Search Results

Search found 18422 results on 737 pages for 'down town'.

Page 591/737 | < Previous Page | 587 588 589 590 591 592 593 594 595 596 597 598  | Next Page >

• De-normalization alternative to specific MYSQL problem?

  - by Booker

  I am facing quite a specific optimization problem. I currently have 4 normalized tables of data. Every second, possibly thousands of users will pull down up-to-date info from these tables using AJAX. The thing is that I can predict relatively easily which subset of data they need... The most recent 100 or so entries in those 4 normalized tables. I have been researching de-normalization... but feel that perhaps there is an easier solution. I was thinking that I could somehow every second run one sql query to condense the needed info, store it in a temp cached table and then have all of the user queries just draw from this. This will allow the complex join of 4 tables to only be run once, and then from there the users just need to do a simple lookup from the cached table. I really don't know if this is feasible. Comments on this or any other suggestions would be much appreciated. Thanks!

  Read the article

• Message queue proxy in Python + Twisted

  - by gasper_k

  Hi, I want to implement a lightweight Message Queue proxy. It's job is to receive messages from a web application (PHP) and send them to the Message Queue server asynchronously. The reason for this proxy is that the MQ isn't always avaliable and is sometimes lagging, or even down, but I want to make sure the messages are delivered, and the web application returns immediately. So, PHP would send the message to the MQ proxy running on the same host. That proxy would save the messages to SQLite for persistence, in case of crashes. At the same time it would send the messages from SQLite to the MQ in batches when the connection is available, and delete them from SQLite. Now, the way I understand, there are these components in this service: message listener (listens to the messages from PHP and writes them to a Incoming Queue) DB flusher (reads messages from the Incoming Queue and saves them to a database; due to SQLite single-threadedness) MQ connection handler (keeps the connection to the MQ server online by reconnecting) message sender (collects messages from SQlite db and sends them to the MQ server, then removes them from db) I was thinking of using Twisted for #1 (TCPServer), but I'm having problem with integrating it with other points, which aren't event-driven. Intuition tells me that each of these points should be running in a separate thread, because all are IO-bound and independent of each other, but I could easily put them in a single thread. Even though, I couldn't find any good and clear (to me) examples on how to implement this worker thread aside of Twisted's main loop. The example I've started with is the chatserver.py, which uses service.Application and internet.TCPServer objects. If I start my own thread prior to creating TCPServer service, it runs a few times, but the it stops and never runs again. I'm not sure, why this is happening, but it's probably because I don't use threads with Twisted correctly. Any suggestions on how to implement a separate worker thread and keep Twisted? Do you have any alternative architectures in mind?

  Read the article

• How to prevent external translation of a movieclip object on stage in AS3?

  - by Aaron H.

  I have a MovieClip object, which is exported for actionscript (AS3) in an .swc file. When I place an instance of the clip on the stage without any modifications, it appears in the upper left corner, about half off stage (i.e. only the lower right quadrant of the object is visible). I understand that this is because the clip has a registration point which is not the upper left corner. If you call getBounds() on the movieclip you can get the bounds of the clip (presumably from the "point" that it's aligned on) which looks something like (left: -303, top: -100, right: 303, bottom: 100), you can subtract the left and top values from the clip x and y: clip.x -= bounds.left; clip.y -= bounds.top; This seems to properly align the clip fully on stage with the top left of the clip squarely in the corner of the stage. But! Following that logic doesn't seem to work when aligning it on the center of the stage! clip.x = (stage.stageWidth / 2); etc... This creates the crazy parallel universe where the clip is now down in the lower right corner of the stage. The only clue I have is that looking at: clip.transform.matrix and clip.transform.concatenatedMatrix matrix has a tx value of 748 (half of stage height) ty value of 426 (Half of stage height) concatenatedMatrix has a tx value of 1699.5 and ty value of 967.75 That's also obviously where the movieclip is getting positioned, but why? Where is this additional translation coming from?

