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• Type of computer for a developer on the road

  - by nabucosound

  Hi developers: I am planning to be traveling through eurasia and asia (russia, china, korea, japan, south east asia...) for a while and, although there are plenty of marvelous things to see and to do, I must keep on working :(. I am a python developer, dedicated mainly to web projects. I use django, sqlite3, browsers, and ocassionaly (only if I have no choice) I install postgres, mysql, apache or any other servers commonly used in the internets. I do my coding on vim, use ssh to connect, lftp to transfer files, IRC, grep/ack... So I spend most of my time in the terminal shells. But I also use IM or Skype to communicate with my clients and peers, as well as some other software (that after all is not mandatory for my day-to-day work). I currently work with a Macbook Pro (3 years old now) and so far I am very happy with the performance. But I don't want to carry it if I am going to be "on transit" for long time, it is simply huge and heavy for what I am planning to load in my rather small backpack (while traveling, less is more, you know). So here I am reading all kind of opinions about netbooks, because at first sight this is the kind of computer I thought I had to choose. I am going to use Linux for it, Microsoft is not my cup of tea and Mac is not available for them, unless I were to buy a Macbook air, something that I won't do because if I am robbed or rain/dust/truck loaders break it I would burst in tears. I am concerned about wifi performance and connectivity, I am going to use one of those linux distros/tools to hack/test on "open" networks (if you know what I mean) in case I am not in a place with real free wifi access and I find myself in an emergency. CPU speed should be acceptable, but since I don't plan to run Photoshop or expensive IDEs, I guess most of the time I won't be overloading the machine. Apart from this, maybe (surely) I am missing other features to consider. With that said (sorry about the length) here it comes my question, raised from a deep ignorance regarding the wars betweeb betbooks vs notebooks (I assume tablet PCs are not for programming yet): If I buy a netbook will I have to throw it away after 1 month on the road and buy a notebook? Or will I be OK? Thanks! Hector Update I have received great feedback so far! I would like to insist on the fact that I will be traveling through many different countries and scenarios. I am sure that while in Japan I will be more than fine with anything related to technology, connectivity, etc. But consider that I will be, for example, on a train through Russia (transsiberian) and will cross Mongolia as well. I will stay in friends' places sometimes, but most of the time I will have to work from hostel rooms, trains, buses, beaches (hey this last one doesn't sound too bad hehe!). I think some of your answers guys seem to focus on the geek part but loose the point of this "on the road" fact. I am very aware and agree that netbooks suck compared to notebooks, but what I am trying to do here is to find a balance and discover your experiences with netbooks to see first hand if a netbook will be a fail in the mid-long term of the trip for my purposes. So I have resumed the main concepts expressed here on this small list, in no particular order: keyboard/touchpad feel: I use vim so no need of moving mouse pointers that much, unless I am browsing the web, but intensive use of keyboard screen real state: again, terminal work for most of the time battery life: I think something very important weight/size: also very important looks not worth stealing it, don't give a shit if it is lost/stolen/broken: this may depend on kind of person, your economy, etc. Also to prevent losing work, I will upload EVERYTHING to the cloud whenever I'll have a chance. wifi: don't want to discover my wifi is one of those that cannot deal with half the routers on this planet or has poor connectivity. Thanks again for your answers and comments!

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• Stale statistics on a newly created temporary table in a stored procedure can lead to poor performance

  - by sqlworkshops

  When you create a temporary table you expect a new table with no past history (statistics based on past existence), this is not true if you have less than 6 updates to the temporary table. This might lead to poor performance of queries which are sensitive to the content of temporary tables.I was optimizing SQL Server Performance at one of my customers who provides search functionality on their website. They use stored procedure with temporary table for the search. The performance of the search depended on who searched what in the past, option (recompile) by itself had no effect. Sometimes a simple search led to timeout because of non-optimal plan usage due to this behavior. This is not a plan caching issue rather temporary table statistics caching issue, which was part of the temporary object caching feature that was introduced in SQL Server 2005 and is also present in SQL Server 2008 and SQL Server 2012. In this customer case we implemented a workaround to avoid this issue (see below for example for workarounds).When temporary tables are cached, the statistics are not newly created rather cached from the past and updated based on automatic update statistics threshold. Caching temporary tables/objects is good for performance, but caching stale statistics from the past is not optimal.We can work around this issue by disabling temporary table caching by explicitly executing a DDL statement on the temporary table. One possibility is to execute an alter table statement, but this can lead to duplicate constraint name error on concurrent stored procedure execution. The other way to work around this is to create an index.I think there might be many customers in such a situation without knowing that stale statistics are being cached along with temporary table leading to poor performance.Ideal solution is to have more aggressive statistics update when the temporary table has less number of rows when temporary table caching is used. I will open a connect item to report this issue.Meanwhile you can mitigate the issue by creating an index on the temporary table. You can monitor active temporary tables using Windows Server Performance Monitor counter: SQL Server: General Statistics->Active Temp Tables. The script to understand the issue and the workaround is listed below:set nocount onset statistics time offset statistics io offdrop table tab7gocreate table tab7 (c1 int primary key clustered, c2 int, c3 char(200))gocreate index test on tab7(c2, c1, c3)gobegin trandeclare @i intset @i = 1while @i <= 50000begininsert into tab7 values (@i, 1, ‘a’)set @i = @i + 1endcommit trangoinsert into tab7 values (50001, 1, ‘a’)gocheckpointgodrop proc test_slowgocreate proc test_slow @i intasbegindeclare @j intcreate table #temp1 (c1 int primary key)insert into #temp1 (c1) select @iselect @j = t7.c1 from tab7 t7 inner join #temp1 t on (t7.c2 = t.c1)endgodbcc dropcleanbuffersset statistics time onset statistics io ongo–high reads as expected for parameter ’1'exec test_slow 1godbcc dropcleanbuffersgo–high reads that are not expected for parameter ’2'exec test_slow 2godrop proc test_with_recompilegocreate proc test_with_recompile @i intasbegindeclare @j intcreate table #temp1 (c1 int primary key)insert into #temp1 (c1) select @iselect @j = t7.c1 from tab7 t7 inner join #temp1 t on (t7.c2 = t.c1)option (recompile)endgodbcc dropcleanbuffersset statistics time onset statistics io ongo–high reads as expected for parameter ’1'exec test_with_recompile 1godbcc dropcleanbuffersgo–high reads that are not expected for parameter ’2'–low reads on 3rd execution as expected for parameter ’2'exec test_with_recompile 2godrop proc test_with_alter_table_recompilegocreate proc test_with_alter_table_recompile @i intasbegindeclare @j intcreate table #temp1 (c1 int primary key)–to avoid caching of temporary tables one can create a constraint–but this might lead to duplicate constraint name error on concurrent usagealter table #temp1 add constraint test123 unique(c1)insert into #temp1 (c1) select @iselect @j = t7.c1 from tab7 t7 inner join #temp1 t on (t7.c2 = t.c1)option (recompile)endgodbcc dropcleanbuffersset statistics time onset statistics io ongo–high reads as expected for parameter ’1'exec test_with_alter_table_recompile 1godbcc dropcleanbuffersgo–low reads as expected for parameter ’2'exec test_with_alter_table_recompile 2godrop proc test_with_index_recompilegocreate proc test_with_index_recompile @i intasbegindeclare @j intcreate table #temp1 (c1 int primary key)–to avoid caching of temporary tables one can create an indexcreate index test on #temp1(c1)insert into #temp1 (c1) select @iselect @j = t7.c1 from tab7 t7 inner join #temp1 t on (t7.c2 = t.c1)option (recompile)endgoset statistics time onset statistics io ondbcc dropcleanbuffersgo–high reads as expected for parameter ’1'exec test_with_index_recompile 1godbcc dropcleanbuffersgo–low reads as expected for parameter ’2'exec test_with_index_recompile 2go

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• AI to move custom-shaped spaceships (shape affecting movement behaviour)

  - by kaoD

  I'm designing a networked turn based 3D-6DOF space fleet combat strategy game which relies heavily on ship customization. Let me explain the game a bit, since you need to know a bit about it to set the question. What I aim for is the ability to create your own fleet of ships with custom shapes and attached modules (propellers, tractor beams...) which would give advantages and disadvantages to each ship, so you have lots of different fleet distributions. E.g., long ship with two propellers at the side would let the ship spin around that plane easily, bigger ships would move slowly unless you place lots of propellers at the back (therefore spending more "construction" points and energy when moving, and it will only move fast towards that direction.) I plan to balance all the game around this feature. The game would revolve around two phases: orders and combat phase. During the orders phase, you command the different ships. When all players finish the order phase, the combat phase begins and the ship orders get resolved in real-time for some time, then the action pauses and there's a new orders phase. The problem comes when I think about player input. To move a ship, you need to turn on or off different propellers if you want to steer, travel forward, brake, rotate in place... These propellers don't have to work at their whole power, so you can achieve more movement combinations with less propellers. I think this approach is a bit boring. The player doesn't want to fiddle with motors or anything, you just want to MOVE and KILL. The way I intend the player to give orders to these ships is by a destination and a rotation, and then the AI would calculate the correct propeller power to achive that movement and rotation. Propulsion doesn't have to be the same throught the entire turn calculation (after the orders have been given) so it would be cool if the ships reacted as they move, adjusting the power of the propellers for their needs dynamically, but it may be too hard to implement and it's not really needed for the game to work. In both cases, how would that AI decide which propellers to activate for the best (or at least not worst) trajectory to be achieved? I though about some approaches: Learning AI: The ship types would learn about their movement by trial and error, adjusting their behaviour with more uses, and finally becoming "smart". I don't want to get involved THAT far in AI coding, and I think it can be frustrating for the player (even if you can let it learn without playing.) Pre-calculated timestep movement: Upon ship creation, ALL possible movements are calculated for each propeller configuration and power for a given delta-time. Memory intensive, ugly, bad. Pre-calculated trajectories: The same as above but not for each delta-time but the whole trajectory, which would then be fitted as much as possible. Requires a fixed propeller configuration for the whole combat phase and is still memory intensive, ugly and bad. Continuous brute forcing: The AI continously checks ALL possible propeller configurations throughout the entire combat phase, precalculates a few time steps and decides which is the best one based on that. Con: what's good now might not be that good later, and it's too CPU intensive, ugly, and bad too. Single brute forcing: Same as above, but only brute forcing at the beginning of the simulation, so it needs constant propeller configuration throughout the entire combat phase. Coninuous angle check: This is not a full movement method, but maybe a way to discard "stupid" propeller configurations. Given the current propeller's normal vector and the final one, you can approximate the power needed for the propeller based on the angle. You must do this continuously throughout the whole combat phase. I figured this one out recently so I didn't put in too much thought. A priori, it has the "what's good now might not be that good later" drawback too, and it doesn't care about the other propellers which may act together to make a better propelling configuration. I'm really stuck here. Any ideas?

