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  • Mercurial vs Subversion. Whose performance is better?

    - by Chicago
    There are a lot of articles about SVN vs. Hg in general. I would like to concentrate only on performance. Real-live experiences preferred. Here is my set-up: (future setup) Windows with IIS fro Hg (current setup) SVN 1.3.2 on top of apache under windows I would like to have statistics for most commons operations (commits, stats, local/remote pulls, pushes, etc...). I am not really sure what are the most common operations for Hg.

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  • What steps can you take to ensure sane build environments when compiling software?

    - by Chris Adams
    Hi guys, I've been stuck with a compilation problem when building a standardised virtual machine on CentOS 5.4, and I'm in the dark here as to a) why this error is occurring, and b) how to fix it, and in the hope that someone else stumbles across this problem too, I'm hoping someone can help me find the solution here. I'm getting a configure: error: newly created file is older than distributed files! error when trying to compile Ruby Enterprise like below when I try to run the installer, and the solutions offered to on the forums (of checking the tine, and touching the files to update the time associated with them) don't seem to be helping here. What steps can I take to work out what the cause of this problem? [vagrant@vagrant-centos-5 ruby-enterprise-1.8.7-2009.10]$ sudo ./installer Welcome to the Ruby Enterprise Edition installer This installer will help you install Ruby Enterprise Edition 1.8.7-2009.10. Don't worry, none of your system files will be touched if you don't want them to, so there is no risk that things will screw up. You can expect this from the installation process: 1. Ruby Enterprise Edition will be compiled and optimized for speed for this system. 2. Ruby on Rails will be installed for Ruby Enterprise Edition. 3. You will learn how to tell Phusion Passenger to use Ruby Enterprise Edition instead of regular Ruby. Press Enter to continue, or Ctrl-C to abort. Checking for required software... * C compiler... found at /usr/bin/gcc * C++ compiler... found at /usr/bin/g++ * The 'make' tool... found at /usr/bin/make * Zlib development headers... found * OpenSSL development headers... found * GNU Readline development headers... found -------------------------------------------- Target directory Where would you like to install Ruby Enterprise Edition to? (All Ruby Enterprise Edition files will be put inside that directory.) [/opt/ruby-enterprise] : -------------------------------------------- Compiling and optimizing the memory allocator for Ruby Enterprise Edition In the mean time, feel free to grab a cup of coffee. ./configure --prefix=/opt/ruby-enterprise --disable-dependency-tracking checking build system type... i686-pc-linux-gnu checking host system type... i686-pc-linux-gnu checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... configure: error: newly created file is older than distributed files! Check your system clock This is a virtual machine running on virtualbox, and the time of the host and the virtual machine are identical, and up to date. I've also tried running this after updating time with an ntp-client, so no avail. I tried this after reading this post here of someone having a similar problem [vagrant@vagrant-centos-5 ruby-enterprise-1.8.7-2009.10]$ date Tue Apr 27 08:09:05 BST 2010 The other approach I've tried is to touch the top level the files in the build folder like suggested here, but this hasn't worked either (an to be honest, I'm not sure why it would have worked either) [vagrant@vagrant-centos-5 ruby-enterprise-1.8.7-2009.10]$ sudo touch ruby-enterprise-1.8.7-2009.10/* I'm not sure what I can do next here - the problem seems to be the bash configure script that returns this error error: newly created file is older than distributed files!, at line :2214 { echo "$as_me:$LINENO: checking whether build environment is sane" >&5 echo $ECHO_N "checking whether build environment is sane... $ECHO_C" >&6; } # Just in case sleep 1 echo timestamp > conftest.file # Do `set' in a subshell so we don't clobber the current shell's # arguments. Must try -L first in case configure is actually a # symlink; some systems play weird games with the mod time of symlinks # (eg FreeBSD returns the mod time of the symlink's containing # directory). if ( set X `ls -Lt $srcdir/configure conftest.file 2> /dev/null` if test "$*" = "X"; then # -L didn't work. set X `ls -t $srcdir/configure conftest.file` fi rm -f conftest.file if test "$*" != "X $srcdir/configure conftest.file" \ && test "$*" != "X conftest.file $srcdir/configure"; then # If neither matched, then we have a broken ls. This can happen # if, for instance, CONFIG_SHELL is bash and it inherits a # broken ls alias from the environment. This has actually # happened. Such a system could not be considered "sane". { { echo "$as_me:$LINENO: error: ls -t appears to fail. Make sure there is not a broken alias in your environment" >&5 echo "$as_me: error: ls -t appears to fail. Make sure there is not a broken alias in your environment" >&2;} { (exit 1); exit 1; }; } fi ### PROBLEM LINE #### # this line is the problem line - this is returned true, sometimes it isn't and I can't # see a pattern that that determines when this will test will pass or not. test "$2" = conftest.file ) then # Ok. : else { { echo "$as_me:$LINENO: error: newly created file is older than distributed files! Check your system clock" >&5 echo "$as_me: error: newly created file is older than distributed files! Check your system clock" >&2;} { (exit 1); exit 1; }; } fi the thing that makes this really frustrating is that this script works sometimes, when the VM has been running for an hour or so it works, but not at boot. There's nothing I see in the crontab that suggests any hourly tasks are run that might change the state of the system enough make a difference to this script working. I'm totally at a loss when it comes to debugging beyond here. What's the best approach to take here? Thanks

