system. These are two very different platforms.

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  • File descriptor limits and default stack sizes

    - by Charles
    Where I work we build and distribute a library and a couple complex programs built on that library. All code is written in C and is available on most 'standard' systems like Windows, Linux, Aix, Solaris, Darwin. I started in the QA department and while running tests recently I have been reminded several times that I need to remember to set the file descriptor limits and default stack sizes higher or bad things will happen. This is particularly the case with Solaris and now Darwin. Now this is very strange to me because I am a believer in 0 required environment fiddling to make a product work. So I am wondering if there are times where this sort of requirement is a necessary evil, or if we are doing something wrong. Edit: Great comments that describe the problem and a little background. However I do not believe I worded the question well enough. Currently, we require customers, and hence, us the testers, to set these limits before running our code. We do not do this programatically. And this is not a situation where they MIGHT run out, under normal load our programs WILL run out and seg fault. So rewording the question, is requiring the customer to change these ulimit values to run our software to be expected on some platforms, ie, Solaris, Aix, or are we as a company making it to difficult for these users to get going? Bounty: I added a bounty to hopefully get a little more information on what other companies are doing to manage these limits. Can you set these pragmatically? Should we? Should our programs even be hitting these limits or could this be a sign that things might be a bit messy under the covers? That is really what I want to know, as a perfectionist a seemingly dirty program really bugs me.

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  • If You Could Cut Your Meeting Times in ½ Would You?

    - by Brian Dayton
                    I know it sounds like a big promise. And what I'm thinking about may not cut a :60 minute meeting into :30 minutes, but it could make meetings and interactions up to 2X more productive. How? Social Media for the Enterprise, Not Social Media In the Enterprise Bear with me. I'm not talking about whether or not workers should or shouldn't have access to Facebook on corporate networks. That topic has been discussed @ length. I'm also not talking about the direct benefits of Social Networking tools like Presence (the ability to see someone online and ask a question in real-time), blogs, RSS feeds or external tools like Twitter. The Un-Measurable Benefits Would you do something that you believe will have a positive effect--but can't be measured? It's impossible to quantify the effectiveness of a meeting. However, what I am talking about would be more of a byproduct of all of the social networking tools above. Here's the hypothesis: As I've gotten more and more busy with work, family, travel and kids--and the same has happened to my friends and family--I'm less and less connected. But by introducing Facebook to my life I've not only made connections with longtime friends whom I haven't spoken to in years--but I've increased the pace and quality of interactions, on and offline, with close friends who I see and speak to every week. In some cases it even enhances the connections and interactions with those I see or speak to every day. The same holds true in an organization. Especially a larger one with highly matrixed organizational structures. You work with people on a project, new people come in with each different project and a disproportionate amount of time is spent getting oriented and staying current. Going back to the initial value proposition--making meetings shorter/more effective--a large amount of time is spent: -          At Project Kick-off: Meeting and understanding team member's histories, goals & roles -          Ongoing: Summarizing events since the last meeting or update email In my personal, Facebook life today I know that: -          My best friend from college - has been stranded in India for 5 days because of the volcano in Iceland and is now only 250 miles from home -          One of my co-workers started conference calls at 6:30 this morning -          My wife wasn't terribly pleased with my painting skills in our new bathroom (disclosure: she told me this face to face too) Strengthening Weak Links A recent article in CIO Magazine, Three Dangerous Social Media Misconceptions (Kristen Burnham, March 12, 2010) calls out the #1 misconception as follows: 1. "Face-to-face relationships are far more valuable than virtual ones." While some level of physical interaction will always add value to relationships, Gartner says that come 2020, most relationships and teams will be based on "weak links"--that is, you may not have personally met a contact, but you'll know of or may have interacted with him via social sites like Facebook, LinkedIn and Twitter. The sooner your enterprise adopts these tools, the sooner your employees will learn them, and the sooner you'll begin to cultivate these relationships-of-the-future.   I personally believe that it's not an either/or choice between face-to-face and virtual interactions. In fact, I'll be as bold as saying it doesn't matter. I can point to two extremely valuable work relationships that I've had over the past 5 years: -          I shared an office with one of them -          I met the other person, face-to-face, only once Both relationships were very productive. The dynamics were similar. The communication tactics differed immensely. What does matter is the quality, frequency and relevance of interactions. Still sound like too much? An over-promise? Stay tuned for my next post The Gap Between Facebook and LinkedIn. I'll also connect some of the dots with where Oracle Applications and technologies are headed.        

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  • Session Report: What’s New in JSF: A Complete Tour of JSF 2.2

