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• No, iCloud Isn’t Backing Them All Up: How to Manage Photos on Your iPhone or iPad

  - by Chris Hoffman

  Are the photos you take with your iPhone or iPad backed up in case you lose your device? If you’re just relying on iCloud to manage your important memories, your photos may not be backed up at all. Apple’s iCloud has a photo-syncing feature in the form of “Photo Stream,” but Photo Stream doesn’t actually perform any long-term backups of your photos. iCloud’s Photo Backup Limitations Assuming you’ve set up iCloud on your iPhone or iPad, your device is using a feature called “Photo Stream” to automatically upload the photos you take to your iCloud storage and sync them across your devices. Unfortunately, there are some big limitations here. 1000 Photos: Photo Stream only backs up the latest 1000 photos. Do you have 1500 photos in your Camera Roll folder on your phone? If so, only the latest 1000 photos are stored in your iCloud account online. If you don’t have those photos backed up elsewhere, you’ll lose them when you lose your phone. If you have 1000 photos and take one more, the oldest photo will be removed from your iCloud Photo Stream. 30 Days: Apple also states that photos in your Photo Stream will be automatically deleted after 30 days “to give your devices plenty of time to connect and download them.” Some people report photos aren’t deleted after 30 days, but it’s clear you shouldn’t rely on iCloud for more than 30 days of storage. iCloud Storage Limits: Apple only gives you 5 GB of iCloud storage space for free, and this is shared between backups, documents, and all other iCloud data. This 5 GB can fill up pretty quickly. If your iCloud storage is full and you haven’t purchased any more storage more from Apple, your photos aren’t being backed up. Videos Aren’t Included: Photo Stream doesn’t include videos, so any videos you take aren’t automatically backed up. It’s clear that iCloud’s Photo Stream isn’t designed as a long-term way to store your photos, just a convenient way to access recent photos on all your devices before you back them up for real. iCloud’s Photo Stream is Designed for Desktop Backups If you have a Mac, you can launch iPhoto and enable the Automatic Import option under Photo Stream in its preferences pane. Assuming your Mac is on and connected to the Internet, iPhoto will automatically download photos from your photo stream and make local backups of them on your hard drive. You’ll then have to back up your photos manually so you don’t lose them if your Mac’s hard drive ever fails. If you have a Windows PC, you can install the iCloud Control Panel, which will create a Photo Stream folder on your PC. Your photos will be automatically downloaded to this folder and stored in it. You’ll want to back up your photos so you don’t lose them if your PC’s hard drive ever fails. Photo Stream is clearly designed to be used along with a desktop application. Photo Stream temporarily backs up your photos to iCloud so iPhoto or iCloud Control Panel can download them to your Mac or PC and make a local backup before they’re deleted. You could also use iTunes to sync your photos from your device to your PC or Mac, but we don’t really recommend it — you should never have to use iTunes. How to Actually Back Up All Your Photos Online So Photo Stream is actually pretty inconvenient — or, at least, it’s just a way to temporarily sync photos between your devices without storing them long-term. But what if you actually want to automatically back up your photos online without them being deleted automatically? The solution here is a third-party app that does this for you, offering the automatic photo uploads with long-term storage. There are several good services with apps in the App Store: Dropbox: Dropbox’s Camera Upload feature allows you to automatically upload the photos — and videos — you take to your Dropbox account. They’ll be easily accessible anywhere there’s a Dropbox app and you can get much more free Dropbox storage than you can iCloud storage. Dropbox will never automatically delete your old photos. Google+: Google+ offers photo and video backups with its Auto Upload feature, too. Photos will be stored in your Google+ Photos — formerly Picasa Web Albums — and will be marked as private by default so no one else can view them. Full-size photos will count against your free 15 GB of Google account storage space, but you can also choose to upload an unlimited amount of photos at a smaller resolution. Flickr: The Flickr app is no longer a mess. Flickr offers an Auto Upload feature for uploading full-size photos you take and free Flickr accounts offer a massive 1 TB of storage for you to store your photos. The massive amount of free storage alone makes Flickr worth a look. Use any of these services and you’ll get an online, automatic photo backup solution you can rely on. You’ll get a good chunk of free space, your photos will never be automatically deleted, and you can easily access them from any device. You won’t have to worry about storing local copies of your photos and backing them up manually. Apple should fix this mess and offer a better solution for long-term photo backup, especially considering the limitations aren’t immediately obvious to users. Until they do, third-party apps are ready to step in and take their place. You can also automatically back up your photos to the web on Android with Google+’s Auto Upload or Dropbox’s Camera Upload. Image Credit: Simon Yeo on Flickr     

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• SQL SERVER – Service Broker and CAP_CPU_PERCENT – Limiting SQL Server Instances to CPU Usage

  - by pinaldave

  I have mentioned several times on this blog that the best part of blogging is the questions I receive from readers. They are often very interesting. The questions from readers give me a good idea what other readers might be thinking as well. After reading my earlier article Simple Example to Configure Resource Governor – Introduction to Resource Governor – I received an email from a reader and we exchanged a few emails. After exchanging emails we both figured out what is going on. It was indeed interesting and reader suggested to that I should blog about it.  I asked for permission to publish his name but he does not like the attention so we will just call him Jeff. I have converted our emails into chat for easy consumption. Jeff: Your script does not work at all. I think either there is a bug in SQL Server. Pinal: Would you please explain in detail? Jeff: Your code does not limit the CPU usage? Pinal: How did you measure it? Jeff: Well, we have third party tools for it but let us say I have limited the resources for Reporting Services and used your script described in your blog. After that I ran only reporting service workload the CPU is still used more than 100% and it is not limited to 30% as described in your script. Clearly something is wrong somewhere. Pinal: Did you say you ONLY ran reporting server load? Jeff: Yeah, to validate I ran ONLY reporting server load and CPU did not throttle at 30% as per your script. Pinal: Oh! I get it here is the answer - CAP_CPU_PERCENT = 30. Use it. Jeff: What is that, I think your earlier script says it will throttle the Reporting Service workload and Application/OLTP workload and balance it. Pinal: Exactly, that is correct. Jeff: You need to write more in email buddy! Just like your blogs, your answers do not make sense! No Offense! Pinal: Hmm…feedback well taken. Let me try again. In SQL Server 2012 there are a few enhancements with regards to SQL Server Resource Governor. One of the enhancement is how the resources are allocated. Let me explain you with examples. Configuration: [Read Earlier Post] Reporting Workload: MIN_CPU_PERCENT=0, MAX_CPU_PERCENT=30 Application/OLTP Workload: MIN_CPU_PERCENT=50, MAX_CPU_PERCENT=100 Example 1: If there is only Reporting Workload on the server: SQL Server will not limit usage of CPU to only 30% workload but SQL Server instance will use all available CPU (if needed). In another word in this scenario it will use more than 30% CPU. Example 2: If there is Reproting Workload and heavy Application/OLTP workload: SQL Server will allocate a maximum of 30% CPU resources to Reporting Workload and allocate remaining resources to heavy application/OLTP workload. The reason for this enhancement is for better utilization of the resources. Let us think, if there is only single workload, which we have limited to max CPU usage to 30%. The other unused available CPU resources is now wasted. In this situation SQL Server allows the workload to use more than 30% resources leading to overall improved/optimized performance. However, in the case of multiple workload where lots of resources are needed the limits specified in MAX_CPU_PERCENT are acknowledged. Example 3: If there is a situation where the max CPU workload has to be enforced: This is a very interesting scenario, in the case when the max CPU workload has to be enforced irrespective of the workload and enhanced algorithm, the keyword CAP_CPU_PERCENT is essential. It specifies a hard cap on the CPU bandwidth that all requests in the resource pool will receive. It will never let CPU usage for reporting workload to go over 30% in our case. You can use the key word as follows: -- Creating Resource Pool for Report Server CREATE RESOURCE POOL ReportServerPool WITH ( MIN_CPU_PERCENT=0, MAX_CPU_PERCENT=30, CAP_CPU_PERCENT=40, MIN_MEMORY_PERCENT=0, MAX_MEMORY_PERCENT=30) GO Notice that there is MAX_CPU_PERCENT=30 and CAP_CPU_PERCENT=40, what it means is that when SQL Server Instance is under heavy load under different workload it will use the maximum CPU at 30%. However, when the SQL Server instance is not under workload it will go over the 30% limit. However, as CAP_CPU_PERCENT is set to 40, it will not go over 40% in any case by limiting the usage of CPU. CAP_CPU_PERCENT puts a hard limit on the resources usage by workload. Jeff: Nice Pinal, you should blog about it. [A day passes by] Pinal: Jeff, it is done! Click here to read it. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Service Broker

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• New .NET Library for Accessing the Survey Monkey API

  - by Ben Emmett

  I’ve used Survey Monkey’s API for a while, and though it’s pretty powerful, there’s a lot of boilerplate each time it’s used in a new project, and the json it returns needs a bunch of processing to be able to use the raw information. So I’ve finally got around to releasing a .NET library you can use to consume the API more easily. The main advantages are: Only ever deal with strongly-typed .NET objects, making everything much more robust and a lot faster to get going Automatically handles things like rate-limiting and paging through results Uses combinations of endpoints to get all relevant data for you, and processes raw response data to map responses to questions To start, either install it using NuGet with PM> Install-Package SurveyMonkeyApi (easier option), or grab the source from https://github.com/bcemmett/SurveyMonkeyApi if you prefer to build it yourself. You’ll also need to have signed up for a developer account with Survey Monkey, and have both your API key and an OAuth token. A simple usage would be something like: string apiKey = "KEY"; string token = "TOKEN"; var sm = new SurveyMonkeyApi(apiKey, token); List<Survey> surveys = sm.GetSurveyList(); The surveys object is now a list of surveys with all the information available from the /surveys/get_survey_list API endpoint, including the title, id, date it was created and last modified, language, number of questions / responses, and relevant urls. If there are more than 1000 surveys in your account, the library pages through the results for you, making multiple requests to get a complete list of surveys. All the filtering available in the API can be controlled using .NET objects. For example you might only want surveys created in the last year and containing “pineapple” in the title: var settings = new GetSurveyListSettings { Title = "pineapple", StartDate = DateTime.Now.AddYears(-1) }; List<Survey> surveys = sm.GetSurveyList(settings); By default, whenever optional fields can be requested with a response, they will all be fetched for you. You can change this behaviour if for some reason you explicitly don’t want the information, using var settings = new GetSurveyListSettings { OptionalData = new GetSurveyListSettingsOptionalData { DateCreated = false, AnalysisUrl = false } }; Survey Monkey’s 7 read-only endpoints are supported, and the other 4 which make modifications to data might be supported in the future. The endpoints are: Endpoint Method Object returned /surveys/get_survey_list GetSurveyList() List<Survey> /surveys/get_survey_details GetSurveyDetails() Survey /surveys/get_collector_list GetCollectorList() List<Collector> /surveys/get_respondent_list GetRespondentList() List<Respondent> /surveys/get_responses GetResponses() List<Response> /surveys/get_response_counts GetResponseCounts() Collector /user/get_user_details GetUserDetails() UserDetails /batch/create_flow Not supported Not supported /batch/send_flow Not supported Not supported /templates/get_template_list Not supported Not supported /collectors/create_collector Not supported Not supported The hierarchy of objects the library can return is Survey List<Page> List<Question> QuestionType List<Answer> List<Item> List<Collector> List<Response> Respondent List<ResponseQuestion> List<ResponseAnswer> Each of these classes has properties which map directly to the names of properties returned by the API itself (though using PascalCasing which is more natural for .NET, rather than the snake_casing used by SurveyMonkey). For most users, Survey Monkey imposes a rate limit of 2 requests per second, so by default the library leaves at least 500ms between requests. You can request higher limits from them, so if you want to change the delay between requests just use a different constructor: var sm = new SurveyMonkeyApi(apiKey, token, 200); //200ms delay = 5 reqs per sec There’s a separate cap of 1000 requests per day for each API key, which the library doesn’t currently enforce, so if you think you’ll be in danger of exceeding that you’ll need to handle it yourself for now.  To help, you can see how many requests the current instance of the SurveyMonkeyApi object has made by reading its RequestsMade property. If the library encounters any errors, including communicating with the API, it will throw a SurveyMonkeyException, so be sure to handle that sensibly any time you use it to make calls. Finally, if you have a survey (or list of surveys) obtained using GetSurveyList(), the library can automatically fill in all available information using sm.FillMissingSurveyInformation(surveys); For each survey in the list, it uses the other endpoints to fill in the missing information about the survey’s question structure, respondents, and responses. This results in at least 5 API calls being made per survey, so be careful before passing it a large list. It also joins up the raw response information to the survey’s question structure, so that for each question in a respondent’s set of replies, you can access a ProcessedAnswer object. For example, a response to a dropdown question (from the /surveys/get_responses endpoint) might be represented in json as { "answers": [ { "row": "9384627365", } ], "question_id": "615487516" } Separately, the question’s structure (from the /surveys/get_survey_details endpoint) might have several possible answers, one of which might look like { "text": "Fourth item in dropdown list", "visible": true, "position": 4, "type": "row", "answer_id": "9384627365" } The library understands how this mapping works, and uses that to give you the following ProcessedAnswer object, which first describes the family and type of question, and secondly gives you the respondent’s answers as they relate to the question. Survey Monkey has many different question types, with 11 distinct data structures, each of which are supported by the library. If you have suggestions or spot any bugs, let me know in the comments, or even better submit a pull request .