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  • nm-applet gone?

    - by welp
    nm-applet seems to have disappeared from my system. I am running 12.10. Here's what I get when I check my package manager logs: ? ~ grep network-manager /var/log/dpkg.log 2012-10-06 10:37:08 upgrade network-manager-gnome:amd64 0.9.6.2-0ubuntu5 0.9.6.2-0ubuntu6 2012-10-06 10:37:08 status half-configured network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:08 status unpacked network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:08 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:08 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:08 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:08 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:08 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:08 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:08 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:09 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu5 2012-10-06 10:37:09 status unpacked network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-06 10:37:09 status unpacked network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-06 10:39:50 configure network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-06 10:39:50 status unpacked network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-06 10:39:50 status unpacked network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-06 10:39:50 status half-configured network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-06 10:39:50 status installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 remove network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status half-configured network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status config-files network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-28 22:27:23 status config-files network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 install network-manager-gnome:amd64 0.9.6.2-0ubuntu6 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status half-installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status unpacked network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:03 status unpacked network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:06 configure network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:06 status unpacked network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:07 status unpacked network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:07 status half-configured network-manager-gnome:amd64 0.9.6.2-0ubuntu6 2012-10-31 19:58:07 status installed network-manager-gnome:amd64 0.9.6.2-0ubuntu6 ? ~ Unfortunately, I cannot find network-manager-applet package at all: ? ~ apt-cache search network-manager-applet ? ~ Here are the contents of /etc/apt/sources.list: ? ~ cat /etc/apt/sources.list # deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Release amd64 (20120425)]/ dists/precise/main/binary-i386/ # deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Release amd64 (20120425)]/ dists/precise/restricted/binary-i386/ # deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Release amd64 (20120425)]/ precise main restricted # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://gb.archive.ubuntu.com/ubuntu/ quantal main restricted deb-src http://gb.archive.ubuntu.com/ubuntu/ quantal main restricted ## Major bug fix updates produced after the final release of the ## distribution. deb http://gb.archive.ubuntu.com/ubuntu/ quantal-updates main restricted deb-src http://gb.archive.ubuntu.com/ubuntu/ quantal-updates main restricted ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://gb.archive.ubuntu.com/ubuntu/ quantal universe deb-src http://gb.archive.ubuntu.com/ubuntu/ quantal universe deb http://gb.archive.ubuntu.com/ubuntu/ quantal-updates universe deb-src http://gb.archive.ubuntu.com/ubuntu/ quantal-updates universe ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://gb.archive.ubuntu.com/ubuntu/ quantal multiverse deb-src http://gb.archive.ubuntu.com/ubuntu/ quantal multiverse deb http://gb.archive.ubuntu.com/ubuntu/ quantal-updates multiverse deb-src http://gb.archive.ubuntu.com/ubuntu/ quantal-updates multiverse ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. deb http://gb.archive.ubuntu.com/ubuntu/ quantal-backports main restricted universe multiverse deb-src http://gb.archive.ubuntu.com/ubuntu/ quantal-backports main restricted universe multiverse deb http://security.ubuntu.com/ubuntu quantal-security main restricted deb-src http://security.ubuntu.com/ubuntu quantal-security main restricted deb http://security.ubuntu.com/ubuntu quantal-security universe deb-src http://security.ubuntu.com/ubuntu quantal-security universe deb http://security.ubuntu.com/ubuntu quantal-security multiverse deb-src http://security.ubuntu.com/ubuntu quantal-security multiverse ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. # deb http://archive.canonical.com/ubuntu precise partner # deb-src http://archive.canonical.com/ubuntu precise partner ## This software is not part of Ubuntu, but is offered by third-party ## developers who want to ship their latest software. deb http://extras.ubuntu.com/ubuntu quantal main deb-src http://extras.ubuntu.com/ubuntu quantal main ? ~ Right now, I can't think of anything else. Happy to provide more info upon request.

