Search Results

Search found 4136 results on 166 pages for 'micro optimization'.

Page 69/166 | < Previous Page | 65 66 67 68 69 70 71 72 73 74 75 76  | Next Page >

  • Ways to optimize Android App code based on function call stack?

    - by K-RAN
    I've been told that Android OS stores all function calls in a stack. This can lead to many problems and cause the 'hiccups' during runtime, even if a program is functionalized properly, correct? So the question is, how can we prevent this from happening? The obvious solution is to functionalize less, along with other sensible acts such as refraining from excessively/needlessly creating objects, performing static calls to functions that don't access fields, etc... Is there another way though? Or can this only be done through careful code writing on the programmers' part? Does the JVM/JIT automatically optimize the bytecode during compile time to account for this?? Thanks a lot for your responses!!

    Read the article

  • Does anybody have any suggestions on which of these two approaches is better for large delete?

    - by RPS
    Approach #1: DECLARE @count int SET @count = 2000 DECLARE @rowcount int SET @rowcount = @count WHILE @rowcount = @count BEGIN DELETE TOP (@count) FROM ProductOrderInfo WHERE ProductId = @product_id AND bCopied = 1 AND FileNameCRC = @localNameCrc SELECT @rowcount = @@ROWCOUNT WAITFOR DELAY '000:00:00.400' Approach #2: DECLARE @count int SET @count = 2000 DECLARE @rowcount int SET @rowcount = @count WHILE @rowcount = @count BEGIN DELETE FROM ProductOrderInfo WHERE ProductId = @product_id AND FileNameCRC IN ( SELECT TOP(@count) FileNameCRC FROM ProductOrderInfo WITH (NOLOCK) WHERE bCopied = 1 AND FileNameCRC = @localNameCrc ) SELECT @rowcount = @@ROWCOUNT WAITFOR DELAY '000:00:00.400' END

    Read the article

  • How to batch retrieve documents with mongoDB?

    - by edude05
    Hello everyone, I have an application that queries data from a mongoDB using the mongoDB C# driver something like this: public void main() { foreach (int i in listOfKey) { list.add(getObjectfromDB(i); } } public myObject getObjFromDb(int primaryKey) { document query = new document(); query["primKey"] = primaryKey; document result= mongo["myDatabase"]["myCollection"].findOne(query); return parseObject(result); } On my local (development) machine to get 100 object this way takes less than a second. However, I recently moved the database to a server on the internet, and this query takes about 30 seconds to execute for the same number of object. Furthermore, looking at the mongoDB log, it seems to open about 8-10 connections to the DB to perform this query. So what I'd like to do is have the query the database for an array of primaryKeys and get them all back at once, then do the parsing in a loop afterwards, using one connection if possible. How could I optimize my query to do so? Thanks, --Michael

    Read the article

  • PHP Increasing writing to page speed.

    - by Frederico
    I'm currently writing out xml and have done the following: header ("content-type: text/xml"); header ("content-length: ".strlen($xml)); $xml being the xml to be written out. I'm near about 1.8 megs of text (which I found via firebug), it seems as the writing is taking more time than the script to run.. is there a way to increase this write speed? Thank you in advance.

    Read the article

  • iPhone App takes up too much memory

    - by Stephen Furlani
    Ok, so here's my problem. My iPhone app is 1.2MB on disk. Granted I have a bunch of Images for the GUI buttons and backgrounds, etc. In-memory, my app takes up a whopping 15MB! That means if I then take a picture with the camera, 8MB default, it gives a memory warning (several) even before the picker calls its delegate! How can I tell what is grabbing so much memory, and how to remove it? I've removed all of my debugging symbols and added [-Os], but it still takes up a huge amount of memory! Also, (how) can I change the default resolution of the camera?

    Read the article

  • How to simplify my code... 2D array in Objective C...?

