Search Results

Search found 6805 results on 273 pages for 'fast formula'.

Page 228/273 | < Previous Page | 224 225 226 227 228 229 230 231 232 233 234 235  | Next Page >

• How to find Part Time development/IT work?

  - by Jonathan

  I've been working in the IT field now for 10 years. Originally trained as an Engineer, started out with C++ and have been a .Net specialist since beta. Currently seconded to a major city and working in the finance industry as freelance, I really feel like i've hit the glass ceiling. Have been contracting now for 5 years as the company politics and frustration of not being promoted and poor pay rises for excellent work but during the last decade of corporate cost cutting took its toll on my morale. Freelance made all the difference and i've had a very decorated career for good clients. What any Engineering student could ever dream of when starting out. The problem is, it doesn't particularly make me happy. It's good work, and i enjoy the problem solving aspects of it and having something to do each day. However there is always a large overhead of non-technical work and dealing with poor managers etc. I guess the Engineering was always a bit of a mistake i made the best out of, and now having 10 years behind a computer hasn't done wonders for my health or eye sight. In a nutshell i am in the process of retraining as a therapist and would like to open my own clinic. However, never having done this before, the fast pace IT skills outdate and the fact that all my experience and skills are non transferrable, i am a little worried. Any ideas how i can find part time IT work as i build up my business? (it's incredibly hard to find freelancing work that doesn't require long hours and overtime). Or other ideas to make the transition easier, and perhaps backout if it financially doesn't work/or i have enough marketing skills? I'd be interested to hear from people who have made a similar transition, successfully or unsuccessfully. Many thanks

  Read the article

• HttpURLConnection inside a loop

  - by Carlos Garces

  Hi! I'm trying to connect to one URL that I know that exist but I don't know when. I don't have access to this server so I can't change anything to receive a event. The actual code is this. URL url = new URL(urlName); for(int j = 0 ; j< POOLING && disconnected; j++){ HttpURLConnection connection = (HttpURLConnection) url.openConnection(); int status = connection.getResponseCode(); if(status == HttpURLConnection.HTTP_OK || status == HttpURLConnection.HTTP_NOT_MODIFIED){ //Some work }else{ //wait 3s Thread.sleep(3000); } } Java not is my best skill and I'm not sure if this code is good from the point of view of performance. I'm opening a new connection every 3 seconds? or the connection is reused? If I call to disconnect() I ensure that no new connections are open in the loop, but... it will impact in performance?. Suggestions? What is the fast/best ways to know it a URL exist?

  Read the article

• Eclipse on windows doesnt start

  - by sap

  I usually do all my java development on linux, using fedora package manager setting up a development environment is easy and fast. Now I have to start using windows but I never used it for java development and im having a few difficulties having it setup. So I downloaded and installed thye java 6 JDK (just the standard edition, not the EE) and installed it. Next I downloaded eclipse classic package, which doesnt have an installer, you just unzip it and run it. I had to add the java bin directory to the PATH variable, which I did. But when I start eclipse.exe I get this: http://img02.imagefra.me/img/img02/1/12/12/f_12c33ivd2m_c79c09f.jpg I already made a new environment variable called CLASSPATH and add the d:/java sdk/lib directory to it, but it the same thing. Am I missing something? Thanks. UPDATE: so i wrote the path to the java.exe on the eclipse.ini file (linking to jvm.dll didnt work) and now it just opens a console window for a few seconds and then closes (doesnt output anything). also launching it like: java -jar plugins/org.eclipse.equinox.launcher_1.0.0.v20070208a.jar make the vm work for about 1-2 seconds and then it returns, with no outputs. UPDATE2: i didnt know it was writting a log file, found it and read it and it said i was using GWT x32 libraries on a x64 VM, so i just downloaded an eclipse x64 version and it worked. i still had to use the .ini trick to say where the JVM is installed. thanks a lot for the help.

