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  • Microsoft and the open source community

    - by Charles Young
    For the last decade, I have repeatedly, in my imitable Microsoft fan boy style, offered an alternative view to commonly held beliefs about Microsoft's stance on open source licensing.  In earlier times, leading figures in Microsoft were very vocal in resisting the idea that commercial licensing is outmoded or morally reprehensible.  Many people interpreted this as all-out corporate opposition to open source licensing.  I never read it that way. It is true that I've met individual employees of Microsoft who are antagonistic towards FOSS (free and open source software), but I've met more who are supportive or at least neutral on the subject.  In any case, individual attitudes of employees don't necessarily reflect a corporate stance.  The strongest opposition I've encountered has actually come from outside the company.  It's not a charitable thought, but I sometimes wonder if there are people in the .NET community who are opposed to FOSS simply because they believe, erroneously, that Microsoft is opposed. Here, for what it is worth, are the points I've repeated endlessly over the years and which have often been received with quizzical scepticism. a)  A decade ago, Microsoft's big problem was not FOSS per se, or even with copyleft.  The thing which really kept them awake at night was the fear that one day, someone might find, deep in the heart of the Windows code base, some code that should not be there and which was published under GPL.  The likelihood of this ever happening has long since faded away, but there was a time when MS was running scared.  I suspect this is why they held out for a while from making Windows source code open to inspection.  Nowadays, as an MVP, I am positively encouraged to ask to see Windows source. b)  Microsoft has never opposed the open source community.  They have had problems with specific people and organisations in the FOSS community.  Back in the 1990s, Richard Stallman gave time and energy to a successful campaign to launch antitrust proceedings against Microsoft.  In more recent times, the negative attitude of certain people to Microsoft's submission of two FOSS licences to the OSI (both of which have long since been accepted), and the mad scramble to try to find any argument, however tenuous, to block their submission was not, let us say, edifying. c) Microsoft has never, to my knowledge, written off the FOSS model.  They certainly don't agree that more traditional forms of licensing are inappropriate or immoral, and they've always been prepared to say so.  One reason why it was so hard to convince people that Microsoft is not rabidly antagonistic towards FOSS licensing is that so many people think they have no involvement in open source.  A decade ago, there was virtually no evidence of any such involvement.  However, that was a long time ago.  Quietly over the years, Microsoft has got on with the job of working out how to make use of FOSS licensing and how to support the FOSS community.  For example, as well as making increasingly extensive use of Github, they run an important FOSS forge (CodePlex) on which they, themselves, host many hundreds of distinct projects.  The total count may even be in the thousands now.  I suspect there is a limit of about 500 records on CodePlex searches because, for the past few years, whenever I search for Microsoft-specific projects on CodePlex, I always get approx. 500 hits.  Admittedly, a large volume of the stuff they publish under FOSS licences amounts to code samples, but many of those 'samples' have grown into useful and fully featured frameworks, libraries and tools. All this is leading up to the observation that yesterday's announcement by Scott Guthrie marks a significant milestone and should not go unnoticed.  If you missed it, let me summarise.   From the first release of .NET, Microsoft has offered a web development framework called ASP.NET.  The core libraries are included in the .NET framework which is released free of charge, but which is not open source.   However, in recent years, the number of libraries that constitute ASP.NET have grown considerably.  Today, most professional ASP.NET web development exploits the ASP.NET MVC framework.  This, together with several other important parts of the ASP.NET technology stack, is released on CodePlex under the Apache 2.0 licence.   Hence, today, a huge swathe of web development on the .NET/Azure platform relies four-square on the use of FOSS frameworks and libraries. Yesterday, Scott Guthrie announced the next stage of ASP.NET's journey towards FOSS nirvana.  This involves extending ASP.NET's FOSS stack to include Web API and the MVC Razor view engine which is rapidly becoming the de facto 'standard' for building web pages in ASP.NET.  However, perhaps the more important announcement is that the ASP.NET team will now accept and review contributions from the community.  Scott points out that this model is already in place elsewhere in Microsoft, and specifically draws attention to development of the Windows Azure SDKs.  These SDKs are central to Azure development.   The .NET and Java SDKs are published under Apache 2.0 on Github and Microsoft is open to community contributions.  Accepting contributions is a more profound move than simply releasing code under FOSS licensing.  It means that Microsoft is wholeheartedly moving towards a full-blooded open source approach for future evolution of some of their central and most widely used .NET and Azure frameworks and libraries.  In conjunction with Scott's announcement, Microsoft has also released Git support for CodePlex (at long last!) and, perhaps more importantly, announced significant new investment in their own FOSS forge. Here at Solidsoft we have several reasons to be very interested in Scott's announcement. I'll draw attention to one of them.  Earlier this year we wrote the initial version of a new UK Government web application called CloudStore.  CloudStore provides a way for local and central government to discover and purchase applications and services. We wrote the web site using ASP.NET MVC which is FOSS.  However, this point has been lost on the ladies and gentlemen of the press and, I suspect, on some of the decision makers on the government side.  They announced a few weeks ago that future versions of CloudStore will move to a FOSS framework, clearly oblivious of the fact that it is already built on a FOSS framework.  We are, it is fair to say, mildly irked by the uninformed and badly out-of-date assumption that “if it is Microsoft, it can't be FOSS”.  Old prejudices live on.

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  • New Replication, Optimizer and High Availability features in MySQL 5.6.5!