    - by Janice J. Heiss
    On Wednesday, Ed Burns, Consulting Staff Member at Oracle, presented a session, CON3870 -- “What’s New in JSF: A Complete Tour of JSF 2.2,” in which he provided an update on recent developments in JavaServer Faces 2.2. He began by emphasizing that, “JavaServer Faces 2.2 continues the evolution of the Java EE standard user interface technology. Like previous releases, this iteration is very community-driven and transparent.” He pointed out that since JSF was introduced at the 2001 JavaOne Keynote, it has had a long and successful run and has found a home in applications where the UI logic resides entirely on the server where the model and UI logic is. In such cases, the browser performs fairly simple functions. However, developers can take advantage of the power of browsers, something that Project Avatar is focused on by letting developers author their applications so the UI logic is running on the client and communicating to the back end via RESTful web services. “Most importantly,” remarked Burns, “JSF 2.2 offers a really good migration path because even in the scope of one application you could have an app written with JSF that has its UI logic on the server and, on a gradual basis, you could migrate parts of the app over to use client-side technologies. This can be done at any level of granularity – per page or per collection of pages. It all depends on what you want to do.” His presentation, which focused on the basic new features of JSF 2.2, began by restating the scope of JSF and encouraged attendees to check out Roger Kitain’s session: CON5133 “Techniques for Responsive Real-Time Web UIs.” Burns explained that JSF has endured because, “We still need web apps that are maintainable, localizable, quick to build, accessible, secure, look great and are fun to use.” It is used on every continent – the curious can go here to check out where its unofficial usage is tracked. He emphasized the significance of the UI logic being substantially on the server. This: Separates Component Semantics from Rendering, Allows components to “own” their little patch of the UI -- encode/decode, And offers a well-defined lifecycle: Inversion of Control. Burns reminded attendees that JSR-344, the spec for JSF 2.2, is now on Java Community Process 2.8, a revised version of the JCP that allows for more openness and transparency. He then offered some tools for community access to JSF 2.2:    * Public java.net projects spec http://jsf-spec.java.net/ impl http://jsf.java.net/ Open Source: GPL+Classpath Exception    * Mailing Lists [email protected]                                Public readable archive, JSPA signed member read/write [email protected]                                     Public readable archive, any java.net member read/write                         All mail sent to jsr344-experts is sent to users. * Issue Tracker spec http://jsf-spec.java.net/issues/ impl http://jsf.java.net/issues/ JSF 2.2, which is JSR 344, has a Public Review Draft planned by December 2012 with no need for a Renewal Ballot. The Early Draft Review of JSR 344 was published on December 8, 2011. Interested developers are encouraged to offer their input. Six Big Ticket Features of JSF 2.2 Burns summarized the six big ticket features of JSF 2.2:* HTML5 Friendly Markup Support Pass through attributes and elements * Faces Flows* Cross Site Request Forgery Protection* Loading Facelets via ResourceHandler* File Upload Component* Multi-Templating He explained that he called it “HTML 5 friendly” because there is really nothing HTML 5 specific about it -- it could be 4. But it enables developers to use new elements that are present in HTML5 without having a JSF component library that is written to take advantage of those specifically. It gives the page author the ability to use plain HTML5 to write their page, but to still take advantage of the server-side available in JSF. He presented a demo showing JSF 2.2’s ability to leverage the expressiveness of HTML5. Burns then explained the significance of face flows, which offer function points and quantify how much work has taken place, something of great value to JSF users. He went on to talk about JSF 2.2.’s cross-site request forgery protection (CSRF) and offered details about how it protects applications against attack. Then he talked about JSF 2.2’s File Upload Component and explained that the final specification will have Ajax and non-Ajax support. The current milestone has non-Ajax support implemented. He then went on to explain its capacity to add facelets through ResourceHandler. Previously, JSF 2.0 added Facelets and ResourceHandler as disparate units; now in JSF 2.2 the two concepts are unified. Finally, he explained the concept of multi-templating in JSF 2.2 and went on to discuss more medium-level features of the release. For an easy, low maintenance way of staying in touch with JSF developments go to JSF’s Twitter page where every month or so, important updates are offered.

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  • Book Review Charlene Li's New Book: Open Leadership

    - by david.talamelli
    A few weeks ago, I was surprised when I looked in our mail box. I had received an Advance Copy of Charlene Li's new book titled "Open Leadership: How Social Technology Can Transform the Way You Lead". Charlene sent a tweet a while back asking anyone interested in receiving the book to submit their details. I sent off my details and didn't think I would hear anything back, so it was a pleasant surprise. With that I almost feel bad that it has taken me 3 weeks to read her book. It took this long mainly because it has been hard to fit in some quality reading time for myself with work, the kids, volunteering, etc..... I am happy to report I have finished her book and wanted to run through my initial thoughts with you. I first came across Charlene Li after reading her book "Groundswell" a few years ago, her latest book "Open Leadership" is a follow on from Groundswell and to me it seems like a natural progression from the question "Ok the business landscape is changing, what do we do now?" For me these two books have a different writing style to them. Groundswell from memory spoke about broad social media concepts and adoption and alerted us to some of the changes taking place in the SM landscape. Open Leadership seems to be focussed on taking those broad concepts and finding ways to implement them into your environment. That is breaking broad concepts down into individual action items that can be measured and analysed. As the business world changes Leaders must change their approach and let go of control to more control. One of the things I love reading about is seeing real life examples of how people and organisations are making these things happen. In this book Charlene has collected some great collateral and case studies from companies such as Cisco, Best Buy, The Red Cross and The State Bank of India (as a side-note, I wish now that I submitted my input for the Leaders I work with here at Oracle - there are some great examples here of people who empower their staff). As society becomes more adept at using social media it is inevitable that Leaders must become open with their employees, clients and partners. From the book some of the key points I took away are (I actually took away a lot more from this book, this is just an overview) : 1) Organisations should encourage risk taking. Without being a "hacker", how can we improve ourselves, our processes, our business, etc... The old saying you only fail by not trying applies here. If Leaders create a culture where people are afraid to stick their neck out - how will you innovate? 2) Leaders need to lead by example - if you want to promote an open and transparent business, a Leader needs to exemplify the traits they would like to see out of their employees. 3) The definition of a Leader is changing, open leadership is about being a catalyst to change that uses networks to spread a vision as opposed to traditional leadership that is viewed as a role. 4) There is a cultural and business shift taking place. Information is more wide-spread and is being disseminated faster than any other time in the past. Leaders who are open and transparent will thrive in this new business environment. 5) Leadership is not defined by a title - it is defined by a person's actions. Also anyone can be a Leader or has Leadership potential in them- it is a matter of drawing that out of people. I found this book useful and I also found myself looking at my own actions and the actions of others around me (including my management) to see how open and transparent I am in my work. For me I am glad I read this book as it validated my own thoughts of the changes we are seeing take place. This book has certainly given me some new ideas and helped me push my own boundaries of what I can do. The book has a number of action plans at the end of some of the chapters such as "Conducting you Openness Audit" that I think have helped me take thoughts and ideas and turn them into concrete action items. I have included a link to the introduction of the book here if anyone wants to have a read of it. If anyone else has read this book, it would be great to hear your thoughts/comments/review. Leave your comments below. This article was originally posted on David Talamelli's Blog - David's Journal on Tap

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  • WebLogic Server Performance and Tuning: Part I - Tuning JVM