  Read the article

• Testing subpackage modules in Python 3

  - by Mitchell Model

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

  Read the article

• Monotouch threads, GC, WCF

  - by cvista

  Hi This is a question about best practices i guess but it applies directly to my current MT project. I'm using WCF services to communicate with the server. To do this i do the following: services.MethodToCall(params); and the asynch: services.OnMethodToCallCompleted += delegate{ //do stuff and ting }; This can lead to issues if you're not careful in that variables defined within the scope of the asynch callback can sometimes be cleaned up by the gc and this can cause crashes. So - I am making it a practice to declare these outside of the scope of the callback unless I am 100% sure they are not needed. Now - when doing stuff and ting implies changing the ui - i wrap it all in an InvokeOnMainThread call. I guess wrapping everything in this would slow the main thread down and rubbish the point of having multi threads. Even though I'm being careful about all this i am still getting crashes and I have no idea why! I am certain it has something to do with threads, scope and all that. Now - the only thing I can think of outside of updating the UI that may need to happen inside of InvokeOnMainThread is that I have a singleton 'Database' class. This is based on the version 5 code from this thread http://www.yoda.arachsys.com/csharp/singleton.html So now if the service method returns data that needs to be added/updated to the Database class -I also wrap this inside an InvokeOnMainThread call. Still getting random crashes. So... My question is this: I am new to thick client dev - I'm coming from a web dev perspective where we don't need to worry about threads so much :) Aside from what I have mentioned -are there any other things I should be aware of? Is the above stuff correct? Or am i miss-understanding something? Cheers w://

  Read the article

• jQuery "growl-like" effect in VB.net

  - by StealthRT

  Hey all, i have made a simple form that mimiks the jQuery "GROWL" effect seen here http://www.sandbox.timbenniks.com/projects/jquery-notice/ However, i have ran into a problem. If i have more than one call to the form to display a "Growl" then it just refreshes the same form with whatever call i send it. In other words, i can only display one form at a time instead of having one drop down and a new one appear above it. Here is my simple form code for the "GROWL" form: Public Class msgWindow Public howLong As Integer Public theType As String Private loading As Boolean Protected Overrides Sub OnPaint(ByVal pe As System.Windows.Forms.PaintEventArgs) Dim pn As New Pen(Color.DarkGreen) If theType = "OK" Then pn.Color = Color.DarkGreen ElseIf theType = "ERR" Then pn.Color = Color.DarkRed Else pn.Color = Color.DarkOrange End If pn.Width = 2 pe.Graphics.DrawRectangle(pn, 0, 0, Me.Width, Me.Height) pn = Nothing End Sub Public Sub showMessageBox(ByVal typeOfBox As String, ByVal theMessage As String) Me.Opacity = 0 Me.Show() Me.SetDesktopLocation(My.Computer.Screen.WorkingArea.Width - 350, 15) Me.loading = True theType = typeOfBox lblSaying.Text = theMessage If typeOfBox = "OK" Then Me.BackColor = Color.FromArgb(192, 255, 192) ElseIf typeOfBox = "ERR" Then Me.BackColor = Color.FromArgb(255, 192, 192) Else Me.BackColor = Color.FromArgb(255, 255, 192) End If If Len(theMessage) <= 30 Then howLong = 4000 ElseIf Len(theMessage) >= 31 And Len(theMessage) <= 80 Then howLong = 7000 ElseIf Len(theMessage) >= 81 And Len(theMessage) <= 100 Then howLong = 12000 Else howLong = 17000 End If Me.opacityTimer.Start() End Sub Private Sub opacityTimer_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles opacityTimer.Tick If Me.loading Then Me.Opacity += 0.07 If Me.Opacity >= 0.8 Then Me.opacityTimer.Stop() Me.opacityTimer.Dispose() Pause(howLong) Me.loading = False Me.opacityTimer.Start() End If Else Me.Opacity -= 0.08 If Me.Opacity <= 0 Then Me.opacityTimer.Stop() Me.Close() End If End If End Sub Public Sub Pause(ByVal Milliseconds As Integer) Dim dTimer As Date dTimer = Now.AddMilliseconds(Milliseconds) Do While dTimer > Now Application.DoEvents() Loop End Sub End Class I call the form by this simple call: Call msgWindow.showMessageBox("OK", "Finished searching images.") Does anyone know a way where i can have the same setup but would allow me to add any number of forms without refreshing the same form over and over again? Like always, any help would be great! :) David

  Read the article

• backbone js or knockout js as a web framework with jquery mobile

  - by Dan

  without trying to cause a mass discussion I would like some advice from the fellow users of stack overflow. I am about to start building a mobile website that gets it data from JSON that comes from a PHP rest api. I have looked into different mobile frameworks and feel that JQM will work best for us as we have the knowledge of jQuery even though a little large. Currently at work however we are using jQuery for all our sites and realise that now we are building a mobile website I need to think about javascript frameworks to move us onto a more MV* approach, which I understand the benefits of and will bring much needed structure to this mobile site and future web applications we may bring. I have made a comparision table where I have managed to bring the selection down to 2 - backbone and knockout. I have been looking around the web and it seems that there is more support for backbone in general and maybe even more support for backbone with JQM. http://jquerymobile.com/test/docs/pages/backbone-require.html One thing I have noticed however is that backbone doesnt support view bindings (declarative approach) whereas knockout does - is this a massive bonus? one of the main reasons for using a mv* for us is to get more structure - so I would like to use the library that will intergrate best with jQuery and especially jQuery mobile. neither of them seem to have that similar syntax... Thanks