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• Deliberate Practice

  - by Jeff Foster

  It’s easy to assume, as software engineers, that there is little need to “practice” writing code. After all, we write code all day long! Just by writing a little each day, we’re constantly learning and getting better, right? Unfortunately, that’s just not true. Of course, developers do improve with experience. Each time we encounter a problem we’re more likely to avoid it next time. If we’re in a team that deploys software early and often, we hone and improve the deployment process each time we practice it. However, not all practice makes perfect. To develop true expertise requires a particular type of practice, deliberate practice, the only goal of which is to make us better programmers. Everyday software development has other constraints and goals, not least the pressure to deliver. We rarely get the chance in the course of a “sprint” to experiment with potential solutions that are outside our current comfort zone. However, if we believe that software is a craft then it’s our duty to strive continuously to raise the standard of software development. This requires specific and sustained efforts to get better at something we currently can’t do well (from Harvard Business Review July/August 2007). One interesting way to introduce deliberate practice, in a sustainable way, is the code kata. The term kata derives from martial arts and refers to a set of movements practiced either solo or in pairs. One of the better-known examples is the Bowling Game kata by Bob Martin, the goal of which is simply to write some code to do the scoring for 10-pin bowling. It sounds too easy, right? What could we possibly learn from such a simple example? Trust me, though, that it’s not as simple as five minutes of typing and a solution. Of course, we can reach a solution in a short time, but the important thing about code katas is that we explore each technique fully and in a controlled way. We tackle the same problem multiple times, using different techniques and making different decisions, understanding the ramifications of each one, and exploring edge cases. The short feedback loop optimizes opportunities to learn. Another good example is Conway’s Game of Life. It’s a simple problem to solve, but try solving it in a functional style. If you’re used to mutability, solving the problem without mutating state will push you outside of your comfort zone. Similarly, if you try to solve it with the focus of “tell-don’t-ask“, how will the responsibilities of each object change? As software engineers, we don’t get enough opportunities to explore new ideas. In the middle of a development cycle, we can’t suddenly start experimenting on the team’s code base. Code katas offer an opportunity to explore new techniques in a safe environment. If you’re still skeptical, my challenge to you is simply to try it out. Convince a willing colleague to pair with you and work through a kata or two. It only takes an hour and I’m willing to bet you learn a few new things each time. The next step is to make it a sustainable team practice. Start with an hour every Friday afternoon (after all who wants to commit code to production just before they leave for the weekend?) for month and see how that works out. Finally, consider signing up for the Global Day of Code Retreat. It’s like a daylong code kata, it’s on December 8th and there’s probably an event in your area!

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• E-Business Suite : Role of CHUNK_SIZE in Oracle Payroll

  - by Giri Mandalika

  Different batch processes in Oracle Payroll flow have the ability to spawn multiple child processes (or threads) to complete the work in hand. The number of child processes to fork is controlled by the THREADS parameter in APPS.PAY_ACTION_PARAMETERS view. THREADS parameter The default value for THREADS parameter is 1, which is fine for a single-processor system but not optimal for the modern multi-core multi-processor systems. Setting the THREADS parameter to a value equal to or less than the total number of [virtual] processors available on the system may improve the performance of payroll processing. However on the down side, since multiple child processes operate against the same set of payroll tables in HR schema, database may experience undesired consequences such as buffer busy waits and index contention, which results in giving up some of the gains achieved by using multiple child processes/threads to process the work. Couple of other action parameters, CHUNK_SIZE and CHUNK_SHUFFLE, help alleviate the database contention. eg., Set a value for THREADS parameter as shown below. CONNECT APPS/APPS_PASSWORD UPDATE PAY_ACTION_PARAMETERS SET PARAMETER_VALUE = DESIRED_VALUE WHERE PARAMETER_NAME = 'THREADS'; COMMIT; (I am not aware of any maximum value for THREADS parameter) CHUNK_SIZE parameter The size of each commit unit for the batch process is controlled by the CHUNK_SIZE action parameter. In other words, chunking is the act of splitting the assignment actions into commit groups of desired size represented by the CHUNK_SIZE parameter. The default value is 20, and each thread processes one chunk at a time -- which means each child process inserts or processes 20 assignment actions at any time. When multiple threads are configured, each thread picks up a chunk to process, completes the assignment actions and then picks up another chunk. This is repeated until all the chunks are exhausted. It is possible to use different chunk sizes in different batch processes. During the initial phase of processing, CHUNK_SIZE number of assignment actions are inserted into relevant table(s). When multiple child processes are inserting data at the same time into the same set of tables, as explained earlier, database may experience contention. The default value of 20 is mostly optimal in such a case. Experiment with different values for the initial phase by +/-10 for CHUNK_SIZE parameter and observe the performance impact. A larger value may make sense during the main processing phase. Again experimentation is the key in finding the suitable value for your environment. Start with a large value such as 2000 for the chunk size, then increment or decrement the size by 500 at a time until an optimal value is found. eg., Set a value for CHUNK_SIZE parameter as shown below. CONNECT APPS/APPS_PASSWORD UPDATE PAY_ACTION_PARAMETERS SET PARAMETER_VALUE = DESIRED_VALUE WHERE PARAMETER_NAME = 'CHUNK_SIZE'; COMMIT; CHUNK_SIZE action parameter accepts a value that is as low as 1 or as high as 16000. CHUNK SHUFFLE parameter By default, chunks of assignment actions are processed sequentially by all threads - which may not be a good thing especially given that all child processes/threads performing similar actions against the same set of tables almost at the same time. By saying not a good thing, I mean to say that the default behavior leads to contention in the database (in data blocks, for example). It is possible to relieve some of that database contention by randomizing the processing order of chunks of assignment actions. This behavior is controlled by the CHUNK SHUFFLE action parameter. Chunk processing is not randomized unless explicitly configured. eg., Set chunk shuffling as shown below. CONNECT APPS/APPS_PASSWORD UPDATE PAY_ACTION_PARAMETERS SET PARAMETER_VALUE = 'Y' WHERE PARAMETER_NAME = 'CHUNK SHUFFLE'; COMMIT; Finally I recommend checking the following document out for additional details and additional pay action tunable parameters that may speed up the processing of Oracle Payroll.     My Oracle Support Doc ID: 226987.1 Oracle 11i & R12 Human Resources (HRMS) & Benefits (BEN) Tuning & System Health Checks Also experiment with different combinations of parameters and values until the right set of action parameters and values are found for your deployment.

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• How to deal with overly aggressive "Link Take Down Demands"?

  - by Eoin

  I've been receiving a large number of emails recently requesting I clean from link spam from my forum. Initially the emails were very polite and professional, and I was happy to remove the links. Recently the email have gotten very abrasive, here is a particularly rude example: From: [email protected] To: [email protected] Hi, This is the second time we are reaching out to you regarding your link to our site hxxp://www.company-two.com from hxxp://www.my-forum.com/some-topic-id. We really do need to remove this link. We have to report to Google any link we were unable to remove, and I wouldn't want to have to include your site in the list. Could you please remove our link from this page and any other page on your site? Thank You, Name Changed Behind the superficial pleasantries I feel there is some very real maliciousness. Note the email address, DMCA Violations, I don't see how the DMCA is involved here, except as a word which tends to strike fear in many people. Also relating to the email address, it doesn't match the company being linked to at all. How am I to trust they are truely operating on behalf of company-two when they don't even use one of it's email addresses. My email is hidden by privacypost. While a service with legitimate uses, I feel it's highly unprofessional for communications between to companies. The claim "This is the second time..." Every email I've received has started like this, but a check of my spam filters has never revealed a 1st mail. Initially I gave them the benefit of the doubt, by now though it's clear this is a cheap ploy to start me off on the defensive. And finally worst of all- the threats of reporting me to Google if I don't do everything they ask. I sent a polite reply asking for more information. I have no idea if the email address was even valid but I never received any response. Much later I got this followup mail From: [email protected] To: [email protected] Hi, This is the final time we are reaching out to you regarding your link to our site hxxp://www.company-two.com from hxxp://www.my-forum.com/some-topic-id. We will soon be reporting to Google any link we were unable to remove, and currently your site will have to be on the list. Could you please remove our link from this page and any other page on your site? I appreciate your urgent attention to this matter. Thank You, Name Changed This time the from address was more personal, though still not obviously connected to the spammed company. Lets be honest, I don't for one second believe that the companies were the victim of a 3rd party spammer as they claim. The links in questions were generated well over a year ago, and I firmly believe the companies were directly responsible for the spam links in question, a type of spam that has plagued my forum. Now they have the audacity to demand I spend my time cleaning up their mess, using threats to ensure they get their way. Have recent changes in Googles algorithms meant all the cash they spent spamming the web has now turned into a liability? If so I can see why these companies are all of a sudden running scared. Frankly, cleaning up my forum is a good things, but the threats they are using sickens me. So my question here is specifically about the threats: Are they vaild, and would such reports to Google destroy my page rankings? Is there a way I can report this abusive behaviour to Google?

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• Brazil is Hot for Social Media

  - by Mike Stiles

  Today’s guest blog is from Oracle SVP Product Development Reggie Bradford, fresh off a visit to Sao Paulo, Brazil where he spoke at the Dachis Social Business Summit and spent some time getting a personal taste for the astonishing growth of social in Brazil, both in terms of usage and engagement. I knew it was big, but I now have an all-new appreciation for why the Wall Street Journal branded Brazil the “social media capital of the universe.” Brazil has the world’s 5th largest economy, an expanding middle class, an active younger demo market, a connected & outgoing culture, and an ongoing embrace of the social media platforms. According to comScore's 2012 Brazil Digital Future in Focus report, 97% are using social media, and that’s not even taking mobile-only users into account. There were 65 million Facebook users in 2012, spending an average 535 minutes there, up 208%. It’s one of Twitter’s fastest growing markets and the 2nd biggest market for YouTube. Instagram usage has grown over 300% since last year. That by itself is exciting, but look at the opportunity for social marketing brands. 74% of Brazilian social users follow brands on Facebook, and 59% have praised a company on either Twitter or Facebook. A 2011 Oh! Panel study found 81% of social networkers there used social to research new products and 75% went there looking for discounts. B2C eCommerce sales in Brazil is projected to hit $26.9 billion by 2015. I bet I’m not the only one who sees great things ahead, and I was fortunate enough give a keynote ABRADI, an association of leading digital agencies in Brazil with 53 execs from 35 agencies attending. I was also afforded the opportunity to give my impressions of what’s going on in Brazil to Jornal Propoganda & Marketing, one of the most popular publications in Latin America for marketers. I conveyed that especially in an environment like Brazil, where social users are so willing to connect and engage brands, marketers need to back away from the heavy-handed, one-way messaging of old school advertising and move toward genuine relationships and trust-building. To aide in this, organizational and operation changes must be embraced inside the enterprise. We've talked often about the new, tighter partnership forming between the CIO and CMO. If this partnership is not encouraged, fostered and resourced, the increasing amount of time consumers spend on mobile and digital, and the efficiencies and integrations offered by cloud-based software cannot be exploited. These are the kinds of changes that can yield social data that, when combined with enterprise data, helps you come to know your social audiences intimately and predict their needs. Consumers are always connected and need your brand to be accessible at any time, be it for information or customer service. And, of course, all of this is happening quite publicly. The holistic, socially-enable enterprise connects social to customer service systems and all other customer touch points, facilitating the kind of immediate, real-time, gratifying response customers are coming to expect. Social users in Brazil are highly active and clearly willing to meet us as brands more than halfway. Empowering yourself with a social management technology platform will have you set up to maximize this booming social market…from listening & monitoring to engagement to analytics to workflow & automation to globalization & language support. Brands, it’s time to be as social as the great people of Brazil are. Obrigado! @reggiebradfordPhoto: Gualberto107, freedigitalphotos.net

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• Looking for a real-world example illustrating that composition can be superior to inheritance