    - by Gokhan Gungor
    Each WebLogic Server instance runs in its own dedicated Java Virtual Machine (JVM) which is their runtime environment. Every Admin Server in any domain executes within a JVM. The same also applies for Managed Servers. WebLogic Server can be used for a wide variety of applications and services which uses the same runtime environment and resources. Oracle WebLogic ships with 2 different JVM, HotSpot and JRocket but you can choose which JVM you want to use. JVM is designed to optimize itself however it also provides some startup options to make small changes. There are default values for its memory and garbage collection. In real world, you will not want to stick with the default values provided by the JVM rather want to customize these values based on your applications which can produce large gains in performance by making small changes with the JVM parameters. We can tell the garbage collector how to delete garbage and we can also tell JVM how much space to allocate for each generation (of java Objects) or for heap. Remember during the garbage collection no other process is executed within the JVM or runtime, which is called STOP THE WORLD which can affect the overall throughput. Each JVM has its own memory segment called Heap Memory which is the storage for java Objects. These objects can be grouped based on their age like young generation (recently created objects) or old generation (surviving objects that have lived to some extent), etc. A java object is considered garbage when it can no longer be reached from anywhere in the running program. Each generation has its own memory segment within the heap. When this segment gets full, garbage collector deletes all the objects that are marked as garbage to create space. When the old generation space gets full, the JVM performs a major collection to remove the unused objects and reclaim their space. A major garbage collect takes a significant amount of time and can affect system performance. When we create a managed server either on the same machine or on remote machine it gets its initial startup parameters from $DOMAIN_HOME/bin/setDomainEnv.sh/cmd file. By default two parameters are set:     Xms: The initial heapsize     Xmx: The max heapsize Try to set equal initial and max heapsize. The startup time can be a little longer but for long running applications it will provide a better performance. When we set -Xms512m -Xmx1024m, the physical heap size will be 512m. This means that there are pages of memory (in the state of the 512m) that the JVM does not explicitly control. It will be controlled by OS which could be reserve for the other tasks. In this case, it is an advantage if the JVM claims the entire memory at once and try not to spend time to extend when more memory is needed. Also you can use -XX:MaxPermSize (Maximum size of the permanent generation) option for Sun JVM. You should adjust the size accordingly if your application dynamically load and unload a lot of classes in order to optimize the performance. You can set the JVM options/heap size from the following places:     Through the Admin console, in the Server start tab     In the startManagedWeblogic script for the managed servers     $DOMAIN_HOME/bin/startManagedWebLogic.sh/cmd     JAVA_OPTIONS="-Xms1024m -Xmx1024m" ${JAVA_OPTIONS}     In the setDomainEnv script for the managed servers and admin server (domain wide)     USER_MEM_ARGS="-Xms1024m -Xmx1024m" When there is free memory available in the heap but it is too fragmented and not contiguously located to store the object or when there is actually insufficient memory we can get java.lang.OutOfMemoryError. We should create Thread Dump and analyze if that is possible in case of such error. The second option we can use to produce higher throughput is to garbage collection. We can roughly divide GC algorithms into 2 categories: parallel and concurrent. Parallel GC stops the execution of all the application and performs the full GC, this generally provides better throughput but also high latency using all the CPU resources during GC. Concurrent GC on the other hand, produces low latency but also low throughput since it performs GC while application executes. The JRockit JVM provides some useful command-line parameters that to control of its GC scheme like -XgcPrio command-line parameter which takes the following options; XgcPrio:pausetime (To minimize latency, parallel GC) XgcPrio:throughput (To minimize throughput, concurrent GC ) XgcPrio:deterministic (To guarantee maximum pause time, for real time systems) Sun JVM has similar parameters (like  -XX:UseParallelGC or -XX:+UseConcMarkSweepGC) to control its GC scheme. We can add -verbosegc -XX:+PrintGCDetails to monitor indications of a problem with garbage collection. Try configuring JVM’s of all managed servers to execute in -server mode to ensure that it is optimized for a server-side production environment.

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  • Dynamic Grouping and Columns

    - by Tim Dexter
    Some good collaboration between myself and Kan Nishida (Oracle BIP Consulting) over at bipconsulting on a question that came in yesterday to an internal mailing list. Is there a way to allow columns to be place into a template dynamically? This would be similar to the Answers Column selector. A customer has said Crystal can do this and I am trying to see how BI Pub can do the same. Example: Report has Regions as a dimension in a table, they want the user to select a parameter that will insert either Units or Dollars without having to create multiple templates. Now whether Crystal can actually do it or not is another question, can Publisher? Yes we can! Kan took the first stab. His approach, was to allow to swap out columns in a table in the report. Some quick steps: 1. Create a parameter from BIP server UI 2. Declare the parameter in RTF template You can check this post to see how you can declare the parameter from the server. http://bipconsulting.blogspot.com/2010/02/how-to-pass-user-input-values-to-report.html 3. Use the parameter value to condition if a particular column needs to be displayed or not. You can use <?if@column:.....?> syntax for Column level IF condition. The if@column is covered in user documentation. This would allow a developer to create a report with the parameter or multiple parameters to allow the user to pick a column to be included in the report. I took a slightly different tack, with the mention of the column selector in the Answers report I took that to mean that the user wanted to select more of a dimensional column and then have the report recalculate all its totals and subtotals based on that selected column. This is a little bit more involved and involves some smart XSL and XPATH expressions, but still very doable. The user can select a column as a parameter, that is passed to the template rather than the query. The parameter value that is actually passed is the element name that you want to regroup the data by. Inside the template we then reference that parameter value in our for-each-group loop. That's where we need the trixy XSL/XPATH code to get the regrouping to happen. At this juncture, I need to hat tip to Klaus, for his article on dynamic sorting that he wrote back in 2006. I basically took his sorting code and applied it to the for-each loop. You can follow both of Kan's first two steps above i.e. Create a parameter from BIP server UI - this just needs to be based on a 'list' type list of value with name/value pairs e.g. Department/DEPARTMENT_NAME, Job/JOB_TITLE, etc. The user picks the 'friendly' value and the server passes the element name to the template. Declare the parameter in RTF template - been here before lots of times right? <?param@begin:group1;'"DEPARTMENT_NAME"'?> I have used a default value so that I can test the funtionality inside the template builder (notice the single and double quotes.) Next step is to use the template builder to build a re-grouped report layout. It does not matter if its hard coded right now; we will add in the dynamic piece next. Once you have a functioning template that is re-grouping correctly. Open up the for-each-group field and modify it to use the parameter: <?for-each-group:ROW;./*[name(.) = $group1]?> 'group1' is my grouping parameter, declared above. We need the XPATH expression to find the column in the XML structure we want to group that matches the one passed by the parameter. Its essentially looking through the data tree for a match. We can show the actual grouping value in the report output with a similar XPATH expression <?./*[name(.) = $group1]?> In my example, I took things a little further so that I could have a dynamic label for the parameter value. For instance if I am using MANAGER as the parameter I want to show: Manager: Tim Dexter My XML elements are readable e.g. DEPARTMENT_NAME. Its a simple case of replacing the underscore with a space and then 'initcapping' the result: <?xdoxslt:init_cap(translate($group1,'_',' '))?> With this in place, the user can now select a grouping column in the BIP report viewer and the layout will re-group the data and any calculations based on that column. I built a group above report but you could equally build the group left version to truly mimic the Answers column selector. If you are interested you can get an example report, sample data and layout template here. Of course, you can combine Klaus' dynamic sorting, Kan's conditional column approach and this dynamic grouping to build a real kick ass report for users that will keep them happy for hours..