  Read the article

• PostgreSQL, Foreign Keys, Insert speed & Django

  - by Miles

  A few days ago, I ran into an unexpected performance problem with a pretty standard Django setup. For an upcoming feature, we have to regenerate a table hourly, containing about 100k rows of data, 9M on the disk, 10M indexes according to pgAdmin. The problem is that inserting them by whatever method literally takes ages, up to 3 minutes of 100% disk busy time. That's not something you want on a production site. It doesn't matter if the inserts were in a transaction, issued via plain insert, multi-row insert, COPY FROM or even INSERT INTO t1 SELECT * FROM t2. After noticing this isn't Django's fault, I followed a trial and error route, and hey, the problem disappeared after dropping all foreign keys! Instead of 3 minutes, the INSERT INTO SELECT FROM took less than a second to execute, which isn't too surprising for a table <= 20M on the disk. What is weird is that PostgreSQL manages to slow down inserts by 180x just by using 3 foreign keys. Oh, disk activity was pure writing, as everything is cached in RAM; only writes go to the disks. It looks like PostgreSQL is working very hard to touch every row in the referred tables, as 3MB/sec * 180s is way more data than the 20MB this new table takes on disk. No WAL for the 180s case, I was testing in psql directly, in Django, add ~50% overhead for WAL logging. Tried @commit_on_success, same slowness, I had even implemented multi row insert and COPY FROM with psycopg2. That's another weird thing, how can 10M worth of inserts generate 10x 16M log segments? Table layout: id serial primary, a bunch of int32, 3 foreign keys to small table, 198 rows, 16k on disk large table, 1.2M rows, 59 data + 89 index MB on disk large table, 2.2M rows, 198 + 210MB So, am I doomed to either drop the foreign keys manually or use the table in a very un-Django way by defining saving bla_id x3 and skip using models.ForeignKey? I'd love to hear about some magical antidote / pg setting to fix this.

  Read the article

• Optimal two variable linear regression calculation

  - by Dave Jarvis

  Problem Am looking to apply the y = mx + b equation (where m is SLOPE, b is INTERCEPT) to a data set, which is retrieved as shown in the SQL code. The values from the (MySQL) query are: SLOPE = 0.0276653965651912 INTERCEPT = -57.2338357550468 SQL Code SELECT ((sum(t.YEAR) * sum(t.AMOUNT)) - (count(1) * sum(t.YEAR * t.AMOUNT))) / (power(sum(t.YEAR), 2) - count(1) * sum(power(t.YEAR, 2))) as SLOPE, ((sum( t.YEAR ) * sum( t.YEAR * t.AMOUNT )) - (sum( t.AMOUNT ) * sum(power(t.YEAR, 2)))) / (power(sum(t.YEAR), 2) - count(1) * sum(power(t.YEAR, 2))) as INTERCEPT, FROM (SELECT D.AMOUNT, Y.YEAR FROM CITY C, STATION S, YEAR_REF Y, MONTH_REF M, DAILY D WHERE -- For a specific city ... -- C.ID = 8590 AND -- Find all the stations within a 15 unit radius ... -- SQRT( POW( C.LATITUDE - S.LATITUDE, 2 ) + POW( C.LONGITUDE - S.LONGITUDE, 2 ) ) < 15 AND -- Gather all known years for that station ... -- S.STATION_DISTRICT_ID = Y.STATION_DISTRICT_ID AND -- The data before 1900 is shaky; insufficient after 2009. -- Y.YEAR BETWEEN 1900 AND 2009 AND -- Filtered by all known months ... -- M.YEAR_REF_ID = Y.ID AND -- Whittled down by category ... -- M.CATEGORY_ID = '001' AND -- Into the valid daily climate data. -- M.ID = D.MONTH_REF_ID AND D.DAILY_FLAG_ID <> 'M' GROUP BY Y.YEAR ORDER BY Y.YEAR ) t Data The data is visualized here: Question The following results (to calculate the start and end points of the line) appear incorrect. Why are the results off by ~10 degrees (e.g., outliers skewing the data)? (1900 * 0.0276653965651912) + (-57.2338357550468) = -4.66958228 (2009 * 0.0276653965651912) + (-57.2338357550468) = -1.65405406 I would have expected the 1900 result to be around 10 (not -4.67) and the 2009 result to be around 11.50 (not -1.65). Related Sites Least absolute deviations Robust regression Thank you!