  - by Job

  I watched a bunch of lectures on Clojure and functional programming by Rich Hickey as well as some of the SICP lectures, and I am sold on many concepts of functional programming. I incorporated some of them into my C# code at a previous job, and luckily it was easy to write C# code in a more functional style. At my new job we use Python and multiple inheritance is all the rage. My co-workers are very smart but they have to produce code fast given the nature of the company. I am learning both the tools and the codebase, but the architecture itself slows me down as well. I have not written the existing class hierarchy (neither would I be able to remember everything about it), and so, when I started adding a fairly small feature, I realized that I had to read a lot of code in the process. At the surface the code is neatly organized and split into small functions/methods and not copy-paste-repetitive, but the flip side of being not repetitive is that there is some magic functionality hidden somewhere in the hierarchy chain that magically glues things together and does work on my behalf, but it is very hard to find and follow. I had to fire up a profiler and run it through several examples and plot the execution graph as well as step through a debugger a few times, search the code for some substring and just read pages at the time. I am pretty sure that once I am done, my resulting code will be short and neatly organized, and yet not very readable. What I write feels declarative, as if I was writing an XML file that drives some other magic engine, except that there is no clear documentation on what the XML should look like and what the engine does except for the existing examples that I can read as well as the source code for the 'engine'. There has got to be a better way. IMO using composition over inheritance can help quite a bit. That way the computation will be linear rather than jumping all over the hierarchy tree. Whenever the functionality does not quite fit into an inheritance model, it will need to be mangled to fit in, or the entire inheritance hierarchy will need to be refactored/rebalanced, sort of like an unbalanced binary tree needs reshuffling from time to time in order to improve the average seek time. As I mentioned before, my co-workers are very smart; they just have been doing things a certain way and probably have an ability to hold a lot of unrelated crap in their head at once. I want to convince them to give composition and functional as opposed to OOP approach a try. To do that, I need to find some very good material. I do not think that a SCIP lecture or one by Rich Hickey will do - I am afraid it will be flagged down as too academic. Then, simple examples of Dog and Frog and AddressBook classes do not really connivence one way or the other - they show how inheritance can be converted to composition but not why it is truly and objectively better. What I am looking for is some real-world example of code that has been written with a lot of inheritance, then hit a wall and re-written in a different style that uses composition. Perhaps there is a blog or a chapter. I am looking for something that can summarize and illustrate the sort of pain that I am going through. I already have been throwing the phrase "composition over inheritance" around, but it was not received as enthusiastically as I had hoped. I do not want to be perceived as a new guy who likes to complain and bash existing code while looking for a perfect approach while not contributing fast enough. At the same time, my gut is convinced that inheritance is often the instrument of evil and I want to show a better way in a near future. Have you stumbled upon any great resources that can help me?

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• What are they buying &ndash; work or value?

  - by Jamie Kurtz

  When was the last time you ordered a pizza like this: “I want the high school kid in the back to do the following… make a big circle with some dough, curl up the edges, then put some sauce on it using a small ladle, then I want him to take a handful of shredded cheese from the metal container and spread it over the circle and sauce, then finally I want the kid to place 36 pieces of pepperoni over the top of the cheese” ?? Probably never. My typical pizza order usually goes more like this: “I want a large pepperoni pizza”. In the world of software development, we try so hard to be all things agile. We: Write lots of unit tests We refactor our code, then refactor it some more We avoid writing lengthy requirements documents We try to keep processes to a minimum, and give developers freedom And we are proud of our constantly shifting focus (i.e. we’re “responding to change”) Yet, after all this, we fail to really lean and capitalize on one of agile’s main differentiators (from the twelve principles behind the Agile Manifesto): “Working software is the primary measure of progress.” That is, we foolishly commit to delivering tasks instead of features and bug fixes. Like my pizza example above, we fall into the trap of signing contracts that bind us to doing tasks – rather than delivering working software. And the biggest problem here… by far the most troubling outcome… is that we don’t let working software be a major force in all the work we do. When teams manage to ruthlessly focus on the end product, it puts them on the path of true agile. It doesn’t let them accidentally write too much documentation, or spend lots of time and money on processes and fancy tools. It forces early testing that reveals problems in the feature or bug fix. And it forces lots and lots of customer interaction.  Without that focus on the end product as your deliverable… by committing to a list of tasks instead of a list features and bug fixes… you are doomed to NOT be agile. You will end up just doing stuff, spending time on the keyboard, burning time on timesheets. Doing tasks doesn’t force you to minimize documentation. It makes it much harder to respond to change. And it will eventually force you and the client into contract haggling. Because the customer isn’t really paying you to do stuff. He’s ultimately paying for features and bug fixes. And when the customer doesn’t get what they want, responding with “well, look at the contract - we did all the tasks we committed to” doesn’t typically generate referrals or callbacks. In short, if you’re trying to deliver real value to the customer by going agile, you will most certainly fail if all you commit to is a list of things you’re going to do. Give agile what it needs by committing to features and bug fixes – not a list of ToDo items. So the next time you are writing up a contract, remember that the customer should be buying this: Not this:

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• How to Load Oracle Tables From Hadoop Tutorial (Part 5 - Leveraging Parallelism in OSCH)

  - by Bob Hanckel

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Using OSCH: Beyond Hello World In the previous post we discussed a “Hello World” example for OSCH focusing on the mechanics of getting a toy end-to-end example working. In this post we are going to talk about how to make it work for big data loads. We will explain how to optimize an OSCH external table for load, paying particular attention to Oracle’s DOP (degree of parallelism), the number of external table location files we use, and the number of HDFS files that make up the payload. We will provide some rules that serve as best practices when using OSCH. The assumption is that you have read the previous post and have some end to end OSCH external tables working and now you want to ramp up the size of the loads. Using OSCH External Tables for Access and Loading OSCH external tables are no different from any other Oracle external tables.  They can be used to access HDFS content using Oracle SQL: SELECT * FROM my_hdfs_external_table; or use the same SQL access to load a table in Oracle. INSERT INTO my_oracle_table SELECT * FROM my_hdfs_external_table; To speed up the load time, you will want to control the degree of parallelism (i.e. DOP) and add two SQL hints. ALTER SESSION FORCE PARALLEL DML PARALLEL  8; ALTER SESSION FORCE PARALLEL QUERY PARALLEL 8; INSERT /*+ append pq_distribute(my_oracle_table, none) */ INTO my_oracle_table SELECT * FROM my_hdfs_external_table; There are various ways of either hinting at what level of DOP you want to use.  The ALTER SESSION statements above force the issue assuming you (the user of the session) are allowed to assert the DOP (more on that in the next section).  Alternatively you could embed additional parallel hints directly into the INSERT and SELECT clause respectively. /*+ parallel(my_oracle_table,8) *//*+ parallel(my_hdfs_external_table,8) */ Note that the "append" hint lets you load a target table by reserving space above a given "high watermark" in storage and uses Direct Path load.  In other doesn't try to fill blocks that are already allocated and partially filled. It uses unallocated blocks.  It is an optimized way of loading a table without incurring the typical resource overhead associated with run-of-the-mill inserts.  The "pq_distribute" hint in this context unifies the INSERT and SELECT operators to make data flow during a load more efficient. Finally your target Oracle table should be defined with "NOLOGGING" and "PARALLEL" attributes.   The combination of the "NOLOGGING" and use of the "append" hint disables REDO logging, and its overhead.  The "PARALLEL" clause tells Oracle to try to use parallel execution when operating on the target table. Determine Your DOP It might feel natural to build your datasets in Hadoop, then afterwards figure out how to tune the OSCH external table definition, but you should start backwards. You should focus on Oracle database, specifically the DOP you want to use when loading (or accessing) HDFS content using external tables. The DOP in Oracle controls how many PQ slaves are launched in parallel when executing an external table. Typically the DOP is something you want to Oracle to control transparently, but for loading content from Hadoop with OSCH, it's something that you will want to control. Oracle computes the maximum DOP that can be used by an Oracle user. The maximum value that can be assigned is an integer value typically equal to the number of CPUs on your Oracle instances, times the number of cores per CPU, times the number of Oracle instances. For example, suppose you have a RAC environment with 2 Oracle instances. And suppose that each system has 2 CPUs with 32 cores. The maximum DOP would be 128 (i.e. 2*2*32). In point of fact if you are running on a production system, the maximum DOP you are allowed to use will be restricted by the Oracle DBA. This is because using a system maximum DOP can subsume all system resources on Oracle and starve anything else that is executing. Obviously on a production system where resources need to be shared 24x7, this can’t be allowed to happen. The use cases for being able to run OSCH with a maximum DOP are when you have exclusive access to all the resources on an Oracle system. This can be in situations when your are first seeding tables in a new Oracle database, or there is a time where normal activity in the production database can be safely taken off-line for a few hours to free up resources for a big incremental load. Using OSCH on high end machines (specifically Oracle Exadata and Oracle BDA cabled with Infiniband), this mode of operation can load up to 15TB per hour. The bottom line is that you should first figure out what DOP you will be allowed to run with by talking to the DBAs who manage the production system. You then use that number to derive the number of location files, and (optionally) the number of HDFS data files that you want to generate, assuming that is flexible. Rule 1: Find out the maximum DOP you will be allowed to use with OSCH on the target Oracle system Determining the Number of Location Files Let’s assume that the DBA told you that your maximum DOP was 8. You want the number of location files in your external table to be big enough to utilize all 8 PQ slaves, and you want them to represent equally balanced workloads. Remember location files in OSCH are metadata lists of HDFS files and are created using OSCH’s External Table tool. They also represent the workload size given to an individual Oracle PQ slave (i.e. a PQ slave is given one location file to process at a time, and only it will process the contents of the location file.) Rule 2: The size of the workload of a single location file (and the PQ slave that processes it) is the sum of the content size of the HDFS files it lists For example, if a location file lists 5 HDFS files which are each 100GB in size, the workload size for that location file is 500GB. The number of location files that you generate is something you control by providing a number as input to OSCH’s External Table tool. Rule 3: The number of location files chosen should be a small multiple of the DOP Each location file represents one workload for one PQ slave. So the goal is to keep all slaves busy and try to give them equivalent workloads. Obviously if you run with a DOP of 8 but have 5 location files, only five PQ slaves will have something to do and the other three will have nothing to do and will quietly exit. If you run with 9 location files, then the PQ slaves will pick up the first 8 location files, and assuming they have equal work loads, will finish up about the same time. But the first PQ slave to finish its job will then be rescheduled to process the ninth location file, potentially doubling the end to end processing time. So for this DOP using 8, 16, or 32 location files would be a good idea. Determining the Number of HDFS Files Let’s start with the next rule and then explain it: Rule 4: The number of HDFS files should try to be a multiple of the number of location files and try to be relatively the same size In our running example, the DOP is 8. This means that the number of location files should be a small multiple of 8. Remember that each location file represents a list of unique HDFS files to load, and that the sum of the files listed in each location file is a workload for one Oracle PQ slave. The OSCH External Table tool will look in an HDFS directory for a set of HDFS files to load.  It will generate N number of location files (where N is the value you gave to the tool). It will then try to divvy up the HDFS files and do its best to make sure the workload across location files is as balanced as possible. (The tool uses a greedy algorithm that grabs the biggest HDFS file and delegates it to a particular location file. It then looks for the next biggest file and puts in some other location file, and so on). The tools ability to balance is reduced if HDFS file sizes are grossly out of balance or are too few. For example suppose my DOP is 8 and the number of location files is 8. Suppose I have only 8 HDFS files, where one file is 900GB and the others are 100GB. When the tool tries to balance the load it will be forced to put the singleton 900GB into one location file, and put each of the 100GB files in the 7 remaining location files. The load balance skew is 9 to 1. One PQ slave will be working overtime, while the slacker PQ slaves are off enjoying happy hour. If however the total payload (1600 GB) were broken up into smaller HDFS files, the OSCH External Table tool would have an easier time generating a list where each workload for each location file is relatively the same.  Applying Rule 4 above to our DOP of 8, we could divide the workload into160 files that were approximately 10 GB in size.  For this scenario the OSCH External Table tool would populate each location file with 20 HDFS file references, and all location files would have similar workloads (approximately 200GB per location file.) As a rule, when the OSCH External Table tool has to deal with more and smaller files it will be able to create more balanced loads. How small should HDFS files get? Not so small that the HDFS open and close file overhead starts having a substantial impact. For our performance test system (Exadata/BDA with Infiniband), I compared three OSCH loads of 1 TiB. One load had 128 HDFS files living in 64 location files where each HDFS file was about 8GB. I then did the same load with 12800 files where each HDFS file was about 80MB size. The end to end load time was virtually the same. However when I got ridiculously small (i.e. 128000 files at about 8MB per file), it started to make an impact and slow down the load time. What happens if you break rules 3 or 4 above? Nothing draconian, everything will still function. You just won’t be taking full advantage of the generous DOP that was allocated to you by your friendly DBA. The key point of the rules articulated above is this: if you know that HDFS content is ultimately going to be loaded into Oracle using OSCH, it makes sense to chop them up into the right number of files roughly the same size, derived from the DOP that you expect to use for loading. Next Steps So far we have talked about OLH and OSCH as alternative models for loading. That’s not quite the whole story. They can be used together in a way that provides for more efficient OSCH loads and allows one to be more flexible about scheduling on a Hadoop cluster and an Oracle Database to perform load operations. The next lesson will talk about Oracle Data Pump files generated by OLH, and loaded using OSCH. It will also outline the pros and cons of using various load methods.  This will be followed up with a final tutorial lesson focusing on how to optimize OLH and OSCH for use on Oracle's engineered systems: specifically Exadata and the BDA. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

