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• H.264 over RTP - Identify SPS and PPS Frames

  - by Toby

  I have a raw H.264 Stream from an IP Camera packed in RTP frames. I want to get raw H.264 data into a file so I can convert it with ffmpeg. So when I want to write the data into my raw H.264 file I found out it has to look like this: 00 00 01 [SPS] 00 00 01 [PPS] 00 00 01 [NALByte] [PAYLOAD RTP Frame 1] // Payload always without the first 2 Bytes -> NAL [PAYLOAD RTP Frame 2] [... until PAYLOAD Frame with Mark Bit received] // From here its a new Video Frame 00 00 01 [NAL BYTE] [PAYLOAD RTP Frame 1] .... So I get the SPS and the PPS from the Session Description Protocol out of my preceding RTSP communication. Additionally the camera sends the SPS and the PPSin two single messages before starting with the video stream itself. So I capture the messages in this order: 1. Preceding RTSP Communication here ( including SDP with SPS and PPS ) 2. RTP Frame with Payload: 67 42 80 28 DA 01 40 16 C4 // This is the SPS 3. RTP Frame with Payload: 68 CE 3C 80 // This is the PPS 4. RTP Frame with Payload: ... // Video Data Then there come some Frames with Payload and at some point a RTP Frame with the Marker Bit = 1. This means ( if I got it right) that I have a complete video frame. Afer this I write the Prefix Sequence ( 00 00 01 ) and the NALfrom the payload again and go on with the same procedure. Now my camera sends me after every 8 complete Video Frames the SPS and the PPS again. ( Again in two RTP Frames, as seen in the example above ). I know that especially the PPS can change in between streaming but that's not the problem. My questions are now: 1. Do I need to write the SPS/PPS every 8th Video Frame? If my SPS and my PPS don't change it should be enough to have them written at the very beginning of my file and nothing more? 2. How to distinguish between SPS/PPS and normal RTP Frames? In my C++ Code which parses the transmitted data I need make a difference between the RTP Frames with normal Payload an the ones carrying the SPS/PPS. How can I distinguish them? Okay the SPS/PPS frames are usually way smaller, but that's not a save call to rely on. Because if I ignore them I need to know which data I can throw away, or if I need to write them I need to put the 00 00 01 Prefix in front of them. ? Or is it a fixed rule that they occur every 8th Video Frame?

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• Would Apache running on port 8080 prevent dynamically loaded scripts in JavaScript?

  - by editor

  Had a nice PHP/HTML/JS prototype working on my personal Linode, then tried to throw it into a work machine. The page adds a script tag dynamically with some JavaScript. It's a bunch of Google charts that update based on different timeslices. That code looks something like this: // jQuery $.post to send the beginning and end timestamps $.post("channel_functions.php", data_to_post, function(data){ // the data that's returned is the javascript I want to load var script = document.createElement('script'); var head= document.getElementsByTagName('head')[0]; var script= document.createElement('script'); var text = document.createTextNode(data); script.type= 'text/javascript'; script.id = 'chart_data'; script.appendChild(text); // Adding script tag to page head.appendChild(script); // Call the function I know were present in the script tag loadTheCharts(); }); function loadTheCharts() { // These are the functions that were loaded dynamically // By this point the script tag is supposed be loaded, added and eval'd function1(); function2(); } Function1() and function2() don't exist until they get added to the dom, but I don't call loadTheCharts() until after the $.post has run so this doesn't seem to be a problem. I'm one of those dirty PHP coders you mother warned you about, so I'm not well versed in JavaScript beyond what I've read in the typical go-to O'Reilly books. But this code worked fine on my personal dev server, so I'm wondering why it wouldn't work on this new machine. The only difference in setup, from what I can tell, is that the new machine is running on port 8080, so it's 192.168.blah.blah:8080/index.php instead of nicedomain.com/index.php. I see the code was indeed added to the dom when I use webmaster tools to "view generated source" but in Firebug I get an error like "function2() is undefined" even though my understanding was that all script tags are eval'ed when added to . My question: Given what I've laid out, and that the machine is running on :8080, is there a reason anyone can think of as to why a dynamically loaded function like function2() would be defined on the Linode and not on the machine running Apache on 8080?

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• Flipping PDF pages in QuartzDemo application