  Read the article

• PowerShell PSCX Read-Archive: Cannot bind parameter... problem

  - by Robert

  I'm running across a problem I can't seem to wrap my head around using the Read-Archive cmdlet available via PowerShell Community Extensions (v2.0.3782.38614). Here is a cut down sample used to exhibit the problem I'm running into: $mainPath = "p:\temp" $dest = Join-Path $mainPath "ps\CenCodes.zip" Read-Archive -Path $dest -Format zip Running the above produces the following error: Read-Archive : Cannot bind parameter 'Path'. Cannot convert the "p:\temp\ps\CenCodes.zip" value of type "System.String" to type "Pscx.IO.PscxPathInfo". At line:3 char:19 + Read-Archive -Path <<<< $dest -Format zip + CategoryInfo : InvalidArgument: (:) [Read-Archive], ParameterBindingException + FullyQualifiedErrorId : CannotConvertArgumentNoMessage,Pscx.Commands.IO.Compression.ReadArchiveCommand If I do not use Join-Path to build the path passed to Read-Archive it works, as in this example: $mainPath = "p:\temp" $path = $mainPath + "\ps\CenCodes.zip" Read-Archive -Path $path -Format zip Output from above: ZIP Folder: CenCodes.zip#\ Index LastWriteTime Size Ratio Name ----- ------------- ---- ----- ---- 0 6/17/2010 2:03 AM 3009106 24.53 % CenCodes.xls Even more confusing is if I compare the two variables passed as the Path argument in the two Read-Archive samples above, they seem identical: This... Write-Host "dest=$dest" Write-Host "path=$path" Write-Host ("path -eq dest is " + ($dest -eq $path).ToString()) Outputs... dest=p:\temp\ps\CenCodes.zip path=p:\temp\ps\CenCodes.zip path -eq dest is True Anyone have any ideas as to why the first sample gripes but the second one works fine?

  Read the article

• I need some pointers on how to implement inertia

  - by gargantaun

  Ok, so I've created a little plugin that takes a bunch of elements and creates a sort of never ending list. I'll try to explain... I have a div, and it's got about 20 elements tags in it. When the user scrolls up, the top element moves out of view and is moved to the bottom of the list. And vice-versa so that when the user scrolls down, the bottom element is moved to the top of the list. This is specifically for Mobile Safari (iPad, iPhone) web content and you can see the work in progress here... http://appliedworks.co.uk/files/times/SVGTests/drumView/drum.html You'll need an iPad or iPhone top see the scrolling in action. You can see the plugin code here... http://appliedworks.co.uk/files/times/SVGTests/drumView/drumView-0.1b.js What I would like to do is implement inertia so the scrolling slows to a halt in response to how fast or slow the user is scrolling when their finger leaves the screen. Just like the inertia commonly found in the iPhone / iPad UI. The problem is, every time an element moves to the top or the bottom of the list, the scollTop value for the parent div is adjusted to make it look like all the elements are staying in the same place. Which means the scrollTop value is never more than the top elements total height. So there's no value I can think of that I can keep on manipulating to give the illusion of inertia. I'm stumped. Does anyone have any suggestions?

  Read the article

• UIButton and UIControlEventState issue

  - by Typeoneerror

  I'm having a very specific "bug" in my iPhone application. I'm setting two images for the highlighted and normal states of a button. It works as expected when you "press" and then "touch up" at a slow pace, but if you click/tap it quickly, there's a noticeable flicker between states. Is this a known bug or am I setting the states incorrectly? Here's the code that creates the buttons: UIImage *normalImage = [[UIImage imageNamed:@"btn-small.png"] stretchableImageWithLeftCapWidth:10.0f topCapHeight:0.0f]; UIImage *highlightedImage = [[UIImage imageNamed:@"btn-small-down.png"] stretchableImageWithLeftCapWidth:10.0f topCapHeight:0.0f]; [self setBackgroundColor:[UIColor clearColor]]; [self setBackgroundImage:normalImage forState:UIControlStateNormal]; [self setBackgroundImage:highlightedImage forState:UIControlStateDisabled]; [self setBackgroundImage:highlightedImage forState:UIControlStateHighlighted]; [self setAdjustsImageWhenDisabled:FALSE]; [self setAdjustsImageWhenHighlighted:FALSE]; When a button is tapped it simply disables itself and enables the other button: - (IBAction)aboutButtonTouched:(id)sender { aboutButton.enabled = FALSE; rulesButton.enabled = TRUE; } - (IBAction)rulesButtonTouched:(id)sender { rulesButton.enabled = FALSE; aboutButton.enabled = TRUE; } Any thoughts on this quick-click flicker?