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• Faster Memory Allocation Using vmtasks

  - by Steve Sistare

  You may have noticed a new system process called "vmtasks" on Solaris 11 systems: % pgrep vmtasks 8 % prstat -p 8 PID USERNAME SIZE RSS STATE PRI NICE TIME CPU PROCESS/NLWP 8 root 0K 0K sleep 99 -20 9:10:59 0.0% vmtasks/32 What is vmtasks, and why should you care? In a nutshell, vmtasks accelerates creation, locking, and destruction of pages in shared memory segments. This is particularly helpful for locked memory, as creating a page of physical memory is much more expensive than creating a page of virtual memory. For example, an ISM segment (shmflag & SHM_SHARE_MMU) is locked in memory on the first shmat() call, and a DISM segment (shmflg & SHM_PAGEABLE) is locked using mlock() or memcntl(). Segment operations such as creation and locking are typically single threaded, performed by the thread making the system call. In many applications, the size of a shared memory segment is a large fraction of total physical memory, and the single-threaded initialization is a scalability bottleneck which increases application startup time. To break the bottleneck, we apply parallel processing, harnessing the power of the additional CPUs that are always present on modern platforms. For sufficiently large segments, as many of 16 threads of vmtasks are employed to assist an application thread during creation, locking, and destruction operations. The segment is implicitly divided at page boundaries, and each thread is given a chunk of pages to process. The per-page processing time can vary, so for dynamic load balancing, the number of chunks is greater than the number of threads, and threads grab chunks dynamically as they finish their work. Because the threads modify a single application address space in compressed time interval, contention on locks protecting VM data structures locks was a problem, and we had to re-scale a number of VM locks to get good parallel efficiency. The vmtasks process has 1 thread per CPU and may accelerate multiple segment operations simultaneously, but each operation gets at most 16 helper threads to avoid monopolizing CPU resources. We may reconsider this limit in the future. Acceleration using vmtasks is enabled out of the box, with no tuning required, and works for all Solaris platform architectures (SPARC sun4u, SPARC sun4v, x86). The following tables show the time to create + lock + destroy a large segment, normalized as milliseconds per gigabyte, before and after the introduction of vmtasks: ISM system ncpu before after speedup ------ ---- ------ ----- ------- x4600 32 1386 245 6X X7560 64 1016 153 7X M9000 512 1196 206 6X T5240 128 2506 234 11X T4-2 128 1197 107 11x DISM system ncpu before after speedup ------ ---- ------ ----- ------- x4600 32 1582 265 6X X7560 64 1116 158 7X M9000 512 1165 152 8X T5240 128 2796 198 14X (I am missing the data for T4 DISM, for no good reason; it works fine). The following table separates the creation and destruction times: ISM, T4-2 before after ------ ----- create 702 64 destroy 495 43 To put this in perspective, consider creating a 512 GB ISM segment on T4-2. Creating the segment would take 6 minutes with the old code, and only 33 seconds with the new. If this is your Oracle SGA, you save over 5 minutes when starting the database, and you also save when shutting it down prior to a restart. Those minutes go directly to your bottom line for service availability.

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• Where are my date ranges in Analytics coming from?

  - by Jeffrey McDaniel

  In the P6 Reporting Database there are two main tables to consider when viewing time - W_DAY_D and W_Calendar_FS.  W_DAY_D is populated internally during the ETL process and will provide a row for every day in the given time range. Each row will contain aspects of that day such as calendar year, month, week, quarter, etc. to allow it to be used in the time element when creating requests in Analytics to group data into these time granularities. W_Calendar_FS is used for calculations such as spreads, but is also based on the same set date range. The min and max day_dt (W_DAY_D) and daydate (W_Calendar_FS) will be related to the date range defined, which is a start date and a rolling interval plus a certain range. Generally start date plus 3 years.  In P6 Reporting Database 2.0 this date range was defined in the Configuration utility.  As of P6 Reporting Database 3.0, with the introduction of the Extended Schema this date range is set in the P6 web application. The Extended Schema uses this date range to calculate the data for near real time reporting in P6.  This same date range is validated and used for the P6 Reporting Database.  The rolling date range means if today is April 1, 2010 and the rolling interval is set to three years, the min date will be 1/1/2010 and the max date will be 4/1/2013.  1/1/2010 will be the min date because we always back fill to the beginning of the year. On April 2nd, the Extended schema services are run and the date range is adjusted there to move the max date forward to 4/2/2013.  When the ETL process is run the Reporting Database will pick up this change and also adjust the max date on the W_DAY_D and W_Calendar_FS. There are scenarios where date ranges affecting areas like resource limit may not be adjusted until a change occurs to cause a recalculation, but based on general system usage these dates in these tables will progress forward with the rolling intervals. Choosing a large date range can have an effect on the ETL process for the P6 Reporting Database. The extract portion of the process will pull spread data over into the STAR. The date range defines how long activity and resource assignment spread data is spread out in these tables. If an activity lasts 5 days it will have 5 days of spread data. If a project lasts 5 years, and the date range is 3 years the spread data after that 3 year date range will be bucketed into the last day in the date range. For the overall project and even the activity level you will still see the correct total values.  You just would not be able to see the daily spread 5 years from now. This is an important question when choosing your date range, do you really need to see spread data down to the day 5 years in the future?  Generally this amount of granularity years in the future is not needed. Remember all those values 5, 10, 15, 20 years in the future are still available to report on they would be in more of a summary format on the activity or project.  The data is always there, the level of granularity is the decision.

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• Dynamically Changing the Display Names of Menus and Popups

  - by Geertjan

  Very interesting thing and handy to know when needed is the fact that "menuText" and "popupText" (from org.openide.awt.ActionRegistration) can be changed dynamically, via "putValue" as shown below for "popupText". The Action class, in this case, needs to be eager, hence you won't receive the object of interest via the constructor, but you can easily use the global Lookup for that purpose instead, as also shown below. import java.awt.event.ActionEvent; import java.text.DateFormat; import java.text.SimpleDateFormat; import javax.swing.AbstractAction; import org.netbeans.api.project.Project; import org.netbeans.api.project.ProjectInformation; import org.netbeans.api.project.ProjectUtils; import org.openide.awt.ActionID; import org.openide.awt.ActionReference; import org.openide.awt.ActionRegistration; import org.openide.util.Utilities; @ActionID( category = "Project", id = "org.ptt.DemoProjectAction") @ActionRegistration( lazy = false, displayName = "NOT-USED") @ActionReference(path = "Projects/Actions", position = 0) public final class DemoProjectAction extends AbstractAction{ private final ProjectInformation context; public DemoProjectAction() { putValue("popupText", "Select Me To See Current Time!"); context = ProjectUtils.getInformation( Utilities.actionsGlobalContext().lookup(Project.class)); } @Override public void actionPerformed(ActionEvent e) { refresh(); } protected void refresh() { DateFormat formatter = new SimpleDateFormat("HH:mm:ss"); String formatted = formatter.format(System.currentTimeMillis()); putValue("popupText", "Time: " + formatted + " (" + context.getDisplayName() +")"); } } Now, let's do something semi useful and display, in the popup, which is available when you right-click a project, the time since the last change was made anywhere in the project, i.e., we can listen recursively to any changes done within a project and then update the popup with the newly acquired information, dynamically: import java.awt.event.ActionEvent; import java.text.DateFormat; import java.text.SimpleDateFormat; import javax.swing.AbstractAction; import org.netbeans.api.project.Project; import org.netbeans.api.project.ProjectUtils; import org.openide.awt.ActionID; import org.openide.awt.ActionReference; import org.openide.awt.ActionRegistration; import org.openide.filesystems.FileAttributeEvent; import org.openide.filesystems.FileChangeListener; import org.openide.filesystems.FileEvent; import org.openide.filesystems.FileRenameEvent; import org.openide.util.Utilities; @ActionID( category = "Project", id = "org.ptt.TrackProjectTimerAction") @ActionRegistration( lazy = false, displayName = "NOT-USED") @ActionReference( path = "Projects/Actions", position = 0) public final class TrackProjectTimerAction extends AbstractAction implements FileChangeListener { private final Project context; private Long startTime; private Long changedTime; private DateFormat formatter; public TrackProjectTimerAction() { putValue("popupText", "Enable project time tracker"); this.formatter = new SimpleDateFormat("HH:mm:ss"); context = Utilities.actionsGlobalContext().lookup(Project.class); context.getProjectDirectory().addRecursiveListener(this); } @Override public void actionPerformed(ActionEvent e) { startTimer(); } protected void startTimer() { startTime = System.currentTimeMillis(); String formattedStartTime = formatter.format(startTime); putValue("popupText", "Timer started: " + formattedStartTime + " (" + ProjectUtils.getInformation(context).getDisplayName() + ")"); } @Override public void fileChanged(FileEvent fe) { changedTime = System.currentTimeMillis(); formatter = new SimpleDateFormat("mm:ss"); String formattedLapse = formatter.format(changedTime - startTime); putValue("popupText", "Time since last change: " + formattedLapse + " (" + ProjectUtils.getInformation(context).getDisplayName() + ")"); startTime = changedTime; } @Override public void fileFolderCreated(FileEvent fe) {} @Override public void fileDataCreated(FileEvent fe) {} @Override public void fileDeleted(FileEvent fe) {} @Override public void fileRenamed(FileRenameEvent fre) {} @Override public void fileAttributeChanged(FileAttributeEvent fae) {} }

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• SSMS Tools Pack 2.7 is released. New website, improved licensing and features.

