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• Code golf - hex to (raw) binary conversion

  - by Alnitak

  In response to this question asking about hex to (raw) binary conversion, a comment suggested that it could be solved in "5-10 lines of C, or any other language." I'm sure that for (some) scripting languages that could be achieved, and would like to see how. Can we prove that comment true, for C, too? NB: this doesn't mean hex to ASCII binary - specifically the output should be a raw octet stream corresponding to the input ASCII hex. Also, the input parser should skip/ignore white space. edit (by Brian Campbell) May I propose the following rules, for consistency? Feel free to edit or delete these if you don't think these are helpful, but I think that since there has been some discussion of how certain cases should work, some clarification would be helpful. The program must read from stdin and write to stdout (we could also allow reading from and writing to files passed in on the command line, but I can't imagine that would be shorter in any language than stdin and stdout) The program must use only packages included with your base, standard language distribution. In the case of C/C++, this means their respective standard libraries, and not POSIX. The program must compile or run without any special options passed to the compiler or interpreter (so, 'gcc myprog.c' or 'python myprog.py' or 'ruby myprog.rb' are OK, while 'ruby -rscanf myprog.rb' is not allowed; requiring/importing modules counts against your character count). The program should read integer bytes represented by pairs of adjacent hexadecimal digits (upper, lower, or mixed case), optionally separated by whitespace, and write the corresponding bytes to output. Each pair of hexadecimal digits is written with most significant nibble first. The behavior of the program on invalid input (characters besides [a-fA-F \t\r\n], spaces separating the two characters in an individual byte, an odd number of hex digits in the input) is undefined; any behavior (other than actively damaging the user's computer or something) on bad input is acceptable (throwing an error, stopping output, ignoring bad characters, treating a single character as the value of one byte, are all OK) The program may write no additional bytes to output. Code is scored by fewest total bytes in the source file. (Or, if we wanted to be more true to the original challenge, the score would be based on lowest number of lines of code; I would impose an 80 character limit per line in that case, since otherwise you'd get a bunch of ties for 1 line).

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• Implementing a logging library in .NET with a database as the storage medium

  - by Dave

  I'm just starting to work on a logging library that everyone can use to keep track of any sort of system information while the user is running our application. The simplest example so far is to track Info, Warnings, and Errors. I want all plugins to be able to use this feature, but since each developer might have a different idea of what's important to report, I want to keep this as generic as possible. In the C++ world, I would normally use something like a stl::pair<string,string> to act as a key value pair structure, and have a stl::list of these to act as a "row" in the log. The log cache would then be a list<list<pair<string,string>>> (ugh!). This way, the developers can use a const string key like INFO, WARNING, ERROR to have a consistent naming for a column in the database (for SELECTing specific types of information). I'd like the database to be able to deal with any number of distinct column names. For example, John might have an INFO row with a column called USER, and Bill might have an INFO row with a column called FILENAME. I want the log viewer to be able to display all information, and if one report doesn't have a value for INFO / FILENAME, those fields should just appear blank. So one option is to use List<List<KeyValuePair<String,String>>, and the another is to have the log library consumer somehow "register" its schema, and then have the database do an ALTER TABLE to handle this situation. Yet another idea is to have a table that's just for key value pairs, with a foreign key that maps the key value pairs back to the original log entry. I obviously don't want logging to bog down the system, so I only lock the log cache to make a copy of the data (and remove the already-copied data), then a background thread will dump the information to the database. My specific questions regarding this are: Do you see any performance issues? In other words, have you ever tried something like this and found that certain things just don't work well in practice? Is there a more .NETish way to implement the key value pairs, other than List<List<KeyValuePair<String,String>>>? Even if there is a way to do #2 better, is the ALTER TABLE idea I proposed above a Bad Thing? Would you recommend multiple databases over a single one? I don't yet have an idea of how frequently the log would get written to, but we ideally would like to have lots of low level information. Perhaps there should be a DB with a fixed schema only for the low level stuff, and then another DB that's more flexible for reporting information back to users.

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• Why does my Perl regular expression only find the last occurrence?

  - by scharan

  I have the following input to a Perl script and I wish to get the first occurrence of NAME="..." strings in each of the <table>...</table> structures. The entire file is read into a single string and the regex acts on that input. However, the regex always returns the last occurrence of NAME="..." strings. Can anyone explain what is going on and how this can be fixed? Input file: ADSDF <TABLE> NAME="ORDERSAA" line1 line2 NAME="ORDERSA" line3 NAME="ORDERSAB" </TABLE> <TABLE> line1 line2 NAME="ORDERSB" line3 </TABLE> <TABLE> line1 line2 NAME="ORDERSC" line3 </TABLE> <TABLE> line1 line2 NAME="ORDERSD" line3 line3 line3 </TABLE> <TABLE> line1 line2 NAME="QUOTES2" line3 NAME="QUOTES3" NAME="QUOTES4" line3 NAME="QUOTES5" line3 </TABLE> <TABLE> line1 line2 NAME="QUOTES6" NAME="QUOTES7" NAME="QUOTES8" NAME="QUOTES9" line3 line3 </TABLE> <TABLE> NAME="MyName IsKhan" </TABLE> Perl Code starts here: use warnings; use strict; my $nameRegExp = '(<table>((NAME="(.+)")|(.*|\n))*</table>)'; sub extractNames($$){ my ($ifh, $ofh) = @_; my $fullFile; read ($ifh, $fullFile, 1024);#Hardcoded to read just 1024 bytes. while( $fullFile =~ m#$nameRegExp#gi){ print "found: ".$4."\n"; } } sub main(){ if( ($#ARGV + 1 )!= 1){ die("Usage: extractNames infile\n"); } my $infileName = $ARGV[0]; my $outfileName = $ARGV[1]; open my $inFile, "<$infileName" or die("Could not open log file $infileName"); my $outFile; #open my $outFile, ">$outfileName" or die("Could not open log file $outfileName"); extractNames( $inFile, $outFile ); close( $inFile ); #close( $outFile ); } #call main();

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• Scalable Database Tagging Schema

  - by Longpoke

  EDIT: To people building tagging systems. Don't read this. It is not what you are looking for. I asked this when I wasn't aware that RDBMS all have their own optimization methods, just use a simple many to many scheme. I have a posting system that has millions of posts. Each post can have an infinite number of tags associated with it. Users can create tags which have notes, date created, owner, etc. A tag is almost like a post itself, because people can post notes about the tag. Each tag association has an owner and date, so we can see who added the tag and when. My question is how can I implement this? It has to be fast searching posts by tag, or tags by post. Also, users can add tags to posts by typing the name into a field, kind of like the google search bar, it has to fill in the rest of the tag name for you. I have 3 solutions at the moment, but not sure which is the best, or if there is a better way. Note that I'm not showing the layout of notes since it will be trivial once I get a proper solution for tags. Method 1. Linked list tagId in post points to a linked list in tag_assoc, the application must traverse the list until flink=0 post: id, content, ownerId, date, tagId, notesId tag_assoc: id, tagId, ownerId, flink tag: id, name, notesId Method 2. Denormalization tags is simply a VARCHAR or TEXT field containing a tab delimited array of tagId:ownerId. It cannot be a fixed size. post: id, content, ownerId, date, tags, notesId tag: id, name, notesId Method 3. Toxi (from: http://www.pui.ch/phred/archives/2005/04/tags-database-schemas.html, also same thing here: http://stackoverflow.com/questions/20856/how-do-you-recommend-implementing-tags-or-tagging) post: id, content, ownerId, date, notesId tag_assoc: ownerId, tagId, postId tag: id, name, notesId Method 3 raises the question, how fast will it be to iterate through every single row in tag_assoc? Methods 1 and 2 should be fast for returning tags by post, but for posts by tag, another lookup table must be made. The last thing I have to worry about is optimizing searching tags by name, I have not worked that out yet. I made an ASCII diagram here: http://pastebin.com/f1c4e0e53