  Read the article

• Displaying tree path of record in SQL Server 2005

  - by jskiles1

  An example of my tree table is: ([id] is an identity) [id], [parent_id], [path] 1, NULL, 1 2, 1, 1-2 3, 1, 1-3 4, 3, 1-3-4 My goal is to query quickly for multiple rows of this table and view the full path of the node from its root, through its superiors, down to itself. The ultimate question is, should I generate this path on inserts and maintain it in its own column or generate this path on query to save disk space? I guess it depends if this table is write heavy or read heavy. I've been contemplating several approaches to using the "path" characteristic of this parent/child relationship and I just can't seem to settle on one. This "path" is simply for display purposes and serves absolutely no purpose other than that. Here is what I have done to implement this "path." AFTER INSERT TRIGGER - requires passing a NULL path to the insert and updating the path for the record at the inserted rows identity INSTEAD OF INSERT TRIGGER - does not require insert to have NULL path passed, but does require the trigger to insert with a NULL path and updating the path for the record at SCOPE_IDENTITY() STORED PROCEDURE - requiring all inserts into this table to be done through the stored procedure implementing the trigger logic VIEW - requires building the path in the view 1 and 2 seem annoying if massive amounts of data are entered at once. 3 seems annoying because all inserts must go through the procedure in order to have a valid path populated. 1, 2, and 3 require maintaining a path column on the table. 4 removes all the limitations of the above but require the view to perform the path logic and requires use of the view if a path is to be displayed. I have successfully implemented all of the above approaches and I'm mainly looking for some advice. Am I way off the mark here or are any of the above acceptable? Each has it's advantages and disadvantages.

  Read the article

• array or list into Oracle using cfprocparam

  - by Travis

  I have a list of values I want to insert into a table via a stored procedure. I figured I would pass an array to oracle and loop through the array but I don't see how to pass an array into Oracle. I'd pass a list but I don't see how to work with the list to turn it into an array using PL/SQL (I'm fairly new to PL/SQL). Am I approaching this the wrong way? Using Oracle 9i and CF8. TIA! EDIT Perhaps I'm thinking about this the wrong way? I'm sure I'm not doing anything new here... I figured I'd convert the list to an associative array then loop the array because Oracle doesn't seem to work well with lists (in my limited observation). I'm trying to add a product, then add records for the management team. -- product table productName = 'foo' productDescription = 'bar' ... ... etc -- The managementteam table just has the id of the product and id of the users selected from a drop down. The user IDs are passed in via a list like "1,3,6,20" How should I go about adding the records to the management team table?

  Read the article

• How to publish internal data to the internet - as simple as possible

  - by mlarsen

  We have a .net 2-tier application where a desktop program is talking to a database. We support MS SQL Server 2000, 2005, 2008 and Oracle 9, 10 and 11. The application is sold, not as shrink-wrap, but pretty close. It is quite important for us that the installation and configuration is as easy as possible as installation instructions are usually supplied in written form to the customers internal IT-department. Our application is usually not seen as mission critical for the IT-department, so we need to keep their work down to a minimum. Now we are starting to get wishes for a web application build on top of the same data. The web application will be hosted by us and delivered as a SaaS application. Now the challenge is how to move data back and forth between the web application and the customers internal database. as I see it we have some requirements: We must be ready to handle the situation where the customers database is not accessible from the DMZ. I guess the easiest solution is that all communication is initiated from inside the customers lan. As little firewall configuration as possible. The best is if we can run without any special configuration as long as outgoing traffic from the customers lan are not blocked. If we need something changed in the firewall, we must be able to document that the change is secure. It doesn't have to be real time. Moving data in batches every ten minutes or so is OK. Data moves both ways, but not the same tables, so we don't have to support merges. It would be nice if we don't have to roll our own framework completely. Looking forward to hear your suggestions.