  - by Mladen Prajdic

  New website Nice, isn't it? Cleaner, simpler, better looking and more modern. If you have any suggestions for further improvements I'd be glad to hear them. Simpler licensing With SSMS tools Pack 2.7 the licensing is finally where it should be. It is now based on the activate/deactivate model. This way you can move a license from machine to machine with simple deactivation on one and reactivation on another machine. Much better, no? Because of very good feedback I have added an option for 6 machines and lowered the 4 machines option to 3 machines. This should make it much simpler for you to choose the right option for yourself. Improved features Version 2.5.3 was already extremely stable and 2.7 continues with that tradition. Because of that I could fully focus on features and why 3.0 will rock even more that 2.7! ;) In version 2.7 I have addressed quite a few improvements you were requesting for a while now. SQL History This is probably the biggest time saver out there, therefore it's only fair it gets a few important updates. If you have an existing .sql file opened, the Window Content History now saves your code to that existing file and also makes a backup in the SQL History log default location. Search is still done through the SQL History log but the Tab Sessions Restore opens your existing .sql file. This way you don't have to remember to save your existing files by yourself anymore. A bug when you couldn't search properly if you copied the log files to a new location was fixed. Unfortunately this removed the option to filter a search with the time component. The smallest search interval is now one day. The SSMS Tools Pack now remembers the visibility of the Current Window History window when you exit SSMS. SQL Snippets You can now set the position of the cursor in your snippets by placing {C} somewhere in your snippet. It's a small improvement but can be a huge time saver since you don't have to move through the snippet to the desired location anymore. Run script on multiple databases Database choices can now be saved with a name and then loaded again next time. You can also choose to run the script in a new window for each chosen database. Search through grid results You can now go previous/next search result with the Prev/Next control inside the search window. This is extremely useful if you have a large resultset. IT saves you the scrolling. CRUD generator Four new variables have been added: |CurrentDate| writes current date in format yyyy-MM-dd to your script |CurrentTime| writes current time in 24h format HH:mm:ss to your script |CurrentWinUser| writes current Windows logged on user to your script |CurrentSqlUser| writes current SQL logged on login to your script This was actually quite a requested feature so if you have any other ideas for extra variables, do let me know. That's about it. I hope you're going to enjoy this version as much as the previous ones. Have fun!

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• ?12c database ????Adaptive Execution Plans ????????

  - by Liu Maclean(???)