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• Need a fast programming language that can drive two printers

  - by Pete

  I have a rather unusual application that isn't working the way I need, and I hope someone here will have some suggestions or at least a direction to investigate. We have a museum exhibit that has a computer at the entrance driving two small receipt printers. There are two buttons on a console, wired to the left and right buttons of a disemboweled mouse. The two printers and associated buttons are for girls and boys, each button does a random selection from a database of names and prints a small ticket on the appropriate printer with a graphic image, a few words about the exhibit and the randomly chosen name. Conceptually all is well, but it hangs quite often. I got the project at the last minute, because the original designer got bogged down and couldn't deliver, so the exhibit's author asked me the day before opening, whether I could write something that would work. I did it in Word, since I am an experienced VBA programmer. Several other avenues I attempted first all lead to dead ends - one couldn't do graphics, another couldn't handle two printers, yet another couldn't change fonts and so on. The problem is that it simply isn't fast enough - Word can only drive one printer at a time and changing the active printer takes a long time. Not by office standards, where a second or two of delay before a printer starts working on your document is not an issue, but here I need more or less instant response. If kids press a button and nothing happens, they press it over and over until something does happen, resulting in maybe half a dozen commands being sent before the printer starts reacting. Sometimes it jams the program completely, since boys and girls will be pressing the two buttons simultaneously and Word locks up, and even when it doesn't jam, the printers then spit out a stream of tickets, making a mess. The kids start squabbling over which ticket is whose, pulling them out of the printers, snarling the paper tape, jamming the printer and generally making a mess of the whole affair, often necessitating the exhibit caretakers having to restart the computer and clear torn bits of paper out the printers. What I need is some sort of fast programming language that can drive two printers *-simultaneously-*, not the MSOffice claptrap of having to switch the active printer, that can react to both left and right mouse button click events, can print a small graphic image and can print in different font sizes and styles and. I don't need many, but it's not all in one typeface. Can anyone suggest what I might use for this? I don't even know if it's possible at all under Windows, whether the "single active printer" garbage is an Office artifact, or a Windows restriction. My little Commodore-64 twenty-five years ago had two printers attached to it and drove both simultaneously with no difficulties - it doesn't seem to me it should be such an impossible requirement today.

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• Windows Question: RunOnce/Second Boot Issues [closed]

  - by Greg

  Moved to Super User: Windows Question: RunOnce/Second Boot Issues I am attempting to create a Windows XP SP3 image that will run my application on Second Boot. Here is the intended workflow. 1) Run Image Prep Utility (I wrote) on windows to add my runonce entries and clean a few things up. 2) Reboot to ghost, make image file. 3) Package into my ISO and distribute. 4) System will be imaged by user. 5) On first boot, I have about 5 things that run, one of which includes a driver updater (I wrote) for my own specific devices. 6) One of the entries inside of HKCU/../runonce is a reg file, which adds another key to HKLM/../runonce. This is how second boot is acquired. 7) As a result of the driver updater, user is prompted to reboot. 8) My application is then launched from HKLM/../runonce on second boot. This workflow works perfectly, except for a select few legacy systems that contain devices that cause the add hardware wizard to pop up. When the add hardware wizard pops up is when I begin to see problems. It's important to note, that if I manually inspect the registry after the add hardware wizard pops up, it appears as I would expect, with all the first boot scripts having run, and it's sitting in a state I would correctly expect it to be in for a second boot scenario. The problem comes when I click next on the add hardware wizard, it seems to re-run the single entry I've added, and re-executes the runonce scripts. (only one script now as it's already executed and cleared out the initial entries). This causes my application to open as if it were a second boot, only when next is clicked on the add hardware wizard. If I click cancel, and reboot, then it also works as expected. I don't care as much about other solutions, because I could design a system that doesn't fully rely on Microsoft's registry. I simply can't find any information as to WHY this is happening. I believe this is some type of Microsoft issue that's presenting itself as a result of an overstretched image that's expected to support too many legacy platforms, but any help that can be provided would be appreciated. Thanks,

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• SQL Server CTE referred in self joins slow

  - by Kharlos Dominguez

  Hello, I have written a table-valued UDF that starts by a CTE to return a subset of the rows from a large table. There are several joins in the CTE. A couple of inner and one left join to other tables, which don't contain a lot of rows. The CTE has a where clause that returns the rows within a date range, in order to return only the rows needed. I'm then referencing this CTE in 4 self left joins, in order to build subtotals using different criterias. The query is quite complex but here is a simplified pseudo-version of it WITH DataCTE as ( SELECT [columns] FROM table INNER JOIN table2 ON [...] INNER JOIN table3 ON [...] LEFT JOIN table3 ON [...] ) SELECT [aggregates_columns of each subset] FROM DataCTE Main LEFT JOIN DataCTE BananasSubset ON [...] AND Product = 'Bananas' AND Quality = 100 LEFT JOIN DataCTE DamagedBananasSubset ON [...] AND Product = 'Bananas' AND Quality < 20 LEFT JOIN DataCTE MangosSubset ON [...] GROUP BY [ I have the feeling that SQL Server gets confused and calls the CTE for each self join, which seems confirmed by looking at the execution plan, although I confess not being an expert at reading those. I would have assumed SQL Server to be smart enough to only perform the data retrieval from the CTE only once, rather than do it several times. I have tried the same approach but rather than using a CTE to get the subset of the data, I used the same select query as in the CTE, but made it output to a temp table instead. The version referring the CTE version takes 40 seconds. The version referring the temp table takes between 1 and 2 seconds. Why isn't SQL Server smart enough to keep the CTE results in memory? I like CTEs, especially in this case as my UDF is a table-valued one, so it allowed me to keep everything in a single statement. To use a temp table, I would need to write a multi-statement table valued UDF, which I find a slightly less elegant solution. Did some of you had this kind of performance issues with CTE, and if so, how did you get them sorted? Thanks, Kharlos

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• objective C convert NSString to unsigned

