Search Results

Search found 13249 results on 530 pages for 'performance tuning'.

Page 469/530 | < Previous Page | 465 466 467 468 469 470 471 472 473 474 475 476  | Next Page >

• Can I automatically throw descriptive exceptions with parameter values and class feild information?

  - by Robert H.

  I honestly don't throw exceptions often. I catch them even less, ironically. I currently work in shop where we let them bubble up to avicode. For whatever reason, however, avicode isn't configured to capture some of the critical bits I need when these exceptions come bouncing back to my attention. Specifically, I'd like to see the parameter values and the class’s field data at the time of the exception. I’d guess with the large suite of .Net services that I could create a static method to crawl up the stack, gather these bits and store them in a string that I could stick in my exception message. I really don't are how long such a method would take to execute as performance is no longer a concern when I hit one of these scenarios. If it's possible, I'm sure someone has done it. If that's the case, I'm having a hard time finding it. I think any search containing "exception" brings back too many resutls. Anyway, can this be done? If so, some examples or links would be great. Thanks in advance for your time, Robert

  Read the article

• sem-dynamic cdn

  - by dwi kristianto

  i'm developing couple of websites using php (directory script, etc.) and wordpress as cms. i need to improve its performance, by using cdn for static files (css, js, images). the problem is, css and javascript files are generated on the fly. i did that due to yahoo and some expert advice to combine the files into one file. also changing basic color of css files. for the time being, i use couple of small vps but still its not fast enough. i already contact maxcdn and the support guy said that they dont have such kind of services. what i need is: a cdn that will serve the request from user/visitor and there's no file in local disk, the cdn will redirect/fetch it from another domain/server. in vps, it could be done easily using combination of .htaccess and php, but NOT in the cdn. most of cdn only support purely static files. is there any such cdn that will server semi-dynamic files?

  Read the article

• Stack usage with MMX intrinsics and Microsoft C++

  - by arik-funke

  I have an inline assembler loop that cumulatively adds elements from an int32 data array with MMX instructions. In particular, it uses the fact that the MMX registers can accommodate 16 int32s to calculate 16 different cumulative sums in parallel. I would now like to convert this piece of code to MMX intrinsics but I am afraid that I will suffer a performance penalty because one cannot explicitly intruct the compiler to use the 8 MMX registers to accomulate 16 independent sums. Can anybody comment on this and maybe propose a solution on how to convert the piece of code below to use intrinsics? == inline assembler (only part within the loop) == paddd mm0, [esi+edx+8*0] ; add first & second pair of int32 elements paddd mm1, [esi+edx+8*1] ; add third & fourth pair of int32 elements ... paddd mm2, [esi+edx+8*2] paddd mm3, [esi+edx+8*3] paddd mm4, [esi+edx+8*4] paddd mm5, [esi+edx+8*5] paddd mm6, [esi+edx+8*6] paddd mm7, [esi+edx+8*7] ; add 15th & 16th pair of int32 elements esi points to the beginning of the data array edx provides the offset in the data array for the current loop iteration the data array is arranged such that the elements for the 16 independent sums are interleaved.

  Read the article

• Handling form from different view and passing form validation through session in django

