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  • MySql too many connections

    - by MichaelMcCabe
    I hate to bring up a question which is widely asked on the web, but I cant seem to solve it. I started a project a while back and after a month of testing, I hit a "Too many connections" error. I looked into it, and "Solved" it by increasing the max_connections. This then worked. Since then more and more people started to use it, and it hit again. When I am the only user on the site, i type "show processlist" and it comes up with about 50 connections which are still open (saying "Sleep" in the command). Now, I dont know enough to speculate why these are open, but in my code I tripple checked and every connection I open, I close. ie. public int getSiteIdFromName(String name, String company)throws DataAccessException,java.sql.SQLException{ Connection conn = this.getSession().connection(); Statement smt = conn.createStatement(); ResultSet rs=null; String query="SELECT id FROM site WHERE name='"+name+"' and company_id='"+company+"'"; rs=smt.executeQuery(query); rs.next(); int id=rs.getInt("id"); rs.close(); smt.close(); conn.close(); return id; } Every time I do something else on the site, another load of connections are opened and not closed. Is there something wrong with my code? and if not, what could be the problem?

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  • Which software for intranet CMS - Django or Joomla?

    - by zalun
    In my company we are thinking of moving from wiki style intranet to a more bespoke CMS solution. Natural choice would be Joomla, but we have a specific architecture. There is a few hundred people who will use the system. System should be self explainable (easier than wiki). We use a lot of tools web, applications and integrated within 3rd party software. The superior element which is a glue for all of them is API. In example for the intranet tools we do use Django, but it's used without ORM, kind of limited to templates and url - every application has an adequate methods within our API. We do not use the Django admin interface, because it is hardly dependent on ORM. Because of that Joomla may be hard to integrate. Every employee should be able to edit most of the pages, authentication and privileges have to be managed by our API. How hard is it to plug Joomla to use a different authentication process? (extension only - no hacks) If one knows Django better than Joomla, should Django be used?

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  • Should a setter return immediately if assigned the same value?

    - by Andrei Rinea
    In classes that implement INotifyPropertyChanged I often see this pattern : public string FirstName { get { return _customer.FirstName; } set { if (value == _customer.FirstName) return; _customer.FirstName = value; base.OnPropertyChanged("FirstName"); } } Precisely the lines if (value == _customer.FirstName) return; are bothering me. I've often did this but I am not that sure it's needed nor good. After all if a caller assigns the very same value I don't want to reassign the field and, especially, notify my subscribers that the property has changed when, semantically it didn't. Except saving some CPU/RAM/etc by freeing the UI from updating something that will probably look the same on the screen/whatever_medium what do we obtain? Could some people force a refresh by reassigning the same value on a property (NOT THAT THIS WOULD BE A GOOD PRACTICE HOWEVER)? 1. Should we do it or shouldn't we? 2. Why?

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  • Testing subpackage modules in Python 3

    - by Mitchell Model
    I have been experimenting with various uses of hierarchies like this and the differences between absolute and relative imports, and can't figure out how to do routine things with the package, subpackages, and modules without simply putting everything on sys.path. I have a two-level package hierarchy: MyApp __init__.py Application __init__.py Module1 Module2 ... Domain __init__.py Module1 Module2 ... UI __init__.py Module1 Module2 ... I want to be able to do the following: Run test code in a Module's "if main" when the module imports from other modules in the same directory. Have one or more test code modules in each subpackage that runs unit tests on the modules in the subpackage. Have a set of unit tests that reside in someplace reasonable, but outside the subpackages, either in a sibling package, at the top-level package, or outside the top-level package (though all these might end up doing is running the tests in each subpackage) "Enter" the structure from any of the three subpackage levels, e.g. run code that just uses Domain modules, run code that just uses Application modules, but Application uses code from both Application and Domain modules, and run code from GUI uses code from both GUI and Application; for instance, Application test code would import Application modules but not Domain modules. After developing the bulk of the code without subpackages, continue developing and testing after organizing the modules into this hierarchy. I know how to use relative imports so that external code that puts MyApp on its sys.path can import MyApp, import any subpackages it wants, and import things from their modules, while the modules in each subpackage can import other modules from the same subpackage or from sibling packages. However, the development needs listed above seem incompatible with subpackage structuring -- in other words, I can't have it both ways: a well-structured multi-level package hierarchy used from the outside and also used from within, in particular for testing but also because modules from one design level (in particular the UI) should not import modules from a design level below the next one down. Sorry for the long essay, but I think it fairly represents the struggles a lot of people have been having adopting to the new relative import mechanisms.