  12c R1 ????SQL??????- Adaptive Execution Plans ????????,???????optimizer ??????(runtime)???????????????, ????????????????????? SQL???????? ????????????, ?????????????????????????????????????????????????????????????adaptive plan ????????????????????????????????????,?????subplan???????????????????? ??????, ???????? ???????????????,?????????, ?????? ???????????????”???”????, ???????????????????buffer ???????  ????????????,?????,??????????????????? ???optimizer ?????????????????????????,?????????????????????????????????????????plan???? ??12C?????????????, ???????????????????,?????? ???????????? ????????????2???: Dynamic Plans????: ???????????????????????;??????,???optimizer??????????subplans??????????????, ???????????????????,?????????????? Reoptimization????: ?Dynamic Plans????,Reoptimization??????????????????????Reoptimization??,?????????????????????????,??reoptimization????? OPTIMIZER_ADAPTIVE_REPORTING_ONLY ???? report-only????????????????TRUE,?????????report-only????,???????????????,??????????????? Dynamic Plans ??????????????,????????????????????????, ?????????????,???????????,????????????????????????????????????????? ?????????????final plan??????????????default plan, ??final plan?default plan???????,????????????? subplan ???????????????,???????????????????????? ??????,???????statistics collector ?buffer???????????statistics collector?????????????????,???????????????????????????? ?????????????????????????????????????????,??????????,?????????????? ???????????,???????buffer???? ???????????????,?????????????????????????????,??????buffer,??????final plan? ????????,???????????????????????,????????????????? ?V$SQL??????IS_RESOLVED_DYNAMIC_PLAN??????????final plan???default plan? ??????dynamic plan ???????SQL PLAN directives?????? declare cursor PLAN_DIRECTIVE_IDS is select directive_id from DBA_SQL_PLAN_DIRECTIVES; begin for z in PLAN_DIRECTIVE_IDS loop DBMS_SPD.DROP_SQL_PLAN_DIRECTIVE(z.directive_id); end loop; end; / explain plan for select /*MALCEAN*/ product_name from oe.order_items o, oe.product_information p where o.unit_price=15 and quantity>1 and p.product_id=o.product_id; select * from table(dbms_xplan.display()); Plan hash value: 1255158658 www.askmaclean.com ------------------------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 4 | 128 | 7 (0)| 00:00:01 | | 1 | NESTED LOOPS | | | | | | | 2 | NESTED LOOPS | | 4 | 128 | 7 (0)| 00:00:01 | |* 3 | TABLE ACCESS FULL | ORDER_ITEMS | 4 | 48 | 3 (0)| 00:00:01 | |* 4 | INDEX UNIQUE SCAN | PRODUCT_INFORMATION_PK | 1 | | 0 (0)| 00:00:01 | | 5 | TABLE ACCESS BY INDEX ROWID| PRODUCT_INFORMATION | 1 | 20 | 1 (0)| 00:00:01 | ------------------------------------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 3 - filter("O"."UNIT_PRICE"=15 AND "QUANTITY">1) 4 - access("P"."PRODUCT_ID"="O"."PRODUCT_ID") alter session set events '10053 trace name context forever,level 1'; OR alter session set events 'trace[SQL_Plan_Directive] disk highest'; select /*MALCEAN*/ product_name from oe.order_items o, oe.product_information p where o.unit_price=15 and quantity>1 and p.product_id=o.product_id; ---------------------------------------------------------------+-----------------------------------+ | Id | Operation | Name | Rows | Bytes | Cost | Time | ---------------------------------------------------------------+-----------------------------------+ | 0 | SELECT STATEMENT | | | | 7 | | | 1 | HASH JOIN | | 4 | 128 | 7 | 00:00:01 | | 2 | NESTED LOOPS | | | | | | | 3 | NESTED LOOPS | | 4 | 128 | 7 | 00:00:01 | | 4 | STATISTICS COLLECTOR | | | | | | | 5 | TABLE ACCESS FULL | ORDER_ITEMS | 4 | 48 | 3 | 00:00:01 | | 6 | INDEX UNIQUE SCAN | PRODUCT_INFORMATION_PK| 1 | | 0 | | | 7 | TABLE ACCESS BY INDEX ROWID | PRODUCT_INFORMATION | 1 | 20 | 1 | 00:00:01 | | 8 | TABLE ACCESS FULL | PRODUCT_INFORMATION | 1 | 20 | 1 | 00:00:01 | ---------------------------------------------------------------+-----------------------------------+ Predicate Information: ---------------------- 1 - access("P"."PRODUCT_ID"="O"."PRODUCT_ID") 5 - filter(("O"."UNIT_PRICE"=15 AND "QUANTITY">1)) 6 - access("P"."PRODUCT_ID"="O"."PRODUCT_ID") ===================================== SPD: BEGIN context at statement level ===================================== Stmt: ******* UNPARSED QUERY IS ******* SELECT /*+ OPT_ESTIMATE (@"SEL$1" JOIN ("P"@"SEL$1" "O"@"SEL$1") ROWS=13.000000 ) OPT_ESTIMATE (@"SEL$1" TABLE "O"@"SEL$1" ROWS=13.000000 ) */ "P"."PRODUCT_NAME" "PRODUCT_NAME" FROM "OE"."ORDER_ITEMS" "O","OE"."PRODUCT_INFORMATION" "P" WHERE "O"."UNIT_PRICE"=15 AND "O"."QUANTITY">1 AND "P"."PRODUCT_ID"="O"."PRODUCT_ID" Objects referenced in the statement PRODUCT_INFORMATION[P] 92194, type = 1 ORDER_ITEMS[O] 92197, type = 1 Objects in the hash table Hash table Object 92197, type = 1, ownerid = 6573730143572393221: No Dynamic Sampling Directives for the object Hash table Object 92194, type = 1, ownerid = 17822962561575639002: No Dynamic Sampling Directives for the object Return code in qosdInitDirCtx: ENBLD =================================== SPD: END context at statement level =================================== ======================================= SPD: BEGIN context at query block level ======================================= Query Block SEL$1 (#0) Return code in qosdSetupDirCtx4QB: NOCTX ===================================== SPD: END context at query block level ===================================== SPD: Return code in qosdDSDirSetup: NOCTX, estType = TABLE SPD: Generating finding id: type = 1, reason = 1, objcnt = 1, obItr = 0, objid = 92197, objtyp = 1, vecsize = 6, colvec = [4, 5, ], fid = 2896834833840853267 SPD: Inserted felem, fid=2896834833840853267, ftype = 1, freason = 1, dtype = 0, dstate = 0, dflag = 0, ver = YES, keep = YES SPD: qosdCreateFindingSingTab retCode = CREATED, fid = 2896834833840853267 SPD: qosdCreateDirCmp retCode = CREATED, fid = 2896834833840853267 SPD: Return code in qosdDSDirSetup: NOCTX, estType = TABLE SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = JOIN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SKIP_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = JOIN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Generating finding id: type = 1, reason = 1, objcnt = 1, obItr = 0, objid = 92197, objtyp = 1, vecsize = 6, colvec = [4, 5, ], fid = 2896834833840853267 SPD: Modified felem, fid=2896834833840853267, ftype = 1, freason = 1, dtype = 0, dstate = 0, dflag = 0, ver = YES, keep = YES SPD: Generating finding id: type = 1, reason = 1, objcnt = 1, obItr = 0, objid = 92194, objtyp = 1, vecsize = 2, colvec = [1, ], fid = 5618517328604016300 SPD: Modified felem, fid=5618517328604016300, ftype = 1, freason = 1, dtype = 0, dstate = 0, dflag = 0, ver = NO, keep = NO SPD: Generating finding id: type = 1, reason = 1, objcnt = 1, obItr = 0, objid = 92194, objtyp = 1, vecsize = 2, colvec = [1, ], fid = 1142802697078608149 SPD: Modified felem, fid=1142802697078608149, ftype = 1, freason = 1, dtype = 0, dstate = 0, dflag = 0, ver = NO, keep = NO SPD: Generating finding id: type = 1, reason = 2, objcnt = 2, obItr = 0, objid = 92194, objtyp = 1, vecsize = 0, obItr = 1, objid = 92197, objtyp = 1, vecsize = 0, fid = 1437680122701058051 SPD: Modified felem, fid=1437680122701058051, ftype = 1, freason = 2, dtype = 0, dstate = 0, dflag = 0, ver = NO, keep = NO select * from table(dbms_xplan.display_cursor(format=>'report')) ; ????report????adaptive plan Adaptive plan: ------------- This cursor has an adaptive plan, but adaptive plans are enabled for reporting mode only.  The plan that would be executed if adaptive plans were enabled is displayed below. ------------------------------------------------------------------------------------------ | Id  | Operation          | Name                | Rows  | Bytes | Cost (%CPU)| Time     | ------------------------------------------------------------------------------------------ |   0 | SELECT STATEMENT   |                     |       |       |     7 (100)|          | |*  1 |  HASH JOIN         |                     |     4 |   128 |     7   (0)| 00:00:01 | |*  2 |   TABLE ACCESS FULL| ORDER_ITEMS         |     4 |    48 |     3   (0)| 00:00:01 | |   3 |   TABLE ACCESS FULL| PRODUCT_INFORMATION |     1 |    20 |     1   (0)| 00:00:01 | ------------------------------------------------------------------------------------------ SQL> select SQL_ID,IS_RESOLVED_DYNAMIC_PLAN,sql_text from v$SQL WHERE SQL_TEXT like '%MALCEAN%' and sql_text not like '%like%'; SQL_ID IS -------------------------- -- SQL_TEXT -------------------------------------------------------------------------------- 6ydj1bn1bng17 Y select /*MALCEAN*/ product_name from oe.order_items o, oe.product_information p where o.unit_price=15 and quantity>1 and p.product_id=o.product_id ???? explain plan for ????default plan, ??????optimizer???final plan,??V$SQL.IS_RESOLVED_DYNAMIC_PLAN???Y,????????????? DBA_SQL_PLAN_DIRECTIVES?????????????SQL PLAN DIRECTIVES, ???12c? ???MMON?????DML ???column usage??????????,????SMON??? MMON????SGA??PLAN DIRECTIVES??? ?????DBMS_SPD.flush_sql_plan_directive???? select directive_id,type,reason from DBA_SQL_PLAN_DIRECTIVES / DIRECTIVE_ID TYPE REASON ----------------------------------- -------------------------------- ----------------------------- 10321283028317893030 DYNAMIC_SAMPLING JOIN CARDINALITY MISESTIMATE 4757086536465754886 DYNAMIC_SAMPLING JOIN CARDINALITY MISESTIMATE 16085268038103121260 DYNAMIC_SAMPLING JOIN CARDINALITY MISESTIMATE SQL> set pages 9999 SQL> set lines 300 SQL> col state format a5 SQL> col subobject_name format a11 SQL> col col_name format a11 SQL> col object_name format a13 SQL> select d.directive_id, o.object_type, o.object_name, o.subobject_name col_name, d.type, d.state, d.reason 2 from dba_sql_plan_directives d, dba_sql_plan_dir_objects o 3 where d.DIRECTIVE_ID=o.DIRECTIVE_ID 4 and o.object_name in ('ORDER_ITEMS') 5 order by d.directive_id; DIRECTIVE_ID OBJECT_TYPE OBJECT_NAME COL_NAME TYPE STATE REASON ------------ ------------ ------------- ----------- -------------------------------- ----- ------------------------------------- --- 1.8156E+19 COLUMN ORDER_ITEMS UNIT_PRICE DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE 1.8156E+19 TABLE ORDER_ITEMS DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE 1.8156E+19 COLUMN ORDER_ITEMS QUANTITY DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE DBA_SQL_PLAN_DIRECTIVES????? _BASE_OPT_DIRECTIVE ? _BASE_OPT_FINDING SELECT d.dir_own#, d.dir_id, d.f_id, decode(type, 1, 'DYNAMIC_SAMPLING', 'UNKNOWN'), decode(state, 1, 'NEW', 2, 'MISSING_STATS', 3, 'HAS_STATS', 4, 'CANDIDATE', 5, 'PERMANENT', 6, 'DISABLED', 'UNKNOWN'), decode(bitand(flags, 1), 1, 'YES', 'NO'), cast(d.created as timestamp), cast(d.last_modified as timestamp), -- Please see QOSD_DAYS_TO_UPDATE and QOSD_PLUS_SECONDS for more details -- about 6.5 cast(d.last_used as timestamp) - NUMTODSINTERVAL(6.5, 'day') FROM sys.opt_directive$ d ??dbms_spd??? SQL PLAN DIRECTIVES, SQL PLAN DIRECTIVES???retention ???53?: Package: DBMS_SPD This package provides subprograms for managing Sql Plan Directives(SPD). SPD are objects generated automatically by Oracle server. For example, if server detects that the single table cardinality estimated by optimizer is off from the actual number of rows returned when accessing the table, it will automatically create a directive to do dynamic sampling for the table. When any Sql statement referencing the table is compiled, optimizer will perform dynamic sampling for the table to get more accurate estimate. Notes: DBMSL_SPD is a invoker-rights package. The invoker requires ADMINISTER SQL MANAGEMENT OBJECT privilege for executing most of the subprograms of this package. Also the subprograms commit the current transaction (if any), perform the operation and commit it again. DBA view dba_sql_plan_directives shows all the directives created in the system and the view dba_sql_plan_dir_objects displays the objects that are included in the directives. -- Default value for SPD_RETENTION_WEEKS SPD_RETENTION_WEEKS_DEFAULT CONSTANT varchar2(4) := '53'; | STATE : NEW : Newly created directive. | : MISSING_STATS : The directive objects do not | have relevant stats. | : HAS_STATS : The objects have stats. | : PERMANENT : A permanent directive. Server | evaluated effectiveness and these | directives are useful. | | AUTO_DROP : YES : Directive will be dropped | automatically if not | used for SPD_RETENTION_WEEKS. | This is the default behavior. | NO : Directive will not be dropped | automatically. Procedure: flush_sql_plan_directive This procedure allows manually flushing the Sql Plan directives that are automatically recorded in SGA memory while executing sql statements. The information recorded in SGA are periodically flushed by oracle background processes. This procedure just provides a way to flush the information manually. ????”_optimizer_dynamic_plans”(enable dynamic plans)????????,???TRUE??DYNAMIC PLAN? ???FALSE???????????? ????,Dynamic Plan????????????Nested Loop?Hash Join???case ,????????Nested loop???????????HASH JOIN,?HASH JOIN????????????????? ????????subplan?????,???? pass?? ?join method???,?????STATISTICS COLLECTOR???cardinality?,???????HASH JOIN?????Nested Loop,????????????subplan?????access path; ???????Sales??????????????????,????HASH JOIN,??SUBPLAN??customers?????????;?????Nested Loop,???????cust_id?????Range Scan+Access by Rowid? Cardinality feedback Cardinality feedback????????11.2????,????????re-optimization???;  ???????????,Cardinality feedback?????????????????????????? ???????????????????,?????????????????,??????????Cardinality feedback????????????? ????????????????????????? ??????????????Cardinality feedback ??: ????????,???????????,??????????,????????????????selectivity ??? ????????????: ??????,?????????????????????????????????,??????????????????? ????????????????????????????????????????,?????????????????????????? ?????????,???????????????,?????????? ??????????Cardinality ????,??????join Cardinality ????????? Cardinality feedback???????cursor?,?Cursor???aged out????? SELECT /*+ gather_plan_statistics */ product_name FROM order_items o, product_information p WHERE o.unit_price = 15 AND quantity > 1 AND p.product_id = o.product_id Plan hash value: 1553478007 ---------------------------------------------------------------------------------------------------------------------------------------- | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads | OMem | 1Mem | Used-Mem | ---------------------------------------------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 13 |00:00:00.01 | 24 | 20 | | | | |* 1 | HASH JOIN | | 1 | 4 | 13 |00:00:00.01 | 24 | 20 | 2061K| 2061K| 429K (0)| |* 2 | TABLE ACCESS FULL| ORDER_ITEMS | 1 | 4 | 13 |00:00:00.01 | 7 | 6 | | | | | 3 | TABLE ACCESS FULL| PRODUCT_INFORMATION | 1 | 1 | 288 |00:00:00.01 | 17 | 14 | | | | ---------------------------------------------------------------------------------------------------------------------------------------- SELECT /*+ gather_plan_statistics */ product_name FROM order_items o, product_information p WHERE o.unit_price = 15 AND quantity > 1 AND p.product_id = o.product_id Plan hash value: 1553478007 ------------------------------------------------------------------------------------------------------------------------------- | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | OMem | 1Mem | Used-Mem | ------------------------------------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 13 |00:00:00.01 | 24 | | | | |* 1 | HASH JOIN | | 1 | 13 | 13 |00:00:00.01 | 24 | 2061K| 2061K| 413K (0)| |* 2 | TABLE ACCESS FULL| ORDER_ITEMS | 1 | 13 | 13 |00:00:00.01 | 7 | | | | | 3 | TABLE ACCESS FULL| PRODUCT_INFORMATION | 1 | 288 | 288 |00:00:00.01 | 17 | | | | ------------------------------------------------------------------------------------------------------------------------------- Note ----- - statistics feedback used for this statement SQL> select count(*) from v$SQL where SQL_ID='cz0hg2zkvd10y'; COUNT(*) ---------- 2 SQL>select sql_ID,USE_FEEDBACK_STATS FROM V$SQL_SHARED_CURSOR where USE_FEEDBACK_STATS ='Y'; SQL_ID U ------------- - cz0hg2zkvd10y Y ????????Cardinality feedback????,???????????????????????????,????????????order_items???????? ????2??????plan hash value??