  - by Mo J. Mughrabi

  I have a requirement here to build a comment-like app in my django project, the app has a view to receive a submitted form process it and return the errors to where ever it came from. I finally managed to get it to work, but I have doubt for the way am using it might be wrong since am passing the entire validated form in the session. below is the code comment/templatetags/comment.py @register.inclusion_tag('comment/form.html', takes_context=True) def comment_form(context, model, object_id, next): """ comment_form() is responsible for rendering the comment form """ # clear sessions from variable incase it was found content_type = ContentType.objects.get_for_model(model) try: request = context['request'] if request.session.get('comment_form', False): form = CommentForm(request.session['comment_form']) form.fields['content_type'].initial = 15 form.fields['object_id'].initial = 2 form.fields['next'].initial = next else: form = CommentForm(initial={ 'content_type' : content_type.id, 'object_id' : object_id, 'next' : next }) except Exception as e: logging.error(str(e)) form = None return { 'form' : form } comment/view.py def save_comment(request): """ save_comment: """ if request.method == 'POST': # clear sessions from variable incase it was found if request.session.get('comment_form', False): del request.session['comment_form'] form = CommentForm(request.POST) if form.is_valid(): obj = form.save(commit=False) if request.user.is_authenticated(): obj.created_by = request.user obj.save() messages.info(request, _('Your comment has been posted.')) return redirect(form.data.get('next')) else: request.session['comment_form'] = request.POST return redirect(form.data.get('next')) else: raise Http404 the usage is by loading the template tag and firing {% comment_form article article.id article.get_absolute_url %} my doubt is if am doing the correct approach or not by passing the validated form to the session. Would that be a problem? security risk? performance issues? Please advise Update In response to Pol question. The reason why I went with this approach is because comment form is handled in a separate app. In my scenario, I render objects such as article and all I do is invoke the templatetag to render the form. What would be an alternative approach for my case? You also shared with me the django comment app, which am aware of but the client am working with requires a lot of complex work to be done in the comment app thats why am working on a new one.

  Read the article

• Count rows against to SQL server (2005) table?

  - by David.Chu.ca

  I have a simple question with two options to get count of rows in a SQL server (2005). I am using VS 2005. There are two options to get the count: SELECT id FROM Table1 WHERE dt >= startDt AND dt < endDt;; I get a list of ids from above call in cache and then I get count by List.Count. Another option is SELECT COUNT(*) FROM Table1 WHERE dt >= startDt AND dt < endDt; The above call will get the count directly. The issue is that I had several cases of exceptions with the second method: timeout. What I found is that the table1 is too big with millions of data. When I used the first option, it seems OK. I am confused by the fact that Count() takes more time than getting all the rows(is that true?). Not sure if the aggregation call with Count() would cause SQL server to create temporary table or cache on server side and it would result in slow performance when table is too big? I am not sure what is the best way to get the count?

  Read the article

• Porting - Shared Memory x32 & x64 processes

  - by dpb

  A 32 bit host Windows application setups shared memory (using memory mapped file / CreateFileMapping() API), and then other 32 bit client processes use this shared memory to communicate with each other. I am planning to port the host application to 64 bit platform and once it is ready, I intend that both 32 bit and 64 bit client processes should be able to use the shared memory setup by the main 64 bit host application. The original code written for host x32 application uses "size_t" almost everywhere, since this differs from 4 bytes to 8 bytes as we move from x32 to x64, I am looking for replacing it. I intend to replace "size_t" by "unsigned long long", so that its size will be same on 32 bit & 64 bit. Can you please suggest me better alternative? Also, will the use of "unsigned long long" have performance impact on x32 app .. i guess yes? Research Done - Found very useful articles - a) 20 issue in porting from 32 bit to 64 bit (www.viva64.com) b) No way to restrict/change "size_t" on x64 platform to 4 bytes using compiler flags or any hooks/crooks since it is typedef

  Read the article

• Can parser combinators be made efficient?

  - by Jon Harrop

  Around 6 years ago, I benchmarked my own parser combinators in OCaml and found that they were ~5× slower than the parser generators on offer at the time. I recently revisited this subject and benchmarked Haskell's Parsec vs a simple hand-rolled precedence climbing parser written in F# and was surprised to find the F# to be 25× faster than the Haskell. Here's the Haskell code I used to read a large mathematical expression from file, parse and evaluate it: import Control.Applicative import Text.Parsec hiding ((<|>)) expr = chainl1 term ((+) <$ char '+' <|> (-) <$ char '-') term = chainl1 fact ((*) <$ char '*' <|> div <$ char '/') fact = read <$> many1 digit <|> char '(' *> expr <* char ')' eval :: String -> Int eval = either (error . show) id . parse expr "" . filter (/= ' ') main :: IO () main = do file <- readFile "expr" putStr $ show $ eval file putStr "\n" and here's my self-contained precedence climbing parser in F#: let rec (|Expr|) (P(f, xs)) = Expr(loop (' ', f, xs)) and loop = function | ' ' as oop, f, ('+' | '-' as op)::P(g, xs) | (' ' | '+' | '-' as oop), f, ('*' | '/' as op)::P(g, xs) -> let h, xs = loop (op, g, xs) let op = match op with | '+' -> (+) | '-' -> (-) | '*' -> (*) | '/' -> (/) loop (oop, op f h, xs) | _, f, xs -> f, xs and (|P|) = function | '('::Expr(f, ')'::xs) -> P(f, xs) | c::xs when '0' <= c && c <= '9' -> P(int(string c), xs) My impression is that even state-of-the-art parser combinators waste a lot of time back tracking. Is that correct? If so, is it possible to write parser combinators that generate state machines to obtain competitive performance or is it necessary to use code generation?