  Read the article

• In .NET, What Is Fastest Way to Initialize Multi-Dimensional Array to Non-Default Value

  - by AMissico

  How do I initialize a multi-dimensional array of a primitive type as fast as possible? I am stuck with using multi-dimensional arrays. My problem is performance. The following routine initializes a 100x100 array in approx. 500 ticks. Removing the int.MaxValue initialization results in approx. 180 ticks just for the looping. Approximately 100 ticks to create the array without looping and without initializing to int.MaxValue. Routines similiar to this are called a few tens-of-thousands to several million times. I am open to suggestions on how to optimize this non-default initialization of an array. One idea I had is to use a smaller primitive type when available. For instance, using byte instead of int, saves 100 ticks. I would be happy with this, but I am hoping that I don't have to change the primitive data type. public int[,] CreateArray(Size size) { int[,] array = new int[size.Width, size.Height]; for (int x = 0; x < size.Width; x++) { for (int y = 0; y < size.Height; y++) { array[x, y] = int.MaxValue; } } return array; }

  Read the article

• Design considerations for temporarily transforming a player into an animal in a role playing game

  - by mikedev

  I am working on a role playing game for fun and to practice design patterns. I would like players to be able to transform themselves into different animals. For example, a Druid might be able to shape shift into a cheetah. Right now I'm planning on using the decorator pattern to do this but my question is - how do I make it so that when a druid is in the cheetah form, they can only access skills for the cheetah? In other words, they should not be able to access their normal Druid skills. Using the decorator pattern it appears that even in the cheetah form my druid will be able to access their normal druid skills. class Druid : Character { // many cool druid skills and spells void LightHeal(Character target) { } } abstract class CharacterDecorator : Character { Character DecoratedCharacter; } class CheetahForm : CharacterDecorator { Character DecoratedCharacter; public CheetahForm(Character decoratedCharacter) { DecoratedCharacter= decoratedCharacter; } // many cool cheetah related skills void CheetahRun() { // let player move very fast } } now using the classes Druid myDruid = new Druid(); myDruid.LightHeal(myDruid); // casting light heal here is fine myDruid = new CheetahForm(myDruid); myDruid.LightHeal(myDruid); // casting here should not be allowed Hmmmm...now that I think about it, will myDruid be unable to us the Druid class spells/skills unless the class is down-casted? But even if that's the case, is there a better way to ensure that myDruid at this point is locked out from all Druid related spells/skills until it is cast back to a Druid (since currently it's in CheetahForm)

  Read the article

• How to make a product catalog in C#?

  - by Ervin

  I need to develop a product catalog (about 4000 products) application, which would be given to clients on CD or DVD. The catalog exists in webpage format using PHP and MySQL. IMPORTANT: the application is given to clients who maight have old PC, old System. For minimal requirements I would put Windows XP and Internet Explorer 6 (if needed). I need the following features: 1 search option (after productID AND after keyword) 2 print option (by selecting multiple products) 3 shopping cart (making a list which will be sent to an email address if there is any Internet Connection on the computer) When I was asked to do it I had 2 days to realise a very basic version, so I took the whole website and exported it in HTML pages, and developed an application in C# which contains an embeded browser. So the whole website is now static and put on a CD. Everything fine so far. Now here are the problems: 1. the search option was realized by parsing the html files and reading the productID or looking for keywords inside of them. Put on a CD it was extremely slow (searching in 600MB of html files). FOR THIS I WOULD NEED A SOLUTION WITH A STATIC DATABASE (USING ACCESS OR SOMETHING) TO HAVE INDEXED ROWS, SO THE SEARCH COULD BE A VERY FAST ONE. 2. the printing option was a simply call of the embeded Internet Explorer print functions. Here are two problems: a) user needs IE7 for printing the website scaled (FIT TO PAGE), otherwise the edges of the page are cut down. b) users of this app does not have even the basic PC usage skills, so they can't set the printing settings, so there will appear in header and footer the page numbers and titles. QUESTION: can I set these settings from CSS for printing? 3. couldn't make a a shopping cart as I don't use a database, so I have static websites and content is inside the HTML. QUESTION: WHICH ARE THE BEST SOLUTIONS FOR THE PROBLEMS DESCRIBED ABOVE? PLEASE ANSWER EVEN IF YOUR ANSWER IS FOR ONE QUESTION ONLY. THANKS