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• Installing gtk-config and/or fsv in Ubuntu 10.10

  - by Wayne Werner

  Hi, I'm trying to install the File System Visualizer (think "It's a UNIX System! I know this!" from Jurassic Park) on Ubuntu 10.10. I've got the .tar.gz downloaded, and extracted. However, when I ./configure, I get this output: loading cache ./config.cache checking for a BSD compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking whether make sets ${MAKE}... yes checking for working aclocal... found checking for working autoconf... found checking for working automake... found checking for working autoheader... found checking for working makeinfo... missing checking for gcc... gcc checking whether the C compiler (gcc ) works... yes checking whether the C compiler (gcc ) is a cross-compiler... no checking whether we are using GNU C... yes checking whether gcc accepts -g... yes checking how to run the C preprocessor... gcc -E checking for ranlib... ranlib checking for POSIXized ISC... no checking for dirent.h that defines DIR... yes checking for opendir in -ldir... no checking for ANSI C header files... yes checking whether time.h and sys/time.h may both be included... yes checking for strings.h... yes checking for sys/time.h... yes checking for unistd.h... yes checking for working const... yes checking for mode_t... yes checking for uid_t in sys/types.h... yes checking for pid_t... yes checking for size_t... yes checking for comparison_fn_t... yes checking for st_blocks in struct stat... yes checking whether struct tm is in sys/time.h or time.h... time.h checking for working alloca.h... yes checking for alloca... yes checking for working fnmatch... yes checking for strftime... yes checking for getcwd... yes checking for gettimeofday... yes checking for mktime... yes checking for strcspn... yes checking for strdup... yes checking for strspn... yes checking for strtod... yes checking for strtoul... yes checking for scandir... yes checking for inline... inline checking for off_t... yes checking for unistd.h... (cached) yes checking for getpagesize... yes checking for working mmap... yes checking for argz.h... yes checking for limits.h... yes checking for locale.h... yes checking for nl_types.h... yes checking for malloc.h... yes checking for string.h... yes checking for unistd.h... (cached) yes checking for sys/param.h... yes checking for getcwd... (cached) yes checking for munmap... yes checking for putenv... yes checking for setenv... yes checking for setlocale... yes checking for strchr... yes checking for strcasecmp... yes checking for strdup... (cached) yes checking for __argz_count... yes checking for __argz_stringify... yes checking for __argz_next... yes checking for stpcpy... yes checking for LC_MESSAGES... yes checking whether NLS is requested... yes checking whether included gettext is requested... no checking for libintl.h... yes checking for gettext in libc... yes checking for msgfmt... /usr/bin/msgfmt checking for dcgettext... yes checking for gmsgfmt... /usr/bin/msgfmt checking for xgettext... /usr/bin/xgettext checking for gtk-config... no checking for GTK - version >= 1.2.1... no *** The gtk-config script installed by GTK could not be found *** If GTK was installed in PREFIX, make sure PREFIX/bin is in *** your path, or set the GTK_CONFIG environment variable to the *** full path to gtk-config. configure: error: Cannot find proper GTK+ version Obviously it's looking for gtk-config. However, apparently it doesn't exist in the repos anymore. Then this post mentioned that gtkglarea solved their problem, as mentioned in this file. Of course that poster neatly forgets to mention exactly what and how gtkglarea solved their problem, and Google is mostly devoid of information on the problem. So I come here asking for help! I would like to install fsv, but it tells me gtk-config doesn't exist. How can I fix this problem in Ubuntu 10.10? Thanks!

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• How to find domain registrar and DNS hosting with good DNSSEC support?

  - by rsp

  Simplified problem I want to buy a domain and make a website that is fully secured with DNSSEC. Background I've been hearing about the insecurity of DNS for years. I've watched all of the talks by Dan Kaminsky and others from DNS exploits to The future of DNS Security Panel. I knew that using DNS without security is a disaster waiting to happen. I followed the development of the DNSSEC standard. I celebrated the key signing ceremony. Everything was on the right track to finally have a secure DNS system in place. And now more than 2 years later I wanted to just do what everyone said I should do: use DNSSEC for a new domain. So I need a domain registrar and a DNS hosting service that supports DNSSEC. Surprisingly it is not that easy to even find out who does support DNSSEC. It was actually much easier to find info on DNSSEC two years ago when everyone was going to support DNSSEC Real Soon Now but now years passed and I hardly see any progress done. I just hope that I was just looking in the wrong places and someone here will explain all of the doubts. I hope that other people who want to have a secure website will also find this question useful. What is needed registrar and DNS servers with full DNSSEC support for .com domains What is not needed IPv6 support Web hosting anything more What I found out so far Go Daddy offers Premium DNS service for additional $36 per year that lets you "Secure up to 5 domains with DNSSEC". easyDNS has DNSSEC available in Beta across all service levels (you need to enable the "beta" flag in configuration) but it doesn't seem to be production ready and judging from the lack of updates it isn't a feature of highest priority (the last update from March 2011 on the easyDNS blog). Name.com - according to The Register (US domain registrar does IPv6, DNSSEC) it has DNSSEC support since 2010 but right now (October 2012) I couldn't find anything related to DNSSEC on their website. Dynadot that is very often recommended doesn't support DNSSEC Namecheap that is also often recommended doesn't support DNSSEC. The support answer from 2011 suggested that it was being added but in 2012 still no ETA is given to customers. DynDNS was supposed to support DNSSEC, I found a link explaining DNSSEC support but it gives 404 Not Found page and offers a search box - when searching for DNSSEC I get "No results were found for your query." GKG was recommended online for DNSSEC support but it's hard to find any information on the level of DNSSEC support - there is a brief explanation on what is DNSSEC and how to sign Delegation Signer records in their FAQ but no information about the level of actual support can be found. Ask Slashdot: Which Registrars Support DNSSEC? from July 2011 - Answers list Go Daddy, DynDNS, GKG, Name.com as registrars that support DNSSEC but: see above. Related questions How to find web hosting that meets my requirements? What is needed to add DNSSEC to my site? DNS hosting better managed by Domain provider or Hosting provider? Registrar with good security, DNS hosting, and DNSSEC and IPv6 resolvers? In no. 1 no one is ever mentioning DNS at all. In no. 2 answers only mention the .se TLD, there are very few answers and they seem very outdated. In no. 3 one answer says "On projects that demand higher security, I might look for a web host that supports DNSSEC" but no more information is provided. The only relevant answers are in no. 4 where easyDNS is recommended by someone who has never used them personally. Meanwhile, as of October 2012, the support of DNSSEC is described as "in beta" on the easyDNS feature list. Another one recommends SiteGround but searching their site for DNSSEC returns no results. Other answers recommend web hosting providers that don't meet the requirement of DNSSEC support. Also the question mentioned above lists 9 very specific requirements other than only DNSSEC (like eg. HTTP-only login cookies, two-factor authentications, no DNS record limits, DNS statistics of queries/day, audit trails etc.) which might have excluded many possible recommendations if one is only interested in DNSSEC support. Conclusions I thought that by the end of 2012 the support of DNSSEC among domain registrars and DNS providers would be nearly universal. I am shocked that the support seems virtually nonexistent. Is this a result of some serious problems with the DNSSEC adoption? Or is it just not a hot topic and no one bothers anymore? According to the DNSSEC Scoreboard roughly about 0.1% of .com domains support DNSSEC. Could that be caused by the lack of DNSSEC support among registrars and DNS providers, is the information too hard to find or maybe no one cares? There is even no "dnssec" tag here. Questions The information is surprisingly hard to find. That is why I am asking for first-hand experience and personal recommendations. Has anyone here actually set up a website with DNSSEC, from the domain registration to the configuration of DNS servers? Can anyone recommend any of the registrars mentioned above? Can anyone recommend any registrar not mentioned above?