  - by BittenApple

  I am working on modifying the quartzdemo application so that it can show another page from a multipage pdf on tap screen event. So far I have stripped it down to the point where it displays the PDF on any page as initial page, but I can't seem to get it figured out how to make the quartzview display anything else then the initial page. I'm guessing that the pushViewController has something to do with this. Anyway, here's my method that draws the initial page and in sits in QuartzImages.m file: -(void)drawNewPage:(CGContextRef)myContext { CGContextTranslateCTM(myContext, 0.0, self.bounds.size.height); CGContextScaleCTM(myContext, 1.0, -1.0); CGContextSetRGBFillColor(myContext, 255, 255, 255, 1); CGContextFillRect(myContext, CGRectMake(0, 0, 320, 412)); CGPDFPageRef page = CGPDFDocumentGetPage(pdfFajl, pageNumber); CGContextSaveGState(myContext); CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(page, kCGPDFCropBox, self.bounds, 0, true); CGContextConcatCTM(myContext, pdfTransform); CGContextDrawPDFPage(myContext, page); CGContextRestoreGState(myContext); } This gets fired up in MainViewController.m so: - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { // ### DISPLAY DESIRED PAGE QuartzViewController *targetViewController = [self controllerAtIndexPath:indexPath]; if ([targetViewController.quartzView isKindOfClass:[QuartzPDFView1 class]]) { ((QuartzPDFView1 *)targetViewController.quartzView).pageNumber = 1; CFURLRef pdfURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(), CFSTR("mypdftest.pdf"), NULL, NULL); ((QuartzPDFView1 *)targetViewController.quartzView).pdfFajl = CGPDFDocumentCreateWithURL((CFURLRef)pdfURL); CFRelease(pdfURL); } [[self navigationController] pushViewController:targetViewController animated:YES]; } Since I'm fairly new to the iPhone development (I'm currently only on page 123 in "beginning iphone 3 development" book) these controllers confuse me as hell. I have setup an event which gets fired up fine on screen tap. The event sits in QuartzView.m and I get a simple alert on screen tap showing that the tap was registered. I would like to use this method to draw a new page instead of showing the alert, page number doesn't matter, I'll work on incrementing (page flipping) later, I need an example of how to call these methods (if its even possible). These are defined in QuartzView.h and I planned on using them in the tap event method: CGPDFDocumentRef pdfFajl; int pageNumber; Thankful for any useful input from "the internets" :)

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• Understanding PTS and DTS in video frames

  - by theateist

  I had fps issues when transcoding from avi to mp4(x264). Eventually the problem was in PTS and DTS values, so lines 12-15 where added before av_interleaved_write_frame function: 1. AVFormatContext* outContainer = NULL; 2. avformat_alloc_output_context2(&outContainer, NULL, "mp4", "c:\\test.mp4"; 3. AVCodec *encoder = avcodec_find_encoder(AV_CODEC_ID_H264); 4. AVStream *outStream = avformat_new_stream(outContainer, encoder); 5. // outStream->codec initiation 6. // ... 7. avformat_write_header(outContainer, NULL); 8. // reading and decoding packet 9. // ... 10. avcodec_encode_video2(outStream->codec, &encodedPacket, decodedFrame, &got_frame) 11. 12. if (encodedPacket.pts != AV_NOPTS_VALUE) 13. encodedPacket.pts = av_rescale_q(encodedPacket.pts, outStream->codec->time_base, outStream->time_base); 14. if (encodedPacket.dts != AV_NOPTS_VALUE) 15. encodedPacket.dts = av_rescale_q(encodedPacket.dts, outStream->codec->time_base, outStream->time_base); 16. 17. av_interleaved_write_frame(outContainer, &encodedPacket) After reading many posts I still do not understand: outStream->codec->time_base = 1/25 and outStream->time_base = 1/12800. The 1st one was set by me but I cannot figure out why and who set 12800? I noticed that before line (7) outStream->time_base = 1/90000 and right after it it changes to 1/12800, why? When I transcode from avi to avi, meaning changing the line (2) to avformat_alloc_output_context2(&outContainer, NULL, "avi", "c:\\test.avi"; , so before and after line (7) outStream->time_base remains always 1/25 and not like in mp4 case, why? What is the difference between time_base of outStream->codec and outStream? To calc the pts av_rescale_q does: takes 2 time_base, multiplies their fractions in cross and then compute the pts. Why it does this in this way? As I debugged, the encodedPacket.pts has value incremental by 1, so why changing it if it does has value? At the beginning the dts value is -2 and after each rescaling it still has negative number, but despite this the video played correctly! Shouldn't it be positive?

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• MySQL-problem when baking with CakePHP.

  - by timkl

  I am currently reading "Beginning CakePHP:From Novice to Professional" by David Golding. At one point I have to use the CLI-command "cake bake", I get the welcome-screen but when I try to bake e.g. a Controller I get the following error messages: Warning: mysql_connect(): Can't connect to local MySQL server through socket '/var/mysql/mysql.sock' (2) in /Applications/MAMP/htdocs/blog/cake/libs/model/datasources/dbo/dbo_mysql.php on line 117 Warning: mysql_select_db(): supplied argument is not a valid MySQL-Link resource in /Applications/MAMP/htdocs/blog/cake/libs/model/datasources/dbo/dbo_mysql.php on line 122 Warning: mysql_get_server_info(): supplied argument is not a valid MySQL-Link resource in /Applications/MAMP/htdocs/blog/cake/libs/model/datasources/dbo/dbo_mysql.php on line 130 Warning: mysql_query(): supplied argument is not a valid MySQL-Link resource in /Applications/MAMP/htdocs/blog/cake/libs/model/datasources/dbo/dbo_mysql.php on line 154 Error: Your database does not have any tables. I suspect that the error-messages has to do with php trying to access the wrong mysql-socket, namely the default osx mysql-socket - instead of the one that MAMP uses. Hence I change my database configurations to connect to the UNIX mysql-socket (:/Applications/MAMP/tmp/mysql/mysql.sock): class DATABASE_CONFIG { var $default = array( 'driver' => 'mysql', 'connect' => 'mysql_connect', 'persistent' => false, 'host' =>':/Applications/MAMP/tmp/mysql/mysql.sock', // UNIX MySQL-socket 'login' => 'my_user', 'password' => 'my_pass', 'database' => 'blog', 'prefix' => '', ); } But I get the same error-messages with the new socket: Warning: mysql_connect(): Can't connect to local MySQL server through socket '/Applications/MAMP/tmp/mysql/mysql.sock:3306' (2) in /Applications/MAMP/htdocs/blog/cake/libs/model/datasources/dbo/dbo_mysql.php on line 117 Warning: mysql_select_db(): supplied argument is not a valid MySQL-Link resource in /Applications/MAMP/htdocs/blog/cake/libs/model/datasources/dbo/dbo_mysql.php on line 122 Warning: mysql_get_server_info(): supplied argument is not a valid MySQL-Link resource in /Applications/MAMP/htdocs/blog/cake/libs/model/datasources/dbo/dbo_mysql.php on line 130 Warning: mysql_query(): supplied argument is not a valid MySQL-Link resource in /Applications/MAMP/htdocs/blog/cake/libs/model/datasources/dbo/dbo_mysql.php on line 154 Error: Your database does not have any tables. Also, even though I use the UNIX-socket that MAMP show on it's welcome-screen, CakePHP loses the database-connection, when using this socket instead of localhost. Any ideas on how I can get bake to work?