  Read the article

• How to avoid multiple, unused has_many associations when using multiple models for the same entity (

  - by mikep

  Hello, I'm looking for a nice, Ruby/Rails-esque solution for something. I'm trying to split up some data using multiple tables, rather than just using one gigantic table. My reasoning is pretty much to try and avoid the performance drop that would come with having a big table. So, rather than have one table called books, I have multiple tables: books1, books2, books3, etc. (I know that I could use a partition, but, for now, I've decided to go the 'multiple tables' route.) Each user has their books placed into a specific table. The actual book table is chosen when the user is created, and all of their books go into the same table. The goal is to try and keep each table pretty much even -- but that's a different issue. One thing I don't particularly want to have is a bunch of unused associations in the User class. Right now, it looks like I'd have to do the following: class User < ActiveRecord::Base has_many :books1, :books2, :books3, :books4, :books5 end class Books1 < ActiveRecord::Base belongs_to :user end class Books2 < ActiveRecord::Base belongs_to :user end First off, for each specific user, only one of the book tables would be usable/applicable, since all of a user's books are stored in the same table. So, only one of the associations would be in use at any time and any other has_many :bookX association that was loaded would be a waste. I don't really know Ruby/Rails does internally with all of those has_many associations though, so maybe it's not so bad. But right now I'm thinking that it's really wasteful, and that there may just be a better, more efficient way of doing this. Is there's some sort of special Ruby/Rails methodology that could be applied here to avoid having to have all of those has_many associations? Also, does anyone have any advice on how to abstract the fact that there's multiple book tables behind a single books model/class?

  Read the article

• How to implement custom JSF component for drawing chart?

  - by Roman

  I want to create a component which can be used like: <mc:chart data="#{bean.data}" width="200" height="300" /> where #{bean.data} returns a collection of some objects or chart model object or something else what can be represented as a chart (to put it simple, let's assume it returns a collection of integers). I want this component to generate html like this: <img src="someimg123.png" width="200" height="300"/> The problem is that I have some method which can receive data and return image, like: public RenderedImage getChartImage (Collection<Integer> data) { ... } and I also have a component for drawing dynamic image: <o:dynamicImage width="200" height="300" data="#{bean.readyChartImage}/> This component generates html just as I need but it's parameter is array of bytes or RenderedImage i.e. it needs method in bean like this: public RenderedImage getReadyChartImage () { ... } So, one approach is to use propertyChangedListener on submit to set data (Collection<Integer>) for drawing chart and then use <o:dynamicImage /> component. But I'd like to create my own component which receives data and draws chart. I'm using facelets but it's not so important indeed. Any ideas how to create the desired component? P.S. One solution I was thinking about is not to use <o:dynamicImage/> and use some servlet to stream image. But I don't know how to implement that correctly and how to tie jsf component with servlet and how to save already built chart images (generating new same image for each request can cause performance problems imho) and so on..