    - by Rob Young
    As the Product Manager for the MySQL database it is always great to announce when the MySQL Engineering team delivers another great product release.  As a field DBA and developer it is even better when that release contains improvements and innovation that I know will help those currently using MySQL for apps that range from modest intranet sites to the most highly trafficked web sites on the web.  That said, it is my pleasure to take my hat off to MySQL Engineering for today's release of the MySQL 5.6.5 Development Milestone Release ("DMR"). The new highlighted features in MySQL 5.6.5 are discussed here: New Self-Healing Replication ClustersThe 5.6.5 DMR improves MySQL Replication by adding Global Transaction Ids and automated utilities for self-healing Replication clusters.  Prior to 5.6.5 this has been somewhat of a pain point for MySQL users with most developing custom solutions or looking to costly, complex third-party solutions for these capabilities.  With 5.6.5 these shackles are all but removed by a solution that is included with the GPL version of the database and supporting GPL tools.  You can learn all about the details of the great, problem solving Replication features in MySQL 5.6 in Mat Keep's Developer Zone article.  New Replication Administration and Failover UtilitiesAs mentioned above, the new Replication features, Global Transaction Ids specifically, are now supported by a set of automated GPL utilities that leverage the new GTIDs to provide administration and manual or auto failover to the most up to date slave (that is the default, but user configurable if needed) in the event of a master failure. The new utilities, along with links to Engineering related blogs, are discussed in detail in the DevZone Article noted above. Better Query Optimization and ThroughputThe MySQL Optimizer team continues to amaze with the latest round of improvements in 5.6.5. Along with much refactoring of the legacy code base, the Optimizer team has improved complex query optimization and throughput by adding these functional improvements: Subquery Optimizations - Subqueries are now included in the Optimizer path for runtime optimization.  Better throughput of nested queries enables application developers to simplify and consolidate multiple queries and result sets into a single unit or work. Optimizer now uses CURRENT_TIMESTAMP as default for DATETIME columns - For simplification, this eliminates the need for application developers to assign this value when a column of this type is blank by default. Optimizations for Range based queries - Optimizer now uses ready statistics vs Index based scans for queries with multiple range values. Optimizations for queries using filesort and ORDER BY.  Optimization criteria/decision on execution method is done now at optimization vs parsing stage. Print EXPLAIN in JSON format for hierarchical readability and Enterprise tool consumption. You can learn the details about these new features as well all of the Optimizer based improvements in MySQL 5.6 by following the Optimizer team blog. You can download and try the MySQL 5.6.5 DMR here. (look under "Development Releases")  Please let us know what you think!  The new HA utilities for Replication Administration and Failover are available as part of the MySQL Workbench Community Edition, which you can download here .Also New in MySQL LabsAs has become our tradition when announcing DMRs we also like to provide "Early Access" development features to the MySQL Community via the MySQL Labs.  Today is no exception as we are also releasing the following to Labs for you to download, try and let us know your thoughts on where we need to improve:InnoDB Online OperationsMySQL 5.6 now provides Online ADD Index, FK Drop and Online Column RENAME.  These operations are non-blocking and will continue to evolve in future DMRs.  You can learn the grainy details by following John Russell's blog.InnoDB data access via Memcached API ("NotOnlySQL") - Improved refresh of an earlier feature releaseSimilar to Cluster 7.2, MySQL 5.6 provides direct NotOnlySQL access to InnoDB data via the familiar Memcached API. This provides the ultimate in flexibility for developers who need fast, simple key/value access and complex query support commingled within their applications.Improved Transactional Performance, ScaleThe InnoDB Engineering team has once again under promised and over delivered in the area of improved performance and scale.  These improvements are also included in the aggregated Spring 2012 labs release:InnoDB CPU cache performance improvements for modern, multi-core/CPU systems show great promise with internal tests showing:    2x throughput improvement for read only activity 6x throughput improvement for SELECT range Read/Write benchmarks are in progress More details on the above are available here. You can download all of the above in an aggregated "InnoDB 2012 Spring Labs Release" binary from the MySQL Labs. You can also learn more about these improvements and about related fixes to mysys mutex and hash sort by checking out the InnoDB team blog.MySQL 5.6.5 is another installment in what we believe will be the best release of the MySQL database ever.  It also serves as a shining example of how the MySQL Engineering team at Oracle leads in MySQL innovation.You can get the overall Oracle message on the MySQL 5.6.5 DMR and Early Access labs features here. As always, thanks for your continued support of MySQL, the #1 open source database on the planet!

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  • What's New in 5.6 RC and more from MySQL Connect conference

    - by Rob Young
    Keeping with the tradition of great MySQL Community events, the first annual MySQL Connect conference is now in the books.  It was great to see so many familiar faces in the crowd and at the podium sharing their ideas and thoughts on the evolution of MySQL under Oracle. The headliner of the conference was Tomas' keynote announcement of the fully featured and fully enabled MySQL 5.6 Release Candidate.  This new article on the MySQL DevZone summarizes all of the great new features ready for Community adoption, all MySQL Engineering blogs and where and how to download all of the bits. As always, early adoption and feedback on the 5.6 RC is appreciated and the sooner we get your feedback the sooner we release the "ready for production" sanctioned GA product.    Also available now, Cluster 7.3 provides support for Foreign Keys, node.js NoSQL access to underlying data and a new Auto Installer that helps you quickly and easily get up and running with Cluster 7.2 and 7.3.  The 7.3 downloads are provided in the first 7.3 Development Milestone Release (under "Development Releases" tab) and via the MySQL Labs. Oracle also announced key new additions to MySQL Enterprise Edition: New policy-based compliance Auditing. MySQL Enterprise Edition Audit adds policy-based auditing compliance to existing MySQL applications without the need to change any code.  This new plugin is available for MySQL 5.5.28 and higher; existing MySQL Enterprise Edition customers can download the upgrade from the My Oracle Support portal and all can download for evaluation from Oracle's Software Delivery Cloud. New MySQL Enterprise High Available additions provide even more options for ensuring MySQL applications remain available and running a their peak: Oracle Linux + DRBD Oracle Solaris Clustering for MySQL All in all, the first MySQL Connect conference was a great success and with refinements planned in response to attendee, sponsor and speaker feedback we expect it to grow and improve going forward. As always, thanks for your continued support of MySQL!

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  • Microsoft Cloud Day - the ups and downs

    - by Charles Young
    The term ‘cloud’ can sometimes obscure the obvious.  Today’s Microsoft Cloud Day conference in London provided a good example.  Scott Guthrie was halfway through what was an excellent keynote when he lost network connectivity.  This proved very disruptive to his presentation which centred on a series of demonstrations of the Azure platform in action.  Great efforts were made to find a solution, but no quick fix presented itself.  The venue’s IT facilities were dreadful – no WiFi, poor 3G reception (forget 4G…this is the UK) and, unbelievably, no-one on hand from the venue staff to help with infrastructure issues.  Eventually, after an unscheduled break, a solution was found and Scott managed to complete his demonstrations.  Further connectivity issues occurred during the day. I can say that the cause was prosaic.  A member of the venue staff had interfered with a patch board and inadvertently disconnected Scott Guthrie’s machine from the network by pulling out a cable. I need to state the obvious here.  If your PC is disconnected from the network it can’t communicate with other systems.  This could include a machine under someone’s desk, a mail server located down the hall, a server in the local data centre, an Internet search engine or even, heaven forbid, a role running on Azure. Inadvertently disconnecting a PC from the network does not imply a fundamental problem with the cloud or any specific cloud platform.  Some of the tweeted comments I’ve seen today are analogous to suggesting that, if you accidently unplug your microwave from the mains, this suggests some fundamental flaw with the electricity supply to your house.   This is poor reasoning, to say the least. As far as the conference was concerned, the connectivity issue in the keynote, coupled with some later problems in a couple of presentations, served to exaggerate the perception of poor organisation.   Software problems encountered before the conference prevented the correct set-up of a smartphone app intended to convey agenda information to attendees.  Although some information was available via this app, the organisers decided to print out an agenda at the last moment.  Unfortunately, the agenda sheet did not convey enough information, and attendees were forced to approach conference staff through the day to clarify locations of the various presentations. Despite these problems, the overwhelming feedback from conference attendees was very positive.  There was a real sense of excitement in the morning keynote.  For many, this was their first sight of new Azure features delivered in the ‘spring’ release.  The most common reaction I heard was amazement and appreciation that Azure’s new IaaS features deliver built-in template support for several flavours of Linux from day one.  This coupled with open source SDKs and several presentations on Azure’s support for Java, node.js, PHP, MongoDB and Hadoop served to communicate that the Azure platform is maturing quickly.  The new virtual network capabilities also surprised many attendees, and the much improved portal experience went down very well. So, despite some very irritating and disruptive problems, the event served its purpose well, communicating the breadth and depth of the newly upgraded Azure platform.  I enjoyed the day very much.