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  • Pirates, Treasure Chests and Architectural Mapping

    Pirate 1: Why do pirates create treasure maps? Pirate 2: I do not know.Pirate 1: So they can find their gold. Yes, that was a bad joke, but it does illustrate a point. Pirates are known for drawing treasure maps to their most prized possession. These documents detail the decisions pirates made in order to hide and find their chests of gold. The map allows them to trace the steps they took originally to hide their treasure so that they may return. As software engineers, programmers, and architects we need to treat software implementations much like our treasure chest. Why is software like a treasure chest? It cost money, time,  and resources to develop (Usually) It can make or save money, time, and resources (Hopefully) If we operate under the assumption that software is like a treasure chest then wouldn’t make sense to document the steps, rationale, concerns, and decisions about how it was designed? Pirates are notorious for documenting where they hide their treasure.  Shouldn’t we as creators of software do the same? By documenting our design decisions and rationale behind them will help others be able to understand and maintain implemented systems. This can only be done if the design decisions are correctly mapped to its corresponding implementation. This allows for architectural decisions to be traced from the conceptual model, architectural design and finally to the implementation. Mapping gives software professional a method to trace the reason why specific areas of code were developed verses other options. Just like the pirates we need to able to trace our steps from the start of a project to its implementation,  so that we will understand why specific choices were chosen. The traceability of a software implementation that actually maps back to its originating design decisions is invaluable for ensuring that architectural drifting and erosion does not take place. The drifting and erosion is prevented by allowing others to understand the rational of why an implementation was created in a specific manor or methodology The process of mapping distinct design concerns/decisions to the location of its implemented is called traceability. In this context traceability is defined as method for connecting distinctive software artifacts. This process allows architectural design models and decisions to be directly connected with its physical implementation. The process of mapping architectural design concerns to a software implementation can be very complex. However, most design decision can be placed in  a few generalized categories. Commonly Mapped Design Decisions Design Rationale Components and Connectors Interfaces Behaviors/Properties Design rational is one of the hardest categories to map directly to an implementation. Typically this rational is mapped or document in code via comments. These comments consist of general design decisions and reasoning because they do not directly refer to a specific part of an application. They typically focus more on the higher level concerns. Components and connectors can directly be mapped to architectural concerns. Typically concerns subdivide an application in to distinct functional areas. These functional areas then can map directly back to their originating concerns.Interfaces can be mapped back to design concerns in one of two ways. Interfaces that pertain to specific function definitions can be directly mapped back to its originating concern(s). However, more complicated interfaces require additional analysis to ensure that the proper mappings are created. Depending on the complexity some Behaviors\Properties can be translated directly into a generic implementation structure that is ready for business logic. In addition, some behaviors can be translated directly in to an actual implementation depending on the complexity and architectural tools used. Mapping design concerns to an implementation is a lot of work to maintain, but is doable. In order to ensure that concerns are mapped correctly and that an implementation correctly reflects its design concerns then one of two standard approaches are usually used. All Changes Come From ArchitectureBy forcing all application changes to come through the architectural model prior to implementation then the existing mappings will be used to locate where in the implementation changes need to occur. Allow Changes From Implementation Or Architecture By allowing changes to come from the implementation and/or the architecture then the other area must be kept in sync. This methodology is more complex compared to the previous approach.  One reason to justify the added complexity for an application is due to the fact that this approach tends to detect and prevent architectural drift and erosion. Additionally, this approach is usually maintained via software because of the complexity. Reference:Taylor, R. N., Medvidovic, N., & Dashofy, E. M. (2009). Software architecture: Foundations, theory, and practice Hoboken, NJ: John Wiley & Sons  