    - by Tattat
    self.myArray = [NSArray arrayWithObjects: [NSArray arrayWithObjects: [self d], [self generateMySecretObject],nil], [NSArray arrayWithObjects: [self generateMySecretObject], [self generateMySecretObject],nil],nil]; for (int k=0; k<[self.myArray count]; k++) { for(int s = 0; s<[[self.myArray objectAtIndex:k] count]; s++){ [[[self.myArray objectAtIndex:k] objectAtIndex:s] setAttribute:[self generateSecertAttribute]]; } } As you can see this is a simple 2*2 array, but it takes me lots of code to assign the NSArray in very first place, because I found that the NSArray can't assign the size at very beginning. Also, I want to set attribute one by one. I can't think of if my array change to 10*10. How long it could be. So, I hope you guys can give me some suggestions on shorten the code, and more readable. thz

    Read the article

  • 50 million+ Rows of Data - CSV or MySQL

    - by eWizardII
    Hello, I have a CSV file which is about 1GB big and contains about 50million rows of data, I am wondering is it better to keep it as a CSV file or store it as some form of a database. I don't know a great deal about MySQL to argue for why I should use it or another database framework over just keeping it as a CSV file. I am basically doing a Breadth-First Search with this dataset, so once I get the initial "seed" set the 50million I use this as the first values in my queue. Thanks,

    Read the article

  • How can I speed up line by line reading of an ASCII file? (C++)

    - by Jon
    Here's a bit of code that is a considerable bottleneck after doing some measuring: //----------------------------------------------------------------------------- // Construct dictionary hash set from dictionary file //----------------------------------------------------------------------------- void constructDictionary(unordered_set<string> &dict) { ifstream wordListFile; wordListFile.open("dictionary.txt"); string word; while( wordListFile >> word ) { if( !word.empty() ) { dict.insert(word); } } wordListFile.close(); } I'm reading in ~200,000 words and this takes about 240 ms on my machine. Is the use of ifstream here efficient? Can I do better? I'm reading about mmap() implementations but I'm not understanding them 100%. The input file is simply text strings with *nix line terminations.

    Read the article

  • optimized grid for rectangular items

    - by peterchen
    I have N rectangular items with an aspect ratio Aitem (X:Y). I have a rectangular display area with an aspect ratio Aview The items should be arranged in a table-like layout (i.e. r rows, c columns). what is the ideal grid rows x columns, so that individual items are largest? (rows * colums = N, of course - i.e. there may be "unused" grid places). A simple algorithm could iterate over rows = 1..N, calculate the required number of columns, and keep the row/column pair with the largest items. I wonder if there's a non-iterative algorithm, though (e.g. for Aitem = Aview = 1, rows / cols can be approximated by sqrt(N)).

    Read the article

  • .net Compiler Optimizations

    - by Dested
    I am writing an application that I need to run at incredibly low speeds. The application creates and destroys memory in creative ways throughout its run, and it works just fine. I am wondering what compiler optimizations occur so I can try to build to that. One trick off hand is that the CLR handles arrays much faster than lists, so if you need to handle a ton of elements in a List, you may be better off calling ToArray() and handling it rather than calling ElementAt() again and again. I am wondering if there is any sort of comprehensive list for this kind of thing, or maybe the SO community can create one :-)

    Read the article

  • Common causes of slow performing jQuery and how to optimize the code?

    - by Polaris878
    Hello, This might be a bit of a vague or general question, but I figure it might be able to serve as a good resource for other jQuery-ers. I'm interested in common causes of slow running jQuery and how to optimize these cases. We have a good amount of jQuery/JavaScript performing actions on our page... and performance can really suffer with a large number off elements. What are some obvious performance pitfalls you know of with jQuery? What are some general optimizations a jQuery-er can do to squeeze every last bit of performance out of his/her scripts? One example: a developer may use a selector to access an element that is slower than some other way. Thanks

    Read the article

  • In ArrayBlockingQueue, why copy final member field into local final variable?

    - by mjlee
    In ArrayBlockingQueue, any method that requires lock will get set 'final' local variable before calling 'lock()'. public boolean offer(E e) { if (e == null) throw new NullPointerException(); final ReentrantLock lock = this.lock; lock.lock(); try { if (count == items.length) return false; else { insert(e); return true; } } finally { lock.unlock(); } } Is there any reason to set a local variable 'lock' from 'this.lock' when field 'this.lock' is final also. Additionally, it also set local variable of E[] before acting on. private E extract() { final E[] items = this.items; E x = items[takeIndex]; items[takeIndex] = null; takeIndex = inc(takeIndex); --count; notFull.signal(); return x; } Is there any reason for copying to local final variable?