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  • Top 5 Developer Enabling Nuggets in MySQL 5.6

    - by Rob Young
    MySQL 5.6 is truly a better MySQL and reflects Oracle's commitment to the evolution of the most popular and widelyused open source database on the planet.  The feature-complete 5.6 release candidate was announced at MySQL Connect in late September and the production-ready, generally available ("GA") product should be available in early 2013.  While the message around 5.6 has been focused mainly on mass appeal, advanced topics like performance/scale, high availability, and self-healing replication clusters, MySQL 5.6 also provides many developer-friendly nuggets that are designed to enable those who are building the next generation of web-based and embedded applications and services. Boiling down the 5.6 feature set into a smaller set, of simple, easy to use goodies designed with developer agility in mind, these things deserve a quick look:Subquery Optimizations Using semi-JOINs and late materialization, the MySQL 5.6 Optimizer delivers greatly improved subquery performance. Specifically, the optimizer is now more efficient in handling subqueries in the FROM clause; materialization of subqueries in the FROM clause is now postponed until their contents are needed during execution. Additionally, the optimizer may add an index to derived tables during execution to speed up row retrieval. Internal tests run using the DBT-3 benchmark Query #13, shown below, demonstrate an order of magnitude improvement in execution times (from days to seconds) over previous versions. select c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice, sum(l_quantity)from customer, orders, lineitemwhere o_orderkey in (                select l_orderkey                from lineitem                group by l_orderkey                having sum(l_quantity) > 313  )  and c_custkey = o_custkey  and o_orderkey = l_orderkeygroup by c_name, c_custkey, o_orderkey, o_orderdate, o_totalpriceorder by o_totalprice desc, o_orderdateLIMIT 100;What does this mean for developers?  For starters, simplified subqueries can now be coded instead of complex joins for cross table lookups: SELECT title FROM film WHERE film_id IN (SELECT film_id FROM film_actor GROUP BY film_id HAVING count(*) > 12); And even more importantly subqueries embedded in packaged applications no longer need to be re-written into joins.  This is good news for both ISVs and their customers who have access to the underlying queries and who have spent development cycles writing, testing and maintaining their own versions of re-written queries across updated versions of a packaged app.The details are in the MySQL 5.6 docs. Online DDL OperationsToday's web-based applications are designed to rapidly evolve and adapt to meet business and revenue-generationrequirements. As a result, development SLAs are now most often measured in minutes vs days or weeks. For example, when an application must quickly support new product lines or new products within existing product lines, the backend database schema must adapt in kind, and most commonly while the application remains available for normal business operations.  MySQL 5.6 supports this level of online schema flexibility and agility by providing the following new ALTER TABLE online DDL syntax additions:  CREATE INDEX DROP INDEX Change AUTO_INCREMENT value for a column ADD/DROP FOREIGN KEY Rename COLUMN Change ROW FORMAT, KEY_BLOCK_SIZE for a table Change COLUMN NULL, NOT_NULL Add, drop, reorder COLUMN Again, the details are in the MySQL 5.6 docs. Key-value access to InnoDB via Memcached APIMany of the next generation of web, cloud, social and mobile applications require fast operations against simple Key/Value pairs. At the same time, they must retain the ability to run complex queries against the same data, as well as ensure the data is protected with ACID guarantees. With the new NoSQL API for InnoDB, developers have allthe benefits of a transactional RDBMS, coupled with the performance capabilities of Key/Value store.MySQL 5.6 provides simple, key-value interaction with InnoDB data via the familiar Memcached API.  Implemented via a new Memcached daemon plug-in to mysqld, the new Memcached protocol is mapped directly to the native InnoDB API and enables developers to use existing Memcached clients to bypass the expense of query parsing and go directly to InnoDB data for lookups and transactional compliant updates.  The API makes it possible to re-use standard Memcached libraries and clients, while extending Memcached functionality by integrating a persistent, crash-safe, transactional database back-end.  The implementation is shown here:So does this option provide a performance benefit over SQL?  Internal performance benchmarks using a customized Java application and test harness show some very promising results with a 9X improvement in overall throughput for SET/INSERT operations:You can follow the InnoDB team blog for the methodology, implementation and internal test cases that generated these results here. How to get started with Memcached API to InnoDB is here. New Instrumentation in Performance SchemaThe MySQL Performance Schema was introduced in MySQL 5.5 and is designed to provide point in time metrics for key performance indicators.  MySQL 5.6 improves the Performance Schema in answer to the most common DBA and Developer problems.  New instrumentations include: Statements/Stages What are my most resource intensive queries? Where do they spend time? Table/Index I/O, Table Locks Which application tables/indexes cause the most load or contention? Users/Hosts/Accounts Which application users, hosts, accounts are consuming the most resources? Network I/O What is the network load like? How long do sessions idle? Summaries Aggregated statistics grouped by statement, thread, user, host, account or object. The MySQL 5.6 Performance Schema is now enabled by default in the my.cnf file with optimized and auto-tune settings that minimize overhead (< 5%, but mileage will vary), so using the Performance Schema ona production server to monitor the most common application use cases is less of an issue.  In addition, new atomic levels of instrumentation enable the capture of granular levels of resource consumption by users, hosts, accounts, applications, etc. for billing and chargeback purposes in cloud computing environments.The MySQL docs are an excellent resource for all that is available and that can be done with the 5.6 Performance Schema. Better Condition Handling - GET DIAGNOSTICSMySQL 5.6 enables developers to easily check for error conditions and code for exceptions by introducing the new MySQL Diagnostics Area and corresponding GET DIAGNOSTICS interface command. The Diagnostic Area can be populated via multiple options and provides 2 kinds of information:Statement - which provides affected row count and number of conditions that occurredCondition - which provides error codes and messages for all conditions that were returned by a previous operation The addressable items for each are: The new GET DIAGNOSTICS command provides a standard interface into the Diagnostics Area and can be used via the CLI or from within application code to easily retrieve and handle the results of the most recent statement execution.  An example of how it is used might be:mysql> DROP TABLE test.no_such_table; ERROR 1051 (42S02): Unknown table 'test.no_such_table' mysql> GET DIAGNOSTICS CONDITION 1 -> @p1 = RETURNED_SQLSTATE, @p2 = MESSAGE_TEXT; mysql> SELECT @p1, @p2; +-------+------------------------------------+| @p1   | @p2                                | +-------+------------------------------------+| 42S02 | Unknown table 'test.no_such_table' | +-------+------------------------------------+ Options for leveraging the MySQL Diagnotics Area and GET DIAGNOSTICS are detailed in the MySQL Docs.While the above is a summary of some of the key developer enabling 5.6 features, it is by no means exhaustive. You can dig deeper into what MySQL 5.6 has to offer by reading this developer zone article or checking out "What's New in MySQL 5.6" in the MySQL docs.BONUS ALERT!  If you are developing on Windows or are considering MySQL as an alternative to SQL Server for your next project, application or shipping product, you should check out the MySQL Installer for Windows.  The installer includes the MySQL 5.6 RC database, all drivers, Visual Studio and Excel plugins, tray monitor and development tools all a single download and GUI installer.   So what are your next steps? Register for Dec. 13 "MySQL 5.6: Building the Next Generation of Web-Based Applications and Services" live web event.  Hurry!  Seats are limited. Download the MySQL 5.6 Release Candidate (look under the Development Releases tab) Provide Feedback <link to http://bugs.mysql.com/> Join the Developer discussion on the MySQL Forums Explore all MySQL Products and Developer Tools As always, thanks for your continued support of MySQL!