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• Auto DOP and Concurrency

  - by jean-pierre.dijcks

  After spending some time in the cloud, I figured it is time to come down to earth and start discussing some of the new Auto DOP features some more. As Database Machines (the v2 machine runs Oracle Database 11.2) are effectively selling like hotcakes, it makes some sense to talk about the new parallel features in more detail. For basic understanding make sure you have read the initial post. The focus there is on Auto DOP and queuing, which is to some extend the focus here. But now I want to discuss the concurrency a little and explain some of the relevant parameters and their impact, specifically in a situation with concurrency on the system. The goal of Auto DOP The idea behind calculating the Automatic Degree of Parallelism is to find the highest possible DOP (ideal DOP) that still scales. In other words, if we were to increase the DOP even more  above a certain DOP we would see a tailing off of the performance curve and the resource cost / performance would become less optimal. Therefore the ideal DOP is the best resource/performance point for that statement. The goal of Queuing On a normal production system we should see statements running concurrently. On a Database Machine we typically see high concurrency rates, so we need to find a way to deal with both high DOP’s and high concurrency. Queuing is intended to make sure we Don’t throttle down a DOP because other statements are running on the system Stay within the physical limits of a system’s processing power Instead of making statements go at a lower DOP we queue them to make sure they will get all the resources they want to run efficiently without trashing the system. The theory – and hopefully – practice is that by giving a statement the optimal DOP the sum of all statements runs faster with queuing than without queuing. Increasing the Number of Potential Parallel Statements To determine how many statements we will consider running in parallel a single parameter should be looked at. That parameter is called PARALLEL_MIN_TIME_THRESHOLD. The default value is set to 10 seconds. So far there is nothing new here…, but do realize that anything serial (e.g. that stays under the threshold) goes straight into processing as is not considered in the rest of this post. Now, if you have a system where you have two groups of queries, serial short running and potentially parallel long running ones, you may want to worry only about the long running ones with this parallel statement threshold. As an example, lets assume the short running stuff runs on average between 1 and 15 seconds in serial (and the business is quite happy with that). The long running stuff is in the realm of 1 – 5 minutes. It might be a good choice to set the threshold to somewhere north of 30 seconds. That way the short running queries all run serial as they do today (if it ain’t broken, don’t fix it) and allows the long running ones to be evaluated for (higher degrees of) parallelism. This makes sense because the longer running ones are (at least in theory) more interesting to unleash a parallel processing model on and the benefits of running these in parallel are much more significant (again, that is mostly the case). Setting a Maximum DOP for a Statement Now that you know how to control how many of your statements are considered to run in parallel, lets talk about the specific degree of any given statement that will be evaluated. As the initial post describes this is controlled by PARALLEL_DEGREE_LIMIT. This parameter controls the degree on the entire cluster and by default it is CPU (meaning it equals Default DOP). For the sake of an example, let’s say our Default DOP is 32. Looking at our 5 minute queries from the previous paragraph, the limit to 32 means that none of the statements that are evaluated for Auto DOP ever runs at more than DOP of 32. Concurrently Running a High DOP A basic assumption about running high DOP statements at high concurrency is that you at some point in time (and this is true on any parallel processing platform!) will run into a resource limitation. And yes, you can then buy more hardware (e.g. expand the Database Machine in Oracle’s case), but that is not the point of this post… The goal is to find a balance between the highest possible DOP for each statement and the number of statements running concurrently, but with an emphasis on running each statement at that highest efficiency DOP. The PARALLEL_SERVER_TARGET parameter is the all important concurrency slider here. Setting this parameter to a higher number means more statements get to run at their maximum parallel degree before queuing kicks in.  PARALLEL_SERVER_TARGET is set per instance (so needs to be set to the same value on all 8 nodes in a full rack Database Machine). Just as a side note, this parameter is set in processes, not in DOP, which equates to 4* Default DOP (2 processes for a DOP, default value is 2 * Default DOP, hence a default of 4 * Default DOP). Let’s say we have PARALLEL_SERVER_TARGET set to 128. With our limit set to 32 (the default) we are able to run 4 statements concurrently at the highest DOP possible on this system before we start queuing. If these 4 statements are running, any next statement will be queued. To run a system at high concurrency the PARALLEL_SERVER_TARGET should be raised from its default to be much closer (start with 60% or so) to PARALLEL_MAX_SERVERS. By using both PARALLEL_SERVER_TARGET and PARALLEL_DEGREE_LIMIT you can control easily how many statements run concurrently at good DOPs without excessive queuing. Because each workload is a little different, it makes sense to plan ahead and look at these parameters and set these based on your requirements.

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• Big Data – Evolution of Big Data – Day 3 of 21

  - by Pinal Dave

  In yesterday’s blog post we answered what is the Big Data. Today we will understand why and how the evolution of Big Data has happened. Though the answer is very simple, I would like to tell it in the form of a history lesson. Data in Flat File In earlier days data was stored in the flat file and there was no structure in the flat file.  If any data has to be retrieved from the flat file it was a project by itself. There was no possibility of retrieving the data efficiently and data integrity has been just a term discussed without any modeling or structure around. Database residing in the flat file had more issues than we would like to discuss in today’s world. It was more like a nightmare when there was any data processing involved in the application. Though, applications developed at that time were also not that advanced the need of the data was always there and there was always need of proper data management. Edgar F Codd and 12 Rules Edgar Frank Codd was a British computer scientist who, while working for IBM, invented the relational model for database management, the theoretical basis for relational databases. He presented 12 rules for the Relational Database and suddenly the chaotic world of the database seems to see discipline in the rules. Relational Database was a promising land for all the unstructured database users. Relational Database brought into the relationship between data as well improved the performance of the data retrieval. Database world had immediately seen a major transformation and every single vendors and database users suddenly started to adopt the relational database models. Relational Database Management Systems Since Edgar F Codd proposed 12 rules for the RBDMS there were many different vendors who started them to build applications and tools to support the relationship between database. This was indeed a learning curve for many of the developer who had never worked before with the modeling of the database. However, as time passed by pretty much everybody accepted the relationship of the database and started to evolve product which performs its best with the boundaries of the RDBMS concepts. This was the best era for the databases and it gave the world extreme experts as well as some of the best products. The Entity Relationship model was also evolved at the same time. In software engineering, an Entity–relationship model (ER model) is a data model for describing a database in an abstract way. Enormous Data Growth Well, everything was going fine with the RDBMS in the database world. As there were no major challenges the adoption of the RDBMS applications and tools was pretty much universal. There was a race at times to make the developer’s life much easier with the RDBMS management tools. Due to the extreme popularity and easy to use system pretty much every data was stored in the RDBMS system. New age applications were built and social media took the world by the storm. Every organizations was feeling pressure to provide the best experience for their users based the data they had with them. While this was all going on at the same time data was growing pretty much every organization and application. Data Warehousing The enormous data growth now presented a big challenge for the organizations who wanted to build intelligent systems based on the data and provide near real time superior user experience to their customers. Various organizations immediately start building data warehousing solutions where the data was stored and processed. The trend of the business intelligence becomes the need of everyday. Data was received from the transaction system and overnight was processed to build intelligent reports from it. Though this is a great solution it has its own set of challenges. The relational database model and data warehousing concepts are all built with keeping traditional relational database modeling in the mind and it still has many challenges when unstructured data was present. Interesting Challenge Every organization had expertise to manage structured data but the world had already changed to unstructured data. There was intelligence in the videos, photos, SMS, text, social media messages and various other data sources. All of these needed to now bring to a single platform and build a uniform system which does what businesses need. The way we do business has also been changed. There was a time when user only got the features what technology supported, however, now users ask for the feature and technology is built to support the same. The need of the real time intelligence from the fast paced data flow is now becoming a necessity. Large amount (Volume) of difference (Variety) of high speed data (Velocity) is the properties of the data. The traditional database system has limits to resolve the challenges this new kind of the data presents. Hence the need of the Big Data Science. We need innovation in how we handle and manage data. We need creative ways to capture data and present to users. Big Data is Reality! Tomorrow In tomorrow’s blog post we will try to answer discuss Basics of Big Data Architecture. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• MVVM Light V4 preview 2 (BL0015) #mvvmlight

  - by Laurent Bugnion

  Over the past few weeks, I have worked hard on a few new features for MVVM Light V4. Here is a second early preview (consider this pre-alpha if you wish). The features are unit-tested, but I am now looking for feedback and there might be bugs! Bug correction: Messenger.CleanupList is now thread safe This was an annoying bug that is now corrected: In some circumstances, an exception could be thrown when the Messenger’s recipients list was cleaned up (i.e. the “dead” instances were removed). The method is called now and then and the exception was thrown apparently at random. In fact it was really a multi-threading issue, which is now corrected. Bug correction: AllowPartiallyTrustedCallers prevents EventToCommand to work This is a particularly annoying regression bug that was introduced in BL0014. In order to allow MVVM Light to work in XBAPs too, I added the AllowPartiallyTrustedCallers attribute to the assemblies. However, we just found out that this causes issues when using EventToCommand. In order to allow EventToCommand to continue working, I reverted to the previous state by removing the AllowPartiallyTrustedCallers attribute for now. I will work with my friends at Microsoft to try and find a solution. Stay tuned. Bug correction: XML documentation file is now generated in Release configuration The XML documentation file was not generated for the Release configuration. This was a simple flag in the project file that I had forgotten to set. This is corrected now. Applying EventToCommand to non-FrameworkElements This feature has been requested in order to be able to execute a command when a Storyboard is completed. I implemented this, but unfortunately found out that EventToCommand can only be added to Storyboards in Silverlight 3 and Silverlight 4, but not in WPF or in Windows Phone 7. This obviously limits the usefulness of this change, but I decided to publish it anyway, because it is pretty damn useful in Silverlight… Why not in WPF? In WPF, Storyboards added to a resource dictionary are frozen. This is a feature of WPF which allows to optimize certain objects for performance: By freezing them, it is a contract where we say “this object will not be modified anymore, so do your perf optimization on them without worrying too much”. Unfortunately, adding a Trigger (such as EventTrigger) to an object in resources does not work if this object is frozen… and unfortunately, there is no way to tell WPF not to freeze the Storyboard in the resources… so there is no way around that (at least none I can see. In Silverlight, objects are not frozen, so an EventTrigger can be added without problems. Why not in WP7? In Windows Phone 7, there is a totally different issue: Adding a Trigger can only be done to a FrameworkElement, which Storyboard is not. Here I think that we might see a change in a future version of the framework, so maybe this small trick will work in the future. Workaround? Since you cannot use the EventToCommand on a Storyboard in WPF and in WP7, the workaround is pretty obvious: Handle the Completed event in the code behind, and call the Command from there on the ViewModel. This object can be obtained by casting the DataContext to the ViewModel type. This means that the View needs to know about the ViewModel, but I never had issues with that anyway. New class: NotifyPropertyChanged Sometimes when you implement a model object (for example Customer), you would like to have it implement INotifyPropertyChanged, but without having all the frills of a ViewModelBase. A new class named NotifyPropertyChanged allows you to do that. This class is a simple implementation of INotifyPropertyChaned (with all the overloads of RaisePropertyChanged that were implemented in BL0014). In fact, ViewModelBase inherits NotifyPropertyChanged. ViewModelBase does not implement IDisposable anymore The IDisposable interface and the Dispose method had been marked obsolete in the ViewModelBase class already in V3. Now they have been removed. Note: By this, I do not mean that IDisposable is a bad interface, or that it shouldn’t be used on viewmodels. In the contrary, I know that this interface is very useful in certain circumstances. However, I think that having it by default on every instance of ViewModelBase was sending a wrong message. This interface has a strong meaning in .NET: After Dispose has been executed, the instance should not be used anymore, and should be ready for garbage collection. What I really wanted to have on ViewModelBase was rather a simple cleanup method, something that can be executed now and then during runtime. This is fulfilled by the ICleanup interface and its Cleanup method. If your ViewModels need IDisposable, you can still use it! You will just have to implement the interface on the class itself, because it is not available on ViewModelBase anymore. What’s next? I have a couple exciting new features implemented already but that need more testing before they go live… Just stay tuned and by MIX11 (12-14 April 2011), we should see at least a major addition to MVVM Light Toolkit, as well as another smaller feature which is pretty cool nonetheless More about this later! Happy Coding Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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• Design a T-shirt for .NET Reflector Pro