  Read the article

• parse content away from structure in a binary file

  - by Jeff Godfrey

  Using C#, I need to read a packed binary file created using FORTRAN. The file is stored in an "Unformatted Sequential" format as described here (about half-way down the page in the "Unformatted Sequential Files" section): http://www.tacc.utexas.edu/services/userguides/intel8/fc/f_ug1/pggfmsp.htm As you can see from the URL, the file is organized into "chunks" of 130 bytes or less and includes 2 length bytes (inserted by the FORTRAN compiler) surrounding each chunk. So, I need to find an efficient way to parse the actual file payload away from the compiler-inserted formatting. Once I've extracted the actual payload from the file, I'll then need to parse it up into its varying data types. That'll be the next exercise. My first thoughts are to slurp up the entire file into a byte array using File.ReadAllBytes. Then, just iterate through the bytes, skipping the formatting and transferring the actual data to a second byte array. In the end, that second byte array should contain the actual file contents minus all the formatting, which I'd then need to go back through to get what I need. As I'm fairly new to C#, I thought there might be a better, more accepted way of tackling this. Also, in case it's helpful, these files could be fairly large (say 30MB), though most will be much smaller...

  Read the article

• When is a good time to start thinking about scaling?

  - by Slokun

  I've been designing a site over the past couple days, and been doing some research into different aspects of scaling a site horizontally. If things go as planned, in a few months (years?) I know I'd need to worry about scaling the site up and out, since the resources it would end up consuming would be huge. So, this got me to thinking, when is the best time to start thinking about, and designing for, scalability? If you start too early on, you could easily over complicate your design, and make it impossible to actually build. You could also get too caught up in the details, the architecture, whatever, and wind up getting nothing done. Also, if you do get it working, but the site never takes off, you may have wasted a good chunk of extra effort. On the other hand, you could be saving yourself a ton of effort down the road. Designing it from the ground up to be big would make it much easier later on to let it grow big, with very little rewriting going on. I know for what I'm working on, I've decided to make at least a few choices now on the side of scaling, but I'm not going to do a complete change of thinking to get it to scale completely. Notably, I've redesigned my database from a conventional relational design to one similar to what was suggested on the Reddit site linked below, and I'm going to give memcache a try. So, the basic question, when is a good time to start thinking or worrying about scaling, and what are some good designs, tips, etc. for when doing so? A couple of things I've been reading, for those who are interested: http://www.codinghorror.com/blog/2009/06/scaling-up-vs-scaling-out-hidden-costs.html http://highscalability.com/blog/2010/5/17/7-lessons-learned-while-building-reddit-to-270-million-page.html http://developer.yahoo.com/performance/rules.html

  Read the article

• Which tools to use and how to find file descriptors leaking from Glassfish?

  - by cclark

  We release new code to production every week and Glassfish hasn't had any problems. This weekend we had to move racks at our hosting provider. There were not any code changes (they just powered off, moved, re-racked and powered on) but we're on a new network infrastructure and suddenly we're leaking file descriptors like a sieve. So I'm guessing there is some sort of connection attempting to be made which now fails due to a network change. I'm running Glassfish v2ur2-b04/AS9.1_02 on RHEL4 with an embedded IMQ instance. After the move I started seeing: [#|2010-04-25T05:34:02.783+0000|SEVERE|sun-appserver9.1|javax.enterprise.system.container.web|_ThreadID=33;_ThreadName=SelectorThread-?4848;_RequestID=c4de6f6d-c1d6-416d-ac6e-49750b1a36ff;|WEB0756: Caught exception during HTTP processing. java.io.IOException: Too many open files at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) ... [#|2010-04-25T05:34:03.327+0000|WARNING|sun-appserver9.1|javax.enterprise.system.stream.err|_ThreadID=34;_ThreadName=Timer-1;_RequestID=d27e1b94-d359-4d90-a6e3-c7ec49a0f383;|java.lang.NullPointerException at com.sun.jbi.management.system.AutoAdminTask.pollAutoDirectory(AutoAdminTask.java:1031) Using lsof I check the number of file descriptors and I see quite a few entries which look like: java 18510 root 8556u sock 0,4 1555182 can't identify protocol java 18510 root 8557u sock 0,4 1555320 can't identify protocol java 18510 root 8558u sock 0,4 1555736 can't identify protocol java 18510 root 8559u sock 0,4 1555883 can't identify protocol If I do a count of open file descriptors every minute I see it growing by 12 every minute. I have no idea what these sockets are. I've undeployed my application so there is only a plain Glassfish instance running and I still see it leaking 12 file descriptors a minute. So I think this leak is in Glassfish or potentially IMQ. What approach should I take to tracking down these sockets of unknown protocol? What tools can I use (or flags can I pass to lsof) to get more information about where to look? thanks, chuck