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  • Thank You MySQL Community! MySQL 5.6.9 Release Candidate Available Now!

    - by Rob Young
    The MySQL Community continues its good work in testing and refining MySQL 5.6, and as such the next iteration of the 5.6 Release Candidate is now available for download.  You can get MySQL 5.6.9 here (look under the "Development Releases" tab).  This version is the result of feedback we have gotten since MySQL 5.6.7 was announced at MySQL Connect in late September. As iron sharpens iron, Community feedback sharpens the quality and performance of MySQL so please download 5.6.9 and let us know how we can improve it as we move toward the production-ready product release in early 2013. MySQL 5.6 is designed to meet the agility demands of the next generation of web apps and services and includes across the board improvements to the Optimizer, InnoDB performance/scale and online DDL operations, self-healing Replication, Performance Schema Instrumentation, Security and developer enabling NoSQL functionality.  You can learn all the details and follow MySQL Engineering blogs on all of the key features in this MySQL DevZone article. On a related note, plan to join this week's live webinars to learn more about MySQL 5.6 Self-Healing Replication Clusters and Building the Next Generation of Web, Cloud, SaaS, Embedded Application and Services with MySQL 5.6.  Hurry!  Seating is limited!  As always, thanks for your continued support of MySQL!

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  • MySQL Policy-Based Auditing Webinar Recording Now Availabile

    - by Rob Young
    For those who missed the live event, the recording of the "How to Add Policy-Based Auditing to your MySQL Applications" webinar is now available.  You can view it here. This presentation builds on my earlier blog post on MySQL Enterprise Audit that was announced at MySQL Connect in late September.  The web presentation expands on the introductory blog and covers: The regulatory problem to be solved (internal audit, PCI, Sarbanes-Oxley, HIPAA, others) MySQL Audit solutions for both Community and Enterprise users: General Log - use the basic features of the MySQL server MySQL 5.5 open audit API - or use your time and talent to build your own solution MySQL Enterprise Audit - or use the out of the box, ready for production solution from MySQL Simple, step-by-step process for installing, enabling and configuring the MySQL Enterprise Audit plugin for use with existing apps New variables and options for tuning the MySQL Enterprise Audit plugin for your specific use case Best practices for securing and managing audit log files and archived images Roadmap for adding an integrated solution around MySQL Enterprise Audit for MySQL only and Oracle/MySQL shops You can learn all the technical details on MySQL Enterprise Audit in the MySQL docs and learn all about MySQL Enterprise Edition and Auditing here. As always, thanks for your support of MySQL!

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  • Top 10 Reasons to Use MySQL and MySQL Cluster as an Embedded Database

    - by Rob Young
    If you are considering using MySQL and/or MySQL Cluster as the embedded database solution for your application, you should join us for today's webcast where we will discuss how you can cut costs, add flexibility and benefit from new performance and scalability enhancements that are now available in MySQL 5.6 and MySQL Cluster 7.2.  We will cover the top 10 reasons that make MySQL and MySQL Cluster the best solutions for embedding in both shrink wrapped and SaaS provided applications, how industry leaders leverage MySQL products and how you can get started with the latest innovations and support offerings across the MySQL product line. You can learn more and reserve your seat here. As always, thanks for your support of MySQL!

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  • Tellago releases a RESTful API for BizTalk Server business rules

    - by Charles Young
    Jesus Rodriguez has blogged recently on Tellago Devlabs' release of an open source RESTful API for BizTalk Server Business Rules.   This is an excellent addition to the BizTalk ecosystem and I congratulate Tellago on their work.   See http://weblogs.asp.net/gsusx/archive/2011/02/08/tellago-devlabs-a-restful-api-for-biztalk-server-business-rules.aspx   The Microsoft BRE was originally designed to be used as an embedded library in .NET applications. This is reflected in the implementation of the Rules Engine Update (REU) Service which is a TCP/IP service that is hosted by a Windows service running locally on each BizTalk box. The job of the REU is to distribute rules, managed and held in a central database repository, across the various servers in a BizTalk group.   The engine is therefore distributed on each box, rather than exploited behind a central rules service.   This model is all very well, but proves quite restrictive in enterprise environments. The problem is that the BRE can only run legally on licensed BizTalk boxes. Increasingly we need to deliver rules capabilities across a more widely distributed environment. For example, in the project I am working on currently, we need to surface decisioning capabilities for use within WF workflow services running under AppFabric on non-BTS boxes. The BRE does not, currently, offer any centralised rule service facilities out of the box, and hence you have to roll your own (and then run your rules services on BTS boxes which has raised a few eyebrows on my current project, as all other WCF services run on a dedicated server farm ).   Tellago's API addresses this by providing a RESTful API for querying the rules repository and executing rule sets against XML passed in the request payload. As Jesus points out in his post, using a RESTful approach hugely increases the reach of BRE-based decisioning, allowing simple invocation from code written in dynamic languages, mobile devices, etc.   We developed our own SOAP-based general-purpose rules service to handle scenarios such as the one we face on my current project. SOAP is arguably better suited to enterprise service bus environments (please don't 'flame' me - I refuse to engage in the RESTFul vs. SOAP war). For example, on my current project we use claims based authorisation across the entire service bus and use WIF and WS-Federation for this purpose.   We have extended this to the rules service. I can't release the code for commercial reasons :-( but this approach allows us to legally extend the reach of BRE far beyond the confines of the BizTalk boxes on which it runs and to provide general purpose decisioning capabilities on the bus.   So, well done Tellago.   I haven't had a chance to play with the API yet, but am looking forward to doing so.