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  • Developer Training – 6 Online Courses to Learn SQL Server, MySQL and Technology

    - by Pinal Dave
    Video courses are the next big thing and I am so happy that I have so far authored 6 different video courses with Pluralsight. Here is the list of the courses. I have listed all of my video courses over here. Note: If you click on the courses and it does not open, you need to login to Pluralsight with a valid username and password or sign up for a FREE trial. Please leave a comment with your favorite course in the comment section. Random 10 winners will get surprise gift via email. Bonus: If you list your favorite module from the course site. SQL Server Performance: Introduction to Query Tuning SQL Server performance tuning is an in-depth topic, and an art to master. A key component of overall application performance tuning is query tuning. Writing queries in an efficient manner, and making sure they execute in the most optimal way possible, is always a challenge. The basics revolve around the details of how SQL Server carries out query execution, so the optimizations explored in this course follow along the same lines. Click to View Course SQL Server Performance: Indexing Basics Indexes are the most crucial objects of the database. They are the first stop for any DBA and Developer when it is about performance tuning. There is a good side as well evil side of the indexes. To master the art of performance tuning one has to understand the fundamentals of the indexes and the best practices associated with the same. This course is for every DBA and Developer who deals with performance tuning and wants to use indexes to improve the performance of the server. Click to View Course SQL Server Questions and Answers This course is designed to help you better understand how to use SQL Server effectively. The course presents many of the common misconceptions about SQL Server, and then carefully debunks those misconceptions with clear explanations and short but compelling demos, showing you how SQL Server really works. This course is for anyone working with SQL Server databases who wants to improve her knowledge and understanding of this complex platform. Click to View Course MySQL Fundamentals MySQL is a popular choice of database for use in web applications, and is a central component of the widely used LAMP open source web application software stack. This course covers the fundamentals of MySQL, including how to install MySQL as well as written basic data retrieval and data modification queries. Click to View Course Building a Successful Blog Expressing yourself is the most common behavior of humans. Blogging has made easy to express yourself. Just like a letter or book has a structure and formula, blogging also has structure and formula. In this introductory course on blogging we will go over a few of the basics of blogging and show the way to get started with blogging immediately. If you already have a blog, this course will be even more relevant as this will discuss many of the common questions and issue you face in your blogging routine. Click to View Course Introduction to ColdFusion ColdFusion is rapid web application development platform. In this course you will learn the basics of how to use ColdFusion platform and rapidly develop web sites. The course begins with learning basics of ColdFusion Markup Language and moves to common development language practices. From there we move to frequent database operations and advanced concepts of Forms, Sessions and Cookies. The last module sums up all the concepts covered in the course with sample application. Click to View Course Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, T SQL, Technology

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  • Cloud Adoption Challenges