  - by user1501354

  I have changed my question. I want to convert an NSString to an unsigned int. Why? Because I want to do parallel payment in PayPal. Below I have given my coding in which I want to convert the NSString to an unsigned int. My query is: //optional, set shippingEnabled to TRUE if you want to display shipping //options to the user, default: TRUE [PayPal getPayPalInst].shippingEnabled = TRUE; //optional, set dynamicAmountUpdateEnabled to TRUE if you want to compute //shipping and tax based on the user's address choice, default: FALSE [PayPal getPayPalInst].dynamicAmountUpdateEnabled = TRUE; //optional, choose who pays the fee, default: FEEPAYER_EACHRECEIVER [PayPal getPayPalInst].feePayer = FEEPAYER_EACHRECEIVER; //for a payment with multiple recipients, use a PayPalAdvancedPayment object PayPalAdvancedPayment *payment = [[PayPalAdvancedPayment alloc] init]; payment.paymentCurrency = @"USD"; // A payment note applied to all recipients. payment.memo = @"A Note applied to all recipients"; //receiverPaymentDetails is a list of PPReceiverPaymentDetails objects payment.receiverPaymentDetails = [NSMutableArray array]; NSArray *emailArray = [NSArray arrayWithObjects:@"[email protected]",@"[email protected]", nil]; for (int i = 1; i <= 2; i++) { PayPalReceiverPaymentDetails *details = [[PayPalReceiverPaymentDetails alloc] init]; // Customize the payment notes for one of the three recipient. if (i == 2) { details.description = [NSString stringWithFormat:@"Component %d", i]; } details.recipient = [NSString stringWithFormat:@"%@",[emailArray objectAtIndex:i-1]]; unsigned order; if (i==1) { order = [[feeArray objectAtIndex:0] unsignedIntValue]; } if (i==2) { order = [[amountArray objectAtIndex:0] unsignedIntValue]; } //subtotal of all items for this recipient, without tax and shipping details.subTotal = [NSDecimalNumber decimalNumberWithMantissa:order exponent:-4 isNegative:FALSE]; //invoiceData is a PayPalInvoiceData object which contains tax, shipping, and a list of PayPalInvoiceItem objects details.invoiceData = [[PayPalInvoiceData alloc] init]; //invoiceItems is a list of PayPalInvoiceItem objects //NOTE: sum of totalPrice for all items must equal details.subTotal //NOTE: example only shows a single item, but you can have more than one details.invoiceData.invoiceItems = [NSMutableArray array]; PayPalInvoiceItem *item = [[PayPalInvoiceItem alloc] init]; item.totalPrice = details.subTotal; [details.invoiceData.invoiceItems addObject:item]; [payment.receiverPaymentDetails addObject:details]; } [[PayPal getPayPalInst] advancedCheckoutWithPayment:payment]; Can anybody tell me how to do this conversion? Thanks and regards in advance.

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• Selecting the contents of an ASP.NET TextBox in an UpdatePanel after a partial page postback

  - by Scott Mitchell

  I am having problems selecting the text within a TextBox in an UpdatePanel. Consider a very simple page that contains a single UpdatePanel. Within that UpdatePanel there are two Web controls: A DropDownList with three statically-defined list items, whose AutoPostBack property is set to True, and A TextBox Web control The DropDownList has a server-side event handler for its SelectedIndexChanged event, and in that event handler there's two lines of code: TextBox1.Text = "Whatever"; ScriptManager.RegisterStartupScript(this, this.GetType(), "Select-" + TextBox1.ClientID, string.Format("document.getElementById('{0}').select();", TextBox1.ClientID), true); The idea is that whenever a user chooses and item from the DropDownList there is a partial page postback, at which point the TextBox's Text property is set and selected (via the injected JavaScript). Unfortunately, this doesn't work as-is. (I have also tried putting the script in the pageLoad function with no luck, as in: ScriptManager.RegisterStartupScript(..., "function pageLoad() { ... my script ... }");) What happens is the code runs, but something else on the page receives focus at the conclusion of the partial page postback, causing the TextBox's text to be unselected. I can "fix" this by using JavaScript's setTimeout to delay the execution of my JavaScript code. For instance, if I update the emitted JavaScript to the following: setTimeout("document.getElementById('{0}').select();", 111); It "works." I put works in quotes because it works for this simple page on my computer. In a more complex page on a slower computer with more markup getting passed between the client and server on the partial page postback, I have to up the timeout to over a second to get it to work. I would hope that there is a more foolproof way to achieve this. Rather than saying, "Delay for X milliseconds," it would be ideal to say, "Run this when you're not going to steal the focus." What's perplexing is that the .Focus() method works beautifully. That is, if I scrap my JavaScript and replace it with a call to TextBox1.Focus(); then the TextBox receives focus (although the text is not selected). I've examined the contents of MicrosoftAjaxWebForms.js and see that the focus is set after the registered scripts run, but I'm my JavaScript skills are not strong enough to decode what all is happening here and why the selected text is unselected between the time it is selected and the end of the partial page postback. I've also tried using Firebug's JavaScript debugger and see that when my script runs the TextBox's text is selected. As I continue to step through it the text remains selected, but then after stepping off the last line of script (apparently) it all of the sudden gets unselected. Any ideas? I am pulling my hair out. Thanks in advance...

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• PHP Menu Items Count then add under more button

  - by Adrian M.

  Hello, I use the bellow code to load the main menu elements from some CMS, the present code is perfect except that it loads ALL the main items on a single line of menu - which will make the width of it unusable in any centered design (under 1000px).. I want to change this script so after 15 main elements will add a "MORE" button under which the rest of the main menu items will show as sub-items of this "MORE" button (they will not have their own sub-items as the first 15 do).. How can I do it? Thanks! <?php require_once( '../../../inc/header.inc.php' ); require_once( DIRECTORY_PATH_INC . 'membership_levels.inc.php' ); require_once( DIRECTORY_PATH_ROOT . "templates/tmpl_{$tmpl}/scripts/TemplMenu.php" ); class SimpleMenu extends TemplMenu { function getCode() { $this->iElementsCntInLine = 100; $this->getMenuInfo(); $this->genTopItems(); return $this->sCode; } function genTopItem($sText, $sLink, $sTarget, $sOnclick, $bActive, $iItemID, $isBold = false, $sPicture = '') { $sActiveStyle = ($bActive) ? ' id="tm_active"' : ''; if (!$bActive) { $sAlt= $sOnclick ? ( ' alt="' . $sOnclick . '"' ) : ''; $sTarget = $sTarget ? ( ' target="_parent"' ) : ''; } $sLink = (strpos($sLink, 'http://') === false && !strlen($sOnclick)) ? $this->sSiteUrl . $sLink : $sLink; $sSubMenu = $this->getAllSubMenus($iItemID); $sImgTabStyle = $sPictureRep = ''; if ($isBold && $sPicture != '') { $sPicturePath = getTemplateIcon($sPicture); $sPictureRep = "<img src='{$sPicturePath}' style='vertical-align:middle;width:16px;height:16px;' />"; $sText = '&nbsp;'; $sImgTabStyle = 'style="width:38px;"'; } $sMainSubs = ($sSubMenu=='') ? '' : " {$sSubMenu} </a>"; $this->sCode .= " <li><a href='{$sLink}' {$sOnclick} target='_parent'>{$sPictureRep}{$sText}</a> <div id='submenu'> <ul> <li>{$sMainSubs}</li> </ul> </div> </li> "; } } $objMenu = new SimpleMenu(); echo "<ul id='ddmenu'>"; echo $objMenu->getCode(); echo "</ul>"; ?>