  Read the article

• WPF, C# - Making Intellisense/Autocomplete list, fastest way to filter list of strings

  - by user559548

  Hello everyone, I'm writing an Intellisense/Autocomplete like the one you find in Visual Studio. It's all fine up until when the list contains probably 2000+ items. I'm using a simple LINQ statement for doing the filtering: var filterCollection = from s in listCollection where s.FilterValue.IndexOf(currentWord, StringComparison.OrdinalIgnoreCase) >= 0 orderby s.FilterValue select s; I then assign this collection to a WPF Listbox's ItemSource, and that's the end of it, works fine. Noting that, the Listbox is also virtualised as well, so there will only be at most 7-8 visual elements in memory and in the visual tree. However the caveat right now is that, when the user types extremely fast in the richtextbox, and on every key up I execute the filtering + binding, there's this semi-race condition, or out of sync filtering, like the first key stroke's filtering could still be doing it's filtering or binding work, while the fourth key stroke is also doing the same. I know I could put in a delay before applying the filter, but I'm trying to achieve a seamless filtering much like the one in Visual Studio. I'm not sure where my problem exactly lies, so I'm also attributing it to IndexOf's string operation, or perhaps my list of string's could be optimised in some kind of index, that could speed up searching. Any suggestions of code samples are much welcomed. Thanks.

  Read the article

• How to recalculate all-pairs shorthest paths on-line if nodes are getting removed?

  - by Pavel Shved

  Latest news about underground bombing made me curious about the following problem. Assume we have a weighted undirected graph, nodes of which are sometimes removed. The problem is to re-calculate shortest paths between all pairs of nodes fast after such removals. With a simple modification of Floyd-Warshall algorithm we can calculate shortest paths between all pairs. These paths may be stored in a table, where shortest[i][j] contains the index of the next node on the shortest path between i and j (or NULL value if there's no path). The algorithm requires O(n³) time to build the table, and eacho query shortest(i,j) takes O(1). Unfortunately, we should re-run this algorithm after each removal. The other alternative is to run graph search on each query. This way each removal takes zero time to update an auxiliary structure (because there's none), but each query takes O(E) time. What algorithm can be used to "balance" the query and update time for all-pairs shortest-paths problem when nodes of the graph are being removed?

  Read the article

• How to compile ocaml to native code

  - by Indra Ginanjar

  i'm really interested learning ocaml, it fast (they said it could be compiled to native code) and it's functional. So i tried to code something easy like enabling mysql event scheduler. #load "unix.cma";; #directory "+mysql";; #load "mysql.cma";; let db = Mysql.quick_connect ~user:"username" ~password:"userpassword" ~database:"databasename"();; let sql = Printf.sprintf "SET GLOBAL EVENT_SCHEDULER=1;" in (Mysql.exec db sql);; It work fine on ocaml interpreter, but when i was trying to compile it to native (i'm using ubuntu karmic), neither of these command worked ocamlopt -o mysqleventon mysqleventon.ml unix.cmxa mysql.cmxa ocamlopt -o mysqleventon mysqleventon.ml unix.cma mysql.cma i also tried ocamlc -c mysqleventon.ml unix.cma mysql.cma all of them resulting same message File "mysqleventon.ml", line 1, characters 0-1: Error: Syntax error Then i tried to remove the "# load", so the code goes like this let db = Mysql.quick_connect ~user:"username" ~password:"userpassword" ~database:"databasename"();; let sql = Printf.sprintf "SET GLOBAL EVENT_SCHEDULER=1;" in (Mysql.exec db sql);; The ocamlopt resulting message File "mysqleventon.ml", line 1, characters 9-28: Error: Unbound value Mysql.quick_connect I hope someone could tell me, where did i'm doing wrong.

  Read the article

• How to count term frequency for set of documents?