    Read the article

  • Fastest way to do a weighted tag search in SQL Server

    - by Hasan Khan
    My table is as follows ObjectID bigint Tag nvarchar(50) Weight float Type tinyint I want to get search for all objects that has tags 'big' or 'large' I want the objectid in order of sum of weights (so objects having both the tags will be on top) select objectid, row_number() over (order by sum(weight) desc) as rowid from tags where tag in ('big', 'large') and type=0 group by objectid the reason for row_number() is that i want paging over results. The query in its current form is very slow, takes a minute to execute over 16 million tags. What should I do to make it faster? I have a non clustered index (objectid, tag, type) Any suggestions?

    Read the article

  • Write file need to optimised for heavy traffic part 2

    - by Clayton Leung
    For anyone interest to see where I come from you can refer to part 1, but it is not necessary. write file need to optimised for heavy traffic Below is a snippet of code I have written to capture some financial tick data from the broker API. The code will run without error. I need to optimize the code, because in peak hours the zf_TickEvent method will be call more than 10000 times a second. I use a memorystream to hold the data until it reaches a certain size, then I output it into a text file. The broker API is only single threaded. void zf_TickEvent(object sender, ZenFire.TickEventArgs e) { outputString = string.Format("{0},{1},{2},{3},{4}\r\n", e.TimeStamp.ToString(timeFmt), e.Product.ToString(), Enum.GetName(typeof(ZenFire.TickType), e.Type), e.Price, e.Volume); fillBuffer(outputString); } public class memoryStreamClass { public static MemoryStream ms = new MemoryStream(); } void fillBuffer(string outputString) { byte[] outputByte = Encoding.ASCII.GetBytes(outputString); memoryStreamClass.ms.Write(outputByte, 0, outputByte.Length); if (memoryStreamClass.ms.Length > 8192) { emptyBuffer(memoryStreamClass.ms); memoryStreamClass.ms.SetLength(0); memoryStreamClass.ms.Position = 0; } } void emptyBuffer(MemoryStream ms) { FileStream outStream = new FileStream("c:\\test.txt", FileMode.Append); ms.WriteTo(outStream); outStream.Flush(); outStream.Close(); } Question: Any suggestion to make this even faster? I will try to vary the buffer length but in terms of code structure, is this (almost) the fastest? When memorystream is filled up and I am emptying it to the file, what would happen to the new data coming in? Do I need to implement a second buffer to hold that data while I am emptying my first buffer? Or is c# smart enough to figure it out? Thanks for any advice

    Read the article

  • MySQL Prepared Statements vs Stored Procedures Performance

    - by amardilo
    Hi there, I have an old MySQL 4.1 database with a table that has a few millions rows and an old Java application that connects to this database and returns several thousand rows from this this table on a frequent basis via a simple SQL query (i.e. SELECT * FROM people WHERE first_name = 'Bob'. I think the Java application uses client side prepared statements but was looking at switching this to the server, and in the example mentioned the value for first_name will vary depending on what the user enters). I would like to speed up performance on the select query and was wondering if I should switch to Prepared Statements or Stored Procedures. Is there a general rule of thumb of what is quicker/less resource intensive (or if a combination of both is better)

    Read the article

  • How to optimize this javascript code?