  - by Laila

  Win a .NET Reflector Pro license, a box of Red Gate goodies, and a t-shirt printed with your design! Red Gate likes t-shirts. Each of our teams has one. In fact, each individual person has one, numbered according to when they joined the company: Red Gate's 1st, 2nd, and so on right up to Red Gate's 170th, with the slogan "More than just a number". Those t-shirts are important, chiefly because they remind the people wearing them that they are important. But that isn't enough. What really makes us great are the people who choose to use our tools. So we'd like to extend our tradition of t-shirts to include you and put the design of our next shirt entirely in your hands. We'd like you to come up with a witty slogan or create an inventive or simply beautiful t-shirt design for .NET Reflector Pro, our add-in for Visual Studio, which allows you to step into decompiled assemblies whilst debugging in Visual Studio. When you're done, post your masterpiece to Twitter with the hash tag #reflectortees, and @redgate will take a look! We'll pick the best design, and the winner will get a licensed copy of .NET Reflector Pro and a box of Red Gate goodies - not to mention a copy of their t-shirt. The winning design will go into production and be worn and given out at tradeshows, conferences, and user group events across the world, proudly bearing the name of their designer. We'll also pick three runners-up who will receive licenses for .NET Reflector Pro. Red Gate goodie box Interested? If you're up for the challenge, then we've got some resources to get you started. Inside the .zip file you'll find high-quality versions of the following: T-shirt templates: don't forget to design the front and the back! Different versions of the .NET Reflector Pro logo and Red Gate logo. Colour sheets to give you an easy reference to the Red Gate colours, including hex and RGB values. You can create and send us as many designs as you like, and each of them will be considered for the prize. To submit your designs, simply tweet including the competition hash tag, #reflectortees, and a link to somewhere we can see your design: either an image hosting site such as Twitpic, Flickr or Picasa, or a personal blog. You will need to create a Twitter account (which is free), if you don't already have one. You only have three limits: The background colour of the t-shirt should be one of our brand colours (red, light/dark grey or black), though you're welcome to use other colours in the rest of the design. You need to make use of either the .NET Reflector Pro logo OR the Red Gate logo (please keep them as they are) If you include any text or slogan, stick with just one or two colors for it. Apart from that, go wild. Go and do whatever it is you do when you get creative: whether you walk barefoot on the grass with a pencil and paper, sit cross-legged on a pile of cushions with a laptop, or simply close your eyes and float through a mist of ideas, now is your chance. Make sure you enjoy it. We're looking forward to seeing your creations. Terms and conditions 1. The closing date for entries is June 11th, 2010 (4 p.m. UK time). Red Gate Software Ltd reserves the right to extend the competition deadline at its discretion. If there is a revision, the revised date will be published on this blog and the date for announcing the results will be postponed accordingly. 2. The winning designer will be notified on June 14th, 2010 through Twitter. The winner must claim his/her prize by sending us a high-resolution image of their design via email (i.e. Illustrator EPS files or appropriate format, ideally at 300dpi). If the winner does not come forward within 3 days of the announcement, they will forfeit their prize and another winner will be selected from the runners-up. The names of the winner and runners-up will be posted on this blog by June 18th.  3. Entry is completed on the designer posting a link to their entry in a tweet with the correct hash tag, #reflectortees. 4. Red Gate Software needs to hold the rights to using the winning design in order to put the t-shirt into production. We will make sure that this is fine with the winner before we do so, but if you do not want us holding the rights to your design, please do not submit your designs. We reserve the right to slightly alter or adjust any artwork we decide to use (mainly to make it easier to print), but we will make sure we contact the winner for approval first. The winner will also need to allow us the use of his/her name for purposes of promoting your design. 5. Entries must be entirely your own original work and must not breach any copyright or third party rights. Red Gate Software Ltd will not be made partially or fully liable for any non-original work submitted by you. 6. This competition is free: you do not need to buy anything or be an existing customer to enter. 7. This competition is not open to employees of Red Gate Software Ltd, their families, or any other company directly connected with the administration of this promotion.

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• Profit's COLLABORATE 10 Session Selections

  - by Aaron Lazenby

  COLLABORATE 2010 is a mere 11 days away (thanks for the reminder @ocp_advisor). Every year I publish my a list of the sessions I think reflect some of the more interesting people/trends in enterprise IT. I should be at all of these sessions, so drop by for a chat--I'll be the guy tapping out emails on my iPad... Monday, April 19 9:15 a.m. - Keynote: Transforming Customer Value, Delivering Highest Customer Service Location: Keynote Hall I never miss Charles Phillips when he speaks--it's one of the best opportunities to get an update on Oracle product developments and strategy. And there's certainly occasion for an update: this will be Phillips' first big presentation since the Oracle + Sun Strategy Update in late January. Phillips is appearing with Oracle Executive Vice President of Development Thomas Kurian which means there should be some excellent information about how customers are using Oracle's complete software and hardware stack to address enterprise IT challenges. The session should provide some excellent context for the rest of the week's session...don't miss it. 10:45 a.m. - Oracle Fusion Applications: Functional Overview Location: South Seas FI met Basheer Khan at COLLABORATE 08 in Denver and have followed his work ever since. He's a former member of the OAUG Board of Directors, an Oracle ACE, and a charismatic enterprise IT expert. Having worked with the Oracle Usability Advisory Board, Basheer should have some fascinating insights to share about the features and interface of Oracle's Fusine Applications. This session, along with Nadia Bendjedou's "10 Things You Can Do Today to Prepare for the Next Generation Applications" (on Tuesday, April 20 8:00 a.m. in room 3662) should give attendees the update they need about Oracle's next-generation applications.   1:15p.m. - E-Business Suite in the Amazon Cloud Location: South Seas HI did my first full-fledged cloud computing coverage at last year's COLLABORATE show (check out my interview with Oracle's Bill Hodak), where I first learned about Amazon's EC2 offering. I've since talked with several people who have provisioned server space on Amazon's cloud with great results. So I'm looking forward to watching the audience configure an instance of the Oracle E-Business Suite release 12 on the cloud while Chuck Edwards from Blue Gecko drives. This session should take some of the mist and vapor out of the cloud conversation.2:30 p.m. - "Zero Sign-on" to EBS - Enabling 96000 Users to Login to EBS Without User Maintenance Location: South Seas HI'll be sitting tight in South Seas H for the next session on Monday where Doug Pepka, a ten-year veteran of communications giant Comcast, will be walking attendees through a massive single sign-on (SSO) project across the enterprise. I'm working on a story about SSO for the August issue of Profit, so this session has real practical value to me. Plus the proliferation of user account logins--both personal and professional--makes this a critical usability/change management issue for IT leaders planning for successful long-term IT implementations.   Tuesday 8:00 am  - Information Architecture for Men in Kilts Location: SURF AGetting to a 8:00 a.m. presentation is a tall order in Las Vegas, but presenter Billy Cripe will make it worth your effort. Not only is the title of this session great, but the content should appeal to any IT strategist looking to push the limits of Web 2.0 technologies in the enterprise. Cripe is a product management director of Enterprise 2.0 and Enterprise Content Management at Oracle, author of Reshaping Your Business with Web 2.0, and a prolific blogger--he knows how information architecture is critical to and enterprise 2.0 implementation.    10:30a.m. - Oracle Virtualization: From Desktop to Data Center Location: REEF FData center virtualization is still one of the best ways to reduce the cost of running enterprise IT. With the addition of Sun products, Oracle has the industry's most comprehensive virtualization portfolio. I must admit, I'm no expert in this subject. So I'm looking forward to Monica Kumar's presentation so I can get up to speed.   Wednesday 8:00 a.m. - The Art of the Steal Location: Mandalay Bay Ballroom JMany will know Frank Abagnale from Steven Spielberg's 2002 film "Catch Me if You Can." The one-time con man and international fugitive who swindled $2.5 million in forged checks went on to help U.S. federal officials investigate fraud cases. Now the CEO of Abagnale and Associates, he has become an invaluable source to the business world on the subject of fraud and fraud protection. With identity theft and digital fraud still on the rise, this session should be an entertaining, and sobering, education on the threats facing businesses and customers around the world. A great way to start Wednesday.1:00 p.m. - Google Wave: Will it replace e-mail as we know it today? Location: SURF EBy many assessments (my own included), Google Wave is a bit of an open collaboration failure. It may seem like an odd reason for me to be excited about this session, but I'm looking forward to the chance to revisit the technology. Also, this is a great case study in connecting free, available Internet tools to existing enterprise computing environments--an issue that IT strategists must contend with as workers spreads out and choose their own productivity tools.  

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• Talend Enterprise Data Integration overperforms on Oracle SPARC T4