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  • How to build Open JavaFX for Android.

    - by PictureCo
    Here's a short recipe for baking JavaFX for Android dalvik. We will need just a few ingredients but each one requires special care. So let's get down to the business.  SourcesThe first ingredient is an open JavaFX repository. This should be piece of cake. As always there's a catch. You probably know that dalvik is jdk6 compatible  and also that certain APIs are missing comparing to good old java vm from Oracle.  Fortunately there is a repository which is a backport of regular OpenJFX to jdk7 and going from jdk7 to jdk6 is possible. The first thing to do is to clone or download the repository from https://bitbucket.org/narya/jfx78. Main page of the project says "It works in some cases" so we will presume that it will work in most cases As I've said dalvik vm misses some APIs which would lead to a build failures. To get them use another compatibility repository which is available on GitHub https://github.com/robovm/robovm-jfx78-compat. Download the zip and unzip sources into jfx78/modules/base.We need also a javafx binary stubs. Use jfxrt.jar from jdk8.The last thing to download are freetype sources from http://freetype.org. These will be necessary for native font rendering. Toolchain setup I have to point out that these instructions were tested only on linux. I suppose they will work with minimal changes also on Mac OS. I also presume that you were able to build open JavaFX. That means all tools like ant, gradle, gcc and jdk8 have been installed and are working all right. In addition to this you will need to download and install jdk7, Android SDK and Android NDK for native code compilation.  Installing all of them will take some time. Don't forget to put them in your path. export ANDROID_SDK=/opt/android-sdk-linux export ANDROID_NDK=/opt/android-ndk-r9b export JAVA_HOME=/opt/jdk1.7.0 export PATH=$JAVA_HOME/bin:$ANDROID_SDK/tools:$ANDROID_SDK/platform-tools:$ANDROID_NDK FreetypeUnzip freetype release sources first. We will have to cross compile them for arm. Firstly we will create a standalone toolchain for cross compiling installed in ~/work/ndk-standalone-19. $ANDROID_NDK/build/tools/make-standalone-toolchain.sh  --platform=android-19 --install-dir=~/work/ndk-standalone-19 After the standalone toolchain has been created cross compile freetype with following script: export TOOLCHAIN=~/work/freetype/ndk-standalone-19 export PATH=$TOOLCHAIN/bin:$PATH export FREETYPE=`pwd` ./configure --host=arm-linux-androideabi --prefix=$FREETYPE/install --without-png --without-zlib --enable-shared sed -i 's/\-version\-info \$(version_info)/-avoid-version/' builds/unix/unix-cc.mk make make install It will compile and install freetype library into $FREETYPE/install. We will link to this install dir later on. It would be possible also to link openjfx font support dynamically against skia library available on Android which already contains freetype. It creates smaller result but can have compatibility problems. Patching Download patches javafx-android-compat.patch + android-tools.patch and patch jfx78 repository. I recommend to have look at patches. First one android-compat.patch updates openjfx build script, removes dependency on SharedSecret classes and updates LensLogger to remove dependency on jdk specific PlatformLogger. Second one android-tools.patch creates helper script in android-tools. The script helps to setup javaFX Android projects. Building Now is time to try the build. Run following script: JAVA_HOME=/opt/jdk1.7.0 JDK_HOME=/opt/jdk1.7.0 ANDROID_SDK=/opt/android-sdk-linux ANDROID_NDK=/opt/android-ndk-r9b PATH=$JAVA_HOME/bin:$ANDROID_SDK/tools:$ANDROID_SDK/platform-tools:$ANDROID_NDK:$PATH gradle -PDEBUG -PDALVIK_VM=true -PBINARY_STUB=~/work/binary_stub/linux/rt/lib/ext/jfxrt.jar \ -PFREETYPE_DIR=~/work/freetype/install -PCOMPILE_TARGETS=android If everything went all right the output is in build/android-sdk Create first JavaFX Android project Use gradle script int android-tools. The script sets the project structure for you.   Following command creates Android HelloWorld project which links to a freshly built javafx runtime and to a HelloWorld application. NAME is a name of Android project. DIR where to create our first project. PACKAGE is package name required by Android. It has nothing to do with a packaging of javafx application. JFX_SDK points to our recently built runtime. JFX_APP points to dist directory of javafx application. (where all application jars sit) JFX_MAIN is fully qualified name of a main class. gradle -PDEBUG -PDIR=/home/user/work -PNAME=HelloWorld -PPACKAGE=com.helloworld \ -PJFX_SDK=/home/user/work/jfx78/build/android-sdk -PJFX_APP=/home/user/NetBeansProjects/HelloWorld/dist \ -PJFX_MAIN=com.helloworld.HelloWorld createProject Now cd to the created project and use it like any other android project. ant clean, debug, uninstall, installd will work. I haven't tried it from any IDE Eclipse nor Netbeans. Special thanks to Stefan Fuchs and Daniel Zwolenski for the repositories used in this blog post.