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  • Open Source AI Bot interfaces

    - by David Young
    What are some open source AI Bot interfaces? Similar to Pogamut 3 GameBots2004 for custom Unreal Tournament bots or Brood Wars API for Starcraft bots etc. If you could please post one AI bot interface per answer (make sure to provide a link) and give a brief summary as to the content of the blog posts. Please include what type of bot interface structure it is, client/server, server/server, etc e.g. BWAPI is client/server which emulates a real player

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  • RIF PRD: Presentation syntax issues

    - by Charles Young
    Over Christmas I got to play a bit with the W3C RIF PRD and came across a few issues which I thought I would record for posterity. Specifically, I was working on a grammar for the presentation syntax using a GLR grammar parser tool (I was using the current CTP of ‘M’ (MGrammer) and Intellipad – I do so hope the MS guys don’t kill off M and Intellipad now they have dropped the other parts of SQL Server Modelling). I realise that the presentation syntax is non-normative and that any issues with it do not therefore compromise the standard. However, presentation syntax is useful in its own right, and it would be great to iron out any issues in a future revision of the standard. The main issues are actually not to do with the grammar at all, but rather with the ‘running example’ in the RIF PRD recommendation. I started with the code provided in Example 9.1. There are several discrepancies when compared with the EBNF rules documented in the standard. Broadly the problems can be categorised as follows: ·      Parenthesis mismatch – the wrong number of parentheses are used in various places. For example, in GoldRule, the RHS of the rule (the ‘Then’) is nested in the LHS (‘the If’). In NewCustomerAndWidgetRule, the RHS is orphaned from the LHS. Together with additional incorrect parenthesis, this leads to orphanage of UnknownStatusRule from the entire Document. ·      Invalid use of parenthesis in ‘Forall’ constructs. Parenthesis should not be used to enclose formulae. Removal of the invalid parenthesis gave me a feeling of inconsistency when comparing formulae in Forall to formulae in If. The use of parenthesis is not actually inconsistent in these two context, but in an If construct it ‘feels’ as if you are enclosing formulae in parenthesis in a LISP-like fashion. In reality, the parenthesis is simply being used to group subordinate syntax elements. The fact that an If construct can contain only a single formula as an immediate child adds to this feeling of inconsistency. ·      Invalid representation of compact URIs (CURIEs) in the context of Frame productions. In several places the URIs are not qualified with a namespace prefix (‘ex1:’). This conflicts with the definition of CURIEs in the RIF Datatypes and Built-Ins 1.0 document. Here are the productions: CURIE          ::= PNAME_LN                  | PNAME_NS PNAME_LN       ::= PNAME_NS PN_LOCAL PNAME_NS       ::= PN_PREFIX? ':' PN_LOCAL       ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* PN_CHARS)? PN_CHARS       ::= PN_CHARS_U                  | '-' | [0-9] | #x00B7                  | [#x0300-#x036F] | [#x203F-#x2040] PN_CHARS_U     ::= PN_CHARS_BASE                  | '_' PN_CHARS_BASE ::= [A-Z] | [a-z] | [#x00C0-#x00D6] | [#x00D8-#x00F6]                  | [#x00F8-#x02FF] | [#x0370-#x037D] | [#x037F-#x1FFF]                  | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF]                  | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD]                  | [#x10000-#xEFFFF] PN_PREFIX      ::= PN_CHARS_BASE ((PN_CHARS|'.')* PN_CHARS)? The more I look at CURIEs, the more my head hurts! The RIF specification allows prefixes and colons without local names, which surprised me. However, the CURIE Syntax 1.0 working group note specifically states that this form is supported…and then promptly provides a syntactic definition that seems to preclude it! However, on (much) deeper inspection, it appears that ‘ex1:’ (for example) is allowed, but would really represent a ‘fragment’ of the ‘reference’, rather than a prefix! Ouch! This is so completely ambiguous that it surely calls into question the whole CURIE specification.   In any case, RIF does not allow local names without a prefix. ·      Missing ‘External’ specifiers for built-in functions and predicates.  The EBNF specification enforces this for terms within frames, but does not appear to enforce (what I believe is) the correct use of External on built-in predicates. In any case, the running example only specifies ‘External’ once on the predicate in UnknownStatusRule. External() is required in several other places. ·      The List used on the LHS of UnknownStatusRule is comma-delimited. This is not supported by the EBNF definition. Similarly, the argument list of pred:list-contains is illegally comma-delimited. ·      Unnecessary use of conjunction around a single formula in DiscountRule. This is strictly legal in the EBNF, but redundant.   All the above issues concern the presentation syntax used in the running example. There are a few minor issues with the grammar itself. Note that Michael Kiefer stated in his paper “Rule Interchange Format: The Framework” that: “The presentation syntax of RIF … is an abstract syntax and, as such, it omits certain details that might be important for unambiguous parsing.” ·      The grammar cannot differentiate unambiguously between strategies and priorities on groups. A processor is forced to resolve this by detecting the use of IRIs and integers. This could easily be fixed in the grammar.   ·      The grammar cannot unambiguously parse the ‘->’ operator in frames. Specifically, ‘-’ characters are allowed in PN_LOCAL names and hence a parser cannot determine if ‘status->’ is (‘status’ ‘->’) or (‘status-’ ‘>’).   One way to fix this is to amend the PN_LOCAL production as follows: PN_LOCAL ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* ((PN_CHARS)-('-')))? However, unilaterally changing the definition of this production, which is defined in the SPARQL Query Language for RDF specification, makes me uncomfortable. ·      I assume that the presentation syntax is case-sensitive. I couldn’t find this stated anywhere in the documentation, but function/predicate names do appear to be documented as being case-sensitive. ·      The EBNF does not specify whitespace handling. A couple of productions (RULE and ACTION_BLOCK) are crafted to enforce the use of whitespace. This is not necessary. It seems inconsistent with the rest of the specification and can cause parsing issues. In addition, the Const production exhibits whitespaces issues. The intention may have been to disallow the use of whitespace around ‘^^’, but any direct implementation of the EBNF will probably allow whitespace between ‘^^’ and the SYMSPACE. Of course, I am being a little nit-picking about all this. On the whole, the EBNF translated very smoothly and directly to ‘M’ (MGrammar) and proved to be fairly complete. I have encountered far worse issues when translating other EBNF specifications into usable grammars.   I can’t imagine there would be any difficulty in implementing the same grammar in Antlr, COCO/R, gppg, XText, Bison, etc. A general observation, which repeats a point made above, is that the use of parenthesis in the presentation syntax can feel inconsistent and un-intuitive.   It isn’t actually inconsistent, but I think the presentation syntax could be improved by adopting braces, rather than parenthesis, to delimit subordinate syntax elements in a similar way to so many programming languages. The familiarity of braces would communicate the structure of the syntax more clearly to people like me.  If braces were adopted, parentheses could be retained around ‘var (frame | ‘new()’) constructs in action blocks. This use of parenthesis feels very LISP-like, and I think that this is my issue. It’s as if the presentation syntax represents the deformed love-child of LISP and C. In some places (specifically, action blocks), parenthesis is used in a LISP-like fashion. In other places it is used like braces in C. I find this quite confusing. Here is a corrected version of the running example (Example 9.1) in compliant presentation syntax: Document(    Prefix( ex1 <http://example.com/2009/prd2> )    (* ex1:CheckoutRuleset *)  Group rif:forwardChaining (     (* ex1:GoldRule *)    Group 10 (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"Silver"])        (Forall ?shoppingCart such that ?customer[ex1:shoppingCart->?shoppingCart]           (If Exists ?value (And(?shoppingCart[ex1:value->?value]                                  External(pred:numeric-greater-than-or-equal(?value 2000))))            Then Do(Modify(?customer[ex1:status->"Gold"])))))      (* ex1:DiscountRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Or( ?customer[ex1:status->"Silver"]                ?customer[ex1:status->"Gold"])         Then Do ((?s ?customer[ex1:shoppingCart-> ?s])                  (?v ?s[ex1:value->?v])                  Modify(?s [ex1:value->External(func:numeric-multiply (?v 0.95))]))))      (* ex1:NewCustomerAndWidgetRule *)    Group (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"New"] )        (If Exists ?shoppingCart ?item                   (And(?customer[ex1:shoppingCart->?shoppingCart]                        ?shoppingCart[ex1:containsItem->?item]                        ?item # ex1:Widget ) )         Then Do( (?s ?customer[ex1:shoppingCart->?s])                  (?val ?s[ex1:value->?val])                  (?voucher ?customer[ex1:voucher->?voucher])                  Retract(?customer[ex1:voucher->?voucher])                  Retract(?voucher)                  Modify(?s[ex1:value->External(func:numeric-multiply(?val 0.90))]))))      (* ex1:UnknownStatusRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Not(Exists ?status                       (And(?customer[ex1:status->?status]                            External(pred:list-contains(List("New" "Bronze" "Silver" "Gold") ?status)) )))         Then Do( Execute(act:print(External(func:concat("New customer: " ?customer))))                  Assert(?customer[ex1:status->"New"]))))  ) )   I hope that helps someone out there :-)