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• Coldfusion Report Builder - How can you set different datasources externally between prod/staging/de

  - by Smooth Operator

  Coldfusion Report Builder is great. One small issue. We use ANT+CFANT to deploy. When we create the report, say in a datasource called MyApp_dev on a dev box. Everything works great when the report is created. We deploy the report to our staging server, which has a datasource of MyApp_Staging. That server also, may or may not, have the live app working under MyApp_Live. Ant pushes the update to Staging just great. Run the report, crashes and burns. Why? It seems the report is looking for the MyApp_Dev data_source, even though the application is using the MyApp_Staging datasource. In digging around I found a few approaches, I would like to do this one, final, ideal way from the beginning instead of having to go back to do dozens of reports differently when I have a new Aha! moment. 1) Obvious: Pass in the datasource in to the cfreport tag. Doesn't work for ColdFusion Builder Reports as of v8, or v9 as tested on Linux. 2) Most realistic option (but painful) so far: Pass in the query as an object into the ColdFusion Builder report. Let's think about this: Create the Report with the report builder to my heart's content using the RDS, etc on my local box. When I'm done, copy the query into a snippet of code, or into a database column to be dynamically be injected at runtime with correct datasource. Modify my "run report" event to find the query from the database column, insert it into another dynamic cfquery and potentially... evaluate (!?!) it? Fun side is I can set the cfquery datasource to what I would need for each environment. When I modify the report's columns in CF Report Builder, I always have to update the query in the database. Is there a snippet of code that can extract this for me? Hmm. 3) Less than ideal. Suck it up and let all the reports in staging run off the live server. Maybe copy the live data into staging (sans structural changes) to let it seem similar. Are there any eloquent ways to accomplish the above? Thanks in Advance!

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• ASP.NET site sometimes freezing up and/or showing odd text at top of the page while loading, on load

  - by MGOwen

  I have various servers (dev, 2 x test, 2 x prod) running the same asp.net site. The test and prod servers are in load-balanced pairs (prod1 with prod2, and test1 with test2). The test server pair is exhibiting some kind of (super) slowdown or freezing during about one in ten page loads. Sometimes a line of text appears at the very top of the page which looks something like: 00 OK Date: Thu, 01 Apr 2010 01:50:09 GMT Server: Microsoft-IIS/6.0 X-Powered_By: ASP.NET X-AspNet-Version:2.0.50727 Cache-Control:private Content-Type:text/html; charset=ut (the beginning and end are "cut off".) Has anyone seen anything like this before? Any idea what it means or what's causing it? Edit: I often see this too when clicking something - it comes up as red text on a yellow page: XML Parsing Error: not well-formed Location: http://203.111.46.211/3DSS/CompanyCompliance.aspx?cid=14 Line Number 1, Column 24:2mMTehON9OUNKySVaJ3ROpN" / -----------------------^ If I go back and click again, it works (I see the page I clicked on, not the above error message). Update: ...And, instead of the page loading, I sometimes just get a white screen with text like this in black (looks a lot like the above text): HTTP/1.1 302 Found Date: Wed, 21 Apr 2010 04:53:39 GMT Server: Microsoft-IIS/6.0 X-Powered-By: ASP.NET X-AspNet-Version: 2.0.50727 Location: /3DSS/EditSections.aspx?id=3&siteId=56&sectionId=46 Set-Cookie: .3DSS=A6CAC223D0F2517D77C7C68EEF069ABA85E9392E93417FFA4209E2621B8DCE38174AD699C9F0221D30D49E108CAB8A828408CF214549A949501DAFAF59F080375A50162361E4AA94E08874BF0945B2EF; path=/; HttpOnly Cache-Control: private Content-Type: text/html; charset=utf-8 Content-Length: 184 object moved here Where "here" is a link that points to a URL just like the one I'm requesting, except with an extra folder in it, meaning something like: http://123.1.2.3/MySite//MySite/Page.aspx?option=1 instead of: http://123.1.2.3/MySite/Page.aspx?option=1 Update: A colleague of mine found some info saying it might be because the test servers are running iis in 64 bit (64bit win 2003) (prod servers are 32 bit win 2003). So we tried telling IIS to use 32 bit: **cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 1 %SYSTEMROOT%\Microsoft.NET\Framework\v2.0.50727\aspnet_regiis.exe -i ** (from this MS support page) But iis stopped working altogether (got "server unavailable" on a white page instead of web sites). Reversing the above (see the link) didn't work at first either. The ASP.NET tab disappeared from our IIS web site properties and we had to mess around for an hour uninstalling (aspnet_regiis.exe -u) and reinstalling 32 bit ASP.NET and adding Default.aspx manually back into default documents. We'll probably try again in a few days, if anyone has anything to add in the meantime, please do.