  Read the article

• SQL Server becomes slow after restart

  - by Tobi DM

  We use SQL Server 2005 on an Windwos Server 2008. Ther Server has 48 GB RAM. SQL Server is configured to use 40 GB RAM. There is only one database hosted (About 70 GB). The only app beside SQL Server is our App-Server which connects the clients to the database. Now we encounter the following problem: After a restart of the server our the performance is great. The server grabs the 40 GB RAM wich it is allowed to and then runs fast as hell. But after about 4 weeks the system becomes slower and slower. The execution of statements (seen in the profiler) is raising slowly. But I cannot see that there is something going wrong on the server. CPU usage is at about 20% I/O also seems to be no Problem The process monitor does also not show that there are strange apps or something like that. Eventlog does also have no interessting messages No open transactions or blockings to see We tried already the following things without effect: Droped the cache by using the statements DBCC FreeProcCache DBCC FREESYSTEMCACHE('ALL') DBCC DropCleanbuffers Restarted the Appserver we are using. Restart the sql server service But nothing did help exept restarting the whole server. Any ideas?

  Read the article

• Automatic .NET code, nhibernate session, and LINQ datacontext clean-up?

  - by AverageJoe719

  Hi all, in my goal to adopt better coding practices I have a few questions in general about automatic handling of code. I have heard different answers both from online and talking with other developers/programmers at my work. I am not sure if I should have split them into 3 questions, but they all seem sort of related: 1) How does .NET handle instances of classes and other code things that take up memory? I recently found out about using the factory pattern for certain things like service classes so that they are only instantiated once in the entire application, but then I was told that '.NET handles a lot of that stuff automatically when mentioning it.' 2) How does Nhibernate's session handle automatic clean-up of un-used things? I've seen some say that it is great at handling things automatically and you should just use a session factory and that's it, no need to close it. But I have also read and seem many examples where people close the hibernate session. 3) How does LINQ's datacontext handle this? Most of the time I never .disposed my datacontext's and the app didn't see to take a performance hit (though I am not running anything super intensively), but it seems like most people recommend disposing of your datacontext after you are done with it. However, I have seen many many code examples where the dispose method is never called. Also in general I found it kind of annoying that you couldn't access even one-deep child related objects after disposing of the datacontext unless you explicity also grabbed them in the query. Thanks all. I am loving this site so far, I kind of get lost and spend hours just reading things on here. =)

  Read the article

• How does loop address alignment affect the speed on Intel x86_64?

  - by Alexander Gololobov

  I'm seeing 15% performance degradation of the same C++ code compiled to exactly same machine instructions but located on differently aligned addresses. When my tiny main loop starts at 0x415220 it's faster then when it is at 0x415250. I'm running this on Intel Core2 Duo. I use gcc 4.4.5 on x86_64 Ubuntu. Can anybody explain the cause of slowdown and how I can force gcc to optimally align the loop? Here is the disassembly for both cases with profiler annotation: 415220 576 12.56% |XXXXXXXXXXXXXX 48 c1 eb 08 shr $0x8,%rbx 415224 110 2.40% |XX 0f b6 c3 movzbl %bl,%eax 415227 0.00% | 41 0f b6 04 00 movzbl (%r8,%rax,1),%eax 41522c 40 0.87% | 48 8b 04 c1 mov (%rcx,%rax,8),%rax 415230 806 17.58% |XXXXXXXXXXXXXXXXXXX 4c 63 f8 movslq %eax,%r15 415233 186 4.06% |XXXX 48 c1 e8 20 shr $0x20,%rax 415237 102 2.22% |XX 4c 01 f9 add %r15,%rcx 41523a 414 9.03% |XXXXXXXXXX a8 0f test $0xf,%al 41523c 680 14.83% |XXXXXXXXXXXXXXXX 74 45 je 415283 ::Run(char const*, char const*)+0x4b3 41523e 0.00% | 41 89 c7 mov %eax,%r15d 415241 0.00% | 41 83 e7 01 and $0x1,%r15d 415245 0.00% | 41 83 ff 01 cmp $0x1,%r15d 415249 0.00% | 41 89 c7 mov %eax,%r15d 415250 679 13.05% |XXXXXXXXXXXXXXXX 48 c1 eb 08 shr $0x8,%rbx 415254 124 2.38% |XX 0f b6 c3 movzbl %bl,%eax 415257 0.00% | 41 0f b6 04 00 movzbl (%r8,%rax,1),%eax 41525c 43 0.83% |X 48 8b 04 c1 mov (%rcx,%rax,8),%rax 415260 828 15.91% |XXXXXXXXXXXXXXXXXXX 4c 63 f8 movslq %eax,%r15 415263 388 7.46% |XXXXXXXXX 48 c1 e8 20 shr $0x20,%rax 415267 141 2.71% |XXX 4c 01 f9 add %r15,%rcx 41526a 634 12.18% |XXXXXXXXXXXXXXX a8 0f test $0xf,%al 41526c 749 14.39% |XXXXXXXXXXXXXXXXXX 74 45 je 4152b3 ::Run(char const*, char const*)+0x4c3 41526e 0.00% | 41 89 c7 mov %eax,%r15d 415271 0.00% | 41 83 e7 01 and $0x1,%r15d 415275 0.00% | 41 83 ff 01 cmp $0x1,%r15d 415279 0.00% | 41 89 c7 mov %eax,%r15d