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• highlight query string in more than one field using solr search feature

  - by Romi

  i am using solr indexes for showing my search results. to show serch results i am parsing json data received from solr. i am able to highlight a query string in search result but only in a single field. for this i set hl=true and hl.fl="field1". i did it as $.getJSON("http://192.168.1.9:8983/solr/db/select/?wt=json&&start=0&rows=100&q="+lowerCaseQuery+"&hl=true&hl.fl=description,name&hl.usePhraseHighlighter=true&sort=price asc&json.wrf=?", function(result){ var n=result.response.numFound var highlight = new Array(n); $.each(result.highlighting, function(i, hitem){ var match = hitem.text[0].match(/<em>(.*?)<\/em>/); highlight[i]=match[1]; }); $.each(newresult.response.docs, function(i,item){ var word=highlight[item["UID_PK"]]; var result = item.text[0].replace(new RegExp(word,'g'), '<em>' + word + '</em>'); }); for this json object is as : { "responseHeader": { "status": 0, "QTime": 32 }, "response": { "numFound": 21, "start": 0, "docs": [ { "description": "The matte finish waves on this wedding band contrast with the high polish borders. This sharp and elegant design was finely crafted in Japan.", "UID_PK": "8252", }, { "description": "This elegant ring has an Akoya cultured pearl with a band of bezel-set round diamonds making it perfect for her to wear to work or the night out.", "UID_PK": "8142", }, ] }, "highlighting": { "8252": { "description": [ " and <em>elegant</em> design was finely crafted in Japan." ] }, "8142": { "description": [ "This <em>elegant</em> ring has an Akoya cultured pearl with a band of bezel-set round diamonds making" ] }, } } Now if i want to highlight query string in two fields i did as hl=true hl.fl=descrption, name my json is as: { "responseHeader":{ "status":0, "QTime":16 }, "response":{ "numFound":1904, "start":0, "docs":[ { "description":"", "UID_PK":"7780", "name":[ "Diamond bracelet with Milgrain Bezel1" ] }, { "description":"This pendant is sure to win hearts. Round diamonds form a simple and graceful line.", "UID_PK":"8121", "name":[ "Heartline Diamond Pendant" ] }, "highlighting":{ "7780":{ "name":[ "<em>Diamond</em> bracelet with Milgrain Bezel1" ] }, "8121":{ "description":[ "This pendant is sure to win hearts. Round <em>diamonds</em> form a simple and graceful line." ], "name":[ "Heartline <em>Diamond</em> Pendant" ] } } } Now how should i parse it to get the result. suggest me some general technique, so if i want to highlight query in more fields then i could do so. Thanks

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• How to handle environment-specific application configuration organization-wide?

  - by Stuart Lange

  Problem Your organization has many separate applications, some of which interact with each other (to form "systems"). You need to deploy these applications to separate environments to facilitate staged testing (for example, DEV, QA, UAT, PROD). A given application needs to be configured slightly differently in each environment (each environment has a separate database, for example). You want this re-configuration to be handled by some sort of automated mechanism so that your release managers don't have to manually configure each application every time it is deployed to a different environment. Desired Features I would like to design an organization-wide configuration solution with the following properties (ideally): Supports "one click" deployments (only the environment needs to be specified, and no manual re-configuration during/after deployment should be necessary). There should be a single "system of record" where a shared environment-dependent property is specified (such as a database connection string that is shared by many applications). Supports re-configuration of deployed applications (in the event that an environment-specific property needs to change), ideally without requiring a re-deployment of the application. Allows an application to be run on the same machine, but in different environments (run a PROD instance and a DEV instance simultaneously). Possible Solutions I see two basic directions in which a solution could go: Make all applications "environment aware". You would pass the environment name (DEV, QA, etc) at the command line to the app, and then the app is "smart" enough to figure out the environment-specific configuration values at run-time. The app could fetch the values from flat files deployed along with the app, or from a central configuration service. Applications are not "smart" as they are in #1, and simply fetch configuration by property name from config files deployed with the app. The values of these properties are injected into the config files at deploy-time by the install program/script. That install script takes the environment name and fetches all relevant configuration values from a central configuration service. Question How would/have you achieved a configuration solution that solves these problems and supports these desired features? Am I on target with the two possible solutions? Do you have a preference between those solutions? Also, please feel free to tell me that I'm thinking about the problem all wrong. Any feedback would be greatly appreciated.

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• Implementing Skip List in C++

  - by trikker

  [SOLVED] So I decided to try and create a sorted doubly linked skip list... I'm pretty sure I have a good grasp of how it works. When you insert x the program searches the base list for the appropriate place to put x (since it is sorted), (conceptually) flips a coin, and if the "coin" lands on a then that element is added to the list above it(or a new list is created with element in it), linked to the element below it, and the coin is flipped again, etc. If the "coin" lands on b at anytime then the insertion is over. You must also have a -infinite stored in every list as the starting point so that it isn't possible to insert a value that is less than the starting point (meaning that it could never be found.) To search for x, you start at the "top-left" (highest list lowest value) and "move right" to the next element. If the value is less than x than you continue to the next element, etc. until you have "gone too far" and the value is greater than x. In this case you go back to the last element and move down a level, continuing this chain until you either find x or x is never found. To delete x you simply search x and delete it every time it comes up in the lists. For now, I'm simply going to make a skip list that stores numbers. I don't think there is anything in the STL that can assist me, so I will need to create a class List that holds an integer value and has member functions, search, delete, and insert. The problem I'm having is dealing with links. I'm pretty sure I could create a class to handle the "horizontal" links with a pointer to the previous element and the element in front, but I'm not sure how to deal with the "vertical" links (point to corresponding element in other list?) If any of my logic is flawed please tell me, but my main questions are: How to deal with vertical links and whether my link idea is correct Now that I read my class List idea I'm thinking that a List should hold a vector of integers rather than a single integer. In fact I'm pretty positive, but would just like some validation. I'm assuming the coin flip would simply call int function where rand()%2 returns a value of 0 or 1 and if it's 0 then a the value "levels up" and if it's 0 then the insert is over. Is this incorrect? How to store a value similar to -infinite? Edit: I've started writing some code and am considering how to handle the List constructor....I'm guessing that on its construction, the "-infinite" value should be stored in the vectorname[0] element and I can just call insert on it after its creation to put the x in the appropriate place.

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• Why is FLD1 loading NaN instead?