  - by Amir Javanshir

  The SPARC T microprocessor, released in 2005 by Sun Microsystems, and now continued at Oracle, has a good track record in parallel execution and multi-threaded performance. However it was less suited for pure single-threaded workloads. The new SPARC T4 processor is now filling that gap by offering a 5x better single-thread performance over previous generations. Following our long-term relationship with Talend, a fast growing ISV positioned by Gartner in the “Visionaries” quadrant of the “Magic Quadrant for Data Integration Tools”, we decided to test some of their integration components with the T4 chip, more precisely on a T4-1 system, in order to verify first hand if this new processor stands up to its promises. Several tests were performed, mainly focused on: Single-thread performance of the new SPARC T4 processor compared to an older SPARC T2+ processor Overall throughput of the SPARC T4-1 server using multiple threads The tests consisted in reading large amounts of data --ten's of gigabytes--, processing and writing them back to a file or an Oracle 11gR2 database table. They are CPU, memory and IO bound tests. Given the main focus of this project --CPU performance--, bottlenecks were removed as much as possible on the memory and IO sub-systems. When possible, the data to process was put into the ZFS filesystem cache, for instance. Also, two external storage devices were directly attached to the servers under test, each one divided in two ZFS pools for read and write operations. Multi-thread: Testing throughput on the Oracle T4-1 The tests were performed with different number of simultaneous threads (1, 2, 4, 8, 12, 16, 32, 48 and 64) and using different storage devices: Flash, Fibre Channel storage, two stripped internal disks and one single internal disk. All storage devices used ZFS as filesystem and volume management. Each thread read a dedicated 1GB-large file containing 12.5M lines with the following structure: customerID;FirstName;LastName;StreetAddress;City;State;Zip;Cust_Status;Since_DT;Status_DT 1;Ronald;Reagan;South Highway;Santa Fe;Montana;98756;A;04-06-2006;09-08-2008 2;Theodore;Roosevelt;Timberlane Drive;Columbus;Louisiana;75677;A;10-05-2009;27-05-2008 3;Andrew;Madison;S Rustle St;Santa Fe;Arkansas;75677;A;29-04-2005;09-02-2008 4;Dwight;Adams;South Roosevelt Drive;Baton Rouge;Vermont;75677;A;15-02-2004;26-01-2007 […] The following graphs present the results of our tests: Unsurprisingly up to 16 threads, all files fit in the ZFS cache a.k.a L2ARC : once the cache is hot there is no performance difference depending on the underlying storage. From 16 threads upwards however, it is clear that IO becomes a bottleneck, having a good IO subsystem is thus key. Single-disk performance collapses whereas the Sun F5100 and ST6180 arrays allow the T4-1 to scale quite seamlessly. From 32 to 64 threads, the performance is almost constant with just a slow decline. For the database load tests, only the best IO configuration --using external storage devices-- were used, hosting the Oracle table spaces and redo log files. Using the Sun Storage F5100 array allows the T4-1 server to scale up to 48 parallel JVM processes before saturating the CPU. The final result is a staggering 646K lines per second insertion in an Oracle table using 48 parallel threads. Single-thread: Testing the single thread performance Seven different tests were performed on both servers. Given the fact that only one thread, thus one file was read, no IO bottleneck was involved, all data being served from the ZFS cache. Read File ? Filter ? Write File: Read file, filter data, write the filtered data in a new file. The filter is set on the “Status” column: only lines with status set to “A” are selected. This limits each output file to about 500 MB. Read File ? Load Database Table: Read file, insert into a single Oracle table. Average: Read file, compute the average of a numeric column, write the result in a new file. Division & Square Root: Read file, perform a division and square root on a numeric column, write the result data in a new file. Oracle DB Dump: Dump the content of an Oracle table (12.5M rows) into a CSV file. Transform: Read file, transform, write the result data in a new file. The transformations applied are: set the address column to upper case and add an extra column at the end, which is the concatenation of two columns. Sort: Read file, sort a numeric and alpha numeric column, write the result data in a new file. The following table and graph present the final results of the tests: Throughput unit is thousand lines per second processed (K lines/second). Improvement is the % of improvement between the T5140 and T4-1. Test T4-1 (Time s.) T5140 (Time s.) Improvement T4-1 (Throughput) T5140 (Throughput) Read/Filter/Write 125 806 645% 100 16 Read/Load Database 195 1111 570% 64 11 Average 96 557 580% 130 22 Division & Square Root 161 1054 655% 78 12 Oracle DB Dump 164 945 576% 76 13 Transform 159 1124 707% 79 11 Sort 251 1336 532% 50 9 The improvement of single-thread performance is quite dramatic: depending on the tests, the T4 is between 5.4 to 7 times faster than the T2+. It seems clear that the SPARC T4 processor has gone a long way filling the gap in single-thread performance, without sacrifying the multi-threaded capability as it still shows a very impressive scaling on heavy-duty multi-threaded jobs. Finally, as always at Oracle ISV Engineering, we are happy to help our ISV partners test their own applications on our platforms, so don't hesitate to contact us and let's see what the SPARC T4-based systems can do for your application! "As describe in this benchmark, Talend Enterprise Data Integration has overperformed on T4. I was generally happy to see that the T4 gave scaling opportunities for many scenarios like complex aggregations. Row by row insertion in Oracle DB is faster with more than 650,000 rows per seconds without using any bulk Oracle capabilities !" Cedric Carbone, Talend CTO.

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• Autoscaling in a modern world&hellip;. Part 2

  - by Steve Loethen

  When we last left off, we had a web application spinning away in the cloud, and a local console application watching it and reacting to changes in demand.  Reactions that were specified by a set of rules.  Let’s talk about those rules. Constraints.  The first set of rules this application answered to were the constraints. Here is what they looked like: <constraintRules> <rule name="default" enabled="true" rank="1" description="The default constraint rule"> <actions> <range min="1" max="4" target="AutoscalingApplicationRole"/> </actions> </rule> </constraintRules> Pretty basic.  We have one role, the “AutoscalingApplicationRole”, and we have decided to have it live within a range of 1 to 4.  This rule does not adjust, but instead, set’s limits on what other rules can do.  It has a rank, so you can have you can specify other sets of constraints, perhaps based on time or date, to allow for deviations from this set.  But for now, let’s keep it simple.  In the real world, you would probably use the minimum to set a lower end SLA.  A common value might be a 2, to prevent the reactive rules from ever taking you down to 1 role.  The maximum is often used to keep a rule from driving the cost up, setting an upper limit to prevent you waking up one morning and find a bill for hundreds of instances you didn’t expect.  So, here we have the range we want our application to live inside.  This is good for our investigation and testing.  Next, let’s take a look at the reactive rules.  These rules are what you use to react (hence reactive rules) to changing demands on your application.  The HOL has two simple rules.  One that looks at a queue depth, and one that looks at a performance counter that reports cpu utilization.  the XML in the rules file looks like this: <reactiveRules> <rule name="ScaleUp" rank="10" description="Scale Up the web role" enabled="true"> <when> <any> <greaterOrEqual operand="Length_05_holqueue" than="10"/> <greaterOrEqual operand="CPU_05_holwebrole" than="65"/> </any> </when> <actions> <scale target="AutoscalingApplicationRole" by="1"/> </actions> </rule> <rule name="ScaleDown" rank="10" description="Scale down the web role" enabled="true"> <when> <all> <less operand="Length_05_holqueue" than="5"/> <less operand="CPU_05_holwebrole" than="40"/> </all> </when> <actions> <scale target="AutoscalingApplicationRole" by="-1"/> </actions> </rule> </reactiveRules> <operands> <performanceCounter alias="CPU_05_holwebrole" performanceCounterName="\Processor(_Total)\% Processor Time" source="AutoscalingApplicationRole" timespan="00:05:00" aggregate="Average" /> <queueLength alias="Length_05_holqueue" queue="hol-queue" timespan="00:05:00" aggregate="Average"/> </operands> These rules are currently contained in a file called rules.xml, that is in the root of the console application.  The console app, starts up, grabs the rules and starts watching the 2 operands.  When it detects a rule has been satisfied, it performs the desired action.  (here, scale up or down my 1). But I want to host the autoscaler  in the cloud.  For my first trick, I will move the rules (and another file called services.xml) to azure blob storage.  Look for part 3.

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• The Unspoken - The Why of GC Ergonomics

  - by jonthecollector

  Do you use GC ergonomics, -XX:+UseAdaptiveSizePolicy, with the UseParallelGC collector? The jist of GC ergonomics for that collector is that it tries to grow or shrink the heap to meet a specified goal. The goals that you can choose are maximum pause time and/or throughput. Don't get too excited there. I'm speaking about UseParallelGC (the throughput collector) so there are definite limits to what pause goals can be achieved. When you say out loud "I don't care about pause times, give me the best throughput I can get" and then say to yourself "Well, maybe 10 seconds really is too long", then think about a pause time goal. By default there is no pause time goal and the throughput goal is high (98% of the time doing application work and 2% of the time doing GC work). You can get more details on this in my very first blog. GC ergonomics The UseG1GC has its own version of GC ergonomics, but I'll be talking only about the UseParallelGC version. If you use this option and wanted to know what it (GC ergonomics) was thinking, try -XX:AdaptiveSizePolicyOutputInterval=1 This will print out information every i-th GC (above i is 1) about what the GC ergonomics to trying to do. For example, UseAdaptiveSizePolicy actions to meet *** throughput goal *** GC overhead (%) Young generation: 16.10 (attempted to grow) Tenured generation: 4.67 (attempted to grow) Tenuring threshold: (attempted to decrease to balance GC costs) = 1 GC ergonomics tries to meet (in order) Pause time goal Throughput goal Minimum footprint The first line says that it's trying to meet the throughput goal. UseAdaptiveSizePolicy actions to meet *** throughput goal *** This run has the default pause time goal (i.e., no pause time goal) so it is trying to reach a 98% throughput. The lines Young generation: 16.10 (attempted to grow) Tenured generation: 4.67 (attempted to grow) say that we're currently spending about 16% of the time doing young GC's and about 5% of the time doing full GC's. These percentages are a decaying, weighted average (earlier contributions to the average are given less weight). The source code is available as part of the OpenJDK so you can take a look at it if you want the exact definition. GC ergonomics is trying to increase the throughput by growing the heap (so says the "attempted to grow"). The last line Tenuring threshold: (attempted to decrease to balance GC costs) = 1 says that the ergonomics is trying to balance the GC times between young GC's and full GC's by decreasing the tenuring threshold. During a young collection the younger objects are copied to the survivor spaces while the older objects are copied to the tenured generation. Younger and older are defined by the tenuring threshold. If the tenuring threshold hold is 4, an object that has survived fewer than 4 young collections (and has remained in the young generation by being copied to the part of the young generation called a survivor space) it is younger and copied again to a survivor space. If it has survived 4 or more young collections, it is older and gets copied to the tenured generation. A lower tenuring threshold moves objects more eagerly to the tenured generation and, conversely a higher tenuring threshold keeps copying objects between survivor spaces longer. The tenuring threshold varies dynamically with the UseParallelGC collector. That is different than our other collectors which have a static tenuring threshold. GC ergonomics tries to balance the amount of work done by the young GC's and the full GC's by varying the tenuring threshold. Want more work done in the young GC's? Keep objects longer in the survivor spaces by increasing the tenuring threshold. This is an example of the output when GC ergonomics is trying to achieve a pause time goal UseAdaptiveSizePolicy actions to meet *** pause time goal *** GC overhead (%) Young generation: 20.74 (no change) Tenured generation: 31.70 (attempted to shrink) The pause goal was set at 50 millisecs and the last GC was 0.415: [Full GC (Ergonomics) [PSYoungGen: 2048K-0K(26624K)] [ParOldGen: 26095K-9711K(28992K)] 28143K-9711K(55616K), [Metaspace: 1719K-1719K(2473K/6528K)], 0.0758940 secs] [Times: user=0.28 sys=0.00, real=0.08 secs] The full collection took about 76 millisecs so GC ergonomics wants to shrink the tenured generation to reduce that pause time. The previous young GC was 0.346: [GC (Allocation Failure) [PSYoungGen: 26624K-2048K(26624K)] 40547K-22223K(56768K), 0.0136501 secs] [Times: user=0.06 sys=0.00, real=0.02 secs] so the pause time there was about 14 millisecs so no changes are needed. If trying to meet a pause time goal, the generations are typically shrunk. With a pause time goal in play, watch the GC overhead numbers and you will usually see the cost of setting a pause time goal (i.e., throughput goes down). If the pause goal is too low, you won't achieve your pause time goal and you will spend all your time doing GC. GC ergonomics is meant to be simple because it is meant to be used by anyone. It was not meant to be mysterious and so this output was added. If you don't like what GC ergonomics is doing, you can turn it off with -XX:-UseAdaptiveSizePolicy, but be pre-warned that you have to manage the size of the generations explicitly. If UseAdaptiveSizePolicy is turned off, the heap does not grow. The size of the heap (and the generations) at the start of execution is always the size of the heap. I don't like that and tried to fix it once (with some help from an OpenJDK contributor) but it unfortunately never made it out the door. I still have hope though. Just a side note. With the default throughput goal of 98% the heap often grows to it's maximum value and stays there. Definitely reduce the throughput goal if footprint is important. Start with -XX:GCTimeRatio=4 for a more modest throughput goal (%20 of the time spent in GC). A higher value means a smaller amount of time in GC (as the throughput goal).