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• Storing simulation results in a persistent manner for Python?

  - by Az

  Background: I'm running multiple simuations on a set of data. For each session, I'm allocating projects to students. The difference between each session is that I'm randomising the order of the students such that all the students get a shot at being assigned a project they want. I was writing out some of the allocations in a spreadsheet (i.e. Excel) and it basically looked like this (tiny snapshot, actual table extends to a few thousand sessions, roughly 100 students). | | Session 1 | Session 2 | Session 3 | |----------|-----------|-----------|-----------| |Stu1 |Proj_AA |Proj_AB |Proj_AB | |----------|-----------|-----------|-----------| |Stu2 |Proj_AB |Proj_AA |Proj_AC | |----------|-----------|-----------|-----------| |Stu3 |Proj_AC |Proj_AC |Proj_AA | |----------|-----------|-----------|-----------| Now, the code that deals with the allocation currently stores a session in an object. The next time the allocation is run, the object is over-written. Thus what I'd really like to do is to store all the allocation results. This is important since I later need to derive from the data, information such as: which project Stu1 got assigned to the most or perhaps how popular Proj_AC was (how many times it was assigned / number of sessions). Question(s): What methods can I possibly use to basically store such session information persistently? Basically, each session output needs to add itself to the repository after ending and before beginning the next allocation cycle. One solution that was suggested by a friend was mapping these results to a relational database using SQLAlchemy. I kind of like the idea since this does give me an opportunity to delve into databases. Now the database structure I was recommended was: |----------|-----------|-----------| |Session |Student |Project | |----------|-----------|-----------| |1 |Stu1 |Proj_AA | |----------|-----------|-----------| |1 |Stu2 |Proj_AB | |----------|-----------|-----------| |1 |Stu3 |Proj_AC | |----------|-----------|-----------| |2 |Stu1 |Proj_AB | |----------|-----------|-----------| |2 |Stu2 |Proj_AA | |----------|-----------|-----------| |2 |Stu3 |Proj_AC | |----------|-----------|-----------| |3 |Stu1 |Proj_AB | |----------|-----------|-----------| |3 |Stu2 |Proj_AC | |----------|-----------|-----------| |3 |Stu3 |Proj_AA | |----------|-----------|-----------| Here, it was suggested that I make the Session and Student columns a composite key. That way I can access a specific record for a particular student for a particular session. Or I can merely get the entire allocation run for a particular session. Questions: Is the idea a good one? How does one implement and query a composite key using SQLAlchemy? What happens to the database if a particular student is not assigned a project (happens if all projects that he wants are taken)? In the code, if a student is not assigned a project, instead of a proj_id he simply gets None for that field/object. I apologise for asking multiple questions but since these are closely-related, I thought I'd ask them in the same space.

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• What was "The Next Big Thing" when you were just starting out in programming?

  - by Andrew

  I'm at the beginning of my career and there are lots of things which are being touted as "The Next Big Thing". For example: Dependency Injection (Spring, etc) MVC (Struts, ASP.NET MVC) ORMs (Linq To SQL, Hibernate) Agile Software Development These things have probably been around for some time, but I've only just started out. And don't get me wrong, I think these things are great! So, what was "The Next Big Thing" when you were starting out? When was it? Were people sceptical of it at first? Why? Did you think it would catch on? Did it pan out and become widely accepted/used? If not, why not? EDIT It's been nearly a week since I first posted this question and I can safely say that I did not expect such explosive interest. I asked the question so that I could gain a perspective of what kinds of innovations in programming people thought were most important when they were starting out. At the time of writing this I have read ~95% of all answers. To answer a few questions, the "Next Big Things" I listed are ones that I am currently really excited about and that I had not really been exposed to until I started working. I'm hoping to implement some or all of these in the near future at my current workplace. To many people they are probably old news. In regards to the "is this a real question" debate, I can see that obviously hasn't been settled yet. I feel bad whenever I read a comment saying that these kinds of questions take away from the real meaning of SO. I'm not wholly convinced that it doesn't. On the other hand, I have seen a lot of comments saying what a great question it is. Anyway, I have chosen "The Internet!" as my answer to this question. I don't think (in my very humble opinion, and, it seems many SOers opinions) that many things related to programming can compare. Nowadays every business and their dog has a website which can do anything from simply supplying information to purchasing goods halfway around the world to updating your blog. And of course, all these businesses need people like us. Thanks to everyone for all the great answers!

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• unformatted input to a std::string instead of c-string from binary file.