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  • Project Idea - Android

    - by Darren Young
    Hi, I am trying to come up with some project ideas for my final year at University, and I think that I have one that would offer be a (massive) challenge, and something I could potentially make money from. I just want to check something. Is it possible(from a photograph), to be able to determine somebodys face and the individual parts of that face - eyes, ears, nose, etc? This will probably be via Android. Thanks.

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  • Conways Game of Life C#

    - by Darren Young
    Hi, Not sure if this is the correct place for this question or SO - mods please move if necessary. I am going to have a go at creating GoL over the weekend as a little test project : http://en.wikipedia.org/wiki/Conway's_Game_of_Life I understand the algorithm, however I just wanted to check regarding the implementation, from maybe somebody that has tried it. Essentially, my first (basic) implementation, will be a static grid at a set speed. If I understand correctly, these are the steps I will need: Initial seed Create 2d array with initial set up Foreach iteration, create temporary array, calculating each cells new state based on the Game of Life algorithm Assign temp array to proper array. Redraw grid from proper array. My concerns are over speed. When I am populating the grid from the array, would it simply be a case of looping through the array, assigning on or off to each grid cell and then redraw the grid? Am I on the correct path?

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  • CON6714 - Mixed-Language Development: Leveraging Native Code from Java

    - by Darryl Gove
    Here's the abstract from my JavaOne talk: There are some situations in which it is necessary to call native code (C/C++ compiled code) from Java applications. This session describes how to do this efficiently and how to performance-tune the resulting applications. The objectives for the session are: Explain reasons for using native code in Java applications Describe pitfalls of calling native code from Java Discuss performance-tuning of Java apps that use native code I'll cover how to call native code from Java, debugging native code, and then I'll dig into performance tuning the code. The talk is not going too deep on performance tuning - focusing on the JNI specific topics; I'll do a bit more about performance tuning in my OpenWorld talk later in the day.

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  • Current SPARC Architectures

    - by Darryl Gove
    Different generations of SPARC processors implement different architectures. The architecture that the compiler targets is controlled implicitly by the -xtarget flag and explicitly by the -arch flag. If an application targets a recent architecture, then the compiler gets to play with all the instructions that the new architecture provides. The downside is that the application won't work on older processors that don't have the new instructions. So for developer's there is a trade-off between performance and portability. The way we have solved this in the compiler is to assume a "generic" architecture, and we've made this the default behaviour of the compiler. The only flag that doesn't make this assumption is -fast which tells the compiler to assume that the build machine is also the deployment machine - so the compiler can use all the instructions that the build machine provides. The -xtarget=generic flag tells the compiler explicitly to use this generic model. We work hard on making generic code work well across all processors. So in most cases this is a very good choice. It is also of interest to know what processors support the various architectures. The following Venn diagram attempts to show this: A textual description is as follows: The T1 and T2 processors, in addition to most other SPARC processors that were shipped in the last 10+ years supported V9b, or sparcvis2. The SPARC64 processors from Fujitsu, used in the M-series machines, added support for the floating point multiply accumulate instruction in the sparcfmaf architecture. Support for this instruction also appeared in the T3 - this is called sparcvis3 Later SPARC64 processors added the integer multiply accumulate instruction, this architecture is sparcima. Finally the T4 includes support for both the integer and floating point multiply accumulate instructions in the sparc4 architecture. So the conclusion should be: Floating point multiply accumulate is supported in both the T-series and M-series machines, so it should be a relatively safe bet to start using it. The T4 is a very good machine to deploy to because it supports all the current instruction sets.

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  • The Singleton Pattern

    - by Darren Young
    Hi, I am a new programmer (4 months into my first job) and have recently taken an interest in design patterns. One that I have used recently is the Singleton. However, looking at some comments on this thread Overused or abused programming techniques .......it has some bad feedback. Come somebody explain why? I have found it useful in some places, however I could probably have achieved the same without it using a static class. Thanks.

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  • Efficient inline templates and C++

    - by Darryl Gove
    I've talked before about calling inline templates from C++, I've also talked about calling inline templates efficiently. This time I want to talk about efficiently calling inline templates from C++. The obvious starting point is that I need to declare the inline templates as being extern "C": extern "C" { int mytemplate(int); } This enables us to call it, but the call may not be very efficient because the compiler will treat it as a function call, and may produce suboptimal code based on that premise. So we need to add the no_side_effect pragma: extern "C" { int mytemplate(int); #pragma no_side_effect(mytemplate) } However, this may still not produce optimal code. We've discussed how the no_side_effect pragma cannot be combined with exceptions, well we know that the code cannot produce exceptions, but the compiler doesn't know that. If we tell the compiler that information it may be able to produce even better code. We can do this by adding the "throw()" keyword to the template declaration: extern "C" { int mytemplate(int) throw(); #pragma no_side_effect(mytemplate) } The following is an example of how these changes might improve performance. We can take our previous example code and migrate it to C++, adding the use of a try...catch construct: #include <iostream extern "C" { int lzd(int); #pragma no_side_effect(lzd) } int a; int c=0; class myclass { int routine(); }; int myclass::routine() { try { for(a=0; a<1000; a++) { c=lzd(c); } } catch(...) { std::cout << "Something happened" << std::endl; } return 0; } Compiling this produces a slightly suboptimal code sequence in the hot loop: $ CC -O -xtarget=T4 -S t.cpp t.il ... /* 0x0014 23 */ lzd %o0,%o0 /* 0x0018 21 */ add %l6,1,%l6 /* 0x001c */ cmp %l6,1000 /* 0x0020 */ bl,pt %icc,.L77000033 /* 0x0024 23 */ st %o0,[%l7] There's a store in the delay slot of the branch, so we're repeatedly storing data back to memory. If we change the function declaration to include "throw()", we get better code: $ CC -O -xtarget=T4 -S t.cpp t.il ... /* 0x0014 21 */ add %i1,1,%i1 /* 0x0018 23 */ lzd %o0,%o0 /* 0x001c 21 */ cmp %i1,999 /* 0x0020 */ ble,pt %icc,.L77000019 /* 0x0024 */ nop The store has gone, but the code is still suboptimal - there's a nop in the delay slot rather than useful work. However, it's good enough for this example. The point I'm making is that the compiler produces the better code with both the "throw()" and the no side effect pragma.