  - by ManBugra

  i have a Lucene-Index with following documents: doc1 := { caldari, jita, shield, planet } doc2 := { gallente, dodixie, armor, planet } doc3 := { amarr, laser, armor, planet } doc4 := { minmatar, rens, space } doc5 := { jove, space, secret, planet } so these 5 documents use 14 different terms: [ caldari, jita, shield, planet, gallente, dodixie, armor, amarr, laser, minmatar, rens, jove, space, secret ] the frequency of each term: [ 1, 1, 1, 4, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1 ] for easy reading: [ caldari:1, jita:1, shield:1, planet:4, gallente:1, dodixie:1, armor:2, amarr:1, laser:1, minmatar:1, rens:1, jove:1, space:2, secret:1 ] What i do want to know now is, how to obtain the term frequency vector for a set of documents? for example: Set<Documents> docs := [ doc2, doc3 ] termFrequencies = magicFunction(docs); System.out.pring( termFrequencies ); would result in the ouput: [ caldari:0, jita:0, shield:0, planet:2, gallente:1, dodixie:1, armor:2, amarr:1, laser:1, minmatar:0, rens:0, jove:0, space:0, secret:0 ] remove all zeros: [ planet:2, gallente:1, dodixie:1, armor:2, amarr:1, laser:1 ] Notice, that the result vetor contains only the term frequencies of the set of documents. NOT the overall frequencies of the whole index! The term 'planet' is present 4 times in the whole index but the source set of documents only contains it 2 times. A naive implementation would be to just iterate over all documents in the docs set, create a map and count each term. But i need a solution that would also work with a document set size of 100.000 or 500.000. Is there a feature in Lucene i can use to obtain this term vector? If there is no such feature, how would a data structure look like someone can create at index time to obtain such a term vector easily and fast? I'm not that Lucene expert so i'am sorry if the solution is obvious or trivial.

  Read the article

• Building a News-feed that comprises posts "created by user's connections" && "on the topics user is following"

  - by aklin81

  I am working on a project of Questions & Answers website that allows a user to follow questions on certain topics from his network. A user's news-feed wall comprises of only those questions that have been posted by his connections and tagged on the topics that he is following(his expertise topics). I am confused what database's datamodel would be most fitting for such an application. The project needs to consider the future provisions for scalability and high performance issues. I have been looking at Cassandra and MySQL solutions as of now. After my study of Cassandra I realized that Simple news-feed design that shows all the posts from network would be easy to design using Cassandra by executing fast writes to all followers of a user about the post from user. But for my kind of application where there is an additional filter of 'followed topics', (ie, the user receives posts "created by his network" && "on topics user is following"), I could not convince myself with a good schema design in Cassandra. I hope if I missed something because of my short understanding of cassandra, perhaps, can you please help me out with your suggestions of how this news-feed could be implemented in Cassandra ? Looking for a great project with Cassandra ! Edit: There are going to be maximum 5 tags allowed for tagging the question (ie, max 5 topics can be tagged on a question).

  Read the article

• Most efficient way to check for DBNull and then assign to a variable?

  - by ilitirit

  This question comes up occasionally but I haven't seen a satisfactory answer. A typical pattern is (row is a DataRow): if (row["value"] != DBNull.Value) { someObject.Member = row["value"]; } My first question is which is more efficient (I've flipped the condition): row["value"] == DBNull.Value; // Or row["value"] is DBNull; // Or row["value"].GetType() == typeof(DBNull) // Or... any suggestions? This indicates that .GetType() should be faster, but maybe the compiler knows a few tricks I don't? Second question, is it worth caching the value of row["value"] or does the compiler optimize the indexer away anyway? eg. object valueHolder; if (DBNull.Value == (valueHolder = row["value"])) {} Disclaimers: row["value"] exists. I don't know the column index of the column (hence the column name lookup) I'm asking specifically about checking for DBNull and then assignment (not about premature optimization etc). Edit: I benchmarked a few scenarios (time in seconds, 10000000 trials): row["value"] == DBNull.Value: 00:00:01.5478995 row["value"] is DBNull: 00:00:01.6306578 row["value"].GetType() == typeof(DBNull): 00:00:02.0138757 Object.ReferenceEquals has the same performance as "==" The most interesting result? If you mismatch the name of the column by case (eg. "Value" instead of "value", it takes roughly ten times longer (for a string): row["Value"] == DBNull.Value: 00:00:12.2792374 The moral of the story seems to be that if you can't look up a column by it's index, then ensure that the column name you feed to the indexer matches the DataColumn's name exactly. Caching the value also appears to be nearly twice as fast: No Caching: 00:00:03.0996622 With Caching: 00:00:01.5659920 So the most efficient method seems to be: object temp; string variable; if (DBNull.Value != (temp = row["value"]) { variable = temp.ToString(); } This was a good learning experience.