    - by Andrija
    I have a jsp which uses a lot of javascript and it's just not fast enough. I would like to optimize it so first, here's a part of the code: In the jsp I have the initialization: window.onload = function () { formCollection.pageSize.value = "<%= pagingSize%>"; elemCollection = iDom3.Table.all["spis"].XML.DOM; <% if (resultList != null) { %> elementsNumber = <%= resultList.size() %>; <%} else { %> elementsNumber = 0; <% } %> contextPath = "<%= request.getContextPath() %>"; } In my js file I have two types of js functions: // gets the first element and sets it's value to all the other; //the selectSingleNode function is used because I use XSLT transformation //to generate the table _setTehJed = function(){ var resultId = formCollection.elements["idTehJedinice_spis_1"].value; var resultText = formCollection.elements["tehnicka_spis_1"].value; if (resultId != ""){ var counter = 1; while (counter<elementsNumber){ counter++; if(formCollection.elements["idTehJedinice_spis_"+counter] != null){ formCollection.elements["idTehJedinice_spis_"+counter].value=resultId; formCollection.elements["tehnicka_spis_"+counter].value=resultText; } var node=elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'tehnicka']/title"); node.text=resultText; var node2=elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'idTehJedinice']/title"); node2.text=resultId; } } } // sets the elements checkbox to checked or unchecked _SelectCheckRokCuvanja = { all : [], Item : function (oItem, sId) { this.all["spis_"+sId] = oItem.value; if (oItem.checked) { elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "true"); }else{ elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "false"); } } } I've used these tips: http://blogs.msdn.com/b/ie/archive/2006/08/28/728654.aspx http://code.google.com/speed/articles/optimizing-javascript.html but I still think something could be done like defining the functions like this: In the jsp: window.onload = function () { iDom3.DigitalnaArhivaPrihvat.formCollection=document.forms["controller"]; iDom3.DigitalnaArhivaPrihvat.formCollection.pageSize.value = "<%= pagingSize%>"; iDom3.DigitalnaArhivaPrihvat.elemCollection = iDom3.Table.all["spis"].XML.DOM; <% if (resultList != null) { %> iDom3.DigitalnaArhivaPrihvat.elementsNumber = <%= resultList.size() %> <%} else { %> iDom3.DigitalnaArhivaPrihvat.elementsNumber = 0; <% } %> } in the js: iDom3.DigitalnaArhivaPrihvat = { formCollection:null, elemCollection:null, elementsNumber:null, _setTehJed : function(){ var resultId = this.formCollection.elements.idTehJedinice_spis_1.value; var resultText = this.formCollection.elements.tehnicka_spis_1.value; if (resultId != ""){ var counter = 1; while (counter<this.elementsNumber){ counter++; if(this.formCollection.elements["idTehJedinice_spis_"+counter] !== null){ this.formCollection.elements["idTehJedinice_spis_"+counter].value=resultId; this.formCollection.elements["tehnicka_spis_"+counter].value=resultText; } var node=this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'tehnicka']/title"); node.text=resultText; var node2=this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'idTehJedinice']/title"); node2.text=resultId; } } }, _SelectCheckRokCuvanja = { all : [], Item : function (oItem, sId) { this.all["spis_"+sId] = oItem.value; if (oItem.checked) { this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "true"); }else{ this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "false"); } } } but the problem is scoping (if I do it like this, the second function does not execute properly). Any suggestions?

    Read the article

  • Efficiently select top row for each category in the set

    - by VladV
    I need to select a top row for each category from a known set (somewhat similar to this question). The problem is, how to make this query efficient on the large number of rows. For example, let's create a table that stores temperature recording in several places. CREATE TABLE #t ( placeId int, ts datetime, temp int, PRIMARY KEY (ts, placeId) ) -- insert some sample data SET NOCOUNT ON DECLARE @n int, @ts datetime SELECT @n = 1000, @ts = '2000-01-01' WHILE (@n>0) BEGIN INSERT INTO #t VALUES (@n % 10, @ts, @n % 37) IF (@n % 10 = 0) SET @ts = DATEADD(hour, 1, @ts) SET @n = @n - 1 END Now I need to get the latest recording for each of the places 1, 2, 3. This way is efficient, but doesn't scale well (and looks dirty). SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 1 ORDER BY ts DESC ) t1 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 2 ORDER BY ts DESC ) t2 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 3 ORDER BY ts DESC ) t3 The following looks better but works much less efficiently (30% vs 70% according to the optimizer). SELECT placeId, ts, temp FROM ( SELECT placeId, ts, temp, ROW_NUMBER() OVER (PARTITION BY placeId ORDER BY ts DESC) rownum FROM #t WHERE placeId IN (1, 2, 3) ) t WHERE rownum = 1 The problem is, during the latter query execution plan a clustered index scan is performed on #t and 300 rows are retrieved, sorted, numbered, and then filtered, leaving only 3 rows. For the former query three times one row is fetched. Is there a way to perform the query efficiently without lots of unions?

    Read the article

  • Working with PHP and MySQL - need a good and secure design with OO design

    - by Andrew
    I am new to PHP- first time developer. I am working on my web application and it is nearly done; nevertheless, most of my sql was done directly via code using direct mysql requests. This is the way I approached it: In classes_db.php I declared the db settings and created methods that I use to open and close DB connections. I declare those objects on my regular pages: class classes_db { public $dbserver = 'server; public $dbusername = 'user'; public $dbpassword = 'pass'; public $dbname = 'db'; function openDb() { $dbhandle = mysql_connect($this->dbserver, $this->dbusername, $this->dbpassword); if (!$dbhandle) { die('Could not connect: ' . mysql_error()); } $selected = mysql_select_db($this->dbname, $dbhandle) or die("Could not select the database"); return $dbhandle; } function closeDb($con) { mysql_close($con); } } On my regular page, I do this: <?php require 'classes_db.php'; session_start(); //create instance of the DB class $db = new classes_db(); //get dbhandle $dbhandle = $db->openDb(); //process query $result = mysql_query("update user set username = '" . $usernameFromForm . "' where iduser= " . $_SESSION['user']->iduser); //close the connection if (isset($dbhandle)) { $db->closeDb($dbhandle); } ?> My questions is: how to do it right and make it OO and secure? I know that I need incorporate prepared queries- how to do it the best way? Please provide some code

    Read the article

  • Compiler reordering around mutex boundaries?