  Read the article

• Quartz 2D or OpenGL ES? Pros and cons in the long term, possibility of migration to other platforms.

  - by fspirit

  Hi all! I'm having a hard time deciding whether to go with Quartz2D or OpenGL for an iPad game. It will be 2D mostly, but effect-intense (simultaneous lighting effects for 10-30 objects, 10-20 simultaneous animations on the screen). So far, assuming i'm equally dumb in both technologies and have to learn them from the ground, i came to this list. (I've read several topics here, on SO, with names like "Quartz or OpenGL", but i'm still left with some questions) Quartz: Better time-to-market, because of ready to use absractions like UIView, UIImageView, CoreAnimation abstractions Open GL ES Closer to hardware, thus, performance is better. App, implemented with OpenGL ES can be easier migrated to Android, MeeGo, Windows Phone, etc. My questions are: How time will it take to rewrite Quartz 2d app to use OpenGL? Lets say it took me 2 man-month to write Quartz app, how much time will i need to rewrite it? (Please, just some subjective opinions, i'll try to summarize them somehow) Regarding the ease of migration to other platforms, when using OpenGL, is it really so? Or efforts when migrating Quartz app from iPhoneOS to Android will be not so much bigger, compared to OpenGL app migration? (Ease of migration is quite important criterion) Regarding OpenGL, should i go with OpenGL 1.1 or 2.0, concerning migration? (Android supports 2.0 through NDK, but dont know whether NDK's use will increase or decrease migration efforts)

  Read the article

• MKL Accelerated Math Libraries for Java...

  - by Kaopua

  I've looked at the related threads on StackOverflow and Googled with not much luck. I'm also very new to Java (I'm coming from a C# and .NET background) so please bear with me. There is so much available in the Java world it's pretty overwhelming. I'm starting on a new Java-on-Linux project that requires some heavy and highly repetitious numerical calculations (i.e. statistics, FFT, Linear Algebra, Matrices, etc.). So maximizing the performance of the mathematical operations is a requirement, as is ensuring the math is correct. So hence I have an interest in finding a Java library that perhaps leverages native acceleration such as MKL, and is proven (so commercial options are definitely a possibility here). In the .NET space there are highly optimized and MKL accelerated commercial Mathematical libraries such as Centerspace NMath and Extreme Optimization. Is there anything comparable in Java? Most of the math libraries I have found for Java either do not seem to be actively maintained (such as Colt) or do not appear to leverage MKL or other native acceleration (such as Apache Commons Math). I have considered trying to leverage MKL directly from Java myself (e.g. JNI), but me being new to Java (let alone interoperating between Java and native libraries) it seemed smarter finding a Java library that has already done this correctly, efficiently, and is proven. Again I apologize if I am mistaken or misguided (even in regarding any libraries I've mentioned) and my ignorance of the Java offerings. It's a whole new world for me coming from the heavily commercialized Microsoft stock so I could easily be mistaken on where to look and regarding the Java libraries I've mentioned. I would greatly appreciate any help or advice.