  - by posop

  ok i have this program working using c-strings. I am wondering if it is possible to read in blocks of unformatted text to a std::string? I toyed arround with if >> but this reads in line by line. I've been breaking my code and banging my head against the wall trying to use std::string, so I thought it was time to enlist the experts. Here's a working program you need to supply a file "a.txt" with some content to make it run. i tried to fool around with: in.read (const_cast<char *>(memblock.c_str()), read_size); but it was acting odd. I had to do std::cout << memblock.c_str() to get it to print. and memblock.clear() did not clear out the string. anyway, if you can think of a way to use STL I would greatly appreciate it. Here's my program using c-strings // What this program does now: copies a file to a new location byte by byte // What this program is going to do: get small blocks of a file and encrypt them #include <fstream> #include <iostream> #include <string> int main (int argc, char * argv[]) { int read_size = 16; int infile_size; std::ifstream in; std::ofstream out; char * memblock; int completed = 0; memblock = new char [read_size]; in.open ("a.txt", std::ios::in | std::ios::binary | std::ios::ate); if (in.is_open()) infile_size = in.tellg(); out.open("b.txt", std::ios::out | std::ios::trunc | std::ios::binary); in.seekg (0, std::ios::beg);// get to beginning of file while(!in.eof()) { completed = completed + read_size; if(completed < infile_size) { in.read (memblock, read_size); out.write (memblock, read_size); } // end if else // last run { delete[] memblock; memblock = new char [infile_size % read_size]; in.read (memblock, infile_size % read_size + 1); out.write (memblock, infile_size % read_size ); } // end else } // end while } // main if you see anything that would make this code better please feel free to let me know.

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• Help me stabilize this jRun configuration (CF9/Win2k3/IIS6)

  - by jfrobishow

  Not sure if this would be better suited for ServerFault, but since I am not an admin but a developer I figured I would try SO. We've been struggling to keep our multi-server configuration stable for quite some time now. At the end of last month we were running under CF 7.0.2 on a two servers setup (one instance each). At that point we managed to get our uptime to around 1 week per instance before they would restart by themselves. Since the beginning of the month we upgraded to CF 9 and we're back to square one with multi-restart a day. Our current configuration is 2 Win2k3 servers, running a cluster of 4 instances, 2 instances per server. At this point we are pretty certain this is due to improper JVM settings. We've been toying with them and while some are more stable than others we never quite got it right. From the default: java.args=-server -Xmx512m -Dsun.io.useCanonCaches=false -XX:MaxPermSize=192m -XX:+UseParallelGC -Dcoldfusion.rootDir={application.home}/ To currently: java.args=-server -Xmx896m -Dsun.io.useCanonCaches=false -XX:MaxPermSize=512m -XX:SurvivorRatio=8 -XX:TargetSurvivorRatio=90 -XX:+UseParallelGC -Dcoldfusion.rootDir={application.home}/ -verbose:gc -Xloggc:c:/Jrun4/logs/gc/gcInstance1b.log We have determined that we do need more than the default 512MB simply by monitoring with FusionReactor, on average our amount of memory consumed is hovering in the mid 300MB and can go up to low 700MB under heavy load. Most of the crash will be logged in jrun4/bin/hs_err_pid*.log always an "Out of swap space" I've attached links to the hs_err and garbage collector log file from yesterday at the bottom of the post. The relevant part is (I think) this: Heap PSYoungGen total 89856K, used 19025K [0x55490000, 0x5b6f0000, 0x5b810000) eden space 79232K, 16% used [0x55490000,0x561a64c0,0x5a1f0000) from space 10624K, 52% used [0x5ac90000,0x5b20e2f8,0x5b6f0000) to space 10752K, 0% used [0x5a1f0000,0x5a1f0000,0x5ac70000) PSOldGen total 460416K, used 308422K [0x23810000, 0x3f9b0000, 0x55490000) object space 460416K, 66% used [0x23810000,0x36541bb8,0x3f9b0000) PSPermGen total 107520K, used 106079K [0x03810000, 0x0a110000, 0x23810000) object space 107520K, 98% used [0x03810000,0x09fa7e40,0x0a110000) From it, I gather that its the PSPermGen that is full (most logs will show the same before a crash), which is why we increased MaxPermSize but the total still show as 107520K!??! No one here is a jRun expert, so any help or even ideas on what to try next would be greatly appreciated!! The log files: Sorry I know sendspace isn't the friendliest of places - if you have other host suggestion for log files let me know and I'll update the post (SO doesn't like them inline, it blows up the format of the post). The hs_err log file: http://www.sendspace.com/file/fgak8l The gc log: http://www.sendspace.com/file/w0r2ct

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• Searches (and general querying) with HBase and/or Cassandra (best practices?)