(??????????),?????2????child cursor??????gather_plan_statistics???actual : A-ROWS  estimate :E-ROWS????????? Automatic Re-optimization ???dynamic plan, Re-optimization???????????????  ?  ??????????????? ????????????????????????????????  ???????????,??????????????, ???????????????????? ???????????  Re-optimization??, ????????????????????? Re-optimization????dynamic plan??????????  dynamic plan????????????????????, ???????????????????? ????,??????????join order ??????????????,?????????????join order????? ??????,????????Re-optimization, ??Re-optimization ??????????????????? ?Oracle database 12c?,join statistics?????????????????????,??????????????????????Re-optimization???????????adaptive cursor sharing????? ????????????????,???????????? ????? ???????statistics collectors ????????????????????Re-optimization??????2?????????????,???????????????? ??????????????Re-optimization?????,?????????????????????? ???v$SQL??????IS_REOPTIMIZABLE?????????????????????Re-optimization,??????????Re-optimization???,?????Re-optimization ,???????reporting????? IS_REOPTIMIZABLE VARCHAR2(1) This columns shows whether the next execution matching this child cursor will trigger a reoptimization. The values are:   Y: If the next execution will trigger a reoptimization R: If the child cursor contains reoptimization information, but will not trigger reoptimization because the cursor was compiled in reporting mode N: If the child cursor has no reoptimization information ??1: select plan_table_output from table (dbms_xplan.display_cursor('gwf99gfnm0t7g',NULL,'ALLSTATS LAST')); SQL_ID  gwf99gfnm0t7g, child number 0 ------------------------------------- SELECT /*+ SFTEST gather_plan_statistics */ o.order_id, v.product_name FROM  orders o,   ( SELECT order_id, product_name FROM order_items o, product_information p     WHERE  p.product_id = o.product_id AND list_price < 50 AND min_price < 40  ) v WHERE o.order_id = v.order_id Plan hash value: 1906736282 ------------------------------------------------------------------------------------------------------------------------------------------- | Id  | Operation             | Name                | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads  |  OMem |  1Mem | Used-Mem | ------------------------------------------------------------------------------------------------------------------------------------------- |   0 | SELECT STATEMENT      |                     |      1 |        |    269 |00:00:00.02 |    1336 |     18 |       |       |          | |   1 |  NESTED LOOPS         |                     |      1 |      1 |    269 |00:00:00.02 |    1336 |     18 |       |       |          | |   2 |   MERGE JOIN CARTESIAN|                     |      1 |      4 |   9135 |00:00:00.02 |      34 |     15 |       |       |          | |*  3 |    TABLE ACCESS FULL  | PRODUCT_INFORMATION |      1 |      1 |     87 |00:00:00.01 |      33 |     14 |       |       |          | |   4 |    BUFFER SORT        |                     |     87 |    105 |   9135 |00:00:00.01 |       1 |      1 |  4096 |  4096 | 4096  (0)| |   5 |     INDEX FULL SCAN   | ORDER_PK            |      1 |    105 |    105 |00:00:00.01 |       1 |      1 |       |       |          | |*  6 |   INDEX UNIQUE SCAN   | ORDER_ITEMS_UK      |   9135 |      1 |    269 |00:00:00.01 |    1302 |      3 |       |       |          | ------------------------------------------------------------------------------------------------------------------------------------------- Predicate Information (identified by operation id): ---------------------------------------------------    3 - filter(("MIN_PRICE"<40 AND "LIST_PRICE"<50))    6 - access("O"."ORDER_ID"="ORDER_ID" AND "P"."PRODUCT_ID"="O"."PRODUCT_ID") SQL_ID  gwf99gfnm0t7g, child number 1 ------------------------------------- SELECT /*+ SFTEST gather_plan_statistics */ o.order_id, v.product_name FROM  orders o,   ( SELECT order_id, product_name FROM order_items o, product_information p     WHERE  p.product_id = o.product_id AND list_price < 50 AND min_price < 40  ) v WHERE o.order_id = v.order_id Plan hash value: 35479787 -------------------------------------------------------------------------------------------------------------------------------------------- | Id  | Operation              | Name                | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads  |  OMem |  1Mem | Used-Mem | -------------------------------------------------------------------------------------------------------------------------------------------- |   0 | SELECT STATEMENT       |                     |      1 |        |    269 |00:00:00.01 |      63 |      3 |       |       |          | |   1 |  NESTED LOOPS          |                     |      1 |    269 |    269 |00:00:00.01 |      63 |      3 |       |       |          | |*  2 |   HASH JOIN            |                     |      1 |    313 |    269 |00:00:00.01 |      42 |      3 |  1321K|  1321K| 1234K (0)| |*  3 |    TABLE ACCESS FULL   | PRODUCT_INFORMATION |      1 |     87 |     87 |00:00:00.01 |      16 |      0 |       |       |          | |   4 |    INDEX FAST FULL SCAN| ORDER_ITEMS_UK      |      1 |    665 |    665 |00:00:00.01 |      26 |      3 |       |       |          | |*  5 |   INDEX UNIQUE SCAN    | ORDER_PK            |    269 |      1 |    269 |00:00:00.01 |      21 |      0 |       |       |          | -------------------------------------------------------------------------------------------------------------------------------------------- Predicate Information (identified by operation id): ---------------------------------------------------    2 - access("P"."PRODUCT_ID"="O"."PRODUCT_ID")    3 - filter(("MIN_PRICE"<40 AND "LIST_PRICE"<50))    5 - access("O"."ORDER_ID"="ORDER_ID") Note -----    - statistics feedback used for this statement    SQL> select IS_REOPTIMIZABLE,child_number FROM V$SQL  A where A.SQL_ID='gwf99gfnm0t7g'; IS CHILD_NUMBER -- ------------ Y             0 N             1    1* select child_number,other_xml From v$SQL_PLAN  where SQL_ID='gwf99gfnm0t7g' and other_xml is not nul SQL> / CHILD_NUMBER OTHER_XML ------------ --------------------------------------------------------------------------------            1 <other_xml><info type="cardinality_feedback">yes</info><info type="db_version">1              2.1.0.1</info><info type="parse_schema"><![CDATA["OE"]]></info><info type="plan_              hash">35479787</info><info type="plan_hash_2">3382491761</info><outline_data><hi              nt><![CDATA[IGNORE_OPTIM_EMBEDDED_HINTS]]></hint><hint><![CDATA[OPTIMIZER_FEATUR              ES_ENABLE('12.1.0.1')]]></hint><hint><![CDATA[DB_VERSION('12.1.0.1')]]></hint><h              int><![CDATA[ALL_ROWS]]></hint><hint><![CDATA[OUTLINE_LEAF(@"SEL$F5BB74E1")]]></              hint><hint><![CDATA[MERGE(@"SEL$2")]]></hint><hint><![CDATA[OUTLINE(@"SEL$1")]]>              </hint><hint><![CDATA[OUTLINE(@"SEL$2")]]></hint><hint><![CDATA[FULL(@"SEL$F5BB7              4E1" "P"@"SEL$2")]]></hint><hint><![CDATA[INDEX_FFS(@"SEL$F5BB74E1" "O"@"SEL$2"              ("ORDER_ITEMS"."ORDER_ID" "ORDER_ITEMS"."PRODUCT_ID"))]]></hint><hint><![CDATA[I              NDEX(@"SEL$F5BB74E1" "O"@"SEL$1" ("ORDERS"."ORDER_ID"))]]></hint><hint><![CDATA[              LEADING(@"SEL$F5BB74E1" "P"@"SEL$2" "O"@"SEL$2" "O"@"SEL$1")]]></hint><hint><![C              DATA[USE_HASH(@"SEL$F5BB74E1" "O"@"SEL$2")]]></hint><hint><![CDATA[USE_NL(@"SEL$              F5BB74E1" "O"@"SEL$1")]]></hint></outline_data></other_xml>            0 <other_xml><info type="db_version">12.1.0.1</info><info type="parse_schema"><![C              DATA["OE"]]></info><info type="plan_hash">1906736282</info><info type="plan_hash              _2">2579473118</info><outline_data><hint><![CDATA[IGNORE_OPTIM_EMBEDDED_HINTS]]>              </hint><hint><![CDATA[OPTIMIZER_FEATURES_ENABLE('12.1.0.1')]]></hint><hint><![CD              ATA[DB_VERSION('12.1.0.1')]]></hint><hint><![CDATA[ALL_ROWS]]></hint><hint><![CD              ATA[OUTLINE_LEAF(@"SEL$F5BB74E1")]]></hint><hint><![CDATA[MERGE(@"SEL$2")]]></hi              nt><hint><![CDATA[OUTLINE(@"SEL$1")]]></hint><hint><![CDATA[OUTLINE(@"SEL$2")]]>              </hint><hint><![CDATA[FULL(@"SEL$F5BB74E1" "P"@"SEL$2")]]></hint><hint><![CDATA[              INDEX(@"SEL$F5BB74E1" "O"@"SEL$1" ("ORDERS"."ORDER_ID"))]]></hint><hint><![CDATA              [INDEX(@"SEL$F5BB74E1" "O"@"SEL$2" ("ORDER_ITEMS"."ORDER_ID" "ORDER_ITEMS"."PROD              UCT_ID"))]]></hint><hint><![CDATA[LEADING(@"SEL$F5BB74E1" "P"@"SEL$2" "O"@"SEL$1              " "O"@"SEL$2")]]></hint><hint><![CDATA[USE_MERGE_CARTESIAN(@"SEL$F5BB74E1" "O"@"              SEL$1")]]></hint><hint><![CDATA[USE_NL(@"SEL$F5BB74E1" "O"@"SEL$2")]]></hint></o              utline_data></other_xml> ??2: SELECT /*+gather_plan_statistics*/ * FROM customers WHERE cust_state_province='CA' AND country_id='US'; SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST')); PLAN_TABLE_OUTPUT ------------------------------------- SQL_ID b74nw722wjvy3, child number 0 ------------------------------------- select /*+gather_plan_statistics*/ * from customers where CUST_STATE_PROVINCE='CA' and country_id='US' Plan hash value: 1683234692 -------------------------------------------------------------------------------------------------- | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads | -------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 29 |00:00:00.01 | 17 | 14 | |* 1 | TABLE ACCESS FULL| CUSTOMERS | 1 | 8 | 29 |00:00:00.01 | 17 | 14 | -------------------------------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter(("CUST_STATE_PROVINCE"='CA' AND "COUNTRY_ID"='US')) SELECT SQL_ID, CHILD_NUMBER, SQL_TEXT, IS_REOPTIMIZABLE FROM V$SQL WHERE SQL_TEXT LIKE 'SELECT /*+gather_plan_statistics*/%'; SQL_ID CHILD_NUMBER SQL_TEXT I ------------- ------------ ----------- - b74nw722wjvy3 0 select /*+g Y ather_plan_ statistics* / * from cu stomers whe re CUST_STA TE_PROVINCE ='CA' and c ountry_id=' US' EXEC DBMS_SPD.FLUSH_SQL_PLAN_DIRECTIVE; SELECT TO_CHAR(d.DIRECTIVE_ID) dir_id, o.OWNER, o.OBJECT_NAME, o.SUBOBJECT_NAME col_name, o.OBJECT_TYPE, d.TYPE, d.STATE, d.REASON FROM DBA_SQL_PLAN_DIRECTIVES d, DBA_SQL_PLAN_DIR_OBJECTS o WHERE d.DIRECTIVE_ID=o.DIRECTIVE_ID AND o.OWNER IN ('SH') ORDER BY 1,2,3,4,5; DIR_ID OWNER OBJECT_NAME COL_NAME OBJECT TYPE STATE REASON ----------------------- ----- ------------- ----------- ------ ---------------- ----- ------------------------ 1484026771529551585 SH CUSTOMERS COUNTRY_ID COLUMN DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE 1484026771529551585 SH CUSTOMERS CUST_STATE_ COLUMN DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY PROVINCE MISESTIMATE 1484026771529551585 SH CUSTOMERS TABLE DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE SELECT /*+gather_plan_statistics*/ * FROM customers WHERE cust_state_province='CA' AND country_id='US'; ELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST')); PLAN_TABLE_OUTPUT ------------------------------------- SQL_ID b74nw722wjvy3, child number 1 ------------------------------------- select /*+gather_plan_statistics*/ * from customers where CUST_STATE_PROVINCE='CA' and country_id='US' Plan hash value: 1683234692 ----------------------------------------------------------------------------------------- | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | ----------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 29 |00:00:00.01 | 17 | |* 1 | TABLE ACCESS FULL| CUSTOMERS | 1 | 29 | 29 |00:00:00.01 | 17 | ----------------------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter(("CUST_STATE_PROVINCE"='CA' AND "COUNTRY_ID"='US')) Note ----- - cardinality feedback used for this statement SELECT SQL_ID, CHILD_NUMBER, SQL_TEXT, IS_REOPTIMIZABLE FROM V$SQL WHERE SQL_TEXT LIKE 'SELECT /*+gather_plan_statistics*/%'; SQL_ID CHILD_NUMBER SQL_TEXT I ------------- ------------ ----------- - b74nw722wjvy3 0 select /*+g Y ather_plan_ statistics* / * from cu stomers whe re CUST_STA TE_PROVINCE ='CA' and c ountry_id=' US' b74nw722wjvy3 1 select /*+g N ather_plan_ statistics* / * from cu stomers whe re CUST_STA TE_PROVINCE ='CA' and c ountry_id=' US' SELECT /*+gather_plan_statistics*/ CUST_EMAIL FROM CUSTOMERS WHERE CUST_STATE_PROVINCE='MA' AND COUNTRY_ID='US'; SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST')); PLAN_TABLE_OUTPUT ------------------------------------- SQL_ID 3tk6hj3nkcs2u, child number 0 ------------------------------------- Select /*+gather_plan_statistics*/ cust_email From customers Where cust_state_province='MA' And country_id='US' Plan hash value: 1683234692 ------------------------------------------------------------------------------- |Id | Operation | Name | Starts|E-Rows|A-Rows| A-Time |Buffers| ------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 2 |00:00:00.01| 16 | |*1 | TABLE ACCESS FULL| CUSTOMERS | 1 | 2| 2 |00:00:00.01| 16 | ----------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter(("CUST_STATE_PROVINCE"='MA' AND "COUNTRY_ID"='US')) Note ----- - dynamic sampling used for this statement (level=2) - 1 Sql Plan Directive used for this statement EXEC DBMS_SPD.FLUSH_SQL_PLAN_DIRECTIVE; SELECT TO_CHAR(d.DIRECTIVE_ID) dir_id, o.OWNER, o.OBJECT_NAME, o.SUBOBJECT_NAME col_name, o.OBJECT_TYPE, d.TYPE, d.STATE, d.REASON FROM DBA_SQL_PLAN_DIRECTIVES d, DBA_SQL_PLAN_DIR_OBJECTS o WHERE d.DIRECTIVE_ID=o.DIRECTIVE_ID AND o.OWNER IN ('SH') ORDER BY 1,2,3,4,5; DIR_ID OW OBJECT_NA COL_NAME OBJECT TYPE STATE REASON ------------------- -- --------- ---------- ------- --------------- ------------- ------------------------ 1484026771529551585 SH CUSTOMERS COUNTRY_ID COLUMN DYNAMIC_SAMPLING MISSING_STATS SINGLE TABLE CARDINALITY MISESTIMATE 1484026771529551585 SH CUSTOMERS CUST_STATE_ COLUMN DYNAMIC_SAMPLING MISSING_STATS SINGLE TABLE CARDINALITY PROVINCE MISESTIMATE 1484026771529551585 SH CUSTOMERS TABLE DYNAMIC_SAMPLING MISSING_STATS SINGLE TABLE CARDINALITY MISESTIMATE