  - by Bernd Jendrissek

  I have a one-liner C function that is just return value * pow(1.+rate, -delay); - it discounts a future value to a present value. The interesting part of the disassembly is 0x080555b9 : neg %eax 0x080555bb : push %eax 0x080555bc : fildl (%esp) 0x080555bf : lea 0x4(%esp),%esp 0x080555c3 : fldl 0xfffffff0(%ebp) 0x080555c6 : fld1 0x080555c8 : faddp %st,%st(1) 0x080555ca : fxch %st(1) 0x080555cc : fstpl 0x8(%esp) 0x080555d0 : fstpl (%esp) 0x080555d3 : call 0x8051ce0 0x080555d8 : fmull 0xfffffff8(%ebp) While single-stepping through this function, gdb says (rate is 0.02, delay is 2; you can see them on the stack): (gdb) si 0x080555c6 30 return value * pow(1.+rate, -delay); (gdb) info float R7: Valid 0x4004a6c28f5c28f5c000 +41.68999999999999773 R6: Valid 0x4004e15c28f5c28f6000 +56.34000000000000341 R5: Valid 0x4004dceb851eb851e800 +55.22999999999999687 R4: Valid 0xc0008000000000000000 -2 =R3: Valid 0x3ff9a3d70a3d70a3d800 +0.02000000000000000042 R2: Valid 0x4004ff147ae147ae1800 +63.77000000000000313 R1: Valid 0x4004e17ae147ae147800 +56.36999999999999744 R0: Valid 0x4004efb851eb851eb800 +59.92999999999999972 Status Word: 0x1861 IE PE SF TOP: 3 Control Word: 0x037f IM DM ZM OM UM PM PC: Extended Precision (64-bits) RC: Round to nearest Tag Word: 0x0000 Instruction Pointer: 0x73:0x080555c3 Operand Pointer: 0x7b:0xbff41d78 Opcode: 0xdd45 And after the fld1: (gdb) si 0x080555c8 30 return value * pow(1.+rate, -delay); (gdb) info float R7: Valid 0x4004a6c28f5c28f5c000 +41.68999999999999773 R6: Valid 0x4004e15c28f5c28f6000 +56.34000000000000341 R5: Valid 0x4004dceb851eb851e800 +55.22999999999999687 R4: Valid 0xc0008000000000000000 -2 R3: Valid 0x3ff9a3d70a3d70a3d800 +0.02000000000000000042 =R2: Special 0xffffc000000000000000 Real Indefinite (QNaN) R1: Valid 0x4004e17ae147ae147800 +56.36999999999999744 R0: Valid 0x4004efb851eb851eb800 +59.92999999999999972 Status Word: 0x1261 IE PE SF C1 TOP: 2 Control Word: 0x037f IM DM ZM OM UM PM PC: Extended Precision (64-bits) RC: Round to nearest Tag Word: 0x0020 Instruction Pointer: 0x73:0x080555c6 Operand Pointer: 0x7b:0xbff41d78 Opcode: 0xd9e8 After this, everything goes to hell. Things get grossly over or undervalued, so even if there were no other bugs in my freeciv AI attempt, it would choose all the wrong strategies. Like sending the whole army to the arctic. (Sigh, if only I were getting that far.) I must be missing something obvious, or getting blinded by something, because I can't believe that fld1 should ever possibly fail. Even less that it should fail only after a handful of passes through this function. On earlier passes the FPU correctly loads 1 into ST(0). The bytes at 0x080555c6 definitely encode fld1 - checked with x/... on the running process. What gives?

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• Poor performance / speed of regex with lookahead

  - by Hugo Zaragoza

  I have been observing extremely slow execution times with expressions with several lookaheads. I suppose that this is due to underlying data structures, but it seems pretty extreme and I wonder if I do something wrong or if there are known work-arounds. The problem is determining if a set of words are present in a string, in any order. For example we want to find out if two terms "term1" AND "term2" are somewhere in a string. I do this with the expresion: (?=.*\bterm1\b)(?=.*\bterm2\b) But what I observe is that this is an order of magnitude slower than checking first just \bterm1\b and just then \bterm2\b This seems to indicate that I should use an array of patterns instead of a single pattern with lookaheads... is this right? it seems wrong... Here is an example test code and resulting times: public static void speedLookAhead() { Matcher m, m1, m2; boolean find; int its = 1000000; // create long non-matching string char[] str = new char[2000]; for (int i = 0; i < str.length; i++) { str[i] = 'x'; } String test = str.toString(); // First method: use one expression with lookaheads m = Pattern.compile("(?=.*\\bterm1\\b)(?=.*\\bterm2\\b)").matcher(test); long time = System.currentTimeMillis(); ; for (int i = 0; i < its; i++) { m.reset(test); find = m.find(); } time = System.currentTimeMillis() - time; System.out.println(time); // Second method: use two expressions and AND the results m1 = Pattern.compile("\\bterm1\\b").matcher(test); m2 = Pattern.compile("\\bterm2\\b").matcher(test); time = System.currentTimeMillis(); ; for (int i = 0; i < its; i++) { m1.reset(test); m2.reset(test); find = m1.find() && m2.find(); } time = System.currentTimeMillis() - time; System.out.println(time); } This outputs in my computer: 1754 150

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• Problem Fetching JSON Result with jQuery in Firefox and Chrome (IE8 Works)

  - by senfo

  I'm attempting to parse JSON using jQuery and I'm running into issues. Using the code below, the data keeps coming back null: <!DOCTYPE html> <html> <head> <title>JSON Test</title> </head> <body> <div id="msg"></div> <script src="http://code.jquery.com/jquery-latest.js"></script> <script> $.ajax({ url: 'http://datawarehouse.hrsa.gov/ReleaseTest/HGDWDataWebService/HGDWDataService.aspx?service=HC&zip=20002&radius=10&filter=8357&format=JSON', type: 'GET', dataType: 'json', success: function(data) { $('#msg').html(data[0].title); // Always null in Firefox/Chrome. Works in IE8. }, error: function(data) { alert(data); } }); </script> </body> </html> The JSON results look like the following: {"title":"HEALTHPOINT TYEE CAMPUS","link":"http://www.healthpointchc.org","id":"tag:datawarehouse.hrsa.gov,2010-04-29:/8357","org":"HEALTHPOINT TYEE CAMPUS","address":{"street-address":"4424 S. 188TH St.","locality":"Seatac","region":"Washington","postal-code":"98188-5028"},"tel":"206-444-7746","category":"Service Delivery Site","location":"47.4344818181818 -122.277672727273","update":"2010-04-28T00:00:00-05:00"} If I replace my URL with the Flickr API URL (http://api.flickr.com/services/feeds/photos_public.gne?tags=cat&tagmode=any&format=json&jsoncallback=?), I get back a valid JSON result that I am able to make use of. I have successfully validated my JSON at JSONLint, so I've run out of ideas as to what I might be doing wrong. Any thoughts? Update: I had the client switch the content type to application/json. Unfortunately, I'm still experiencing the exact same problem. I also updated my HTML and included the live URL I've been working with. Update 2: I just gave this a try in IE8 and it works fine. For some reason, it doesn't work in either Firefox 3.6.3 or Chrome 4.1.249.1064 (45376). I did notice a mistake with the data being returned (the developer is returning a collection of data, even for queries that will always return a single record), but it still baffles me why it doesn't work in other browsers. It might be important to note that I am working from an HTML file on my local file system. I thought it might be a XSS issue, but that doesn't explain why Flickr works.