  Read the article

• best way to add and delete text lines with jquery product configurator

  - by Daniel White

  I am creating a product configurator with Jquery. My users can add custom text lines to their product. So you could create say... 4 text lines with custom text. I need to know what the best way to add and delete these lines would be. Currently I have the following code for adding lines... //Add Text Button $('a#addText').live('click', function(event) { event.preventDefault(); //Scroll up the text editor $('.textOptions').slideUp(); $('#customText').val(''); //count how many items are in the ul textList var textItems = $('ul#textList li').size(); var nextNumber = textItems + 1; if(textItems <= 5) { //Change input to reflect current text being changed $('input#currentTextNumber').val(nextNumber); //Append a UL Item to the textList $('ul#textList').append('<li id="textItem'+nextNumber+'">Text Line. +$5.00 <a class="deleteTextItem" href="'+nextNumber+'">Delete</a></li>'); //Scroll down the text editor $('.textOptions').slideDown(); }else { alert('you can have a maximum of 6 textual inputs!'); } }); I'm probably not doing this the best way, but basically i have an empty UL list to start with. So when they click "Add Text Line" it finds out how many list elements are in the unordered list, adds a value of 1 to that and places a new list element with the id TextItem1 or TextItem2 or whatever number we're on. The problem i'm running into is that when you click delete item, it screws everything up because when you add an item again all the numbers aren't correct. I thought about writing some kind of logic that says all the numbers above the one you want deleted get 1 subtracted from their value and all the numbers below stay the same. But I think i'm just going about this the wrong way. Any suggestions on the easiest way to add and delete these text lines is appreciated.

  Read the article

• Should I write more SQL to be more efficient, or less SQL to be less buggy?

  - by RenderIn

  I've been writing a lot of one-off SQL queries to return exactly what a certain page needs and no more. I could reuse existing queries and issue a number of SQL requests linear to the number of records on the page. As an example, I have a query to return People and a query to return Job Details for a person. To return a list of people with their job details I could query once for people and then once for each person to retrieve their job details. I've found that in most cases that solution returns things in a reasonable amount of time, but I don't know how well it will scale in my environment. Instead I've been writing queries to join people + job details, or people + salary history, etc. I'm looking at my models and I see how I could shave off maybe 30% of my code if I were to re-use existing queries. This is a big temptation. Is it a bad thing to go for reuse over efficiency in general or does it all come down to the specific situation? Should I first do it the easy way and then optimize later, or is it best to get the code knocked out while everything is fresh in my mind? Thoughts, experiences?

  Read the article

• Center a TextBox over the top of a ScrollViewer in WPF.

  - by Eric

  I have a MainView that contains a navigation bar which selects one of many XAML pages to be displayed in the page view pane. The MainView contains a ScrollViewer around the pages. This allows the pages to be whatever size they need to be and the MainView's ScrollViewer scrolls them. This all works great. On one of the pages, I need to (sometimes) center a TextBox in the middle of the page view pane (over the top of the page content). This was easily done by placing both the page content and the TextBox overlapping each other in a Grid (and I hide the TextBox as necessary). This all seems to work great. However, if the page content grows to be larger than the pane, the TextBox is centered not on the pane, but on the full page content. Thus, it moves from center screen down and/or to the right (and eventually off the screen). Bummer. Options: Remove the ScrollViewer from the MainView. This would require placing one on every page! Argh. Do option #1, and create a ScrolledPage base class. This is a lot of work, and I'm worried about tools issues (Blend issues). It also requires changing every page (to subclass this page). Somehow override the ScrollViewer on just this page. Then, place another ScrollViewer on the page content to Scroll it. Option 3 seems preferable, because it contains the issue to just modifying this page (instead of changing the rest of the pages). However, I can't figure out how to do it. Ideas? Thanks in advance! Eric

  Read the article

• Date Picker Control Not Displaying Proper Date (Access 2003)

  - by JPM

  Hi everyone, I just have a quick question. I am maintaining an app for my summer co-op position, and a new requirement came down today where the user requested to have a date control added to a form to mark the date of when an employee is "laid off". This control is enabled/disabled by a toggle button, and has its control source bound to a field that I added in the database. All the functionality has been added and tested, but.... The issue I am having is that the date picker is on a tab control (the 2nd page) and I am having problems trying to get the control to display the date that is stored in the field I created. I know the control is storing any changes made using it, but since the user asked to move the control over to the 2nd tab (it was on the first), it just shows today's date, not the date entered using the control. To make things a little more strange, if I place the control anywhere except the tab control, it seems to be working fine. I've even placed a textbox on the tab and set its control source to the database field, and it displays just fine. What gives? And I have registered the .ocx with Access, and as I mentioned before, the actual database is storing the data. Just not displaying it. Any ideas as to what I am doing wrong?