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  • How does the socket API accept() function work?

    - by Eli Bendersky
    The socket API is the de-facto standard for TCP/IP and UDP/IP communications (that is, networking code as we know it). However, one of its core functions, accept() is a bit magical. To borrow a semi-formal definition: accept() is used on the server side. It accepts a received incoming attempt to create a new TCP connection from the remote client, and creates a new socket associated with the socket address pair of this connection. In other words, accept returns a new socket through which the server can communicate with the newly connected client. The old socket (on which accept was called) stays open, on the same port, listening for new connections. How does accept work? How is it implemented? There's a lot of confusion on this topic. Many people claim accept opens a new port and you communicate with the client through it. But this obviously isn't true, as no new port is opened. You actually can communicate through the same port with different clients, but how? When several threads call recv on the same port, how does the data know where to go? I guess it's something along the lines of the client's address being associated with a socket descriptor, and whenever data comes through recv it's routed to the correct socket, but I'm not sure. It'd be great to get a thorough explanation of the inner-workings of this mechanism.

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  • [WEB] Local/Dev/Live deployment - best workflow

    - by Adam Kiss
    Hello, situation We our little company with 3 people, each has a localhost webserver and most projects (previous and current) are on one PC network shared disk. We have virtual server, where some of our clients' sites and our site. Our standard workflow is: Coder PC ? Programmer localhost ? dev domain (client.company.com) ? live version (client.com) It often happens, that there are two or three guys working on same projects at the same time - one is on dev version, two are on localhost. When finished, we try to synchronize the files on dev version and ideally not to mess (thanks ILMV:]) up any files, which *knock knock * doesn't happen often. And then one of us deploys dev version on live webserver. question we are looking for a way to simplify this workflow while updating websites - ideally some sort of diff uploader or VCS probably (Git/SVN/VCS/...), but we are not completely sure where to begin or what way would be ideal, therefore I ask you, fellow stackoverflowers for your experience with website / application deployment and recommended workflow. We probably will also need to use Mac in process, so if it won't be a problem, that would be even better. Thank you

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  • PHP: Profiling code and strict environment ~ Improving my coding

    - by DavidYell
    I would like to update my local working environment to be stricter in an effort to improve my code. I know that my code is okay, but as with most things there is always room for improvement. I use XAMPP on my local machine, for simplicities sake Apache Friends XAMPP (Basic Package) version 1.7.2 So I've updated my php.ini : error_reporting to be E_ALL | E_STRICT to help with the code standard. I've also enabled the XDebug extension zend_extension = "C:\xampp\php\ext\php_xdebug.dll" which seems to be working, having tested some broken code and got the nice standard orange error notice. However, having read this question, http://stackoverflow.com/questions/133686/what-is-the-best-way-to-profile-php-code and enabled the profiler, I cannot seem to create a cachegrind file. Many of the guides that I've looked at seem to think you need to install XDebug in XAMPP which leads me to think they are out of date, as XDebug is bundled with XAMPP these days. So I would appreciate it if anyone can help point me in the right direction with both configuring XDebug to output grind files, and or just a great set of default settings for the XDebug config in XAMPP. Seems there is very little documentation to go on. If people have tips on integrating these tools with Netbeans, that would be awesomesauce. I'm happy to get suggestions on other things that I can do to help tighten up my php code, both syntactically and performance wise Thanks, and apologies for the rambling question(s)! Ninja edit I should menion that I'm using named vhosts as my Apache configuration, which I think is why running XDebug on port 9000 isn't working for me. I guess I'd need to edit my vhost to include port 9000

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  • how would you like computer science classes to be taught?