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  • Talking JavaOne with Rock Star Martijn Verburg

    - by Janice J. Heiss
    JavaOne Rock Stars, conceived in 2005, are the top-rated speakers at each JavaOne Conference. They are awarded by their peers, who, through conference surveys, recognize them for their outstanding sessions and speaking ability. Over the years many of the world’s leading Java developers have been so recognized. Martijn Verburg has, in recent years, established himself as an important mover and shaker in the Java community. His “Diabolical Developer” session at the JavaOne 2011 Conference got people’s attention by identifying some of the worst practices Java developers are prone to engage in. Among other things, he is co-leader and organizer of the thriving London Java User Group (JUG) which has more than 2,500 members, co-represents the London JUG on the Executive Committee of the Java Community Process, and leads the global effort for the Java User Group “Adopt a JSR” and “Adopt OpenJDK” programs. Career highlights include overhauling technology stacks and SDLC practices at Mizuho International, mentoring Oracle on technical community management, and running off shore development teams for AIG. He is currently CTO at jClarity, a start-up focusing on automating optimization for Java/JVM related technologies, and Product Advisor at ZeroTurnaround. He co-authored, with Ben Evans, "The Well-Grounded Java Developer" published by Manning and, as a leading authority on technical team optimization, he is in high demand at major software conferences.Verburg is participating in five sessions, a busy man indeed. Here they are: CON6152 - Modern Software Development Antipatterns (with Ben Evans) UGF10434 - JCP and OpenJDK: Using the JUGs’ “Adopt” Programs in Your Group (with Csaba Toth) BOF4047 - OpenJDK Building and Testing: Case Study—Java User Group OpenJDK Bugathon (with Ben Evans and Cecilia Borg) BOF6283 - 101 Ways to Improve Java: Why Developer Participation Matters (with Bruno Souza and Heather Vancura-Chilson) HOL6500 - Finding and Solving Java Deadlocks (with Heinz Kabutz, Kirk Pepperdine, Ellen Kraffmiller and Henri Tremblay) When I asked Verburg about the biggest mistakes Java developers tend to make, he listed three: A lack of communication -- Software development is far more a social activity than a technical one; most projects fail because of communication issues and social dynamics, not because of a bad technical decision. Sadly, many developers never learn this lesson. No source control -- Developers simply storing code in local filesystems and emailing code in order to integrate Design-driven Design -- The need for some developers to cram every design pattern from the Gang of Four (GoF) book into their source code All of which raises the question: If these practices are so bad, why do developers engage in them? “I've seen a wide gamut of reasons,” said Verburg, who lists them as: * They were never taught at high school/university that their bad habits were harmful.* They weren't mentored in their first professional roles.* They've lost passion for their craft.* They're being deliberately malicious!* They think software development is a technical activity and not a social one.* They think that they'll be able to tidy it up later.A couple of key confusions and misconceptions beset Java developers, according to Verburg. “With Java and the JVM in particular I've seen a couple of trends,” he remarked. “One is that developers think that the JVM is a magic box that will clean up their memory, make their code run fast, as well as make them cups of coffee. The JVM does help in a lot of cases, but bad code can and will still lead to terrible results! The other trend is to try and force Java (the language) to do something it's not very good at, such as rapid web development. So you get a proliferation of overly complex frameworks, libraries and techniques trying to get around the fact that Java is a monolithic, statically typed, compiled, OO environment. It's not a Golden Hammer!”I asked him about the keys to running a good Java User Group. “You need to have a ‘Why,’” he observed. “Many user groups know what they do (typically, events) and how they do it (the logistics), but what really drives users to join your group and to stay is to give them a purpose. For example, within the LJC we constantly talk about the ‘Why,’ which in our case is several whys:* Re-ignite the passion that developers have for their craft* Raise the bar of Java developers in London* We want developers to have a voice in deciding the future of Java* We want to inspire the next generation of tech leaders* To bring the disparate tech groups in London together* So we could learn from each other* We believe that the Java ecosystem forms a cornerstone of our society today -- we want to protect that for the futureLooking ahead to Java 8 Verburg expressed excitement about Lambdas. “I cannot wait for Lambdas,” he enthused. “Brian Goetz and his group are doing a great job, especially given some of the backwards compatibility that they have to maintain. It's going to remove a lot of boiler plate and yet maintain readability, plus enable massive scaling.”Check out Martijn Verburg at JavaOne if you get a chance, and, stay tuned for a longer interview yours truly did with Martijn to be publish on otn/java some time after JavaOne.

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  • Adding UCM as a search source in Windows Explorer