  Read the article

• Creating content for rails-based applications

  - by Matthias Hryniszak

  Hi, I'm facing a problem of cleaning up my application in Ruby on Rails. What I have is a pretty standard 3-panel, header and footer layout where different parts of the screen contain different functionality. By that I mean for example that the header contains (among others) a select that allows one to select parts of the application and a context-dependent menu. The main content area contains obviously the most interactive stuff whereas side panels contain quick-links with stuff like shopping-cart preview, list of potentially attractive products for the customer, a selector to narrow down the list of options... I was wondering how do I go about simplifying the design. Right now I have the stuff that provides data for the "common" stuff (as opposed to direct content that's placed in the center) called from all the actions (with a filter) but that doesn't feel right for me. I've read that "components" are also not the way to go for obvious performance reasons. Is there something that's more like component-oriented (other frameworks do have that kind of stuff - Grails: <ui:include ../>, ASP.NET MVC: <% Html.RenderAction() %>)? Best regards, Matthias.

  Read the article

• Dataflow Pipeline holding on to memory

  - by Jesse Carter

  I've created a Dataflow pipeline consisting of 4 blocks (which includes one optional block) which is responsible for receiving a query object from my application across HTTP and retrieving information from a database, doing an optional transform on that data, and then writing the information back in the HTTP response. In some testing I've done I've been pulling down a significant amount of data from the database (570 thousand rows) which are stored in a List object and passed between the different blocks and it seems like even after the final block has been completed the memory isn't being released. Ram usage in Task Manager will spike up to over 2 GB and I can observe several large spikes as the List hits each block. The signatures for my blocks look like this: private TransformBlock<HttpListenerContext, Tuple<HttpListenerContext, QueryObject>> m_ParseHttpRequest; private TransformBlock<Tuple<HttpListenerContext, QueryObject>, Tuple<HttpListenerContext, QueryObject, List<string>>> m_RetrieveDatabaseResults; private TransformBlock<Tuple<HttpListenerContext, QueryObject, List<string>>, Tuple<HttpListenerContext, QueryObject, List<string>>> m_ConvertResults; private ActionBlock<Tuple<HttpListenerContext, QueryObject, List<string>>> m_ReturnHttpResponse; They are linked as follows: m_ParseHttpRequest.LinkTo(m_RetrieveDatabaseResults); m_RetrieveDatabaseResults.LinkTo(m_ConvertResults, tuple => tuple.Item2 is QueryObjectA); m_RetrieveDatabaseResults.LinkTo(m_ReturnHttpResponse, tuple => tuple.Item2 is QueryObjectB); m_ConvertResults.LinkTo(m_ReturnHttpResponse); Is it possible that I can set up the pipeline such that once each block is done with the list they no longer need to hold on to it as well as once the entire pipeline is completed that the memory is released?

  Read the article

• UITouch Events and Table Views

  - by Andy

  I'm working on a navigation-based iPhone-only app that serves two main purposes: One, to present data in a hierarchical view, allowing users to drill down and eventually edit said data, and, two, to all users to perform a default action when the table view cell is tapped. I now need to offer a small set of options tied to the same data; however, both the didSelectRowAtIndexPath: and accessoryButtonTappedForRowAtIndexPath: methods are obviously taken. So, my options seem to be to implement a double-tap method, wherein the small list of additional options would be presented after (you guessed it) a double-tap on said table row; or, preferably, a tap-and-hold method. From what I can tell, tap-and-hold seems like the way to go in SDK 4.0 - which does me no good right this red-hot minute. I decided to go with the double-tap option, but I'm having a little trouble. First and foremost, the touchesBegan:withEvent: method does not seem to be getting called at all; a breakpoint placed within the method is never called while the application runs, and the table view responds exactly as it did before I inserted the method (which is to say, it performs the default action): - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *aTouch = [touches anyObject]; if (aTouch.tapCount == 2) { [NSObject cancelPreviousPerformRequestsWithTarget:self]; } } Second, I don't really need to handle a single-tap - the didSelectRowAtIndexPath: method can handle the single-tap just fine. The double-tap is the funky one I want to handle. I suspect the answer is going to contain the phrase, "You can't have the table view handle the single-tap and the touchesBegan: method handle the double-tap. The touch handling methods have to handle all of them." I would really appreciate some guidance from some of you who've dealt with this issue. Thanks in advance.

  Read the article

< Previous Page | 587 588 589 590 591 592 593 594 595 596 597 598  | Next Page >