    - by aaa
    hello I am a graduate student now, and hopefully someday I will teach. my interests are C++, Python, embedded languages, and scientific computing. Meanwhile I daydream about how I would teach. I was not quite happy with my undergraduate university as I found many computer science classes lacking. so I would like to ask you, if you were a student, how would you like your computer science classes to be taught? I understand it is a very subjective question, but nevertheless I think it's important to know what people want. Some specific points I am interested in: should computer languages be taught explicitly, or should students be required to pick up language on their own? what is better for learning, tests, projects, some sort of take-home exam? how do you think classtime should be used? theory, introduction, explanations, etc.? do you think the group projects are important? how much about computer architecture do you want to learn in computer science class, not necessarily assembler class. should particular operating system/editor be mandated or encouraged? Thanks thank you for your comments. Question has been closed because it is a discussion question rather than Q&A. If you know appropriate website for discussions of such sort with low noise ratio, please let me know.

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  • Use of Syntactic Sugar / Built in Functionality

    - by Kyle Rozendo
    I was busy looking deeper into things like multi-threading and deadlocking etc. The book is aimed at both pseudo-code and C code and I was busy looking at implementations for things such as Mutex locks and Monitors. This brought to mind the following; in C# and in fact .NET we have a lot of syntactic sugar for doing things. For instance (.NET 3.5): lock(obj) { body } Is identical to: var temp = obj; Monitor.Enter(temp); try { body } finally { Monitor.Exit(temp); } There are other examples of course, such as the using() {} construct etc. My question is when is it more applicable to "go it alone" and literally code things oneself than to use the "syntactic sugar" in the language? Should one ever use their own ways rather than those of people who are more experienced in the language you're coding in? I recall having to not use a Process object in a using block to help with some multi-threaded issues and infinite looping before. I still feel dirty for not having the using construct in there. Thanks, Kyle

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  • Selecting a whole database over an individual table to output to file

    - by Daniel Wrigley
    :::::::: EDIT :::::::: New code for people to have a look at, one question I have with this is where do I set were the *.gz file is saved? $backupFile = $dbname . date("Y-m-d-H-i-s") . '.gz'; $command = "mysqldump --opt -h $dbhost -u $dbuser -p $dbpass $dbname | gzip > $backupFile"; system($command); Also why the hell can you not reply yo your own post with answering it? :( :::::::: EDIT :::::::: Ok Im having trouble finding out how to select a full database for backup as an *.sql file rather than only an individual table. On the localhost I have several databases with one named "foo" and it is that which I want to backup and not any of the individual tables inside the database "foo". The code to connect to the database; //Database Information $dbhost = "localhost"; $dbname = "foo"; $dbuser = "bar"; $dbpass = "rulz"; //Connect to database mysql_connect ($dbhost, $dbuser, $dbpass) or die("Could not connect: ".mysql_error()); mysql_select_db($dbname) or die(mysql_error()); The code to backup the database; // Grab the time to know when this post was submitted $time = date('Y-m-d-H-i-s'); $tableName = 'foo'; $backupFile = '/sql/backup/'. $time .'.sql'; $query = "SELECT * INTO OUTFILE '". $backupFile ."' FROM ". $tableName .""; $result = mysql_query($query)or die("Database query died: " . mysql_error()); My brain is hurting near to the end of the day so no doubts i've missed something out very obvious. Thanks in advance to anyone helping me out.

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  • Using the Proxy pattern with C++ iterators