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• Amanda Todd&ndash;What Parents Can Learn From Her Story

  - by D'Arcy Lussier

  Amanda Todd was a bullied teenager who committed suicide this week. Her story has become headline news due in part to her You Tube video she posted telling her story:   The story is heartbreaking for so many reasons, but I wanted to talk about what we as parents can learn from this. Being the dad to two girls, one that’s 10, I’m very aware of the dangers that the internet holds. When I saw her story, one thing jumped out at me – unmonitored internet access at an early age. My daughter (then 9) came home from a friends place once and asked if she could be in a YouTube video with her friend. Apparently this friend was allowed to do whatever she wanted on the internet, including posting goofy videos. This set off warning bells and we ensured our daughter realized the dangers and that she was not to ever post videos of herself. In looking at Amanda’s story, the access to unmonitored internet time along with just being a young girl and being flattered by an online predator were the key events that ultimately led to her suicide. Yes, the reaction of her classmates and “friends” was horrible as well, I’m not diluting that. But our youth don’t fully understand yet that what they do on the internet today will follow them potentially forever. And the people they meet online aren’t necessarily who they claim to be. So what can we as parents learn from Amanda’s story? Parents Shouldn’t Feel Bad About Being Internet Police Our job as parents is in part to protect our kids and keep them safe, even if they don’t like our measures. This includes monitoring, supervising, and restricting their internet activities. In our house we have a family computer in the living room that the kids can watch videos and surf the web. It’s in plain view of everyone, so you can’t hide what you’re looking at. If our daughter goes to a friend’s place, we ask about what they did and what they played. If the computer comes up, we ask about what they did on it. Luckily our daughter is very up front and honest in telling us things, so we have very open discussions. Parents Need to Be Honest About the Dangers of the Internet I’m sure every generation says that “kids grow up so fast these days”, but in our case the internet really does push our kids to be exposed to things they otherwise wouldn’t experience. One wrong word in a Google search, a click of a link in a spam email, or just general curiosity can expose a child to things they aren’t ready for or should never be exposed to (and I’m not just talking about adult material – have you seen some of the graphic pictures from war zones posted on news sites recently?). Our stance as parents has been to be open about discussing the dangers with our kids before they encounter any content – be proactive instead of reactionary. Part of this is alerting them to the monsters that lurk on the internet as well. As kids explore the world wide web, they’re eventually going to encounter some chat room or some Facebook friend invite or other personal connection with someone. More than ever kids need to be educated on the dangers of engaging with people online and sharing personal information. You can think of it as an evolved discussion that our parents had with us about using the phone: “Don’t say ‘I’m home alone’, don’t say when mom or dad get home, don’t tell them any information, etc.” Parents Need to Talk Self Worth at Home Katie makes the point better than I ever could (one bad word towards the end): Our children need to understand their value beyond what the latest issue of TigerBeat says, or the media who continues flaunting physical attributes over intelligence and character, or a society that puts focus on status and wealth. They also have to realize that just because someone pays you a compliment, that doesn’t mean you should ignore personal boundaries and limits. What does this have to do with the internet? Well, in days past if you wanted to be social you had to go out somewhere. Now you can video chat with any number of people from the comfort of wherever your laptop happens to be – and not just text but full HD video with sound! While innocent children head online in the hopes of meeting cool people, predators with bad intentions are heading online too. As much as we try to monitor their online activity and be honest about the dangers of the internet, the human side of our kids isn’t something we can control. But we can try to influence them to see themselves as not needing to search out the acceptance of complete strangers online. Way easier said than done, but ensuring self-worth is something discussed, encouraged, and celebrated is a step in the right direction. Parental Wake Up Call This post is not a critique of Amanda’s parents. The reality is that cyber bullying/abuse is happening every day, and there are millions of parents that have no clue its happening to their children. Amanda’s story is a wake up call that our children’s online activities may be putting them in danger. My heart goes out to the parents of this girl. As a father of daughters, I can’t imagine what I would do if I found my daughter having to hide in a ditch to avoid a mob or call 911 to report my daughter had attempted suicide by drinking bleach or deal with a child turning to drugs/alcohol/cutting to cope. It would be horrendous if we as parents didn’t re-evaluate our family internet policies in light of this event. And in the end, Amanda’s video was meant to bring attention to her plight and encourage others going through the same thing. We may not be kids, but we can still honour her memory by helping safeguard our children.

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• MSSQL: Copying data from one database to another

  - by DigiMortal

  I have database that has data imported from another server using import and export wizard of SQL Server Management Studio. There is also empty database with same tables but it also has primary keys, foreign keys and indexes. How to get data from first database to another? Here is the description of my crusade. And believe me – it is not nice one. Bugs in import and export wizard There is some awful bugs in import and export wizard that makes data imports and exports possible only on very limited manner: wizard is not able to analyze foreign keys, wizard wants to create tables always, whatever you say in settings. The result is faulty and useless package. Now let’s go step by step and make things work in our scenario. Database There are two databases. Let’s name them like this: PLAIN – contains data imported from remote server (no indexes, no keys, no nothing, just plain dumb data) CORRECT – empty database with same structure as remote database (indexes, keys and everything else but no data) Our goal is to get data from PLAIN to CORRECT. 1. Create import and export package In this point we will create faulty SSIS package using SQL Server Management Studio. Run import and export wizard and let it create SSIS package that reads data from CORRECT and writes it to, let’s say, CORRECT-2. Make sure you enable identity insert. Make sure there are no views selected. Make sure you don’t let package to create tables (you can miss this step because it wants to create tables anyway). Save package to SSIS. 2. Modify import and export package Now let’s clean up the package and remove all faulty crap. Connect SQL Server Management Studio to SSIS instance. Select the package you just saved and export it to your hard disc. Run Business Intelligence Studio. Create new SSIS project (DON’T MISS THIS STEP). Add package from disc as existing item to project and open it. Move to Control Flow page do one of following: Remove all preparation SQL-tasks and connect Data Flow tasks. Modify all preparation SQL-tasks so the existence of tables is checked before table is created (yes, you have to do it manually). Add new Execute-SQL task as first task in control flow: Open task properties. Assign destination connection as connection to use. Insert the following SQL as command:   EXEC sp_MSForEachTable 'ALTER TABLE ? NOCHECK CONSTRAINT ALL' GO   EXEC sp_MSForEachTable 'DELETE FROM ?' GO   Save task. Add new Execute-SQL task as last task in control flow: Open task properties. Assign destination connection as connection to use. Insert the following SQL as command:   EXEC sp_MSForEachTable 'ALTER TABLE ? CHECK CONSTRAINT ALL' GO   Save task Now connect first Execute-SQL task with first Data Flow task and last Data Flow task with second Execute-SQL task. Now move to Package Explorer tab and change connections under Connection Managers folder. Make source connection to use database PLAIN. Make destination connection to use database CORRECT. Save package and rebuilt the project. Update package using SQL Server Management Studio. Some hints: Make sure you take the package from solution folder because it is saved there now. Don’t overwrite existing package. Use numeric suffix and let Management Studio to create a new version of package. Now you are done with your package. Run it to test it and clean out all the errors you find. TRUNCATE vs DELETE You can see that I used DELETE FROM instead of TRUNCATE. Why? Because TRUNCATE has some nasty limits (taken from MSDN): “You cannot use TRUNCATE TABLE on a table referenced by a FOREIGN KEY constraint; instead, use DELETE statement without a WHERE clause. Because TRUNCATE TABLE is not logged, it cannot activate a trigger. TRUNCATE TABLE may not be used on tables participating in an indexed view.” As I am not sure what tables you have and how they are used I provided here the solution that should work for all scenarios. If you need better performance then in some cases you can use TRUNCATE table instead of DELETE. Conclusion My conclusion is bitter this time although I am very positive guy. It is A.D. 2010 and still we have to write stupid hacks for simple things. Simple tools that existed before are long gone and we have to live mysterious bloatware that is our only choice when using default tools. If you take a look at the length of this posting and the count of steps I had to do for one easy thing you should treat it as a signal that something has went wrong in last years. Although I got my job done I would be still more happy if out of box tools are more intelligent one day. References T-SQL Trick for Deleting All Data in Your Database (Mauro Cardarelli) TRUNCATE TABLE (MSDN Library) Error Handling in SQL 2000 – a Background (Erland Sommarskog) Disable/Enable Foreign Key and Check constraints in SQL Server (Decipher)

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• Why would GLCapabilities.setHardwareAccelerated(true/false) have no effect on performance?

  - by Luke

  I've got a JOGL application in which I am rendering 1 million textures (all the same texture) and 1 million lines between those textures. Basically it's a ball-and-stick graph. I am storing the vertices in a vertex array on the card and referencing them via index arrays, which are also stored on the card. Each pass through the draw loop I am basically doing this: gl.glBindBuffer(GL.GL_ARRAY_BUFFER, <buffer id>); gl.glBindBuffer(GL.GL_ELEMENT_ARRAY_BUFFER, <buffer id>); gl.glDrawElements(GL.GL_POINTS, <size>, GL.GL_UNSIGNED_INT, 0); gl.glBindBuffer(GL.GL_ARRAY_BUFFER, <buffer id>); gl.glBindBuffer(GL.GL_ELEMENT_ARRAY_BUFFER, <buffer id>); gl.glDrawElements(GL.GL_LINES, <size>, GL.GL_UNSIGNED_INT, 0); I noticed that the JOGL library is pegging one of my CPU cores. Every frame, the run method internal to the library is taking quite long. I'm not sure why this is happening since I have called setHardwareAccelerated(true) on the GLCapabilities used to create my canvas. What's more interesting is that I changed it to setHardwareAccelerated(false) and there was no impact on the performance at all. Is it possible that my code is not using hardware rendering even when it is set to true? Is there any way to check? EDIT: As suggested, I have tested breaking my calls up into smaller chunks. I have tried using glDrawRangeElements and respecting the limits that it requests. All of these simply resulted in the same pegged CPU usage and worse framerates. I have also narrowed the problem down to a simpler example where I just render 4 million textures (no lines). The draw loop then just doing this: gl.glEnableClientState(GL.GL_VERTEX_ARRAY); gl.glEnableClientState(GL.GL_INDEX_ARRAY); gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT); gl.glMatrixMode(GL.GL_MODELVIEW); gl.glLoadIdentity(); <... Camera and transform related code ...> gl.glEnableVertexAttribArray(0); gl.glEnable(GL.GL_TEXTURE_2D); gl.glAlphaFunc(GL.GL_GREATER, ALPHA_TEST_LIMIT); gl.glEnable(GL.GL_ALPHA_TEST); <... Bind texture ...> gl.glBindBuffer(GL.GL_ARRAY_BUFFER, <buffer id>); gl.glBindBuffer(GL.GL_ELEMENT_ARRAY_BUFFER, <buffer id>); gl.glDrawElements(GL.GL_POINTS, <size>, GL.GL_UNSIGNED_INT, 0); gl.glDisable(GL.GL_TEXTURE_2D); gl.glDisable(GL.GL_ALPHA_TEST); gl.glDisableVertexAttribArray(0); gl.glFlush(); Where the first buffer contains 12 million floats (the x,y,z coords of the 4 million textures) and the second (element) buffer contains 4 million integers. In this simple example it is simply the integers 0 through 3999999. I really want to know what is being done in software that is pegging my CPU, and how I can make it stop (if I can). My buffers are generated by the following code: gl.glBindBuffer(GL.GL_ARRAY_BUFFER, <buffer id>); gl.glBufferData(GL.GL_ARRAY_BUFFER, <size> * BufferUtil.SIZEOF_FLOAT, <buffer>, GL.GL_STATIC_DRAW); gl.glVertexAttribPointer(0, 3, GL.GL_FLOAT, false, 0, 0); and: gl.glBindBuffer(GL.GL_ELEMENT_ARRAY_BUFFER, <buffer id>); gl.glBufferData(GL.GL_ELEMENT_ARRAY_BUFFER, <size> * BufferUtil.SIZEOF_INT, <buffer>, GL.GL_STATIC_DRAW); ADDITIONAL INFO: Here is my initialization code: gl.setSwapInterval(1); //Also tried 0 gl.glShadeModel(GL.GL_SMOOTH); gl.glClearDepth(1.0f); gl.glEnable(GL.GL_DEPTH_TEST); gl.glDepthFunc(GL.GL_LESS); gl.glHint(GL.GL_PERSPECTIVE_CORRECTION_HINT, GL.GL_FASTEST); gl.glPointParameterfv(GL.GL_POINT_DISTANCE_ATTENUATION, POINT_DISTANCE_ATTENUATION, 0); gl.glPointParameterfv(GL.GL_POINT_SIZE_MIN, MIN_POINT_SIZE, 0); gl.glPointParameterfv(GL.GL_POINT_SIZE_MAX, MAX_POINT_SIZE, 0); gl.glPointSize(POINT_SIZE); gl.glTexEnvf(GL.GL_POINT_SPRITE, GL.GL_COORD_REPLACE, GL.GL_TRUE); gl.glEnable(GL.GL_POINT_SPRITE); gl.glClearColor(clearColor.getX(), clearColor.getY(), clearColor.getZ(), 0.0f); Also, I'm not sure if this helps or not, but when I drag the entire graph off the screen, the FPS shoots back up and the CPU usage falls to 0%. This seems obvious and intuitive to me, but I thought that might give a hint to someone else.