    - by Herve Roggero
    Originally posted on: http://geekswithblogs.net/hroggero/archive/2013/11/07/cloud-adoption-challenges.aspxWhile cloud computing makes sense for most organizations and countless projects, I have seen customers significantly struggle with cloud adoption challenges. This blog post is not an attempt to provide a generic assessment of cloud adoption; rather it is an account of personal experiences in the field, some of which may or may not apply to your organization. Cloud First, Burst? In the rush to cloud adoption some companies have made the decision to redesign their core system with a cloud first approach. However a cloud first approach means that the system may not work anymore on-premises after it has been redesigned, specifically if the system depends on Platform as a Service (PaaS) components (such as Azure Tables). While PaaS makes sense when your company is in a position to adopt the cloud exclusively, it can be difficult to leverage with systems that need to work in different clouds or on-premises. As a result, some companies are starting to rethink their cloud strategy by designing for on-premises first, and modify only the necessary components to burst when needed in the cloud. This generally means that the components need to work equally well in any environment, which requires leveraging Infrastructure as a Service (IaaS) or additional investments for PaaS applications, or both.  What’s the Problem? Although most companies can benefit from cloud computing, not all of them can clearly identify a business reason for doing so other than in very generic terms. I heard many companies claim “it’s cheaper”, or “it allows us to scale”, without any specific metric or clear strategy behind the adoption decision. Other companies have a very clear strategy behind cloud adoption and can precisely articulate business benefits, such as “we have a 500% increase in traffic twice a year, so we need to burst in the cloud to avoid doubling our network and server capacity”. Understanding the problem being solved through by adopting cloud computing can significantly help organizations determine the optimum path and timeline to adoption. Performance or Scalability? I stopped counting the number of times I heard “the cloud doesn’t scale; our database runs faster on a laptop”.  While performance and scalability are related concepts, they are nonetheless different in nature. Performance is a measure of response time under a given load (meaning with a specific number of users), while scalability is the performance curve over various loads. For example one system could see great performance with 100 users, but timeout with 1,000 users, in which case the system wouldn’t scale. However another system could have average performance with 100 users, but display the exact same performance with 1,000,000 users, in which case the system would scale. Understanding that cloud computing does not usually provide high performance, but instead provides the tools necessary to build a scalable system (usually using PaaS services such as queuing and data federation), is fundamental to proper cloud adoption. Uptime? Last but not least, you may want to read the Service Level Agreement of your cloud provider in detail if you haven’t done so. If you are expecting 99.99% uptime annually you may be in for a surprise. Depending on the component being used, there may be no associated SLA at all! Other components may be restarted at any time, or services may experience failover conditions weekly ( or more) based on current overall conditions of the cloud service provider, most of which are outside of your control. As a result, for PaaS cloud environments (and to a certain extent some IaaS systems), applications need to assume failure and gracefully retry to be successful in the cloud in order to provide service continuity to end users. About Herve Roggero Herve Roggero, Windows Azure MVP, is the founder of Blue Syntax Consulting (http://www.bluesyntax.net). Herve's experience includes software development, architecture, database administration and senior management with both global corporations and startup companies. Herve holds multiple certifications, including an MCDBA, MCSE, MCSD. He also holds a Master's degree in Business Administration from Indiana University. Herve is the co-author of "PRO SQL Azure" and “PRO SQL Server 2012 Practices” from Apress, a PluralSight author, and runs the Azure Florida Association.

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  • What container type provides better (average) performance than std::map?

    - by Truncheon
    In the following example a std::map structure is filled with 26 values from A - Z (for key) and 0 - 26 for value. The time taken (on my system) to lookup the last entry (10000000 times) is roughly 250 ms for the vector, and 125 ms for the map. (I compiled using release mode, with O3 option turned on for g++ 4.4) But if for some odd reason I wanted better performance than the std::map, what data structures and functions would I need to consider using? I apologize if the answer seems obvious to you, but I haven't had much experience in the performance critical aspects of C++ programming. UPDATE: This example is rather trivial and hides the true complexity of what I'm trying to achieve. My real world project is a simple scripting language that uses a parser, data tree, and interpreter (instead of a VM stack system). I need to use some kind of data structure (perhaps map) to store the variables names created by script programmers. These are likely to be pretty randomly named, so I need a lookup method that can quickly find a particular key within a (probably) fairly large list of names. #include <ctime> #include <map> #include <vector> #include <iostream> struct mystruct { char key; int value; mystruct(char k = 0, int v = 0) : key(k), value(v) { } }; int find(const std::vector<mystruct>& ref, char key) { for (std::vector<mystruct>::const_iterator i = ref.begin(); i != ref.end(); ++i) if (i->key == key) return i->value; return -1; } int main() { std::map<char, int> mymap; std::vector<mystruct> myvec; for (int i = 'a'; i < 'a' + 26; ++i) { mymap[i] = i - 'a'; myvec.push_back(mystruct(i, i - 'a')); } int pre = clock(); for (int i = 0; i < 10000000; ++i) { find(myvec, 'z'); } std::cout << "linear scan: milli " << clock() - pre << "\n"; pre = clock(); for (int i = 0; i < 10000000; ++i) { mymap['z']; } std::cout << "map scan: milli " << clock() - pre << "\n"; return 0; }

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  • Oracle Announces New Oracle Exastack Program for ISV Partners