  - by alexeypro

  I have User model object with quite few fields (properties, if you wish) in it. Say "firstname", "lastname", "city" and "year-of-birth". Each user also gets "unique id". I want to be able to search by them. How do I do that properly? How to do that at all? My understanding (will work for pretty much any key-value storage -- first goes key, then value) u:123456789 = serialized_json_object ("u" as a simple prefix for user's keys, 123456789 is "unique id"). Now, thinking that I want to be able to search by firstname and lastname, I can save in: f:Steve = u:384734807,u:2398248764,u:23276263 f:Alex = u:12324355,u:121324334 so key is "f" - which is prefix for firstnames, and "Steve" is actual firstname. For "u:Steve" we save as value all user id's who are "Steve's". That makes every search very-very easy. Querying by few fields (properties) -- say by firstname (i.e. "Steve") and lastname (i.e. "l:Anything") is still easy - first get list of user ids from "f:Steve", then list from "l:Anything", find crossing user ids, an here you go. Problems (and there are quite a few): Saving, updating, deleting user is a pain. It has to be atomic and consistent operation. Also, if we have size of value limited to some value - then we are in (potential) trouble. And really not of an answer here. Only zipping the list of user ids? Not too cool, though. What id we want to add new field to search by. Eventually. Say by "city". We certainly can do the same way "c:Los Angeles" = ..., "c:Chicago" = ..., but if we didn't foresee all those "search choices" from the very beginning, then we will have to be able to create some night job or something to go by all existing User records and update those "c:CITY" for them... Quite a big job! Problems with locking. User "u:123" updates his name "Alex", and user "u:456" updates his name "Alex". They both have to update "f:Alex" with their id's. That means either we get into overwriting problem, or one update will wait for another (and imaging if there are many of them?!). What's the best way of doing that? Keeping in mind that I want to search by many fields? P.S. Please, the question is about HBase/Cassandra/NoSQL/Key-Value storages. Please please - no advices to use MySQL and "read about" SELECTs; and worry about scaling problems "later". There is a reason why I asked MY question exactly the way I did. :-)

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• How hard programming is? Really. [closed]

  - by Bubba88

  Hi! The question is about your perception of programming activity. How hard/exacting this task is? There is much buzz about programming nowadays, people say that programmers are smart, very technical and abstract at a time, know much about world, psychology etc.. They say, that programmers got really powerful brain thing, cause there is much to keep in consideration simultaneously again with much information folded into each other associatively (up 10 levels of folding they say))) Still, there are some terms to specify at our own.. So that is the question: What do you think about programming in general? Is it hard? Is it 'for everyone' or for the particular kind of people only? How much non-CS background do you need to program (just to program, really; enterprise applications for example)? How long is the learning curve? (again, for programming in general) And another bunch of random questions: - If you were not to like/love programming, would that be a serious trouble bothering your current employment? - If you were to start from the beginning, would you chose that direction this time? - What other areas (jobs or maybe hobbies) are comparable to programming in the way they can explode someone's lovely brain? - Is 'non turing-complete programming' (SQL, XML, etc.) comparable to what we do or is it really way easier, less requiring, cheap and akin to cooking :)? Well, the essence is: How would you describe programming activity WRT to its difficulty? Or, on the other hand: Did you ever catch yourself thinking at some point: OMG, it's sooo hard! I don't know how would I ever program, even carried away this way and doing programming just for fun? It's very interesting to know your opinion, your'e the programmers after all. I mean much people must be exaggerating/speculating about the thing they do not really know about. But that musn't be the case here on SO :) P.S.: I'll try my best to update this post later, and you please edit it too. At least I'll get decent English in my question text :)

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• How to make freelance clients understand the costs of developing and maintaining mature products?

  - by John

  I have a freelance web application project where the client requests new features every two weeks or so. I am unable to anticipate the requirements of upcoming features. So when the client requests a new feature, one of several things may happen: I implement the feature with ease because it is compatible with the existing platform I implement the feature with difficulty because I have to rewrite a significant portion of the platform's foundation Client withdraws request because it costs too much to implement against existing platform At the beginning of the project, for about six months, all feature requests fell under category 1) because the system was small and agile. But for the past six months, most feature implementation fell under category 2). The system is mature, forcing me to refactor and test everytime I want to add new modules. Additionally, I find myself breaking things that use to work, and fixing it (I don't get paid for this). The client is starting to express frustration at the time and cost for me to implement new features. To them, many of the feature requests are of the same scale as the features they requested six months ago. For example, a client would ask, "If it took you 1 week to build a ticketing system last year, why does it take you 1 month to build an event registration system today? An event registration system is much simpler than a ticketing system. It should only take you 1 week!" Because of this scenario, I fear feature requests will soon land in category 3). In fact, I'm already eating a lot of the cost myself because I volunteer many hours to support the project. The client is often shocked when I tell him honestly the time it takes to do something. The client always compares my estimates against the early months of a project. I don't think they're prepared for what it really costs to develop, maintain and support a mature web application. When working on a salary for a full time company, managers were more receptive of my estimates and even encouraged me to pad my numbers to prepare for the unexpected. Is there a way to condition my clients to think the same way? Can anyone offer advice on how I can continue to work on this web project without eating too much of the cost myself? Additional info - I've only been freelancing full time for 1 year. I don't yet have the high end clients, but I'm slowly getting there. I'm getting better quality clients as time goes by.