  Read the article

• Complex LINQ paging algorithm

  - by sharepointmonkey

  We have a list of projects that may or may not have a collection of subprojects. Our report needs to contain all the projects except those that are the parent project of a subproject. I need to page this into pages of, say, 25 rows. But if subprojects appear on that page then ALL the subprojects of that project must appear on the same page. So more than 25 items may appear if necessary. I've got as far as var pagedProjects = db.Projects.Where(x => !x.SubProjects.Any()).Skip( (pageNo -1) * pageSize).Take(pageSize); Obviously, this fails the second part of the requirements. As a further pain in the arse, I need to have a pager control on the report. So I'll need to be able to calculate the total number of pages. I could loop through the whole table of projects but the performance will suffer. Can anybody come up with a paged solution? EDIT - I should probably mention that SubProjects joins back onto Projects via a selfreferencing foreign key so the whole lot comes back as an IQueryable<Project>.

  Read the article

• JSON VIEW using GROUP_CONCAT question

  - by Dan Beam

  Hey DBAs and overall smart dudes. I have a question for you. We use MySQL VIEWs to format our data as JSON when it's returned (as a BLOB), which is convenient (though not particularly nice on performance, but we already know this). But, I can't seem to get a particular query working right now (each row contains NULL when it should contain a created JSON object with the values of multiple JOINs). Here's the general idea: SELECT CONCAT( "{", "\"some_list\":[", GROUP_CONCAT( DISTINCT t1.id ), "],", "\"other_list\":[", GROUP_CONCAT( DISTINCT t2.id ), "],", "}" ) cool_json FROM table_name tn INNER JOIN ( some_table st ) ON st.some_id = tn.id LEFT JOIN ( another_table at, another_one ao, used_multiple_times t1 ) ON st.id = at.some_id AND at.different_id = ao.different_id AND ao.different_id = t1.id LEFT JOIN ( another_table2 at2, another_one2 ao2, used_multiple_times t2 ) ON st.id = at2.some_id AND at2.different_id = ao2.different_id AND ao2.different_id = t2.id GROUP BY tn.id ORDER BY tn.name Anybody know the problem here? Am I missing something I should be grouping by? It was working when I was only doing 1 LEFT JOIN & GROUP_CONCAT, but now with multiple JOINs / GROUP_CONCATs it's messing it up. When I move the GROUP_CONCATs from the "cool_json" field they work as expected, but I'd like my data formatted as JSON so I can decode it server-side or client-side in one step.

  Read the article

• Ruby 1.9 GarbageCollector, GC.disable/enable

  - by seb

  I'm developing a Rails 2.3, Ruby 1.9.1 webapplication that does quite a bunch of calculation before each request. For every request it has to calculate a graph with 300 nodes and ~1000 edges. The graph and all its nodes, edges and other objects are initialized for every request (~2000 objects) - actually they are cloned from an uncalculated cached graph using Marshal.load(Marshal.dump()). Performance is quite an issue here. Right now the whole request takes in average 150ms. I then saw that during a request, parts of the calculation randomly take longer. Assuming, that this might be the GarbageCollector kicking in, I wrapped the request in GC.disable and GC.enable, so that the request waits with garbagecollecting until calculating and rendering have finished. def query GC.disable calculate respond_to do |format| format.html {render} end GC.enable end The average request now takes about 100ms (50 ms less). But I'm unsure if this is a good/stable solution, I assume there must be drawbacks doing that. Does anybody has experience with a similar problem or sees problems with the above code?

  Read the article

• Determining the color of a pixel in a bitmap using C# in a WPF app

  - by DanM

  The only way I found so far is System.Drawing.Bitmap.GetPixel(), but Microsoft has warnings for System.Drawing that are making me wonder if this is the "old way" to do it. Are there any alternatives? Here's what Microsoft says about the System.Drawing namespace. I also noticed that the System.Drawing assembly was not automatically added to the references when I created a new WPF project. System.Drawing Namespace The System.Drawing namespace provides access to GDI+ basic graphics functionality. More advanced functionality is provided in the System.Drawing.Drawing2D, System.Drawing.Imaging, and System.Drawing.Text namespaces. The Graphics class provides methods for drawing to the display device. Classes such as Rectangle and Point encapsulate GDI+ primitives. The Pen class is used to draw lines and curves, while classes derived from the abstract class Brush are used to fill the interiors of shapes. Caution Classes within the System.Drawing namespace are not supported for use within a Windows or ASP.NET service. Attempting to use these classes from within one of these application types may produce unexpected problems, such as diminished service performance and run-time exceptions. - http://msdn.microsoft.com/en-us/library/system.drawing.aspx