  Read the article

• Algorithm for finding the best routes for food distribution in game

  - by Tautrimas

  Hello, I'm designing a city building game and got into a problem. Imagine Sierra's Caesar III game mechanics: you have many city districts with one market each. There are several granaries over the distance connected with a directed weighted graph. The difference: people (here cars) are units that form traffic jams (here goes the graph weights). Note: in Ceasar game series, people harvested food and stockpiled it in several big granaries, whereas many markets (small shops) took food from the granaries and delivered it to the citizens. The task: tell each district where they should be getting their food from while taking least time and minimizing congestions on the city's roads. Map example Sample diagram Suppose that yellow districts need 7, 7 and 4 apples accordingly. Bluish granaries have 7 and 11 apples accordingly. Suppose edges weights to be proportional to their length. Then, the solution should be something like the gray numbers indicated on the edges. Eg, first district gets 4 apples from the 1st and 3 apples from the 2nd granary, while the last district gets 4 apples from only the 2nd granary. Here, vertical roads are first occupied to the max, and then the remaining workers are sent to the diagonal paths. Question What practical and very fast algorithm should I use? I was looking at some papers (Congestion Games: Optimization in Competition etc.) describing congestion games, but could not get the big picture. Any help is very appreciated! P. S. I can post very little links and no images because of new user restriction.

  Read the article

• How to trace the connection pool in a Java Web application - DBMS_APPLICATION_INFO

  - by Cleiton Garcia

  Hello, I need improve the traceability in a Web Application that usually run on fixed db user. The DBA should have a fast access for the information about the heavy users that are degrading the database. 5 years ago, I implemented a .NET ORM engine which makes a log of user and the server using the DBMS_APPLICATION_INFO package. Using a wrapper above the connection manager with the following code: DBMS_APPLICATION_INFO.SET_MODULE('" + User + " - " + appServerMachine + "',''); Each time that a connection get a connection from the pool, the package is executed to log the information in the V$SESSION. Has anyone discover or implemented a solution for this problem using the Toplink or Hibernate? Is there a default implementation for this problem? I found here a solutions as I implemented 5 years ago, but I'd like to know with anyone have a better solution and integrated with the ORM. http://stackoverflow.com/questions/53379/using-dbmsapplicationinfo-with-jboss My application is above Spring, the DAO are implemented with JPA (using hibernate) and actually running directly in Tomcat, with plans to (next year) migrate to SAP Netwevare Application Server. Thanks.

  Read the article

• Trouble Shoot JavaScript Function in IE

  - by CreativeNotice

  So this function works fine in geko and webkit browsers, but not IE7. I've busted my brain trying to spot the issue. Anything stick out for you? Basic premise is you pass in a data object (in this case a response from jQuery's $.getJSON) we check for a response code, set the notification's class, append a layer and show it to the user. Then reverse the process after a time limit. function userNotice(data){ // change class based on error code returned var myClass = ''; if(data.code == 200){ myClass='success'; } else if(data.code == 400){ myClass='error'; } else{ myClass='notice'; } // create message html, add to DOM, FadeIn var myNotice = '<div id="notice" class="ajaxMsg '+myClass+'">'+data.msg+'</div>'; $("body").append(myNotice); $("#notice").fadeIn('fast'); // fadeout and remove from DOM after delay var t = setTimeout(function(){ $("#notice").fadeOut('slow',function(){ $(this).remove(); }); },5000); }