    - by pfolgado
    Oracle Exastack Program Enables ISV Partners to Leverage a Scalable, Integrated Infrastructure to Deliver Their Applications Tuned and Optimized for High-Performance News Facts Enabling Independent Software Vendors (ISVs) and other members of Oracle Partner Network (OPN) to rapidly build and deliver faster, more reliable applications to end customers, Oracle today introduced Oracle Exastack Ready, available now, and Oracle Exastack Optimized, available in fall 2011 through OPN. The Oracle Exastack Program focuses on helping ISVs run their solutions on Oracle Exadata Database Machine and Oracle Exalogic Elastic Cloud -- integrated systems in which the software and hardware are engineered to work together. These products provide partners with a lower cost and high performance infrastructure for database and application workloads across on-premise and cloud based environments. Leveraging the new Oracle Exastack Program in which applications can qualify as Oracle Exastack Ready or Oracle Exastack Optimized, partners can use available OPN resources to optimize their applications to run faster and more reliably -- providing increased performance to their end users. By deploying their applications on Oracle Exadata Database Machine and Oracle Exalogic Elastic Cloud, ISVs can reduce the cost, time and support complexities typically associated with building and maintaining a disparate application infrastructure -- enabling them to focus more on their core competencies, accelerating innovation and delivering superior value to customers. After qualifying their applications as Oracle Exastack Ready, partners can note to customers that their applications run on and support Oracle Exadata Database Machine and Oracle Exalogic Elastic Cloud component products including Oracle Solaris, Oracle Linux, Oracle Database and Oracle WebLogic Server. Customers can be confident when choosing a partner's Oracle Exastack Optimized application, knowing it has been tuned by the OPN member on Oracle Exadata Database Machine or Oracle Exalogic Elastic Cloud with a goal of delivering optimum speed, scalability and reliability. Partners participating in the Oracle Exastack Program can also leverage their Oracle Exastack Ready and Oracle Exastack Optimized applications to advance to Platinum or Diamond level in OPN. Oracle Exastack Programs Provide ISVs a Reliable, High-Performance Application Infrastructure With the Oracle Exastack Program ISVs have several options to qualify and tune their applications with Oracle Exastack, including: Oracle Exastack Ready: Oracle Exastack Ready provides qualifying partners with specific branding and promotional benefits based on their adoption of Oracle products. If a partner application supports the latest major release of one of these products, the partner may use the corresponding logo with their product marketing materials: Oracle Solaris Ready, Oracle Linux Ready, Oracle Database Ready, and Oracle WebLogic Ready. Oracle Exastack Ready is available to OPN members at the Gold level or above. Additionally, OPN members participating in the program can leverage their Oracle Exastack Ready applications toward advancement to the Platinum or Diamond levels in the OPN Specialized program and toward achieving Oracle Exastack Optimized status. Oracle Exastack Optimized: When available, for OPN members at the Gold level or above, Oracle Exastack Optimized will provide direct access to Oracle technical resources and dedicated Oracle Exastack lab environments so OPN members can test and tune their applications to deliver optimal performance and scalability on Oracle Exadata Database Machine or Oracle Exalogic Elastic Cloud. Oracle Exastack Optimized will provide OPN members with specific branding and promotional benefits including the use of the Oracle Exastack Optimized logo. OPN members participating in the program will also be able to leverage their Oracle Exastack Optimized applications toward advancement to Platinum or Diamond level in the OPN Specialized program. Oracle Exastack Labs and ISV Enablement: Dedicated Oracle Exastack lab environments and related technical enablement resources (including Guided Learning Paths and Boot Camps) will be available through OPN for OPN members to further their knowledge of Oracle Exastack offerings, and qualify their applications for Oracle Exastack Optimized or Oracle Exastack Ready. Oracle Exastack labs will be available to qualifying OPN members at the Gold level or above. Partners are eligible to participate in the Oracle Exastack Ready program immediately, which will help them meet the requirements to attain Oracle Exastack Optimized status in the future. Guidelines for Oracle Exastack Optimized, as well as Oracle Exastack Labs will be available in fall 2011. Supporting Quotes "In order to effectively differentiate their software applications in the marketplace, ISVs need to rapidly deliver new capabilities and performance improvements," said Judson Althoff, Oracle senior vice president of Worldwide Alliances and Channels and Embedded Sales. "With Oracle Exastack, ISVs have the ability to optimize and deploy their applications with a complete, integrated and cloud-ready infrastructure that will help them accelerate innovation, unlock new features and functionality, and deliver superior value to customers." "We view performance as absolutely critical and a key differentiator," said Tom Stock, SVP of Product Management, GoldenSource. "As a leading provider of enterprise data management solutions for securities and investment management firms, with Oracle Exadata Database Machine, we see an opportunity to notably improve data processing performance -- providing high quality 'golden copy' data in a reduced timeframe. Achieving Oracle Exastack Optimized status will be a stamp of approval that our solution will provide the performance and scalability that our customers demand." "As a leading provider of Revenue Intelligence solutions for telecommunications, media and entertainment service providers, our customers continually demand more readily accessible, enriched and pre-analyzed information to minimize their financial risks and maximize their margins," said Alon Aginsky, President and CEO of cVidya Networks. "Oracle Exastack enables our solutions to deliver the power, infrastructure, and innovation required to transform our customers' business operations and stay ahead of the game." Supporting Resources Oracle PartnerNetwork (OPN) Oracle Exastack Oracle Exastack Datasheet Judson Althoff blog Connect with the Oracle Partner community at OPN on Facebook, OPN on LinkedIn, OPN on YouTube, or OPN on Twitter