  Read the article

• Python socket error on UDP data receive. (10054)

  - by Charles

  I currently have a problem using UDP and Python socket module. We have a server and clients. The problem occurs when we send data to a user. It's possible that user may have closed their connection to the server through a client crash, disconnect by ISP, or some other improper method. As such, it is possible to send data to a closed socket. Of course with UDP you can't tell if the data really reached or if it's closed, as it doesn't care (atleast, it doesn't bring up an exception). However, if you send data and it is closed off, you get data back somehow (???), which ends up giving you a socket error on sock.recvfrom. [Errno 10054] An existing connection was forcibly closed by the remote host. Almost seems like an automatic response from the connection. Although this is fine, and can be handled by a try: except: block (even if it lowers performance of the server a little bit). The problem is, I can't tell who this is coming from or what socket is closed. Is there anyway to find out 'who' (ip, socket #) sent this? It would be great as I could instantly just disconnect them and remove them from the data. Any suggestions? Thanks.

  Read the article

• Looking for combinations of server and embedded database engines

  - by codeelegance

  I'm redesigning an application that will be run as both a single user and multiuser application. It is a .NET 2.0 application. I'm looking for server and embedded databases that work well together. I want to deploy the embedded database in the single user setup and of course, the server in the multiuser setup. Past releases have been based on MSDE but in the past year we've been having a lot of install issues: new installs hanging and leaving the system in an unknown state, upgrades disconnecting the database, etc. I migrated the application to SQL Server 2005 and the install is more reliable (as long as a user doesn't try to install over a broken MSDE installation). Since next year's release will be a complete redesign I figured now's the best time to address the database issue as well. The database has been abstracted from the rest of the application so I just need to choose which database(s) to use and write an implementation for each one. So far I've considered: SQL Server/ SQL Server Compact Edition Firebird (same DB engine is available in two different server modes and an embedded dll) Each has its own merits but I'm also interested in any other suggestions. This is a fairly simple program and its data requirements are simple as well. I don't expect it to strain whatever database I eventually choose. So easy configuration and deployment hold more weight than performance.

  Read the article

• Running an existing LINQ query against a dynamic object (DataTable like)

  - by TomTom

  Hello, I am working on a generic OData provider to go against a custom data provider that we have here. Thsi is fully dynamic in that I query the data provider for the table it knows. I have a basic storage structure in place so far based on the OData sample code. My problem is: OData supports queries and expects me to hand in an IQueryable implementation. On the lowe rside, I dont have any query support. Not a joke - the provider returns tables and the WHERE clause is not supported. Performance is not an issue here - the tables are small. It is ok to sort them in the OData provider. My main problem is this. I submit a SQL statement to get out the data of a table. The result is some sort of ADO.NET data reader here. I need to expose an IQueryable implementation for this data to potentially allow later filtering. Any ide ahow to best touch that? .NET 3.5 only (no 4.0 planned for some time). I was seriously thinking of creating dynamic DTO classes for every table (emitting bytecode) so I can use standard LINQ. Right now I am using a dictionary per entry (not too efficient) but I see no real way to filter / sort based on them.

  Read the article

• Hibernate database integrity with multiple java applications

  - by Austen

  We have 2 java web apps both are read/write and 3 standalone java read/write applications (one loads questions via email, one processes an xml feed, one sends email to subscribers) all use hibernate and share a common code base. The problem we have recently come across is that questions loaded via email sometimes overwrite questions created in one of the web apps. We originally thought this to be a caching issue. We've tried turning off the second level cache, but this doesn't make a difference. We are not explicitly opening and closing sessions, but rather let hibernate manage them via Util.getSessionFactory().getCurrentSession(), which thinking about it, may actually be the issue. We'd rather not setup a clustered 2nd level cache at this stage as this creates another layer of complexity and we're more than happy with the level of performance we get from the app as a whole. So does implementing a open-session-in-view pattern in the web apps and manually managing the sessions in the standalone apps sound like it would fix this? Or any other suggestions/ideas please? <property name="hibernate.transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property> <property name="hibernate.current_session_context_class">thread</property> <property name="hibernate.cache.use_second_level_cache">false</property>