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• What to Expect in Rails 4

  - by mikhailov

  Rails 4 is nearly there, we should be ready before it released. Most developers are trying hard to keep their application on the edge. Must see resources: 1) @sikachu talk: What to Expect in Rails 4.0 - YouTube 2) Rails Guides release notes: http://edgeguides.rubyonrails.org/4_0_release_notes.html There is a mix of all major changes down here: ActionMailer changes excerpt: Asynchronously send messages via the Rails Raise an ActionView::MissingTemplate exception when no implicit template could be found ActionPack changes excerpt Added controller-level etag additions that will be part of the action etag computation Add automatic template digests to all CacheHelper#cache calls (originally spiked in the cache_digests plugin) Add Routing Concerns to declare common routes that can be reused inside others resources and routes Added ActionController::Live. Mix it in to your controller and you can stream data to the client live truncate now always returns an escaped HTML-safe string. The option :escape can be used as false to not escape the result Added ActionDispatch::SSL middleware that when included force all the requests to be under HTTPS protocol ActiveModel changes excerpt AM::Validation#validates ability to pass custom exception to :strict option Changed `AM::Serializers::JSON.include_root_in_json' default value to false. Now, AM Serializers and AR objects have the same default behaviour Added ActiveModel::Model, a mixin to make Ruby objects work with AP out of box Trim down Active Model API by removing valid? and errors.full_messages ActiveRecord changes excerpt Use native mysqldump command instead of structure_dump method when dumping the database structure to a sql file. Attribute predicate methods, such as article.title?, will now raise ActiveModel::MissingAttributeError if the attribute being queried for truthiness was not read from the database, instead of just returning false ActiveRecord::SessionStore has been extracted from Active Record as activerecord-session_store gem. Please read the README.md file on the gem for the usage Fix reset_counters when there are multiple belongs_to association with the same foreign key and one of them have a counter cache Raise ArgumentError if list of attributes to change is empty in update_all Add Relation#load. This method explicitly loads the records and then returns self Deprecated most of the 'dynamic finder' methods. All dynamic methods except for find_by_... and find_by_...! are deprecated Added ability to ActiveRecord::Relation#from to accept other ActiveRecord::Relation objects Remove IdentityMap ActiveSupport changes excerpt ERB::Util.html_escape now escapes single quotes ActiveSupport::Callbacks: deprecate monkey patch of object callbacks Replace deprecated memcache-client gem with dalli in ActiveSupport::Cache::MemCacheStore Object#try will now return nil instead of raise a NoMethodError if the receiving object does not implement the method, but you can still get the old behavior by using the new Object#try! Object#try can't call private methods Add ActiveSupport::Deprecations.behavior = :silence to completely ignore Rails runtime deprecations What are the most important changes for you?

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• To Interface or Not?: Creating a polymorphic model relationship in Ruby on Rails dynamically..

  - by Globalkeith

  Please bear with me for a moment as I try to explain exactly what I would like to achieve. In my Ruby on Rails application I have a model called Page. It represents a web page. I would like to enable the user to arbitrarily attach components to the page. Some examples of "components" would be Picture, PictureCollection, Video, VideoCollection, Background, Audio, Form, Comments. Currently I have a direct relationship between Page and Picture like this: class Page < ActiveRecord::Base has_many :pictures, :as => :imageable, :dependent => :destroy end class Picture < ActiveRecord::Base belongs_to :imageable, :polymorphic => true end This relationship enables the user to associate an arbitrary number of Pictures to the page. Now if I want to provide multiple collections i would need an additional model: class PictureCollection < ActiveRecord::Base belongs_to :collectionable, :polymorphic => true has_many :pictures, :as => :imageable, :dependent => :destroy end And alter Page to reference the new model: class Page < ActiveRecord::Base has_many :picture_collections, :as => :collectionable, :dependent => :destroy end Now it would be possible for the user to add any number of image collections to the page. However this is still very static in term of the :picture_collections reference in the Page model. If I add another "component", for example :video_collections, I would need to declare another reference in page for that component type. So my question is this: Do I need to add a new reference for each component type, or is there some other way? In Actionscript/Java I would declare an interface Component and make all components implement that interface, then I could just have a single attribute :components which contains all of the dynamically associated model objects. This is Rails, and I'm sure there is a great way to achieve this, but its a tricky one to Google. Perhaps you good people have some wise suggestions. Thanks in advance for taking the time to read and answer this.

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• mod_rewrite not working for a specific directory

  - by punkish

  This has got me completely foxed for a couple of days now, and I am convinced that I will look stupid once I solve it, but will be even stupider if I don't ask for help now. I have mod_rewrite working successfully on my localhost (no vhosts involved; this is my laptop, my development machine), and I use .htaccess in various directories to help rewrite crufty URLs to clean ones. EXCEPT... it doesn't work in one directory. Since it is impossible to reproduce my entire laptop in this question, I provide the following details. In my httpd.conf, I have mod_rewrite.so loaded. LoadModule rewrite_module modules/mod_rewrite.so In my httpd.conf, I have included another conf file like so Include /usr/local/apache2/conf/other/punkish.conf In my punkish.conf, I have directories defined like so DocumentRoot "/Users/punkish/Sites" <Directory "/Users/punkish/Sites"> Options ExecCGI AllowOverride None Order allow,deny Allow from all </Directory> <Directory "/Users/punkish/Sites/one"> Options FollowSymLinks AllowOverride All Order allow,deny Allow from all </Directory> <Directory "/Users/punkish/Sites/two"> Options FollowSymLinks AllowOverride All Order allow,deny Allow from all </Directory> In ~/Sites/one I have the following .htaccess file RewriteEngine On RewriteBase /one/ # If an actual file or directory is requested, serve directly RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d # Otherwise, pass everything through to the dispatcher RewriteRule ^(.*)$ index.cgi/$1 [L,QSA] and, everything works just fine. However, in my directory ~/Sites/two I have the following .htaccess file RewriteEngine On RewriteBase /two/ # If an actual file or directory is requested, serve directly RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d # Otherwise, pass everything through to the dispatcher RewriteRule ^(.*)$ index.cgi/$1 [L,QSA] and, nothing works. Nada. Zip. Zilch. I just get a 404. I have determined that mod_rewrite is not even looking at my ~/Sites/two/.htaccess by putting spurious commands in it and not getting any error other than 404. Another confounding issue -- I have turned on RewriteLog in my httpd.conf with RewriteLogLevel 3, but my rewrite_log is completely empty. I know this is hard to trouble shoot unless sitting physically at the computer in question, but I hope someone can give me some indication as to what is going on. **Update: ** There are no aliases involved anywhere. This is my laptop, and everything is under the above stated Document Root, so I just access each directory as http://localhost/. Yes, typos are a big possibility (I did say that I will look stupid once I solve it, however, for now, I have not discovered a single typo anywhere, and yes, I have restarted Apache about a dozen times now. I even thought that perhaps I had two different Apaches running, but no, I have only one, the one under /usr/local/apache2, and I installed it myself a while back.