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  • Do Not Optimize Without Measuring

    - by Alois Kraus
    Recently I had to do some performance work which included reading a lot of code. It is fascinating with what ideas people come up to solve a problem. Especially when there is no problem. When you look at other peoples code you will not be able to tell if it is well performing or not by reading it. You need to execute it with some sort of tracing or even better under a profiler. The first rule of the performance club is not to think and then to optimize but to measure, think and then optimize. The second rule is to do this do this in a loop to prevent slipping in bad things for too long into your code base. If you skip for some reason the measure step and optimize directly it is like changing the wave function in quantum mechanics. This has no observable effect in our world since it does represent only a probability distribution of all possible values. In quantum mechanics you need to let the wave function collapse to a single value. A collapsed wave function has therefore not many but one distinct value. This is what we physicists call a measurement. If you optimize your application without measuring it you are just changing the probability distribution of your potential performance values. Which performance your application actually has is still unknown. You only know that it will be within a specific range with a certain probability. As usual there are unlikely values within your distribution like a startup time of 20 minutes which should only happen once in 100 000 years. 100 000 years are a very short time when the first customer tries your heavily distributed networking application to run over a slow WIFI network… What is the point of this? Every programmer/architect has a mental performance model in his head. A model has always a set of explicit preconditions and a lot more implicit assumptions baked into it. When the model is good it will help you to think of good designs but it can also be the source of problems. In real world systems not all assumptions of your performance model (implicit or explicit) hold true any longer. The only way to connect your performance model and the real world is to measure it. In the WIFI example the model did assume a low latency high bandwidth LAN connection. If this assumption becomes wrong the system did have a drastic change in startup time. Lets look at a example. Lets assume we want to cache some expensive UI resource like fonts objects. For this undertaking we do create a Cache class with the UI themes we want to support. Since Fonts are expensive objects we do create it on demand the first time the theme is requested. A simple example of a Theme cache might look like this: using System; using System.Collections.Generic; using System.Drawing; struct Theme { public Color Color; public Font Font; } static class ThemeCache { static Dictionary<string, Theme> _Cache = new Dictionary<string, Theme> { {"Default", new Theme { Color = Color.AliceBlue }}, {"Theme12", new Theme { Color = Color.Aqua }}, }; public static Theme Get(string theme) { Theme cached = _Cache[theme]; if (cached.Font == null) { Console.WriteLine("Creating new font"); cached.Font = new Font("Arial", 8); } return cached; } } class Program { static void Main(string[] args) { Theme item = ThemeCache.Get("Theme12"); item = ThemeCache.Get("Theme12"); } } This cache does create font objects only once since on first retrieve of the Theme object the font is added to the Theme object. When we let the application run it should print “Creating new font” only once. Right? Wrong! The vigilant readers have spotted the issue already. The creator of this cache class wanted to get maximum performance. So he decided that the Theme object should be a value type (struct) to not put too much pressure on the garbage collector. The code Theme cached = _Cache[theme]; if (cached.Font == null) { Console.WriteLine("Creating new font"); cached.Font = new Font("Arial", 8); } does work with a copy of the value stored in the dictionary. This means we do mutate a copy of the Theme object and return it to our caller. But the original Theme object in the dictionary will have always null for the Font field! The solution is to change the declaration of struct Theme to class Theme or to update the theme object in the dictionary. Our cache as it is currently is actually a non caching cache. The funny thing was that I found out with a profiler by looking at which objects where finalized. I found way too many font objects to be finalized. After a bit debugging I found the allocation source for Font objects was this cache. Since this cache was there for years it means that the cache was never needed since I found no perf issue due to the creation of font objects. the cache was never profiled if it did bring any performance gain. to make the cache beneficial it needs to be accessed much more often. That was the story of the non caching cache. Next time I will write something something about measuring.