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• Tweaking Hudson memory usage

  - by rovarghe

  Hudson 3.1 has some performance optimizations that greatly reduces its memory footprint. Prior to this Hudson used to always hold the entire data model (all jobs and all builds) in memory which affected scalability. Some installations configured heap sizes in excess of 1GB to counteract this. Hudson 3.1.x maintains an MRU cache and only loads jobs and builds as they are required. Because of the inability to change existing APIs and be backward compatible with plugins, there were limits to how far we could go with this approach. Memory optimizations almost always come with a related cost, in this case its additional I/O that has to be performed to load data on request. On a small site that has frequent traffic, this is usually not noticeable since the MRU cache will usually hold on to all the data. A large site with infrequent traffic might experience some delays when the first request hits the server after a long gap. If you have a large heap and are able to allocate more memory, the cache settings can be adjusted to take advantage of this and even go back to pre-3.1 behavior. All the cache settings can be passed as options to the JVM container (Tomcat or the default Jetty container) using the -D option. There are two caches, independant of each other, one for Jobs and the other for Builds. For the jobs cache: hudson.jobs.cache.evict_in_seconds ( default=60 ) Seconds from last access (could be because of a servlet request or a background cron thread) a job should be purged from the cache. Set this to 0 to never purge based on time. hudson.jobs.cache.initial_capacity ( default=1024 ) Initial number of jobs the cache can accomodate. Setting this to the number of jobs you typically display on your Hudson landing page or home page will speed up consecutive access to that page. If the default is too large you may consider downsizing and using that memory for the Builds cache instead. hudson.jobs.cache.max_entries ( default=1024) Maximum number of jobs in the cache. The default is large enough for most installations, but if you find I/O activity when always accessing the hudson home page you might consider increasing this, but first verify if the I/O is caused by frequent eviction (see above), rather than by the cache not being large enough. For the builds cache: The builds cache is used to store Build objects as they are read from storage. Typically this happens when a user drills down into the details of a particular Job from the hudson hom epage. The cache is shared among builds for different jobs since in most installations all jobs are not accessed with the same frequency, so a per-job builds cache would be a waste of memory. hudson.job.builds.cache.evict_in_seconds ( default=60 ) Same as the equivalent Job cache, applied to Build. hudson.job.builds.cache.initial_capacity" ( default=512 ) Same as equivalent Job cache setting. Note the smaller initial size. If your site stores a large number of builds and has frequent access to more builds you might consider bumping this up. hudson.job.builds.cache.max_entries ( default=10240 ) The default max is large enough for most installations, the builds cache has bigger sized objects, so be careful about increasing the upper limit on this. See section on monitoring below. Sample usage: java -jar hudson-war-3.1.2-SNAPSHOT.war -Dhudson.jobs.cache.evict_in_seconds=300 \ -Dhudson.job.builds.cache.evict_in_seconds=300 Monitoring cache usage The 'jmap' tool that comes with the JDK can be used to monitor cache performance in an indirect way by looking at the number of Job and Build objects in each cache. Find the PID of the hudson instance and run $ jmap -histo:live <pid | grep 'hudson.model.*Lazy.*Key$' Here's a sample output: num #instances #bytes class name 523: 28 896 hudson.model.RunMap$LazyRunValue$Key 1200: 3 96 hudson.model.LazyTopLevelItem$Key These are the keys to the Jobs (LazyTopLevelItem$Key) and Builds (RunMap$LazyRunValue$Key) in the caches, so counting the number of keys is a good indicator of the number of items in the cache at any given moment. The size in bytes can be ignored, they are just the size of the keys, not the actual sizes of the objects they hold. Those sizes can only be obtained with a profiler. With the output above we can conclude that there are 3 jobs and 28 builds in memory. The 28 builds can all be from 1 job or all 3 jobs. Over time on an idle system, these should get evicted and memory cache should be empty. In practice, because of background cron threads and triggers, jobs rarely fall down to zero. Access of a job or a build by a cron thread resets the eviction timer.

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• MKMapView memory usage grows out of control with setRegion: calls

  - by Kurt

  Hi, I have a single MKMapView instance that I have programmatically added to a UIView. As part of the UI, the user can cycle through a list of addresses and the map view is updated to show the correct map for each address as the user goes through them. I create the map view once, and simply change what it displays with setRegion:animated:. The problem is that each time the map is changed to show a new address, the memory usage of my program increases by 200K-500K (as reported by Memory Monitor in Instruments). According to Object Allocations, it appears that a lot of 1.0K Mallocs are happening each time, and the Extended Detail pane for these 1.0K allocations shows that the Responsible Caller is convert_image_data and the Extended Detail pane shows that this is the result of [MKMapTileView drawLayer:inContext:]. So, seems likely to me that the memory usage is due to MKMapView not freeing memory it uses to redraw the map each time. In fact, when I don't display the map at all (by not even adding it as a subview of my main UIView) but still cycle through the addresses (which changes various UILabels and other displayed info) the memory usage for the app does NOT increase. If I add the map view but never update it with setRegion:, the memory also does NOT increase when changing to a new address. One more bit of info: if I go to a new address (and therefore ask the map to display the new address) the memory jumps as described above. However, if I go back to an address that was already displayed, the memory does not jump when the map redraws with the old address. Also, this happens on iPad (real device) with 3.2 and on iPhone (again, real device) with 3.1.2. Here's how I initialize the MKMapView (I only do this once): CGRect mapFrame; mapFrame.origin.y = 460; // yes, magic numbers. just for testing. mapFrame.origin.x = 0; mapFrame.size.height = 500; mapFrame.size.width = 768; mapView = [[MKMapView alloc] initWithFrame:mapFrame]; mapView.delegate = self; [self.view insertSubview:mapView atIndex:0]; And in response to the user selecting an address, I set the map like so: MKCoordinateRegion region; MKCoordinateSpan span; span.latitudeDelta=kStreetMapSpan; // 0.003 span.longitudeDelta=kStreetMapSpan; // 0.003 region.center = address.coords; // coords is CLLocationCoordinate2D region.span = span; mapView.region.span = span; [mapView setRegion:region animated:NO]; Any thoughts? I've scoured the net but haven't seen mention of this problem, and I've reached the limits of my Instruments knowledge. Thanks for any ideas.

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• Lots of questions about file I/O (reading/writing message strings)

  - by Nazgulled

  Hi, For this university project I'm doing (for which I've made a couple of posts in the past), which is some sort of social network, it's required the ability for the users to exchange messages. At first, I designed my data structures to hold ALL messages in a linked list, limiting the message size to 256 chars. However, I think my instructors will prefer if I save the messages on disk and read them only when I need them. Of course, they won't say what they prefer, I need to make a choice and justify the best I can why I went that route. One thing to keep in mind is that I only need to save the latest 20 messages from each user, no more. Right now I have an Hash Table that will act as inbox, this will be inside the user profile. This Hash Table will be indexed by name (the user that sent the message). The value for each element will be a data structure holding an array of size_t with 20 elements (20 messages like I said above). The idea is to keep track of the disk file offsets and bytes written. Then, when I need to read a message, I just need to use fseek() and read the necessary bytes. I think this could work nicely... I could use just one single file to hold all messages from all users in the network. I'm saying one single file because a colleague asked an instructor about saving the messages from each user independently which he replied that it might not be the best approach cause the file system has it's limits. That's why I'm thinking of going the single file route. However, this presents a problem... Since I only need to save the latest 20 messages, I need to discard the older ones when I reach this limit. I have no idea how to do this... All I know is about fread() and fwrite() to read/write bytes from/to files. How can I go to a file offset and say "hey, delete the following X bytes"? Even if I could do that, there's another problem... All offsets below that one will be completely different and I would have to process all users mailboxes to fix the problem. Which would be a pain... So, any suggestions to solve my problems? What do you suggest?

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• Make Bluetooth on Android 2.1 discoverable indefinitely

  - by kanov-baekonfat

  Hello all. I'm working on a research project which involves Bluetooth and the Android OS. I need to make Bluetooth discoverable indefinitely in order for the project to continue. The Problem: Android limits discoverability to 300 seconds. I cannot ask the user every 300 seconds to turn discoverability back on as my application is designed to run in the background without disturbing the user. As far as I am aware, there is no way to increase the time though Android's GUI. Some sources have called this a safety feature, others have called this a bug. There may be a bit of truth in both... What I'm Trying / Have Tried: I'm trying to edit a stable release of cyanogenmod to turn the discoverability timer off (it's possible; there's a configuration file that needs to have a single number changed). This isn't working because I'm having verification problems with the resulting package. During the past week, I downloaded the cyanogenmod source code, changed a relevant class in the hope that it would make Bluetooth discoverable indefinitely, and tried to recompile. This did not work because (a) the repo is frequently changed, leading to an unstable code base which fails to compile (OR, it could be that I'm using it incorrectly; just because it looked like it was the code's fault in many instances doesn't mean I should blame it for all the problems I encountered!) and (b) the repo decides to periodically "ignore" me (but not always, as I have gotten the code base before!), replying to my synchronization/connection attempts with: fatal: The remote end hung up unexpectedly As you might imagine, the above two issues are problematic and very frustrating to deal with. More Info: I'm running Android 2.1 via cyanogenmod (v5 I believe). This means the phone is also rooted. I have a developer phone, which means that the bootloader is unlocked. My phone is an HTC Magic (32B). The Big Question: How can I make Bluetooth indefinitely discoverable on Android? Thanks for your time and input. I feel like I'm spinning my tires on this issue and I'd like to move past it.