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• Efficient file buffering & scanning methods for large files in python

  - by eblume

  The description of the problem I am having is a bit complicated, and I will err on the side of providing more complete information. For the impatient, here is the briefest way I can summarize it: What is the fastest (least execution time) way to split a text file in to ALL (overlapping) substrings of size N (bound N, eg 36) while throwing out newline characters. I am writing a module which parses files in the FASTA ascii-based genome format. These files comprise what is known as the 'hg18' human reference genome, which you can download from the UCSC genome browser (go slugs!) if you like. As you will notice, the genome files are composed of chr[1..22].fa and chr[XY].fa, as well as a set of other small files which are not used in this module. Several modules already exist for parsing FASTA files, such as BioPython's SeqIO. (Sorry, I'd post a link, but I don't have the points to do so yet.) Unfortunately, every module I've been able to find doesn't do the specific operation I am trying to do. My module needs to split the genome data ('CAGTACGTCAGACTATACGGAGCTA' could be a line, for instance) in to every single overlapping N-length substring. Let me give an example using a very small file (the actual chromosome files are between 355 and 20 million characters long) and N=8 import cStringIO example_file = cStringIO.StringIO("""\ header CAGTcag TFgcACF """) for read in parse(example_file): ... print read ... CAGTCAGTF AGTCAGTFG GTCAGTFGC TCAGTFGCA CAGTFGCAC AGTFGCACF The function that I found had the absolute best performance from the methods I could think of is this: def parse(file): size = 8 # of course in my code this is a function argument file.readline() # skip past the header buffer = '' for line in file: buffer += line.rstrip().upper() while len(buffer) = size: yield buffer[:size] buffer = buffer[1:] This works, but unfortunately it still takes about 1.5 hours (see note below) to parse the human genome this way. Perhaps this is the very best I am going to see with this method (a complete code refactor might be in order, but I'd like to avoid it as this approach has some very specific advantages in other areas of the code), but I thought I would turn this over to the community. Thanks! Note, this time includes a lot of extra calculation, such as computing the opposing strand read and doing hashtable lookups on a hash of approximately 5G in size. Post-answer conclusion: It turns out that using fileobj.read() and then manipulating the resulting string (string.replace(), etc.) took relatively little time and memory compared to the remainder of the program, and so I used that approach. Thanks everyone!

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• (mySQL) Unable to query 2 tables properly for data

  - by Devner

  I have 2 tables. One is 'page_links' and the other is 'rpp'. Table page_links is the superset of table rpp. The following is the schema of my tables: -- Table structure for table `page_links` -- CREATE TABLE IF NOT EXISTS `page_links` ( `page` varchar(255) NOT NULL, `page_link` varchar(100) NOT NULL, `heading_id` tinyint(3) unsigned NOT NULL, PRIMARY KEY (`page`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -- Dumping data for table `page_links` -- INSERT INTO `page_links` (`page`, `page_link`, `heading_id`) VALUES ('a1.php', 'A1', 8), ('b1.php', 'B1', 8), ('c1.php', 'C1', 5), ('d1.php', 'D1', 5), ('e1.php', 'E1', 8), ('f1.php', 'F1', 8), ('g1.php', 'G1', 8), ('h1.php', 'H1', 1), ('i1.php', 'I1', 1), ('j1.php', 'J1', 8), ('k1.php', 'K1', 8), ('l1.php', 'L1', 8), ('m1.php', 'M1', 8), ('n1.php', 'N1', 8), ('o1.php', 'O1', 8), ('p1.php', 'P1', 4), ('q1.php', 'Q1', 5), ('r1.php', 'R1', 4); -- Table structure for table `rpp` -- CREATE TABLE IF NOT EXISTS `rpp` ( `role_id` tinyint(3) unsigned NOT NULL, `page` varchar(255) NOT NULL, `is_allowed` tinyint(1) NOT NULL, PRIMARY KEY (`role_id`,`page`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; -- -- Dumping data for table `rpp` -- INSERT INTO `rpp` (`role_id`, `page`, `is_allowed`) VALUES (3, 'a1.php', 1), (3, 'b1.php', 1), (3, 'c1.php', 1), (3, 'd1.php', 1), (3, 'e1.php', 1), (3, 'f1.php', 1), (3, 'h1.php', 1), (3, 'i1.php', 1), (3, 'l1.php', 1), (3, 'm1.php', 1), (3, 'n1.php', 1), (4, 'a1.php', 1), (4, 'b1.php', 1), (4, 'q1.php', 1), (5, 'r1.php', 1); WHAT I AM TRYING TO DO: I am trying to query both the above tables (in a single query) in such a way that all the pages from page_links are displayed along with the is_allowed value from rpp for a particular role. For example, I want to get the is_allowed value of all the pages from rpp for role_id = 3 and at the same time, list all the available pages from page_links. A clear example of my expected result would be: page is_allowed role_id ---------------------------------------- a1.php 1 3 b1.php 1 3 c1.php 1 3 d1.php 1 3 e1.php 1 3 f1.php 1 3 g1.php NULL NULL h1.php 1 3 i1.php 1 3 j1.php NULL NULL k1.php NULL NULL l1.php 1 3 m1.php 1 3 n1.php 1 3 o1.php NULL NULL p1.php NULL NULL q1.php NULL NULL r1.php NULL NULL One more example of my desired result could be achieved by doing a LEFT JOIN rpp ON page_links.page = rpp.page but we need to omit using role_id = 3 (or any value) to be able to get that. But I do want to specify the role_id as well and get the results. I need the query to be able to get this result. I would appreciate any replies that could help me with this. If you can suggest me any changes as well to the table(s) design to be able to achieve the desired result, that's good as well. Thanks in advance.

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• Delphi Unit local variables - how to make each instance unique?

  - by Justin

  Ok, this, I'm sure is something simple that is easy to do. The problem : I've inherited scary spaghetti code and am slowly trying to better it when new features need adding - generally when a refactor makes adding the new feature neater. I've got a bunch of code I'm packing into a single unit which, in different places in the application, controls the same physical thing in the outside world. The control appears in several places in the application and operates slightly differently in each instance. What I've done is to create a unit with all of the features I need which I can simply drop, as a frame, into each form that requires it. Each form then uses the unit's interface methods to customise the behaviour for each instance. The problem within the problem : In the unit in question (the frame) I have a variable declared in the IMPLEMENTATION section - local to the unit. I also have a procedure, declared in the TYPE section which takes an argument and assigns that argument to the local variable in question - each form passes a unique variable to each instance of the frame/unit. What I want it to do is for each instance of the frame to keep its own version of that variable, different from the others, and use that to define how it operates. What seems to be happening, however, is that all instances are using the same value, even if I explicitly pass each instance a different variable. ie: Unit FlexibleUnit; interface uses //the uses stuff type TFlexibleUnit=class(TFrame) //declarations including procedure makeThisInstanceX(passMeTheVar:integer); private // public // end; implementation uses //the uses var myLocalVar; procedure makeThisInstanceX(passMeTheVar:integer); begin myLocalVar:=passMeTheVar; end; //other procedures using myLocalVar //etc to the end; Now somewhere in another Form I've dropped this Frame onto the Design pane, sometimes two of these frames on one Form, and have it declared in the proper places, etc. Each is unique in that : ThisFlexibleUnit : TFlexibleUnit; ThatFlexibleUnit : TFlexibleUnit; and when I do a: ThisFlexibleUnit.makeThisInstanceX(var1); //want to behave in way "var1" ThatFlexibleUnit.makeThisInstanceX(var2); //want to behave in way "var2" it seems that they both share the same variable "myLocalVar". Am I doing this wrong, in principle? If this is the correct method then it's a matter of debugging what I have (which is too huge to post) but if this is not correct in principle then is there a way to do what I am suggesting? Thanks in advance, Stack Overflow - you guys (and gals!) are legendary.