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  • Can someone clarify what this Joel On Software quote means?

    - by Bob
    I was reading Joel On Software today and ran across this quote: Without understanding functional programming, you can't invent MapReduce, the algorithm that makes Google so massively scalable. The terms Map and Reduce come from Lisp and functional programming. MapReduce is, in retrospect, obvious to anyone who remembers from their 6.001-equivalent programming class that purely functional programs have no side effects and are thus trivially parallelizable. What does he mean when he says functional programs have no side effects? And how does this make parallelizing trivial?

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  • App_Code in Web Client Software Factory, Is it a good idea.

    - by Blithe
    Hi guys, Just want to hear some opinion on adding App_Code in Web Client Software Factory (WCSF) project. The main purpose is to put reusable UI rendering codes which can be use by various pages. For WCSF, I guess only controller can share across pages within a module which does not seems to be a good place for UI stuff. Suggestions? :)

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  • Any software for pattern-matching and -rewriting source code?

    - by Steven A. Lowe
    I have some old software (in a language that's not dead but is dead to me ;-)) that implements a basic pattern-matching and -rewriting system for source code. I am considering resurrecting this code, translating it into a modern language, and open-sourcing the project as a refactoring power-tool. Before I go much further, I want to know if anything like this exists already (my google-fu is fanning air on this tonight). Here's how it works: the pattern-matching part matches source-code patterns spanning multiple lines of code using a template with binding variables, the pattern-rewriting part uses a template to rewrite the matched code, inserting the contents of the bound variables from the matching template matching and rewriting templates are associated (1:1) by a simple (unconditional) rewrite rule the software operates on the abstract syntax tree (AST) of the input application, and outputs a modified AST which can then be regenerated into new source code for example, suppose we find a bunch of while-loops that really should be for-loops. The following template will match the while-loop pattern: Template oldLoopPtrn int @cnt@ = 0; while (@cnt@ < @max@) { … @body@ ++@cnt@; } End_Template while the following template will specify the output rewrite pattern: Template newLoopPtrn for(int @cnt@ = 0; @cnt@ < @max@; @cnt@++) { @body@ } End_Template and a simple rule to associate them Rule oldLoopPtrn --> newLoopPtrn so code that looks like this int i=0; while(i<arrlen) { printf("element %d: %f\n",i,arr[i]); ++i; } gets automatically rewritten to look like this for(int i = 0; i < arrlen; i++) { printf("element %d: %f\n",i,arr[i]); } The closest thing I've seen like this is some of the code-refactoring tools, but they seem to be geared towards interactive rewriting of selected snippets, not wholesale automated changes. I believe that this kind of tool could supercharge refactoring, and would work on multiple languages (even HTML/CSS). I also believe that converting and polishing the code base would be a huge project that I simply cannot do alone in any reasonable amount of time. So, anything like this out there already? If not, any obvious features (besides rewrite-rule conditions) to consider? EDIT: The one feature of this system that I like very much is that the template patterns are fairly obvious and easy to read because they're written in the same language as the target source code, not in some esoteric mutated regex/BNF format.

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  • Good source for studying professional software development with Visual Studio 2010?

    - by Ben
    I spent a lot of time reading blogs and tutorials on the Net regarding how to do this and that with VS2010, but I thought it would be better to learn it in a more systematic way. Do you know of a good website/book that will teach me how to use Visual Studio 2010/2008 Team System + Microsoft Project to perform various tasks from Project Management to code development and testing in the way the software was designed for? Thank you.

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