    - by Billy ONeal
    Hello everyone :) I've got a moderately complex iterator written which wraps the FindXFile apis on Win32. (See previous question) In order to avoid the overhead of constructing an object that essentially duplicates the work of the WIN32_FIND_DATAW structure, I have a proxy object which simply acts as a sort of const reference to the single WIN32_FIND_DATAW which is declared inside the noncopyable innards of the iterator. This is great because Clients do not pay for construction of irrelevant information they will probably not use (most of the time people are only interested in file names), and Clients can get at all the information provided by the FindXFile APIs if they need or want this information. This becomes an issue though because there is only ever a single copy of the object's actual data. Therefore, when the iterator is incrememnted, all of the proxies are invalidated (set to whatever the next file pointed to by the iterator is). I'm concerned if this is a major problem, because I can think of a case where the proxy object would not behave as somebody would expect: std::vector<MyIterator::value_type> files; std::copy(MyIterator("Hello"), MyIterator(), std::back_inserter(files)); because the vector contains nothing but a bunch of invalid proxies at that point. Instead, clients need to do something like: std::vector<std::wstring> filesToSearch; std::transform( DirectoryIterator<FilesOnly>(L"C:\\Windows\\*"), DirectoryIterator<FilesOnly>(), std::back_inserter(filesToSearch), std::mem_fun_ref(&DirectoryIterator<FilesOnly>::value_type::GetFullFileName) ); Seeing this, I can see why somebody might dislike what the standard library designers did with std::vector<bool>. I'm still wondering though: is this a reasonable trade off in order to achieve (1) and (2) above? If not, is there any way to still achieve (1) and (2) without the proxy?

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  • Practical refactoring using unit tests

    - by awhite
    Having just read the first four chapters of Refactoring: Improving the Design of Existing Code, I embarked on my first refactoring and almost immediately came to a roadblock. It stems from the requirement that before you begin refactoring, you should put unit tests around the legacy code. That allows you to be sure your refactoring didn't change what the original code did (only how it did it). So my first question is this: how do I unit-test a method in legacy code? How can I put a unit test around a 500 line (if I'm lucky) method that doesn't do just one task? It seems to me that I would have to refactor my legacy code just to make it unit-testable. Does anyone have any experience refactoring using unit tests? And, if so, do you have any practical examples you can share with me? My second question is somewhat hard to explain. Here's an example: I want to refactor a legacy method that populates an object from a database record. Wouldn't I have to write a unit test that compares an object retrieved using the old method, with an object retrieved using my refactored method? Otherwise, how would I know that my refactored method produces the same results as the old method? If that is true, then how long do I leave the old deprecated method in the source code? Do I just whack it after I test a few different records? Or, do I need to keep it around for a while in case I encounter a bug in my refactored code? Lastly, since a couple people have asked...the legacy code was originally written in VB6 and then ported to VB.NET with minimal architecture changes.

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  • How to motivate as a project leader?

    - by Zenzen
    Ok so some of you might think this is not stackoverflow related, but since I got a similar question during an interview (for a J2EE dev position) I think you guys will help me in the end. The situation is simple: you're working on a project in a small group (4-5 people), you're the project leader and the guy who's the most competent (technology wise) is also slacking the most. What do you do to motivate him? The problem is, I'm having the same issue at the university - this semester we have a lot of projects going on (6 to be exact) so we decided to dived the work so everyone will do 1-2 projects in a technology he knows/wants to learn. It's been working well for the most part, the problem is the person whom we thought would finish his project way before us as he's the most experienced among us. How am I supposed to make him do his share properly? Till now he was just half assing his part by doing the bare minimum, with which the professor wasn't really pleased to say the least... Now it's only a university project, but in the future I might have the same problem in a real job and losing a really smart and experienced worker (as firing him is the only solution I can come up with now) would really be a waste. Aren't there any better ways? p.s. now that I think about it, are there any books that would help me in becoming a better project manager?

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  • Comprehending the Semantic web and it's methods, syntax, vocabularies and languages

    - by DreamCodeR
    Hi. I have just been introduced to the semantic web and it's family of functions but I have a hard time understanding some of it, which I was hoping someone could explain to me. As far as I've understood, RDF can be written in several syntaxes. RDF/XML, Turtle, etc. Now, I understand XML. How it is presented and how it can be parsed. However, some people write in the turtle syntax, but how do they parse that information? I can't seem to find a single library for any language to "extract" the information written in a turtle syntax into another form. The same goes for N3. How can it be used? Executed or else? I seem to be able to understand RDFa. That it is a way to implement RDF into XHTML. For me that is a way to implement RDF into "something". But how can I compare that to turtle, N3, or the like? Thanks in advance.