    - by kyle.hatlestad
    A customer recently pointed out to me that Windows 7 supports federated search within Windows Explorer. This means you can perform searches to external sources such as Google, Flickr, YouTube, etc right from within Explorer. While we do have the Desktop Integration Suite which offers searching within Explorer, I thought it would be interesting to look into this method which would not require any client software to implement. Basically, federated searching hooks up in Windows Explorer through the OpenSearch protocol. A Search Connector Descriptor file is run and it installs the search provider. The file is a .osdx file which is an OpenSearch Description document. It describes the search provider you are hooking up to along with the URL for the query. If those results can come back as an RSS or ATOM feed, then you're all set. So the first step is to install the RSS Feeds component from the UCM Samples page on OTN. If you're on 11g, I've found the RSS Feeds works just fine on that version too. Next, you want to perform a Quick Search with a particular search term and then copy the RSS link address for that search result. Here is what an example URL might looks like: http://server:16200/cs/idcplg?IdcService=GET_SCS_FEED&feedName=search_results&QueryText=%28+%3cqsch%3eoracle%3c%2fqsch %3e+%29&SortField=dInDate&SortOrder=Desc&ResultCount=20&SearchQueryFormat= Universal&SearchProviders=server& Now you want to create a new text file and start out with this information: <?xml version="1.0" encoding="UTF-8"?><OpenSearchDescription xmlns:ms-ose="http://schemas.microsoft.com/opensearchext/2009/"> <ShortName></ShortName> <Description></Description> <Url type="application/rss+xml" template=""/> <Url type="text/html" template=""/> </OpenSearchDescription> Enter a ShortName and Description. The ShortName will be the value used when displaying the search provider in Explorer. In the template attribute for the first Url element, enter the URL copied previously. You will then need to convert the ampersand symbols to '&' to make them XML compliant. Finally, you'll want to switch out the search term with '{searchTerms}'. For the second Url element, you can do the same thing except you want to copy the UCM search results URL from the page of results. That URL will look something like: http://server:16200/cs/idcplg?IdcService=GET_SEARCH_RESULTS&SortField=dInDate&SortOrder=Desc&ResultCount=20&QueryText=%3Cqsch%3Eoracle%3C%2Fqsch%3E&listTemplateId= &ftx=1&SearchQueryFormat=Universal&TargetedQuickSearchSelection= &MiniSearchText=oracle Again, convert the ampersand symbols and replace the search term with '{searchTerms}'. When complete, save the file with the .osdx extension. The completed file should look like: <?xml version="1.0" encoding="UTF-8"?> <OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/" xmlns:ms-ose="http://schemas.microsoft.com/opensearchext/2009/"> <ShortName>Universal Content Management</ShortName> <Description>OpenSearch for UCM via Windows 7 Search Federation.</Description> <Url type="application/rss+xml" template="http://server:16200/cs/idcplg?IdcService=GET_SCS_FEED&amp;feedName=search_results&amp;QueryText=%28+%3Cqsch%3E{searchTerms}%3C%2fqsch%3E+%29&amp;SortField=dInDate&amp;SortOrder=Desc&amp;ResultCount=200&amp;SearchQueryFormat=Universal"/> <Url type="text/html" template="http://server:16200/cs/idcplg?IdcService=GET_SEARCH_RESULTS&amp;SortField=dInDate&amp;SortOrder=Desc&amp;ResultCount=20&amp;QueryText=%3Cqsch%3E{searchTerms}%3C%2Fqsch%3E&amp;listTemplateId=&amp;ftx=1&amp;SearchQueryFormat=Universal&amp;TargetedQuickSearchSelection=&amp;MiniSearchText={searchTerms}"/> </OpenSearchDescription> After you save the file, simply double-click it to create the provider. It will ask if you want to add the search connector to Windows. Click Add and it will add it to the Searches folder in your user folder as well as your Favorites. Now just click on the search icon and in the upper right search box, enter your term. As you are typing, it begins executing searches and the results will come back in Explorer. Now when you double-click on an item, it will try and download the web viewable for viewing. You also have the ability to save the search, just as you would in UCM. And there is a link to Search On Website which will launch your browser and go directly to the search results page there. And with some tweaks to the RSS component, you can make the results a bit more interesting. It supports the Media RSS standard, so you can pass along the thumbnail of the documents in the results. To enable this, edit the rss_resources.htm file in the RSS Feeds component. In the std_rss_feed_begin resource include, add the namespace 'xmlns:media="http://search.yahoo.com/mrss/' to the rss definition: <rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/" xmlns:media="http://search.yahoo.com/mrss/"> Next, in the rss_channel_item_with_thumb include, below the closing image element, add this element: </images> <media:thumbnail url="<$if strIndexOf(thumbnailUrl, "@t") > 0 or strIndexOf(thumbnailUrl, "@g") > 0 or strIndexOf(thumbnailUrl, "@p") > 0$><$rssHttpHost$><$thumbnailUrl$><$elseif dGif$><$HttpWebRoot$>images/docgifs/<$dGif$><$endif$>" /> <description> This and lots of other tweaks can be done to the RSS component to help extend it for optimum use in Explorer. Hopefully this can get you started. *Note: This post also applies to Universal Records Management (URM).

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  • PTLQueue : a scalable bounded-capacity MPMC queue

    - by Dave
    Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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  • BIP and Mapviewer Mash Up I

    - by Tim Dexter
    I was out in Yellowstone last week soaking up various wildlife and a bit too much rain ... good to be back until the 95F heat yesterday. Taking a little break from the Excel templates; the dev folks are planing an Excel patch in the next week or so that will add a mass of new functionality. At the risk of completely mis leading you I'm going to hang back a while. What I have written so far holds true and will continue to do so. This week, I have been mostly eating 'mapviewer' ... answers on a post card please, TV show and character. I had a request to show how BIP can call mapviewer and render a dynamic map in an output. So I hit the books and colleagues for some answers. Mapviewer is Oracle's geographic information system, hereby known as GIS. I use it a lot in our BIEE demos where the interaction with the maps is very impressive. Need a map of California and its congressional districts? I have contacts; Jerry and David with their little black box of maps. Once in my possession I can build highly interactive, clickable maps that allow the user to drill into more information using a very friendly interface driving BIEE content and navigation. But what about maps in BIP output? Bryan Wise, who has written some articles on this blog did some work a while back with the PL/SQL API interface. The extract for the report called a function that in turn called the mapviewer server, passing a set of mapping requirements, it then returned a URL to a cached copy of that map. Easy to then have BIP render that image. Thats still very doable. You need to install a couple of packages and then load the mapviewer java APIs into the database. Then you can write your function to the APIs. A little involved? Maybe, but the database is doing all the heavy lifting for you. I thought I would investigate another method for getting the maps back into BIP. There is a URL interface you can call, this involves building an XML message to be passed to the mapviewer server. It's pretty straightforward to use on the mapviewer side. On the BIP side things are little more tricksy. After some unexpected messing about I finally got the ubiquitous Hello World map to render using the URL method. Not the most exciting map in the world, lots of ocean and a rather long URL to get it to render. http://127.0.0.1:9704/mapviewer/omserver?xml_request=%3Cmap_request%20title=%22Hello%20World%22%20datasource=%22cagis%22%20format=%22GIF_STREAM%22/%3E Notice all of the encoding in the URL string to handle the spaces, quotes, etc. All necessary to get BIP to make the call to the mapviewer server correctly without truncating the URL if it hits a real space rather than a %20. With that in mind constructing the URL was pretty simple. I'm not going to get into the content of the URL too much, for that you need to bone up on the mapviewer XML API. Check out the home page here and the documentation here. To make the template portable I used the standard CURRENT_SERVER_URL parameter from the BIP server and declared that in my template. <?param@begin:CURRENT_SERVER_URL;'myserver'?> Ignore the 'myserver', that was just a dummy value for testing at runtime it will resolve to: 'http://yourserver:port/xmlpserver' Not quite what we need as mapviewer has its own server path, in my case I needed 'mapviewer/omserver?xml_request=' as the fixed path to the mapviewer request URL. A little concatenation and substringing later I came up with <?param@begin:mURL;concat(substring($CURRENT_SERVER_URL,1,22),'mapviewer/omserver?xml_request=')?> Thats the basic URL that I can then build on. To get the Hello World map I need to add the following: <map_request title="Hello World" datasource="cagis" format="GIF_STREAM"/> Those angle brackets were the source of my headache, BIPs XSLT engine was attempting to process them rather than just pass them. Hok Min to the rescue ... again. I owe him lunch when I get out to HQ again! To solve the problem, I needed to escape all the characters and white space and then use native XSL to assign the string to a parameter. <xsl:param xdofo:ctx="begin"name="pXML">%3Cmap_request%20title=%22Hello%20World%22 %20datasource=%22cagis%22%20format=%22GIF_STREAM%22/%3E</xsl:param> I did not need to assign it to a parameter but I felt that if I were going to do anything more serious than Hello World like plotting points of interest on the map. I would need to dynamically build the URL, so using a set of parameters or variables that I then concatenated would be easier. Now I had the initial server string and the request all I then did was combine the two using a concat: concat($mURL,$pXML) Embedding that into an image tag: <fo:external-graphic src="url({concat($mURL,$pXML)})"/> and I was done. Notice the curly braces to get the concat evaluated prior to the image call. As you will see next time, building the XML message to go onto the URL can get quite complex but I have used it with some data. Ultimately, it would be easier to build an extension to BIP to handle the data to be plotted, it would then build the XML message, call mapviewer and return a URL to the map image for BIP to render. More on that next time ...