  Read the article

• Sendkeys problem from .NET program

  - by user203123

  THe code below I copied from MSDN with a bit of modification: [DllImport("user32.dll", CharSet = CharSet.Unicode)] public static extern IntPtr FindWindow(string lpClassName,string lpWindowName); DllImport("User32")] public static extern bool SetForegroundWindow(IntPtr hWnd); int cnt = 0; private void button1_Click(object sender, EventArgs e) { IntPtr calculatorHandle = FindWindow("Notepad", "Untitled - Notepad"); if (calculatorHandle == IntPtr.Zero) { MessageBox.Show("Calculator is not running."); return; } SetForegroundWindow(calculatorHandle); SendKeys.SendWait(cnt.ToString()); SendKeys.SendWait("{ENTER}"); cnt++; SendKeys.Flush(); System.Threading.Thread.Sleep(1000); } The problem is the number sequence in Notepad is not continuously. The first click always results 0 (as expected). but from the second click, the result is unpredictable (but the sequence is still in order, e.g. 3, 4, 5, 10, 14, 15, ....) If I click the button fast enough, I was able to get the result in continuous order (0,1,2,3,4,....) but sometimes it produces more than 2 same numbers (e.g. 0,1,2,3,3,3,4,5,6,6,6,7,8,9,...)

  Read the article

• What issues to consider when rolling your own data-backend for Silverlight / AJAX on non-ASP.NET ser

  - by Edward Tanguay

  I have read-only Silverlight and AJAX apps which read static text and XML files from a PHP/Apache server, which works very nicely with features such as asynchronous loading, lazy-loading only what I need for each page, loading in the background, developed a little query language to get a PHP script to create custom XML files etc. it's pragmatic read-only REST, and all works fast and fine for read-only sites. Now I want to also add the ability to write data from these apps to a database on the same PHP/Apache server. For those of you who have built similar data-access layers, what do I need to consider while building this, especially regarding security so that not just any client can write and alter my database, e.g.: check HTTP_USER_AGENT for security check REMOTE_ADDR for security require a special code for security, perhaps a list of TAN codes (such as banks use for online transactions) each which can only be used once, both the client and server have these I wonder if there is some kind of standard REST query I should lean on for e.g. building SQL-like statements in the URL parameters, e.g. http://www.thedatalayersite.com/query?insertinto=customers&... Any thoughts, notes from experience, ideas, gotchas, especially ideas on tightening down security in this endeavor would be helpful.

  Read the article

• sybase - fails to use index unless string is hard-coded

  - by Garrett

  I'm using Sybase 12.5.3 (ASE); I'm new to Sybase though I've worked with MSSQL pretty extensively. I'm running into a scenario where a stored procedure is really very slow. I've traced the issue to a single SELECT stmt for a relatively large table. Modifying that statement dramatically improves the performance of the procedure (and reverting it drastically slows it down; i.e., the SELECT stmt is definitely the culprit). -- Sybase optimizes and uses multi-column index... fast!<br> SELECT ID,status,dateTime FROM myTable WHERE status in ('NEW','SENT') ORDER BY ID -- Sybase does not use index and does very slow table scan<br> SELECT ID,status,dateTime FROM myTable WHERE status in (select status from allowableStatusValues) ORDER BY ID The code above is an adapted/simplified version of the actual code. Note that I've already tried recompiling the procedure, updating statistics, etc. I have no idea why Sybase ASE would choose an index only when strings are hard-coded and choose a table scan when choosing from another table. Someone please give me a clue, and thank you in advance.

  Read the article

• Help with Neuroph neural network

  - by user359708

  For my graduate research I am creating a neural network that trains to recognize images. I am going much more complex than just taking a grid of RGB values, downsampling, and and sending them to the input of the network, like many examples do. I actually use over 100 independently trained neural networks that detect features, such as lines, shading patterns, etc. Much more like the human eye, and it works really well so far! The problem is I have quite a bit of training data. I show it over 100 examples of what a car looks like. Then 100 examples of what a person looks like. Then over 100 of what a dog looks like, etc. This is quite a bit of training data! Currently I am running at about one week to train the network. This is kind of killing my progress, as I need to adjust and retrain. I am using Neuroph, as the low-level neural network API. I am running a dual-quadcore machine(16 cores with hyperthreading), so this should be fast. My processor percent is at only 5%. Are there any tricks on Neuroph performance? Or Java peroformance in general? Suggestions? I am a cognitive psych doctoral student, and I am decent as a programmer, but do not know a great deal about performance programming.