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  • What is the optimum way to secure a company wide wiki?

    - by Mark Robinson
    We have a wiki which is used by over half our company. Generally it has been very positively received. However, there is a concern over security - not letting confidential information fall into the wrong hands (i.e. competitors). The default answer is to create a complicated security matrix defining who can read what document (wiki page) based on who created it. Personally I think this mainly solves the wrong problem because it creates barriers within the company instead of a barrier to the external world. But some are concerned that people at a customer site might share information with a customer which then goes to the competitor. The administration of such a matrix is a nightmare because (1) the matrix is based on department and not projects (this is a matrix organisation), and (2) because in a wiki all pages are by definition dynamic so what is confidential today might not be confidential tomorrow (but the history is always readable!). Apart from the security matrix, we've considered restricting content on the wiki to non super secret stuff, but off course that needs to be monitored. Another solution (the current) is to monitor views and report anything suspicious (e.g. one person at a customer site having 2000 views in two days was reported). Again - this is not ideal because this does not directly imply a wrong motive. Does anyone have a better solution? How can a company wide wiki be made secure and yet keep its low threshold USP? BTW we use MediaWiki with Lockdown to exclude some administrative staff.

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  • Powerpoint displays a "can't start the application" error when an Excel Chart object is embedded in

    - by A9S6
    This is a very common problem when Excel Worksheet or Chart is embedded into Word or Powerpoint. I am seeing this problem in both Word and Powerpoint and the reason it seems is the COM addin attached to Excel. The COM addin is written in C# (.NET). See the attached images for error dialogs. I debugged the addin and found a very strange behavior. The OnConnection(...), OnDisConnection(...) etc methods in the COM addin works fine until I add an event handler to the code. i.e. handle the Worksheet_SheetChange, SelectionChange or any similar event available in Excel. As soon as I add even a single event handler (though my code has several), Word and Powerpoint start complaining and do not Activate the embedded object. On some of the posts on the internet, people have been asked to remove the anti-virus addins for office (none in my case) so this makes me believe that the problem is somewhat related to COM addins which are loaded when the host app activates the object. Does anyone have any idea of whats happening here?

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  • User preferences using SQL and JavaScript

    - by Shyam
    Hi, I am using Server Side JavaScript - yes, I am actually using Server Side JavaScript. To complexify things even more, I use Oracle as a backend database (10g). With some crazy XSLT and mutant-like HTML generation, I can build really fancy web forms - yes, I am aware of Rails and other likewise frameworks and I choose the path of horror instead. I have no JQuery or other fancy framework at my disposal, just plain ol' JavaScript that should be supported by the underlying engine called Mozilla Rhino. Yes, it is insane and I love it. So, I have a bunch of tables at my disposal and some of them are filled with associative keys that link to values. As I am a people pleaser, I want to add some nifty user-preference driven solutions. My users have all an unique user_id and this user_id is available during the entire session. My initial idea is to have a user preference table, where I have "three" columns: user_id, feature and pref_string. Using a delimiter, such as : or - (haven't thought about a suitable one yet), I could like store a bunch of preferences as a list and store its elements inside an array using the .split-method (similar like the PHP-explode function). The feature column could be like the table name or some identifier for the "feature" i want to link preferences too. I hate hardcoding objects, especially as I want to be able to back these up and reuse this functionality application-wide. Of course I would love better ideas, just keep in mind I cannot just add a library that easily. These preferences could be like "joined" to the table, so I can query it and use its values. I hope it doesn't sounds too complex, because well.. its basically something really simple I need. Thanks!