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  • Goto for the Java Programming Language

    - by darcy
    Work on JDK 8 is well-underway, but we thought this late-breaking JEP for another language change for the platform couldn't wait another day before being published. Title: Goto for the Java Programming Language Author: Joseph D. Darcy Organization: Oracle. Created: 2012/04/01 Type: Feature State: Funded Exposure: Open Component: core/lang Scope: SE JSR: 901 MR Discussion: compiler dash dev at openjdk dot java dot net Start: 2012/Q2 Effort: XS Duration: S Template: 1.0 Reviewed-by: Duke Endorsed-by: Edsger Dijkstra Funded-by: Blue Sun Corporation Summary Provide the benefits of the time-testing goto control structure to Java programs. The Java language has a history of adding new control structures over time, the assert statement in 1.4, the enhanced for-loop in 1.5,and try-with-resources in 7. Having support for goto is long-overdue and simple to implement since the JVM already has goto instructions. Success Metrics The goto statement will allow inefficient and verbose recursive algorithms and explicit loops to be replaced with more compact code. The effort will be a success if at least twenty five percent of the JDK's explicit loops are replaced with goto's. Coordination with IDE vendors is expected to help facilitate this goal. Motivation The goto construct offers numerous benefits to the Java platform, from increased expressiveness, to more compact code, to providing new programming paradigms to appeal to a broader demographic. In JDK 8, there is a renewed focus on using the Java platform on embedded devices with more modest resources than desktop or server environments. In such contexts, static and dynamic memory footprint is a concern. One significant component of footprint is the code attribute of class files and certain classes of important algorithms can be expressed more compactly using goto than using other constructs, saving footprint. For example, to implement state machines recursively, some parties have asked for the JVM to support tail calls, that is, to perform a complex transformation with security implications to turn a method call into a goto. Such complicated machinery should not be assumed for an embedded context. A better solution is just to expose to the programmer the desired functionality, goto. The web has familiarized users with a model of traversing links among different HTML pages in a free-form fashion with some state being maintained on the side, such as login credentials, to effect behavior. This is exactly the programming model of goto and code. While in the past this has been derided as leading to "spaghetti code," spaghetti is a tasty and nutritious meal for programmers, unlike quiche. The invokedynamic instruction added by JSR 292 exposes the JVM's linkage operation to programmers. This is a low-level operation that can be leveraged by sophisticated programmers. Likewise, goto is a also a low-level operation that should not be hidden from programmers who can use more efficient idioms. Some may object that goto was consciously excluded from the original design of Java as one of the removed feature from C and C++. However, the designers of the Java programming languages have revisited these removals before. The enum construct was also left out only to be added in JDK 5 and multiple inheritance was left out, only to be added back by the virtual extension method methods of Project Lambda. As a living language, the needs of the growing Java community today should be used to judge what features are needed in the platform tomorrow; the language should not be forever bound by the decisions of the past. Description From its initial version, the JVM has had two instructions for unconditional transfer of control within a method, goto (0xa7) and goto_w (0xc8). The goto_w instruction is used for larger jumps. All versions of the Java language have supported labeled statements; however, only the break and continue statements were able to specify a particular label as a target with the onerous restriction that the label must be lexically enclosing. The grammar addition for the goto statement is: GotoStatement: goto Identifier ; The new goto statement similar to break except that the target label can be anywhere inside the method and the identifier is mandatory. The compiler simply translates the goto statement into one of the JVM goto instructions targeting the right offset in the method. Therefore, adding the goto statement to the platform is only a small effort since existing compiler and JVM functionality is reused. Other language changes to support goto include obvious updates to definite assignment analysis, reachability analysis, and exception analysis. Possible future extensions include a computed goto as found in gcc, which would replace the identifier in the goto statement with an expression having the type of a label. Testing Since goto will be implemented using largely existing facilities, only light levels of testing are needed. Impact Compatibility: Since goto is already a keyword, there are no source compatibility implications. Performance/scalability: Performance will improve with more compact code. JVMs already need to handle irreducible flow graphs since goto is a VM instruction.