    - by shojtsy
    Suppose I have my own non-inline functions LockMutex and UnlockMutex, which are using some proper mutex - such as boost - inside. How will the compiler know not to reorder other operations with regard to calls to the LockMutex and UnlockMutex? It can not possibly know how will I implement these functions in some other compilation unit. void SomeClass::store(int i) { LockMutex(_m); _field = i; // could the compiler move this around? UnlockMutex(_m); } ps: One is supposed to use instances of classes for holding locks to guarantee unlocking. I have left this out to simplify the example.

    Read the article

  • How can i optimize this recursive method

    - by Tirdyr
    Hi there. I'm trying to make a word puzzle game, and for that i'm using a recursive method to find all possible words in the given letters. The letters is in a 4x4 board. Like this: ABCD EFGH HIJK LMNO The recursive method is called inside this loop: for (int y = 0; y < width; y++) { for (int x = 0; x < height; x++) { myScabble.Search(letters, y, x, width, height, "", covered, t); } } letters is a 2D array of chars. y & x is ints that shows where in the board width & height is also int, that tells the dimensions of the board "" is the string we are trying to make (the word) covered is an array of bools, to check if we allready used that square. t is a List (wich contains all the words to check against). The recursive method that need optimizing: public void Search(char[,] letters, int y, int x, int width, int height, string build, bool[,] covered, List<aWord> tt) { // Dont get outside the bounds if (y >= width || y < 0 || x >= height || x < 0) { return; } // Dont deal with allrady covered squares if (covered[x, y]) { return; } // Get Letter char letter = letters[x, y]; // Append string pass = build + letter; // check if its a possibel word //List<aWord> t = myWords.aWord.Where(w => w.word.StartsWith(pass)).ToList(); List<aWord> t = tt.Where(w => w.word.StartsWith(pass)).ToList(); // check if the list is emphty if (t.Count < 10 && t.Count != 0) { //stop point } if (t.Count == 0) { return; } // Check if its a complete word. if (t[0].word == pass) { //check if its allrdy present in the _found dictinary if (!_found.ContainsKey(pass)) { //if not add the word to the dictionary _found.Add(pass, true); } } // Check to see if there is more than 1 more that matches string pass // ie. are there more words to find. if (t.Count > 1) { // make a copy of the covered array bool[,] cov = new bool[height, width]; for (int i = 0; i < width; i++) { for (int a = 0; a < height; a++) { cov[a, i] = covered[a, i]; } } // Set the current square as covered. cov[x, y] = true; // Continue in all 8 directions. Search(letters, y + 1, x, width, height, pass, cov, t); Search(letters, y, x + 1, width, height, pass, cov, t); Search(letters, y + 1, x + 1, width, height, pass, cov, t); Search(letters, y - 1, x, width, height, pass, cov, t); Search(letters, y, x - 1, width, height, pass, cov, t); Search(letters, y - 1, x - 1, width, height, pass, cov, t); Search(letters, y - 1, x + 1, width, height, pass, cov, t); Search(letters, y + 1, x - 1, width, height, pass, cov, t); } } The code works as i expected it to do, however it is very slow.. it takes about 2 mins to find the words. EDIT: i clarified that the letters array is 2D

    Read the article

  • How much faster is a database running in RAM?

    - by orokusaki
    I"m looking to run PostgreSQL in RAM for performance enhancement. The database isn't more than 1GB and shouldn't ever grow to more than 5GB. Is it worth doing? Are there any benchmarks out there? Is it buggy? My second major concern is: How easy is it to back things up when it's running purely in RAM. Is this just like using RAM as tier 1 HD, or is it much more complicated?

    Read the article

< Previous Page | 65 66 67 68 69 70 71 72 73 74 75 76  | Next Page >