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  • php fopen function dies, though I have file permissions set to read and write

    - by Matthew Robert Keable
    I'm following a tutorial on php, and am having difficulty getting this to work. I set the appropriate directory permissions to read and write, but every time I run this, I get the die string. The code is: $ourFileName = "testFile.txt"; $ourFileHandle = fopen($ourFileName, 'w') or die("can't open file"); fclose($ourFileHandle); As far as my basic understanding goes, if "testFile.txt" does not exist, fopen should create that file (I have basic knowledge of Python, and remember this same principle in that language). But it...it doesn't. Even if I create the aforementioned file, and put it up, that line of code still returns a die string. My hosting account does not give me permission to execute. Is this a problem? My server runs on Windows. I am using Dreamweaver CS5, on OSX 10.5.8. I've done some searching on this, and see other people having similar issues - but none of them keyed to exactly my range of problems. Being that I'm a beginner, I feel that it might be something I'm overlooking. Thanks!!

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  • How to process AJAX requests more securely in PHP?

    - by animuson
    Ok, so I want to send AJAX requests to my website from my Flash games to process data, but I don't want people downloading them, decompiling them, then sending fake requests to be processed, so I'm trying to figure out the most secure way to process in the PHP files. My first idea was to use Apache's built in Authorization module to require a username and password to access the pages on a separate subdomain of my website, but then you'd have to include that username and password in the AJAX request anyway so that seems kind of pointless to even try. My current option looks pretty promising but I want to make sure it will work. Basically it just checks the IP address being sent using REMOTE_ADDR to make sure it's the IP address that my server runs on. <? $allowed = new Array("64.120.211.89", "64.120.211.90"); if (!in_array($_SERVER['REMOTE_ADDR'], $allowed)) header("HTTP/1.1 403 Forbidden"); ?> Both of those IP addresses point to my server. Things I'm worried about: 1) If I send a request from Flash/ActionScript, will that affect the IP address in any way? 2) Is it possible for malicious users to change the IP address that is being sent with REMOTE_ADDR to one of my IP addresses? Any other ways you would suggest that might be more secure?

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  • What can cause Bonjour to not call me back during browsing?

    - by millenomi
    I have a rather popular Bonjour-based application in App Store. It works perfectly, but around 0.2% of my users report a bizarre bug: "no arrows appear on the edges of the screen, so I can't share stuff with other people!". Needless to say, displaying these arrows is tied to the browsing of a particular Bonjour service on the local domain. The problem is, the Apple review team seems to intermittently happen to be in this 0.2%. This isn't good for review results, as you might imagine. No matter how much I try, I cannot reproduce this bug. From the few logs I have, it looks like my app is running correctly, just not receiving NSNetServiceBrowser delegate calls. What can cause this? Things I've tried: Having a shorter service name < 14 chars in length to be in spec. Publishing on @"local." rather than @"" (aka Go Look For The Default Registration Domain). My app is rather useless on a wide-area network anyway. Things I haven't tried: restarting the browsing machinery periodically. (I have two browsers, though, one looking for the legacy longer name, one for the new shorter one.) What to do?

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  • WYSIWYG in Doxygen

    - by Adam Shiemke
    I'm working on a fairly large project written in C. The idea was to build a library of modular blocks that can be reused across several platforms. Each module is assocaited with a word document in .docx format (huge pain to diff-merge). In these docs, an interface section is specified, listing datatypes and publicly accessable functions. These were often inconsistant with the actual implementation in code, and wading through all this documentation was a pain. I've been working to switch to doxygen to simplify document managemnet. I haven't found a good way to embed the previously written documentation into the doxygen output. I've copy-pasted them into sections and used modules to group the sources together, but the document sections look ugly in the comments (the output is pretty) and since doxygen takes a while to parse through our code (about 30 mins), validating formatting is a pain. Is there some way to WYSIWIG large blocks of documentation into doxygen? I feel this would improve the number of people documenting their code, and the quality of that documentation. I considered linking to html, but that splits out the documentation. I also considered putting them inline in html, but this also seems like a pain and would mean everyone needs a WYSIWIG HTML edditor (or some html skillz). Any ideas on how to make things easier and prettier? Thanks loads.

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  • Is it possible to use SqlGeography with Linq to Sql?