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  • 12c??? - Active Data Guard Far Sync

    - by Jian Zhang(??)
    ?? ================ Active Data Guard Far Sync?Oracle 12c????(???Far Sync Standby),Far Sync?????????????(Primary Database)?????????Far Sync??,??(Primary Database) ??(synchronous)??redo?Far Sync??,??Far Sync????redo??(asynchronous)???????(Standby Database)???????????????????????Far Sync????????,init?????????,???????? ??redo ????Maximum Availability??,???????????(Primary Database)?????????Far Sync??,??(Primary Database)??(synchronous)??redo?Far Sync??,???????(zero data loss),?????Far Sync????,??????,??????????????Far Sync????redo??(asynchronous)???????(Standby Database)? ??redo ????Maximum Performance??,???????????(Primary Database)?????????Far Sync??,??(Primary Database) ????redo?Far Sync??,??Far Sync???????redo?????????(Standby Database)????????????????(Standby Database)??redo???(offload)? Far Sync????Data Guard ????(role transitions)????,?switchover/failover?????12c????? ???????Data Guard ????,?switchover/failover,???????????????Far Sync??,??Far Sync???????????????????? ???Far Sync???????,??????????????2?Far Sync??,???????? ???????Far Sync????? Far Sync??? ================ ????Far Sync ================ 1. ??Data Guard,???11.2??,??????«Active Database Duplication for A standby database» 2. ????Far Sync??,Far Sync????????,init?????????,???????? ??Far Sync???????,?????: SQL> ALTER DATABASE CREATE FAR SYNC INSTANCE CONTROLFILE AS '/tmp/controlfs01.ctl'; 3. ????redo?????Far Sync??,????LOG_ARCHIVE_DEST_2??: LOG_ARCHIVE_DEST_2='SERVICE=dg12cfs SYNC AFFIRM MAX_FAILURE=1 ALTERNATE=LOG_ARCHIVE_DEST_3 VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=dg12cfs' 4. ??Far Sync??????redo???,??Far Sync??LOG_ARCHIVE_DEST_2??: LOG_ARCHIVE_DEST_2='SERVICE=dg12cs ASYNC VALID_FOR=(STANDBY_LOGFILES,STANDBY_ROLE) DB_UNIQUE_NAME=dg12cs' 5. ????Far Sync???????,??????????????2?Far Sync??? 6. ???????: SQL> select * from  V$DATAGUARD_CONFIG; DB_UNIQUE_NAME       PARENT_DBUN       DEST_ROLE         CURRENT_SCN     CON_ID ------------------------------ ------------------------------     ----------------- ----------- ---------- dg12cfs                        dg12cp          FAR SYNC INSTANCE      682995          0 dg12cs                         dg12cfs         PHYSICAL STANDBY       682995          0 dg12cp                        NONE             PRIMARY DATABASE      683138          0 ????????????????:Oracle_12c_Active_Data_Guard_Far_Sync_v1.pdf

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  • Taking a Flying Leap

    - by Lance Shaw
    Yesterday, I went skydiving with three of my children.  It was thrilling, scary, invigorating and exciting. While there is obvious risk involved, the reward and feeling of success was well worth it. You might already be wondering what skydiving would have to with WebCenter, so let me explain. Implementing a skydiving program and becoming an instructor does not happen overnight.  It does not happen with the purchase of the needed technology. Not one of us would go out, buy a parachute, the harnesses, helmet and all the gear and be able to convince anyone that we are now ready to be a skydiving instructor. The fact is that obtaining the technology is merely a small piece of the overall process and so is the case with managing content in your company. You don't just buy the right software (Oracle WebCenter Content) and go to your boss and declare information management success. There is planning, research and effort that goes into deploying software of any kind and especially when it is as mission-critical to the success of your business as Enterprise Content Management. To become a certified skydiving instructor takes at least 3 years of commitment and often longer. In the United States, candidates must complete over 500 solo jumps of their own over a minimum of 36 months and then must complete additional rigorous training under observation.  When you consider the amount of time and effort involved, it's not unlike getting a college degree and anyone that has trusted their lives to one of these instructors will no doubt appreciate their dedication to the curriculum.  Implementing an ECM system won't take that long, but it certainly requires commitment, analysis and consideration. But guess what?  Humans are involved and that means that mistakes can happen and that rules change.  This struck me while reading an excellent post on darkreading.com by Glenn S. Phillips entitled "Mission Impossible: 4 Reasons Compliance is Impossible".  His over-arching point was that with information management and security, environments change and people are involved meaning the work is never done.  He stated that you can never claim your compliance efforts are complete because of the following reasons. People are involved.  And lets face it, some are more trustworthy than others. Change is Constant. There is always some new technology coming along that is disruptive. Consumer grade cloud file sharing and sync tools come to mind here. Compliance is interpreted, not defined.  Laws and the judges that read them are always on the move. Technology is a tool, not a complete solution. There is no magic pill. The skydiving analogy holds true here as well.  Ultimately, a single person packs your parachute.  For obvious reasons, you prefer that this person be trustworthy but there are no absolute guarantees of a 100% error-free scenario.  Weather and wind conditions are never a constant and the best-laid plans for a great day of skydiving are easily disrupted by forces outside of your control.  Rules and regulations vary by location and may be updated at any time and as I mentioned early on, even the best technology on its own will only get you started. The good news is that, like skydiving, with the right technology, the right planning, the right team and a proper understanding of the rules and regulations that govern your industry, your ECM deployment can be a great success.  Failure to plan for any of the 4 factors that Glenn outlined in his article will certainly put your deployment and maybe even your company at risk, so consider them carefully. As a final aside, for those of you who consider skydiving an incredibly dangerous and risky pastime, consider this comparative statistic.  In 2012, the U.S. Parachute Association recorded 19 fatal skydiving accidents in the U.S. out of roughly 3.1 million jumps.  That’s 0.006 fatalities per 1,000 jumps. By comparison, the U.S. National Highway Traffic Safety Administration reports that there were 34,080 deaths due to car accidents in 2012.  Based on the percentages, one could argue that it is safer to jump out of a plane than to drive to the airport where the skydiving will take place. While the way you manage, secure, classify, control, retain and dispose of company files may not carry as much risk as driving or skydiving, it certainly carries risk for the organization when not planned and deployed appropriately.  Consider all the factors involved in your organization as you make your content management plans.  For additional areas of consideration, be sure to download our free whitepaper on the topic entitled "The Top 10 Criteria for Choosing an ECM System" which is available for download here.

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