  Read the article

• Finding a picture in a picture with java?

  - by tarrasch

  what i want to to is analyse input from screen in form of pictures. I want to be able to identify a part of an image in a bigger image and get its coordinates within the bigger picture. Example: would have to be located in And the result would be the upper right corner of the picture in the big picture and the lower left of the part in the big picture. As you can see, the white part of the picture is irrelevant, what i basically need is just the green frame. Is there a library that can do something like this for me? Runtime is not really an issue. What i want to do with this is just generating a few random pixel coordinates and recognize the color in the big picture at that position, to recognize the green box fast later. And how would it decrease performance, if the white box in the middle is transparent? The question has been asked several times on SO as it seems without a single answer. I found i found a solution at http://werner.yellowcouch.org/Papers/subimg/index.html . Unfortunately its in C++ and i do not understand a thing. Would be nice to have a Java implementation on SO.

  Read the article

• Any HTTP proxies with explicit, configurable support for request/response buffering and delayed conn

  - by Carlos Carrasco

  When dealing with mobile clients it is very common to have multisecond delays during the transmission of HTTP requests. If you are serving pages or services out of a prefork Apache the child processes will be tied up for seconds serving a single mobile client, even if your app server logic is done in 5ms. I am looking for a HTTP server, balancer or proxy server that supports the following: A request arrives to the proxy. The proxy starts buffering in RAM or in disk the request, including headers and POST/PUT bodies. The proxy DOES NOT open a connection to the backend server. This is probably the most important part. The proxy server stops buffering the request when: A size limit has been reached (say, 4KB), or The request has been received completely, headers and body Only now, with (part of) the request in memory, a connection is opened to the backend and the request is relayed. The backend sends back the response. Again the proxy server starts buffering it immediately (up to a more generous size, say 64KB.) Since the proxy has a big enough buffer the backend response is stored completely in the proxy server in a matter of miliseconds, and the backend process/thread is free to process more requests. The backend connection is immediately closed. The proxy sends back the response to the mobile client, as fast or as slow as it is capable of, without having a connection to the backend tying up resources. I am fairly sure you can do 4-6 with Squid, and nginx appears to support 1-3 (and looks like fairly unique in this respect). My question is: is there any proxy server that empathizes these buffering and not-opening-connections-until-ready capabilities? Maybe there is just a bit of Apache config-fu that makes this buffering behaviour trivial? Any of them that it is not a dinosaur like Squid and that supports a lean single-process, asynchronous, event-based execution model? (Siderant: I would be using nginx but it doesn't support chunked POST bodies, making it useless for serving stuff to mobile clients. Yes cheap 50$ handsets love chunked POSTs... sigh)

  Read the article

• How to improve performance of non-scalar aggregations on denormalized tables

  - by The Lazy DBA

  Suppose we have a denormalized table with about 80 columns, and grows at the rate of ~10 million rows (about 5GB) per month. We currently have 3 1/2 years of data (~400M rows, ~200GB). We create a clustered index to best suit retrieving data from the table on the following columns that serve as our primary key... [FileDate] ASC, [Region] ASC, [KeyValue1] ASC, [KeyValue2] ASC ... because when we query the table, we always have the entire primary key. So these queries always result in clustered index seeks and are therefore very fast, and fragmentation is kept to a minimum. However, we do have a situation where we want to get the most recent FileDate for every Region, typically for reports, i.e. SELECT [Region] , MAX([FileDate]) AS [FileDate] FROM HugeTable GROUP BY [Region] The "best" solution I can come up to this is to create a non-clustered index on Region. Although it means an additional insert on the table during loads, the hit isn't minimal (we load 4 times per day, so fewer than 100,000 additional index inserts per load). Since the table is also partitioned by FileDate, results to our query come back quickly enough (200ms or so), and that result set is cached until the next load. However I'm guessing that someone with more data warehousing experience might have a solution that's more optimal, as this, for some reason, doesn't "feel right".