    - by cofiem
    I've been having quite a few problems trying to use Microsoft.SqlServer.Types.SqlGeography. I know full well that support for this in Ling to Sql is not great. I've tried numerous ways, beginning with what would the expected way (Database type of geography, CLR type of SqlGeography). This produces the NotSupportedException, which is widely discussed via blogs. I've then gone down the path of treating the geography column as a varbinary(max), as geography is a UDT stored as binary. This seems to work fine (with some binary reading and writing extension methods). However, I'm now running into a rather obscure issue, which does not seem to have happened to many other people. System.InvalidCastException: Unable to cast object of type 'Microsoft.SqlServer.Types.SqlGeography' to type 'System.Byte[]'. This error is thrown from an ObjectMaterializer when iterating through a query. It seems to only occur when the tables containing geography columns are included in a query implicitly (ie. using the EntityRef<> properties to do joins). System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext() My question: If I'm retrieving the geography column as varbinary(max), I might expect the reverse error: can't cast byte[] to SqlGeography. That I would understand. This I don't. I do have some properies on the partial LINQ to SQL classes that hide the binary conversion... could those be the issue? Any help appreciated, and I know there's probably not enough information.

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  • Technical choices in unmarshaling hash-consed data

    - by Pascal Cuoq
    There seems to be quite a bit of folklore knowledge floating about in restricted circles about the pitfalls of hash-consing combined with marshaling-unmarshaling of data. I am looking for citable references to these tidbits. For instance, someone once pointed me to library aterm and mentioned that the authors had clearly thought about this and that the representation on disk was bottom-up (children of a node come before the node itself in the data stream). This is indeed the right way to do things when you need to re-share each node (with a possible identical node already in memory). This re-sharing pass needs to be done bottom-up, so the unmarshaling itself might as well be, too, so that it's possible to do everything in a single pass. I am in the process of describing difficulties encountered in our own context, and the solutions we found. I would appreciate any citable reference to the kind of aforementioned folklore knowledge. Some people obviously have encountered the problems before (the aterm library is only one example). But I didn't find anything in writing. Even the little piece of information I have about aterm is hear-say. I am not worried it's not reliable (you can't make this up), but "personal communication" and "look how it's done in the source code" are considered poor form in citations. I have enough references on hash-consing alone. I am only interested in references where it interferes with other aspects of programming, such as marshaling or distribution.

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  • Looking for a fast, compact, streamable, multi-language, strongly typed serialization format

    - by sanity
    I'm currently using JSON (compressed via gzip) in my Java project, in which I need to store a large number of objects (hundreds of millions) on disk. I have one JSON object per line, and disallow linebreaks within the JSON object. This way I can stream the data off disk line-by-line without having to read the entire file at once. It turns out that parsing the JSON code (using http://www.json.org/java/) is a bigger overhead than either pulling the raw data off disk, or decompressing it (which I do on the fly). Ideally what I'd like is a strongly-typed serialization format, where I can specify "this object field is a list of strings" (for example), and because the system knows what to expect, it can deserialize it quickly. I can also specify the format just by giving someone else its "type". It would also need to be cross-platform. I use Java, but work with people using PHP, Python, and other languages. So, to recap, it should be: Strongly typed Streamable (ie. read a file bit by bit without having to load it all into RAM at once) Cross platform (including Java and PHP) Fast Free (as in speech) Any pointers?

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  • Why does Tex/Latex not speed up in subsequent runs?

    - by Debilski
    I really wonder, why even recent systems of Tex/Latex do not use any caching to speed up later runs. Every time that I fix a single comma*, calling Latex costs me about the same amount of time, because it needs to load and convert every single picture file. (* I know that even changing a tiny comma could affect the whole structure but of course, a well-written cache format could see the impact of that. Also, there might be situations where 100% correctness is not needed as long as it’s fast.) Is there something in the language of Tex which makes this complicated or impossible to accomplish or is it just that in the original implementation of Tex, there was no need for this (because it would have been slow anyway on those large computers)? But then on the other hand, why doesn’t this annoy other people so much that they’ve started a fork which has some sort of caching (or transparent conversion of Tex files to a format which is faster to parse)? Is there anything I can do to speed up subsequent runs of Latex? Except from putting all the stuff into chapterXX.tex files and then commenting them out?

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