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• How to optimize Core Data query for full text search

  - by dk

  Can I optimize a Core Data query when searching for matching words in a text? (This question also pertains to the wisdom of custom SQL versus Core Data on an iPhone.) I'm working on a new (iPhone) app that is a handheld reference tool for a scientific database. The main interface is a standard searchable table view and I want as-you-type response as the user types new words. Words matches must be prefixes of words in the text. The text is composed of 100,000s of words. In my prototype I coded SQL directly. I created a separate "words" table containing every word in the text fields of the main entity. I indexed words and performed searches along the lines of SELECT id, * FROM textTable JOIN (SELECT DISTINCT textTableId FROM words WHERE word BETWEEN 'foo' AND 'fooz' ) ON id=textTableId LIMIT 50 This runs very fast. Using an IN would probably work just as well, i.e. SELECT * FROM textTable WHERE id IN (SELECT textTableId FROM words WHERE word BETWEEN 'foo' AND 'fooz' ) LIMIT 50 The LIMIT is crucial and allows me to display results quickly. I notify the user that there are too many to display if the limit is reached. This is kludgy. I've spent the last several days pondering the advantages of moving to Core Data, but I worry about the lack of control in the schema, indexing, and querying for an important query. Theoretically an NSPredicate of textField MATCHES '.*\bfoo.*' would just work, but I'm sure it will be slow. This sort of text search seems so common that I wonder what is the usual attack? Would you create a words entity as I did above and use a predicate of "word BEGINSWITH 'foo'"? Will that work as fast as my prototype? Will Core Data automatically create the right indexes? I can't find any explicit means of advising the persistent store about indexes. I see some nice advantages of Core Data in my iPhone app. The faulting and other memory considerations allow for efficient database retrievals for tableview queries without setting arbitrary limits. The object graph management allows me to easily traverse entities without writing lots of SQL. Migration features will be nice in the future. On the other hand, in a limited resource environment (iPhone) I worry that an automatically generated database will be bloated with metadata, unnecessary inverse relationships, inefficient attribute datatypes, etc. Should I dive in or proceed with caution?

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• Winform radiobutton data binding

  - by Rajarshi

  I am following the "Presentation Model" design pattern suggested by Martin Fowler for my GUI architecture in a Windows Forms project. "The essence of a Presentation Model is of a fully self-contained class that represents all the data and behavior of the UI window, but without any of the controls used to render that UI on the screen. A view then simply projects the state of the presentation model onto the glass...." - Martin Fowler Read more about this pattern at www.martinfowler.com/eaaDev/PresentationModel.html I am finding the concept very fluid and easy to understand except this one issue of data binding RadioButtons to properties on the Data/Domain object. Suposing I have a Windows Form with 3 radio buttons to depict some "Mode" options as - Auto Manual Import How can I use boolean properties on Data/Domain Objects to DataBind to these buttons? I have tried many ways but to no avail. For example I would like to code like - rbtnAutoMode.DataBindings.Add("Text", myBusinessObject, "IsAutoMode"); rbtnManualMode.DataBindings.Add("Text", myBusinessObject, "IsManualMode"); rbtnImportMode.DataBindings.Add("Text", myBusinessObject, "IsImportMode"); There should be a fourth property like "SelectedMode" on the data/domain object which at the end should depict a single value like "SelectedMode = Auto". I am trying to update this property when any of the "IsAutoMode", "IsManualMode" or "IsImportMode" is changed, e.g. through the property setters. I have INotifyPropertyChanged implemented on my data/domain object so, updating any data/domain object property automatically updates my UI controls, that's not an issue. There is a good example of binding 2 radio buttons here - http://stackoverflow.com/questions/344964/how-do-i-use-databinding-with-windows-forms-radio-buttons but I am missing the link while implementing the same with 3 buttons. I am having very erratic behaviors for the Radio Buttons. I hope I was able to explain reasonably. I am actually in a hurry and could not put a detailed code on post, but any help in this regard is appreciated. There is a simple solution to this issue by exposing a method like - public void SetMode(Modes mode) { this._selectedMode = mode; } which could be called from the "CheckedChanged" event of the Radio Buttons from the UI and would perfectly set the "SelectedMode" on the business object, but I need to stretch the limits to verify whether this can be done by DataBinding.

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• Scipy Negative Distance? What?

  - by disappearedng

  I have a input file which are all floating point numbers to 4 decimal place. i.e. 13359 0.0000 0.0000 0.0001 0.0001 0.0002` 0.0003 0.0007 ... (the first is the id). My class uses the loadVectorsFromFile method which multiplies it by 10000 and then int() these numbers. On top of that, I also loop through each vector to ensure that there are no negative values inside. However, when I perform _hclustering, I am continually seeing the error, "Linkage Z contains negative values". I seriously think this is a bug because: I checked my values, the values are no where small enough or big enough to approach the limits of the floating point numbers and the formula that I used to derive the values in the file uses absolute value (my input is DEFINITELY right). Can someone enligten me as to why I am seeing this weird error? What is going on that is causing this negative distance error? ===== def loadVectorsFromFile(self, limit, loc, assertAllPositive=True, inflate=True): """Inflate to prevent "negative" distance, we use 4 decimal points, so *10000 """ vectors = {} self.winfo("Each vector is set to have %d limit in length" % limit) with open( loc ) as inf: for line in filter(None, inf.read().split('\n')): l = line.split('\t') if limit: scores = map(float, l[1:limit+1]) else: scores = map(float, l[1:]) if inflate: vectors[ l[0]] = map( lambda x: int(x*10000), scores) #int might save space else: vectors[ l[0]] = scores if assertAllPositive: #Assert that it has no negative value for dirID, l in vectors.iteritems(): if reduce(operator.or_, map( lambda x: x < 0, l)): self.werror( "Vector %s has negative values!" % dirID) return vectors def main( self, inputDir, outputDir, limit=0, inFname="data.vectors.all", mappingFname='all.id.features.group.intermediate'): """ Loads vector from a file and start clustering INPUT vectors is { featureID: tfidfVector (list), } """ IDFeatureDic = loadIdFeatureGroupDicFromIntermediate( pjoin(self.configDir, mappingFname)) if not os.path.exists(outputDir): os.makedirs(outputDir) vectors = self.loadVectorsFromFile( limit, pjoin( inputDir, inFname)) for threshold in map( lambda x:float(x)/30, range(20,30)): clusters = self._hclustering(threshold, vectors) if clusters: outputLoc = pjoin(outputDir, "threshold.%s.result" % str(threshold)) with open(outputLoc, 'w') as outf: for clusterNo, cluster in clusters.iteritems(): outf.write('%s\n' % str(clusterNo)) for featureID in cluster: feature, group = IDFeatureDic[featureID] outline = "%s\t%s\n" % (feature, group) outf.write(outline.encode('utf-8')) outf.write("\n") else: continue def _hclustering(self, threshold, vectors): """function which you should call to vary the threshold vectors: { featureID: [ tfidf scores, tfidf score, .. ] """ clusters = defaultdict(list) if len(vectors) > 1: try: results = hierarchy.fclusterdata( vectors.values(), threshold, metric='cosine') except ValueError, e: self.werror("_hclustering: %s" % str(e)) return False for i, featureID in enumerate( vectors.keys()):

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• How to write this Linq SQL as a Dynamic Query (using strings)?

  - by Dr. Zim

  Skip to the "specific question" as needed. Some background: The scenario: I have a set of products with a "drill down" filter (Query Object) populated with DDLs. Each progressive DDL selection will further limit the product list as well as what options are left for the DDLs. For example, selecting a hammer out of tools limits the Product Sizes to only show hammer sizes. Current setup: I created a query object, sent it to a repository, and fed each option to a SQL "table valued function" where null values represent "get all products". I consider this a good effort, but far from DDD acceptable. I want to avoid any "programming" in SQL, hopefully doing everything with a repository. Comments on this topic would be appreciated. Specific question: How would I rewrite this query as a Dynamic Query? A link to something like 101 Linq Examples would be fantastic, but with a Dynamic Query scope. I really want to pass to this method the field in quotes "" for which I want a list of options and how many products have that option. from p in db.Products group p by p.ProductSize into g select new Category { PropertyType = g.Key, Count = g.Count() } Each DDL option will have "The selection (21)" where the (21) is the quantity of products that have that attribute. Upon selecting an option, all other remaining DDLs will update with the remaining options and counts. Edit: Additional notes: .OrderBy("it.City") // "it" refers to the entire record .GroupBy("City", "new(City)") // This produces a unique list of City .Select("it.Count()") //This gives a list of counts... getting closer .Select("key") // Selects a list of unique City .Select("new (key, count() as string)") // +1 to me LOL. key is a row of group .GroupBy("new (City, Manufacturer)", "City") // New = list of fields to group by .GroupBy("City", "new (Manufacturer, Size)") // Second parameter is a projection Product .Where("ProductType == @0", "Maps") .GroupBy("new(City)", "new ( null as string)")// Projection not available later? .Select("new (key.City, it.count() as string)")// GroupBy new makes key an object Product .Where("ProductType == @0", "Maps") .GroupBy("new(City)", "new ( null as string)")// Projection not available later? .Select("new (key.City, it as object)")// the it object is the result of GroupBy var a = Product .Where("ProductType == @0", "Maps") .GroupBy("@0", "it", "City") // This fails to group Product at all .Select("new ( Key, it as Product )"); // "it" is property cast though What I have learned so far is LinqPad is fantastic, but still looking for an answer. Eventually, completely random research like this will prevail I guess. LOL. Edit:

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• Scared of Calculus - Required to pass Differential Calculus as part of my Computer science major

  - by ke3pup

  Hi guys I'm finishing my Computer science degree in university but my fear of maths (lack of background knowledge) made me to leave all my maths units til' the very end which is now. i either take them on and pass or have to give up. I've passed all my programming units easily but knowing my poor maths skills won't do i've been staying clear of the maths units. I have to pass Differential Calculus and Linear Algebra first. With a help of book named "Linear Algebra: A Modern Introduction" i'm finding myself on track and i think i can pass the Linear Algebra unit. But with differential calculus i can't find a book to help me. They're either too advanced or just too simple for what i have to learn. The things i'm required to know for this units are: Set notation, the real number line, Complex numbers in cartesian form. Complex plane, modulus. Complex numbers in polar form. De Moivre’s Theorem. Complex powers and nth roots. Definition of ei? and ez for z complex. Applications to trigonometry. Revision of domain and range of a function Working in R3. Curves and surfaces. Functions of 2 variables. Level curves.Partial derivatives and tangent planes. The derivative as a difference quotient. Geometric significance of the derivative. Discussion of limit. Higher order partial derivatives. Limits of f(x,y). Continuity. Maxima and minima of f(x,y). The chain rule. Implicit differentiation. Directional derivatives and the gradient. Limit laws, l’Hoˆpital’s rule, composition law. Definition of sinh and cosh and their inverses. Taylor polynomials. The remainder term. Taylor series. Is there a book to help me get on track with the above? Being a student i can't buy too many books hence why i'm looking for a book that covers topics I need to know. The University library has a fairly limited collection which i took as loan but didn't find useful as it was too complex.

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