  Read the article

• deepcopy and python - tips to avoid using it?

  - by blackkettle

  Hi, I have a very simple python routine that involves cycling through a list of roughly 20,000 latitude,longitude coordinates and calculating the distance of each point to a reference point. def compute_nearest_points( lat, lon, nPoints=5 ): """Find the nearest N points, given the input coordinates.""" points = session.query(PointIndex).all() oldNearest = [] newNearest = [] for n in xrange(nPoints): oldNearest.append(PointDistance(None,None,None,99999.0,99999.0)) newNearest.append(obj2) #This is almost certainly an inappropriate use of deepcopy # but how SHOULD I be doing this?!?! for point in points: distance = compute_spherical_law_of_cosines( lat, lon, point.avg_lat, point.avg_lon ) k = 0 for p in oldNearest: if distance < p.distance: newNearest[k] = PointDistance( point.point, point.kana, point.english, point.avg_lat, point.avg_lon, distance=distance ) break else: newNearest[k] = deepcopy(oldNearest[k]) k += 1 for j in range(k,nPoints-1): newNearest[j+1] = deepcopy(oldNearest[j]) oldNearest = deepcopy(newNearest) #We're done, now print the result for point in oldNearest: print point.station, point.english, point.distance return I initially wrote this in C, using the exact same approach, and it works fine there, and is basically instantaneous for nPoints<=100. So I decided to port it to python because I wanted to use SqlAlchemy to do some other stuff. I first ported it without the deepcopy statements that now pepper the method, and this caused the results to be 'odd', or partially incorrect, because some of the points were just getting copied as references(I guess? I think?) -- but it was still pretty nearly as fast as the C version. Now with the deepcopy calls added, the routine does it's job correctly, but it has incurred an extreme performance penalty, and now takes several seconds to do the same job. This seems like a pretty common job, but I'm clearly not doing it the pythonic way. How should I be doing this so that I still get the correct results but don't have to include deepcopy everywhere?

  Read the article

• High performance text file parsing in .net

  - by diamandiev

  Here is the situation: I am making a small prog to parse server log files. I tested it with a log file with several thousand requests (between 10000 - 20000 don't know exactly) What i have to do is to load the log text files into memory so that i can query them. This is taking the most resources. The methods that take the most cpu time are those (worst culprits first): string.split - splits the line values into a array of values string.contains - checking if the user agent contains a specific agent string. (determine browser ID) string.tolower - various purposes streamreader.readline - to read the log file line by line. string.startswith - determine if line is a column definition line or a line with values there were some others that i was able to replace. For example the dictionary getter was taking lots of resources too. Which i had not expected since its a dictionary and should have its keys indexed. I replaced it with a multidimensional array and saved some cpu time. Now i am running on a fast dual core and the total time it takes to load the file i mentioned is about 1 sec. Now this is really bad. Imagine a site that has tens of thousands of visits a day. It's going to take minutes to load the log file. So what are my alternatives? If any, cause i think this is just a .net limitation and i can't do much about it.

  Read the article

• jquery slideDown menu

  - by Elliott

  Hi, I have a link which once hovered over a box below slides down, once hover is removed it slides back up. I have it working almost to how I want, although in IE8 (Havent tested in other IE yet) the text in the box which slides down is not centerd. In firefox, when it slides down the corners are not smooth, but they are in IE. Live test here Code: <script type="text/javascript"> $(document).ready(function() { $('#nav_top').corners('5px'); $('#nav_bottom').hide(); $('#nav_bottom').corners(); $('#link').hover(function() { $('#nav_top').corners('10px top'); $('#nav_bottom').stop(true, true).slideDown(); $('#nav_bottom').slideDown("slow"); }, function () { $('#nav_bottom').slideUp("fast"); } ); }); </script> <div id="nav_top"> <a href="javascript:void(0);" id="link">Hover</a> <div id="nav_bottom"> <br />Stuff </div> </div> </div> Any advice, also is it better to use .hover or .mouseEnter / mouseLeave? Thanks

  Read the article

< Previous Page | 224 225 226 227 228 229 230 231 232 233 234 235  | Next Page >