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• executing a script from maven inside a multi module project

  - by Roman

  Hi everyone. I have this multi-module project. In the beginning of each build I would like to run some bat file. So i did the following: <profile> <id>deploy-db</id> <build> <plugins> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>exec-maven-plugin</artifactId> <version>1.1.1</version> </plugin> </plugins> <pluginManagement> <plugins> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>exec-maven-plugin</artifactId> <version>1.1.1</version> <executions> <execution> <phase>validate</phase> <goals> <goal>exec</goal> </goals> <inherited>false</inherited> </execution> </executions> <configuration> <executable>../database/schemas/import_databases.bat</executable> </configuration> </plugin> </plugins> </pluginManagement> </build> </profile> when i run the mvn verify -Pdeploy-db from the root I get this script executed over and over again in each of my modules. I want it to be executed only once, in the root module. What is there that I am missing ? Thanks

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• working on lists in python

  - by owca

  I'm trying to make a small modification to django lfs project, that will allow me to deactivate products with no stocks. Unfortunatelly I'm just beginning to learn python, so I have big trouble with its syntax. That's what I'm trying to do. I'm using method 'has_variants' which returns true if product has any. Then I'm building a list from variants for this product. Next for every product in this list (I've called it 'set') I check it's stock and set bool variable 'inactive' to true if product has no stocks and to false if there are any. Finally if 'inactive' is false I'm setting self.active to 0. Code fails in line with: set[] = s How to correct it ? def deactivate(self): """If there are no stocks, deactivate the product. Used in last step of checkout. """ if self.has_variants(): for s in self.variants.filter(active=True): set[] = s for var in set: if var.get_stock_amount() == 0: inactive = True else: inactive = False else: if self.get_stock_amount() == 0: inactive = True if inactive: self.active = False return 0 error log : Traceback (most recent call last): File "manage.py", line 11, in <module> execute_manager(settings) File "/home/purplecow/rails/purpledev/site-packages/django/core/management/__i nit__.py", line 362, in execute_manager utility.execute() File "/home/purplecow/rails/purpledev/site-packages/django/core/management/__i nit__.py", line 303, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/home/purplecow/rails/purpledev/site-packages/django/core/management/bas e.py", line 195, in run_from_argv self.execute(*args, **options.__dict__) File "/home/purplecow/rails/purpledev/site-packages/django/core/management/bas e.py", line 213, in execute translation.activate('en-us') File "/home/purplecow/rails/purpledev/site-packages/django/utils/translation/_ _init__.py", line 73, in activate return real_activate(language) File "/home/purplecow/rails/purpledev/site-packages/django/utils/translation/_ _init__.py", line 43, in delayed_loader return g['real_%s' % caller](*args, **kwargs) File "/home/purplecow/rails/purpledev/site-packages/django/utils/translation/t rans_real.py", line 205, in activate _active[currentThread()] = translation(language) File "/home/purplecow/rails/purpledev/site-packages/django/utils/translation/t rans_real.py", line 194, in translation default_translation = _fetch(settings.LANGUAGE_CODE) File "/home/purplecow/rails/purpledev/site-packages/django/utils/translation/t rans_real.py", line 180, in _fetch app = import_module(appname) File "/home/purplecow/rails/purpledev/site-packages/django/utils/importlib.py" , line 35, in import_module __import__(name) File "/home/purplecow/rails/purpledev/lfs/caching/__init__.py", line 1, in <mo dule> from listeners import * File "/home/purplecow/rails/purpledev/lfs/caching/listeners.py", line 10, in < module> from lfs.cart.models import Cart File "/home/purplecow/rails/purpledev/lfs/cart/models.py", line 8, in <module> from lfs.catalog.models import Product File "/home/purplecow/rails/purpledev/lfs/catalog/__init__.py", line 1, in <mo dule> from listeners import * File "/home/purplecow/rails/purpledev/lfs/catalog/listeners.py", line 5, in <m odule> from lfs.catalog.models import PropertyGroup File "/home/purplecow/rails/purpledev/lfs/catalog/models.py", line 589 set[] = s ^ SyntaxError: invalid syntax

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• TicTacToe AI Making Incorrect Decisions

  - by Chris Douglass

  A little background: as a way to learn multinode trees in C++, I decided to generate all possible TicTacToe boards and store them in a tree such that the branch beginning at a node are all boards that can follow from that node, and the children of a node are boards that follow in one move. After that, I thought it would be fun to write an AI to play TicTacToe using that tree as a decision tree. TTT is a solvable problem where a perfect player will never lose, so it seemed an easy AI to code for my first time trying an AI. Now when I first implemented the AI, I went back and added two fields to each node upon generation: the # of times X will win & the # of times O will win in all children below that node. I figured the best solution was to simply have my AI on each move choose and go down the subtree where it wins the most times. Then I discovered that while it plays perfect most of the time, I found ways where I could beat it. It wasn't a problem with my code, simply a problem with the way I had the AI choose it's path. Then I decided to have it choose the tree with either the maximum wins for the computer or the maximum losses for the human, whichever was more. This made it perform BETTER, but still not perfect. I could still beat it. So I have two ideas and I'm hoping for input on which is better: 1) Instead of maximizing the wins or losses, instead I could assign values of 1 for a win, 0 for a draw, and -1 for a loss. Then choosing the tree with the highest value will be the best move because that next node can't be a move that results in a loss. It's an easy change in the board generation, but it retains the same search space and memory usage. Or... 2) During board generation, if there is a board such that either X or O will win in their next move, only the child that prevents that win will be generated. No other child nodes will be considered, and then generation will proceed as normal after that. It shrinks the size of the tree, but then I have to implement an algorithm to determine if there is a one move win and I think that can only be done in linear time (making board generation a lot slower I think?) Which is better, or is there an even better solution?