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• Custom Rails 3 Date Format

  - by Jack

  Hi, I am trying to format a date as follows using Rails 3; 3rd June 2003. This is not a standard way of showing the date, so I have looked into a custom way of doing it. Rails 3.0 documentation here suggests that I add a file at config/initializers/time_formats.rb containing the following code: Time::DATE_FORMATS[:custom_date] = lambda { |time| time.strftime("#{time.day.ordinalize} %B %Y") } And then call it using something like: <%= document.publish_date.to_formatted_s(:custom_date) %> However this isn't working and the date is being formatted as YYYY-MM-YY. Does anyone have any suggestions? Cheers

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• Plot numpy datetime64 with matplotlib

  - by enedene

  I have two numpy arrays 1D, one is time of measurement in datetime64 format, for example: array([2011-11-15 01:08:11, 2011-11-16 02:08:04, ..., 2012-07-07 11:08:00], dtype=datetime64[us]) and other array of same length and dimension with integer data. I'd like to make a plot in matplotlib time vs data. If I put the data directly, this is what I get: plot(timeSeries, data) Is there a way to get time in more natural units? For example in this case months/year would be fine.

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• Invalid or expired security context token in WCF web service

  - by Damian

  All, I have a WCF web service (let's called service "B") hosted under IIS using a service account (VM, Windows 2003 SP2). The service exposes an endpoint that use WSHttpBinding with the default values except for maxReceivedMessageSize, maxBufferPoolSize, maxBufferSize and some of the time outs that have been increased. The web service has been load tested using Visual Studio Load Test framework with around 800 concurrent users and successfully passed all tests with no exceptions being thrown. The proxy in the unit test has been created from configuration. There is a sharepoint application that use the Office Sharepoint Server Search service to call web services "A" and "B". The application will get data from service "A" to create a request that will be sent to service "B". The response coming from service "B" is indexed for search. The proxy is created programmatically using the ChannelFactory. When service "A" takes less than 10 minutes, the calls to service "B" are successfull. But when service "A" takes more time (~20 minutes) the calls to service "B" throw the following exception: Exception Message: An unsecured or incorrectly secured fault was received from the other party. See the inner FaultException for the fault code and detail Inner Exception Message: The message could not be processed. This is most likely because the action 'namespace/OperationName' is incorrect or because the message contains an invalid or expired security context token or because there is a mismatch between bindings. The security context token would be invalid if the service aborted the channel due to inactivity. To prevent the service from aborting idle sessions prematurely increase the Receive timeout on the service endpoint's binding. The binding settings are the same, the time in both client server and web service server are synchronize with the Windows Time service, same time zone. When i look at the server where web service "B" is hosted i can see the following security errors being logged: Source: Security Category: Logon/Logoff Event ID: 537 User NT AUTHORITY\SYSTEM Logon Failure: Reason: An error occurred during logon Logon Type: 3 Logon Process: Kerberos Authentication Package: Kerberos Status code: 0xC000006D Substatus code: 0xC0000133 After reading some of the blogs online, the Status code means STATUS_LOGON_FAILURE and the substatus code means STATUS_TIME_DIFFERENCE_AT_DC. but i already checked both server and client clocks and they are syncronized. I also noticed that the security token seems to be cached somewhere in the client server because they have another process that calls the web service "B" using the same service account and successfully gets data the first time is called. Then they start the proccess to update the office sharepoint server search service indexes and it fails. Then if they called the first proccess again it will fail too. Has anyone experienced this type of problems or have any ideas? Regards, --Damian

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• How to build android cts? And how to add and run your test case?

  - by Leox

  From 2.0 the cts is freely downloadable from android's repository. But there is no documents about it. Does anyone can tell me: how to build cts? Is there a standard procedure? How to run cts? How to add customized test case? Here, share my experience. After repo sync all source, you can't directly run "make" to build all source. You will get some errors. Now, I'am trying to first build android source without cts, and then build cts alone. Also, here are some reference for run cts: http://i-miss-erin.blogspot.com/2010/05/how-to-add-test-plan-package-to-android.html www.mentby.com/chenny/how-does-cts-work-where-can-i-get-the-test-streams.html www.jxva.com/?act=blog!article&articleId=157 1st time Update @ 5-13 18:39 +8:00 I do the following steps: 1.build android source without cts (move cts out of the $SDK_ROOT). 2.build cts (move cts back). both jdk1.5 and 1.6 have the following errors: 1.The 1st time "make cts" report: "Caused by: java.io.FileNotFoundException: ...(Too many open files)" 2.The 2nd time "make cts" report: "acp: file 'out/host/linux-x86/obj/EXECUTABLES/vm-tests_intermediates/tests/data' does not exist" 3.The 3rd time "make cts" report: "/bin/bash: line 0: cd: out/host/linux-x86/obj/EXECUTABLES/vm-tests_intermediates/hostjunit_files/classes: No such file or directory" 4.The last time "make cts" report: "zip error: Nothing to do! (try: zip -q -r ../../android.core.vm-tests.jar . -i .)"

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• Using M2Crypto to save and load X509 certs in pem files

  - by Brock Pytlik

  I would expect that if I have a X509 cert as an object in memory, saved it as a pem file, then loaded it back in, I would end up with the same cert I started with. This seems not to be the case however. Let's call the original cert A, and the cert loaded from the pem file B. A.as_text() is identical to B.as_text(), but A.as_pem() differs from B.as_pem(). To say the least, I'm confused by this. As a side note, if A has been signed by another entity C, then A will verify against C's cert, but B will not. I've put together a tiny sample program to demonstrate what I'm seeing. When I run this, the second RuntimeError is raised. Thanks, Brock #!/usr/bin/python2.6 import M2Crypto as m2 import time cur_time = m2.ASN1.ASN1_UTCTIME() cur_time.set_time(int(time.time()) - 60*60*24) expire_time = m2.ASN1.ASN1_UTCTIME() # Expire certs in 1 hour. expire_time.set_time(int(time.time()) + 60 * 60 * 24) cs_rsa = m2.RSA.gen_key(1024, 65537, lambda: None) cs_pk = m2.EVP.PKey() cs_pk.assign_rsa(cs_rsa) cs_cert = m2.X509.X509() # These two seem the minimum necessary to make the as_text function call work # at all cs_cert.set_not_before(cur_time) cs_cert.set_not_after(expire_time) # This seems necessary to fill out the complete cert without errors. cs_cert.set_pubkey(cs_pk) # I've tried with the following set lines commented out and not commented. cs_name = m2.X509.X509_Name() cs_name.C = "US" cs_name.ST = "CA" cs_name.OU = "Fake Org CA 1" cs_name.CN = "www.fakeorg.dex" cs_name.Email = "[email protected]" cs_cert.set_subject(cs_name) cs_cert.set_issuer_name(cs_name) cs_cert.sign(cs_pk, md="sha256") orig_text = cs_cert.as_text() orig_pem = cs_cert.as_pem() print "orig_text:\n%s" % orig_text cs_cert.save_pem("/tmp/foo") tcs = m2.X509.load_cert("/tmp/foo") tcs_text = tcs.as_text() tcs_pem = tcs.as_pem() if orig_text != tcs_text: raise RuntimeError( "Texts were different.\nOrig:\n%s\nAfter load:\n%s" % (orig_text, tcs_text)) if orig_pem != tcs_pem: raise RuntimeError( "Pems were different.\nOrig:\n%s\nAfter load:\n%s" % (orig_pem, tcs_pem))

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• Best practice to calculate the average speed from GPS coordinates

  - by Sebi

  i have here a device which can give me gps coordinates. the time intervall i can define. i want to use it to calculate the average speed during driving or travelling by car. actually i used a orthodrome formula to calculate the distance between two points and then divided it by the given time intervall. by the implemenation i followed this term (http://de.wikipedia.org/wiki/Orthodrome#Genauere_Formel_zur_Abstandsberechnung_auf_der_Erde). Unfortunately i could only find a german link, but i think the formula should be understandable in any language ;) Unfortunately, using this formula and a time intverall of 1 seconds gives very unprecises results. the speed while walking is between 1 km/h and 20km/h. So i wonder if there is a general reference how to implement distance calculation between two gps coordinates (i found something similar on SO) and particulary, which is the best time intervall to update the GPS coordiantes.

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• LDAP socket keep-alive

  - by Dmitry Khalatov

  We are using OpenLDAP client library to conect to an LDAP server. The problem is that if there is no activity for some time, server (or firewall in the middle) drops TCP connection. Our current implementation of "keep-alive" just does search for baseDN from time to time - any better ideas ?

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• How can I stop SQL Server Reporting Services 2008 going to sleep?

  - by Nick

  I have SSRS 2008 set-up on a server. All works fine except that if left inactive for a length of time the next time a request is made to the server it takes a long time for it to service it. I think this is to do with the worker process being shutdown after being idle for a certain length of time. However, as SSRS 2008 isn't managed through IIS I can't find any settings that I can adjust to stop this from happening. In IIS I'd go to the Performance tab of the Application Pool Properties and choose not to shutdown the worker process. How can I do this for SSRS 2008?

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• How countdown get Synchronise with jquery using "jquery.countdown.js" plugin?

  - by ricky roy

  unable to get the correct Ans as i am getting from the Jquery I am using jquery.countdown.js ref. site http://keith-wood.name/countdown.html here is my code [WebMethod] public static String GetTime() { DateTime dt = new DateTime(); dt = Convert.ToDateTime("April 9, 2010 22:38:10"); return dt.ToString("dddd, dd MMMM yyyy HH:mm:ss"); } html file <script type="text/javascript" src="Scripts/jquery-1.3.2.js"></script> <script type="text/javascript" src="Scripts/jquery.countdown.js"></script> <script type="text/javascript"> $(function() { var shortly = new Date('April 9, 2010 22:38:10'); var newTime = new Date('April 9, 2010 22:38:10'); //for loop divid /// $('#defaultCountdown').countdown({ until: shortly, onExpiry: liftOff, onTick: watchCountdown, serverSync: serverTime }); $('#div1').countdown({ until: newTime }); }); function serverTime() { var time = null; $.ajax({ type: "POST", //Page Name (in which the method should be called) and method name url: "Default.aspx/GetTime", // If you want to pass parameter or data to server side function you can try line contentType: "application/json; charset=utf-8", dataType: "json", data: "{}", async: false, //else If you don't want to pass any value to server side function leave the data to blank line below //data: "{}", success: function(msg) { //Got the response from server and render to the client time = new Date(msg.d); alert(time); }, error: function(msg) { time = new Date(); alert('1'); } }); return time; } function watchCountdown() { } function liftOff() { } </script>

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• Traceroute Theory

  - by Hamza Yerlikaya

  I am toying with trace route, my application send a ICMP echo request with a ttl of 0 every time i receive a time exceeded message i increment the ttl by one and resent the package, but what happens is I have 2 routers on my network i can trace the route through these router but third hop always ends up being one of the open dns servers same ip every time no matter where i traceroute to. AFAIK this is the correct traceroute implementation, can anyone tell me what i am doing wrong?

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