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  • Pragmas and exceptions

    - by Darryl Gove
    The compiler pragmas: #pragma no_side_effect(routinename) #pragma does_not_write_global_data(routinename) #pragma does_not_read_global_data(routinename) are used to tell the compiler more about the routine being called, and enable it to do a better job of optimising around the routine. If a routine does not read global data, then global data does not need to be stored to memory before the call to the routine. If the routine does not write global data, then global data does not need to be reloaded after the call. The no side effect directive indicates that the routine does no I/O, does not read or write global data, and the result only depends on the input. However, these pragmas should not be used on routines that throw exceptions. The following example indicates the problem: #include <iostream extern "C" { int exceptional(int); #pragma no_side_effect(exceptional) } int exceptional(int a) { if (a==7) { throw 7; } else { return a+1; } } int a; int c=0; class myclass { public: int routine(); }; int myclass::routine() { for(a=0; a<1000; a++) { c=exceptional(c); } return 0; } int main() { myclass f; try { f.routine(); } catch(...) { std::cout << "Something happened" << a << c << std::endl; } } The routine "exceptional" is declared as having no side effects, however it can throw an exception. The no side effects directive enables the compiler to avoid storing global data back to memory, and retrieving it after the function call, so the loop containing the call to exceptional is quite tight: $ CC -O -S test.cpp ... .L77000061: /* 0x0014 38 */ call exceptional ! params = %o0 ! Result = %o0 /* 0x0018 36 */ add %i1,1,%i1 /* 0x001c */ cmp %i1,999 /* 0x0020 */ ble,pt %icc,.L77000061 /* 0x0024 */ nop However, when the program is run the result is incorrect: $ CC -O t.cpp $ ./a.out Something happend00 If the code had worked correctly, the output would have been "Something happened77" - the exception occurs on the seventh iteration. Yet, the current code produces a message that uses the original values for the variables 'a' and 'c'. The problem is that the exception handler reads global data, and due to the no side effects directive the compiler has not updated the global data before the function call. So these pragmas should not be used on routines that have the potential to throw exceptions.

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  • Library order is important

    - by Darryl Gove
    I've written quite extensively about link ordering issues, but I've not discussed the interaction between archive libraries and shared libraries. So let's take a simple program that calls a maths library function: #include <math.h int main() { for (int i=0; i<10000000; i++) { sin(i); } } We compile and run it to get the following performance: bash-3.2$ cc -g -O fp.c -lm bash-3.2$ timex ./a.out real 6.06 user 6.04 sys 0.01 Now most people will have heard of the optimised maths library which is added by the flag -xlibmopt. This contains optimised versions of key mathematical functions, in this instance, using the library doubles performance: bash-3.2$ cc -g -O -xlibmopt fp.c -lm bash-3.2$ timex ./a.out real 2.70 user 2.69 sys 0.00 The optimised maths library is provided as an archive library (libmopt.a), and the driver adds it to the link line just before the maths library - this causes the linker to pick the definitions provided by the static library in preference to those provided by libm. We can see the processing by asking the compiler to print out the link line: bash-3.2$ cc -### -g -O -xlibmopt fp.c -lm /usr/ccs/bin/ld ... fp.o -lmopt -lm -o a.out... The flag to the linker is -lmopt, and this is placed before the -lm flag. So what happens when the -lm flag is in the wrong place on the command line: bash-3.2$ cc -g -O -xlibmopt -lm fp.c bash-3.2$ timex ./a.out real 6.02 user 6.01 sys 0.01 If the -lm flag is before the source file (or object file for that matter), we get the slower performance from the system maths library. Why's that? If we look at the link line we can see the following ordering: /usr/ccs/bin/ld ... -lmopt -lm fp.o -o a.out So the optimised maths library is still placed before the system maths library, but the object file is placed afterwards. This would be ok if the optimised maths library were a shared library, but it is not - instead it's an archive library, and archive library processing is different - as described in the linker and library guide: "The link-editor searches an archive only to resolve undefined or tentative external references that have previously been encountered." An archive library can only be used resolve symbols that are outstanding at that point in the link processing. When fp.o is placed before the libmopt.a archive library, then the linker has an unresolved symbol defined in fp.o, and it will search the archive library to resolve that symbol. If the archive library is placed before fp.o then there are no unresolved symbols at that point, and so the linker doesn't need to use the archive library. This is why libmopt needs to be placed after the object files on the link line. On the other hand if the linker has observed any shared libraries, then at any point these are checked for any unresolved symbols. The consequence of this is that once the linker "sees" libm it will resolve any symbols it can to that library, and it will not check the archive library to resolve them. This is why libmopt needs to be placed before libm on the link line. This leads to the following order for placing files on the link line: Object files Archive libraries Shared libraries If you use this order, then things will consistently get resolved to the archive libraries rather than to the shared libaries.

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  • Providing feedback on the Solaris Studio 12.4 Beta

    - by Darryl Gove
    Obviously, the point of the Solaris Studio 12.4 Beta programme was for everyone to try out the new version of the compiler and tools, and for us to gather feedback on what was working, what was broken, and what was missing. We've had lots of useful feedback - you can see some of it on the forums. But we're after more. Hence we have a Solaris Studio 12.4 Beta survey where you can tell us more about your experiences. Your comments are really helpful to us. Thanks.