  Read the article

• Java: Efficiency of the readLine method of the BufferedReader and possible alternatives

  - by Luhar

  We are working to reduce the latency and increase the performance of a process written in Java that consumes data (xml strings) from a socket via the readLine() method of the BufferedReader class. The data is delimited by the end of line separater (\n), and each line can be of a variable length (6KBits - 32KBits). Our code looks like: Socket sock = connection; InputStream in = sock.getInputStream(); BufferedReader inputReader = new BufferedReader(new InputStreamReader(in)); ... do { String input = inputReader.readLine(); // Executor call to parse the input thread in a seperate thread }while(true) So I have a couple of questions: Will the inputReader.readLine() method return as soon as it hits the \n character or will it wait till the buffer is full? Is there a faster of picking up data from the socket than using a BufferedReader? What happens when the size of the input string is smaller than the size of the Socket's receive buffer? What happens when the size of the input string is bigger than the size of the Socket's receive buffer? I am getting to grips (slowly) with Java's IO libraries, so any pointers are much appreciated. Thank you!

  Read the article

• Database and logic layer for ASP.NET MVC application

  - by Ismail

  I'm going to start a new project which is going to be small initially but may grow to big over the years. I'm strongly convinced that I'm going to use ASP.NET MVC with jQuery for UI. I want to go for MySQL as database for some reasons but worried on few things. I've a good years of experience working on SQL Server databases and on one project I've had a bad experience creating and managing stored procedures on MySQL database. I'm totally new to Linq but I see that it is easier to use once you are familiar with it. First thing is that accessing data should be easy. So I thought I should use MySQL to Linq but somewhere I read that it is not directly supported but MySQL .NET connector adds support for EntityFramework. I don't know what are the pros and cons of it. I would love if I can implement repository pattern as it allows to apply filter in logic layer rather than in data access layer. Will it be possible if I use Entity Framework? I'm not clear on how I should go about all this or I should just forget every thing and directly use SQL to Linq on SQL Server. I'm also concerned about the performance. Someone told me that if we use Entity framework it fetches lot of data and then filter it. Is that right? So questions basically are - Is MySQL to Linq possible? If yes where can I get more details on it? Pros and cons of using EntityFramework with MySQL? Will it be easy to access data using EntityFramework with MySQL? Will I be able to implement repository patter which allows applying filter in logic layer rather than data access layer (when I use EntityFramework with MySQL) Does it fetches hell lot of data from database and then apply filter on it? If it sounds too many questions from my side in that case, if you can just let me know what you will do (with a considerable reason) in this situation as an experienced person in this area, that should answer my question.

  Read the article

• Ajax heavy JS apps using excessive amounts of memory over time.

  - by Shane Reustle

  I seem to have some pretty large memory leaks in an app that I am working on. The app itself is not very complex. Every 15 seconds, the page requests approx 40kb of JSON from the server, and draws a table on the page using it. It is cheaper to draw the table over because the data is usually always new. I am attaching a few events to the table, approx 5 per line, 30 lines in the table. I used jQuery's .html() method to put the new html into the container and overwrite the existing. I do this specifically so that jQuery's special cleanup functions go in and attempt to detach all events on the elements in the element that it is overwriting. I then also delete the large variables of html once they are sent to the DOM using delete my_var. I have checked for circular references and attached events that are never cleared a few times, but never REALLY dug into it. I was wondering if someone could give me a few pointers on how to optimize a very heavy app like this. I just picked up "High Performance Javascript" by Nicholas Zakas, but didn't have much time to get into it yet. To give an idea on how much memory this is using, after 4~ hours, it is using about 420,000k on chrome, and much more on Firefox or IE. Thanks!

  Read the article

< Previous Page | 465 466 467 468 469 470 471 472 473 474 475 476  | Next Page >