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• Parsing string logic issue c#

  - by N0xus

  This is a follow on from this question My program is taking in a string that is comprised of two parts: a distance value and an id number respectively. I've split these up and stored them in local variables inside my program. All of the id numbers are stored in a dictionary and are used check the incoming distance value. Though I should note that each string that gets sent into my program from the device is passed along on a single string. The next time my program receives that a signal from a device, it overrides the previous data that was there before. Should the id key coming into my program match one inside my dictionary, then a variable held next to my dictionaries key, should be updated. However, when I run my program, I don't get 6 different values, I only get the same value and they all update at the same time. This is all the code I have written trying to do this: Dictionary<string, string> myDictonary = new Dictionary<string, string>(); string Value1 = ""; string Value2 = ""; string Value3 = ""; string Value4 = ""; string Value5 = ""; string Value6 = ""; void Start() { myDictonary.Add("11111111", Value1); myDictonary.Add("22222222", Value2); myDictonary.Add("33333333", Value3); myDictonary.Add("44444444", Value4); myDictonary.Add("55555555", Value5); myDictonary.Add("66666666", Value6); } private void AppendString(string message) { testMessage = message; string[] messages = message.Split(','); foreach(string w in messages) { if(!message.StartsWith(" ")) outputContent.text += w + "\n"; } messageCount = "RSSI number " + messages[0]; uuidString = "UUID number " + messages[1]; if(myDictonary.ContainsKey(messages[1])) { Value1 = messageCount; Value2 = messageCount; Value3 = messageCount; Value4 = messageCount; Value5 = messageCount; Value6 = messageCount; } } How can I get it so that when programs recives the first key, for example 1111111, it only updates Value1? The information that comes through can be dynamic, so I'd like to avoid harding as much information as I possibly can.

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• What database table structure should I use for versions, codebases, deployables?

  - by Zac Thompson

  I'm having doubts about my table structure, and I wonder if there is a better approach. I've got a little database for version control repositories (e.g. SVN), the packages (e.g. Linux RPMs) built therefrom, and the versions (e.g. 1.2.3-4) thereof. A given repository might produce no packages, or several, but if there are more than one for a given repository then a particular version for that repository will indicate a single "tag" of the codebase. A particular version "string" might be used to tag a version of the source code in more than one repository, but there may be no relationship between "1.0" for two different repos. So if packages P and Q both come from repo R, then P 1.0 and Q 1.0 are both built from the 1.0 tag of repo R. But if package X comes from repo Y, then X 1.0 has no relationship to P 1.0. In my (simplified) model, I have the following tables (the x_id columns are auto-incrementing surrogate keys; you can pretend I'm using a different primary key if you wish, it's not really important): repository - repository_id - repository_name (unique) ... version - version_id - version_string (unique for a particular repository) - repository_id ... package - package_id - package_name (unique) - repository_id ... This makes it easy for me to see, for example, what are valid versions of a given package: I can join with the version table using the repository_id. However, suppose I would like to add some information to this database, e.g., to indicate which package versions have been approved for release. I certainly need a new table: package_version - version_id - package_id - package_version_released ... Again, the nature of the keys that I use are not really important to my problem, and you can imagine that the data column is "promotion_level" or something if that helps. My doubts arise when I realize that there's really a very close relationship between the version_id and the package_id in my new table ... they must share the same repository_id. Only a small subset of package/version combinations are valid. So I should have some kind of constraint on those columns, enforcing that ... ... I don't know, it just feels off, somehow. Like I'm including somehow more information than I really need? I don't know how to explain my hesitance here. I can't figure out which (if any) normal form I'm violating, but I also can't find an example of a schema with this sort of structure ... not being a DBA by profession I'm not sure where to look. So I'm asking: am I just being overly sensitive?

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• Can MySQL reasonably perform queries on billions of rows?

  - by haxney

  I am planning on storing scans from a mass spectrometer in a MySQL database and would like to know whether storing and analyzing this amount of data is remotely feasible. I know performance varies wildly depending on the environment, but I'm looking for the rough order of magnitude: will queries take 5 days or 5 milliseconds? Input format Each input file contains a single run of the spectrometer; each run is comprised of a set of scans, and each scan has an ordered array of datapoints. There is a bit of metadata, but the majority of the file is comprised of arrays 32- or 64-bit ints or floats. Host system |----------------+-------------------------------| | OS | Windows 2008 64-bit | | MySQL version | 5.5.24 (x86_64) | | CPU | 2x Xeon E5420 (8 cores total) | | RAM | 8GB | | SSD filesystem | 500 GiB | | HDD RAID | 12 TiB | |----------------+-------------------------------| There are some other services running on the server using negligible processor time. File statistics |------------------+--------------| | number of files | ~16,000 | | total size | 1.3 TiB | | min size | 0 bytes | | max size | 12 GiB | | mean | 800 MiB | | median | 500 MiB | | total datapoints | ~200 billion | |------------------+--------------| The total number of datapoints is a very rough estimate. Proposed schema I'm planning on doing things "right" (i.e. normalizing the data like crazy) and so would have a runs table, a spectra table with a foreign key to runs, and a datapoints table with a foreign key to spectra. The 200 Billion datapoint question I am going to be analyzing across multiple spectra and possibly even multiple runs, resulting in queries which could touch millions of rows. Assuming I index everything properly (which is a topic for another question) and am not trying to shuffle hundreds of MiB across the network, is it remotely plausible for MySQL to handle this? UPDATE: additional info The scan data will be coming from files in the XML-based mzML format. The meat of this format is in the <binaryDataArrayList> elements where the data is stored. Each scan produces = 2 <binaryDataArray> elements which, taken together, form a 2-dimensional (or more) array of the form [[123.456, 234.567, ...], ...]. These data are write-once, so update performance and transaction safety are not concerns. My naïve plan for a database schema is: runs table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | start_time | TIMESTAMP | | name | VARCHAR | |-------------+-------------| spectra table | column name | type | |----------------+-------------| | id | PRIMARY KEY | | name | VARCHAR | | index | INT | | spectrum_type | INT | | representation | INT | | run_id | FOREIGN KEY | |----------------+-------------| datapoints table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | spectrum_id | FOREIGN KEY | | mz | DOUBLE | | num_counts | DOUBLE | | index | INT | |-------------+-------------| Is this reasonable?

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