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  • Inline template efficiency

    - by Darryl Gove
    I like inline templates, and use them quite extensively. Whenever I write code with them I'm always careful to check the disassembly to see that the resulting output is efficient. Here's a potential cause of inefficiency. Suppose we want to use the mis-named Leading Zero Detect (LZD) instruction on T4 (this instruction does a count of the number of leading zero bits in an integer register - so it should really be called leading zero count). So we put together an inline template called lzd.il looking like: .inline lzd lzd %o0,%o0 .end And we throw together some code that uses it: int lzd(int); int a; int c=0; int main() { for(a=0; a<1000; a++) { c=lzd(c); } return 0; } We compile the code with some amount of optimisation, and look at the resulting code: $ cc -O -xtarget=T4 -S lzd.c lzd.il $ more lzd.s .L77000018: /* 0x001c 11 */ lzd %o0,%o0 /* 0x0020 9 */ ld [%i1],%i3 /* 0x0024 11 */ st %o0,[%i2] /* 0x0028 9 */ add %i3,1,%i0 /* 0x002c */ cmp %i0,999 /* 0x0030 */ ble,pt %icc,.L77000018 /* 0x0034 */ st %i0,[%i1] What is surprising is that we're seeing a number of loads and stores in the code. Everything could be held in registers, so why is this happening? The problem is that the code is only inlined at the code generation stage - when the actual instructions are generated. Earlier compiler phases see a function call. The called functions can do all kinds of nastiness to global variables (like 'a' in this code) so we need to load them from memory after the function call, and store them to memory before the function call. Fortunately we can use a #pragma directive to tell the compiler that the routine lzd() has no side effects - meaning that it does not read or write to memory. The directive to do that is #pragma no_side_effect(<routine name), and it needs to be placed after the declaration of the function. The new code looks like: int lzd(int); #pragma no_side_effect(lzd) int a; int c=0; int main() { for(a=0; a<1000; a++) { c=lzd(c); } return 0; } Now the loop looks much neater: /* 0x0014 10 */ add %i1,1,%i1 ! 11 ! { ! 12 ! c=lzd(c); /* 0x0018 12 */ lzd %o0,%o0 /* 0x001c 10 */ cmp %i1,999 /* 0x0020 */ ble,pt %icc,.L77000018 /* 0x0024 */ nop

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  • The Bing Sting - an alternative opinion

    - by Charles Young
    I know I'm a bit of an MS fanboy at times, but please, am I missing something here? Microsoft, with permission of users, exploits clickstream data gathered by observing user behaviour. One use for this data is to improve Bing queries. Google equips twenty of its engineers with laptops and installs the widgets required to provide Microsoft with clickstream data. It then gets their engineers to repeatedly (I assume) type in 'synthetic' queries which bring back 'doctored' hits. It asks its engineers to then click these results (think about this!). So, the behaviour of the engineers is observed and the resulting clickstream data goes off to Microsoft. It is processed and 'improves' Bing results accordingly.   What exactly did Microsoft do wrong here?   Google's so-called 'Bing sting' is clearly a very effective attack from a propaganda perspective, but is poor practice from a company that claims to do no evil. Generating and sending clickstream data deliberately so that you can then subsequently claim that your competitor 'copied' that data from you is neither fair nor reasonable, and suggests to me a degree of desperation in the face of real competition.   Monopolies are undesirable, whether they are Microsoft monopolies or Google monopolies.    Personally, I'm glad Microsoft has technology in place to observe user behaviour (with permission, of course) and improve their search results using such data. I can only assume Google doesn't implement similar capabilities. Sounds to me as if, at least in this respect, Microsoft may offer the better technology.

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  • Compiling for T4

    - by Darryl Gove
    I've recently had quite a few queries about compiling for T4 based systems. So it's probably a good time to review what I consider to be the best practices. Always use the latest compiler. Being in the compiler team, this is bound to be something I'd recommend But the serious points are that (a) Every release the tools get better and better, so you are going to be much more effective using the latest release (b) Every release we improve the generated code, so you will see things get better (c) Old releases cannot know about new hardware. Always use optimisation. You should use at least -O to get some amount of optimisation. -xO4 is typically even better as this will add within-file inlining. Always generate debug information, using -g. This allows the tools to attribute information to lines of source. This is particularly important when profiling an application. The default target of -xtarget=generic is often sufficient. This setting is designed to produce a binary that runs well across all supported platforms. If the binary is going to be deployed on only a subset of architectures, then it is possible to produce a binary that only uses the instructions supported on these architectures, which may lead to some performance gains. I've previously discussed which chips support which architectures, and I'd recommend that you take a look at the chart that goes with the discussion. Crossfile optimisation (-xipo) can be very useful - particularly when the hot source code is distributed across multiple source files. If you're allowed to have something as geeky as favourite compiler optimisations, then this is mine! Profile feedback (-xprofile=[collect: | use:]) will help the compiler make the best code layout decisions, and is particularly effective with crossfile optimisations. But what makes this optimisation really useful is that codes that are dominated by branch instructions don't typically improve much with "traditional" compiler optimisation, but often do respond well to being built with profile feedback. The macro flag -fast aims to provide a one-stop "give me a fast application" flag. This usually gives a best performing binary, but with a few caveats. It assumes the build platform is also the deployment platform, it enables floating point optimisations, and it makes some relatively weak assumptions about pointer aliasing. It's worth investigating. SPARC64 processor, T3, and T4 implement floating point multiply accumulate instructions. These can substantially improve floating point performance. To generate them the compiler needs the flag -fma=fused and also needs an architecture that supports the instruction (at least -xarch=sparcfmaf). The most critical advise is that anyone doing performance work should profile their application. I cannot overstate how important it is to look at where the time is going in order to determine what can be done to improve it. I also presented at Oracle OpenWorld on this topic, so it might be helpful to review those slides.

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  • It could be worse....

    - by Darryl Gove
    As "guest" pointed out, in my file I/O test I didn't open the file with O_SYNC, so in fact the time was spent in OS code rather than in disk I/O. It's a straightforward change to add O_SYNC to the open() call, but it's also useful to reduce the iteration count - since the cost per write is much higher: ... #define SIZE 1024 void test_write() { starttime(); int file = open("./test.dat",O_WRONLY|O_CREAT|O_SYNC,S_IWGRP|S_IWOTH|S_IWUSR); ... Running this gave the following results: Time per iteration 0.000065606310 MB/s Time per iteration 2.709711563906 MB/s Time per iteration 0.178590114758 MB/s Yup, disk I/O is way slower than the original I/O calls. However, it's not a very fair comparison since disks get written in large blocks of data and we're deliberately sending a single byte. A fairer result would be to look at the I/O operations per second; which is about 65 - pretty much what I'd expect for this system. It's also interesting to examine at the profiles for the two cases. When the write() was trapping into the OS the profile indicated that all the time was being spent in system. When the data was being written to disk, the time got attributed to sleep. This gives us an indication how to interpret profiles from apps doing I/O. It's the sleep time that indicates disk activity.

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  • Monday, 1st October: Presenting at JavaOne and Oracle Open World

    - by Darryl Gove
    On Monday 1 October I will be presenting at both JavaOne and Oracle Open World. The full conference schedule is available from here. The logistics for my sessions are as follows: JavaOne: 8:30am Monday 1 October. CON6714: "Mixed-Language Development: Leveraging Native Code from Java". San Francisco Hilton - Continental Ballroom 6 Oracle OpenWorld: 10:45am Monday 1 October. CON6382: "Maximizing Your SPARC T4 Oracle Solaris Application Performance". Marriott Marquis - Golden Gate C3 Hope to see you there!

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