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• Basic Ruby On Rails Linking Help

  - by dweebsonduty

  So I am beginning to work with Rails and I get some of the concepts but am stuck on an important one. Let's say I have customers which has many jobs and jobs which belongs to customers. How would I go about creating a new job for a customer? I can create a link that goes to customers/1/jobs/new and I can grab the customer ID but how do I tell it that I am creating a job for customer 1? I know this is the most basic of things but I just need a push in the right direction. This is my form so far: How do I get :customer_id to populate with the customer_id param? <h1>New job</h1> <% form_for(@job) do |f| %> <%= f.error_messages %> <p> <%= f.label :customer_id %><br /> <%= f.text_field :customer_id %> </p> <p> <%= f.label :manufacturer %><br /> <%= f.text_field :manufacturer %> </p> <p> <%= f.label :serial_number %><br /> <%= f.text_field :serial_number %> </p> <p> <%= f.label :problem %><br /> <%= f.text_area :problem %> </p> <p> <%= f.label :notes %><br /> <%= f.text_area :notes %> </p> <p> <%= f.label :status %><br /> <%= f.text_field :status %> </p> <p> <%= f.label :tech_id %><br /> <%= f.text_field :tech_id %> </p> <p> <%= f.submit 'Create' %> </p> <% end %> <%= link_to 'Back', jobs_path %>

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• do I need to close an audio Clip?

  - by Michael

  have an application that processes real-time data and is supposed to beep when a certain event occurs. The triggering event can occur multiple times per second, and if the beep is already playing when another event triggers the code is just supposed to ignore it (as opposed to interrupting the current beep and starting a new one). Here is the basic code: Clip clickClip public void prepareProcess() { super.prepareProcess(); clickClip = null; try { clipFile = new File("C:/WINDOWS/Media/CHIMES.wav"); ais = AudioSystem.getAudioInputStream(clipFile); clickClip = AudioSystem.getClip(); clickClip.open(ais); fileIsLoaded = true; } catch (Exception ex) { clickClip = null; fileIsLoaded = false; } } public void playSound() { if (fileIsLoaded) { if ((clickClip==null) || (!clickClip.isRunning())) { try { clickClip.setFramePosition(0); clickClip.start(); } catch (Exception ex) { System.out.println("Cannot play click noise"); ex.printStackTrace(); } } } The prepareProcess method gets run once in the beginning, and the playSound method is called every time a triggering event occurs. My question is: do I need to close the clickClip object? I know I could add an actionListener to monitor for a Stop event, but since the event occurs so frequently I'm worried the extra processing is going to slow down the real-time data collection. The code seems to run fine, but my worry is memory leaks. The code above is based on an example I found while searching the net, but the example used an actionListener to close the Clip specifically "to eliminate memory leaks that would occur when the stop method wasn't implemented". My program is intended to run for hours so any memory leaks I have will cause problems. I'll be honest: I have no idea how to verify whether or not I've got a problem. I'm using Netbeans, and running the memory profiler just gave me a huge list of things that I don't know how to read. This is supposed to be the simple part of the program, and I'm spending hours on it. Any help would be greatly appreciated! Michael

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• Zaypay alternatives for payments using call or sms

  - by JohannesH

  We are currently trying to implement a payment provider in zaypay for paying for services using sms or by calling a number. We already have google checkout and paypal working for regular payments but zaypay is rather inflexible, poorly documented and a pain to setup when you have hundreds of products with varying prices. So my question is, do you know of any other european payment providers that take sms and call payments? As a response to Roberts answer/question Hi Robert, I must say that the Zaypay solution is the best and only I've seen thus far regarding phoned payments. However, since its now 2 months ago I finished the implementation of our custom Zaypay UI I can't remember much of the the details of the problems we were having. I'll try to give a brief of them anyways the best I can. First of all I would like to see a redirection type scenario for payalogues. From what I remember you guys are using the JS framework "Prototype" which doesn't play nice with jQuery which we are using so we weren't able to use the popup-type scenario supported by payalogues. Furthermore when implementing our custom interface I remember a lot of missing translations, like words that were codes instead of a word or a phrase. This meant we ended up writing/translating all the messages we needed ourselves. Also, another point of annoyance was the setup of prices and items. I wish we could just send in the order items/prices as a part of the interface like you can in Google Checkout or PayPal (not that they're flawless either), instead of having to define ALL the items you will ever sell through your admin interface beforehand. As far as I can remember it is virtually impossible to use Zaypay for a multi-item order in its current form. Finally there are, as far as I can tell, some security issues that you have to think about when you implement a custom solution... especially a ajax driven one. As I said in my original post you do mention this in the documentation but I believe the documentation wasn't that comprehensive regarding security issues. Again I wish I could give more details but the code & client is long since gone, so I can't look up the comments I wrote. Sorry! Oh yeah, the general API documentation weren't exactly comprehensive and 100% correct either. Again, I don't want to advice people against using Zaypay, I just want to advice that they should try it out first on a realistic prototype and think about their implementation before releasing to production. Maybe its just me who misunderstood a lot of things but I generally had a difficult time using your framework and I was left with a feeling that the API was very new and not thought through from the beginning.

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• How can I capture the keystroke that triggers "CellEndEdit" on a DataGridView in C#?

  - by Andy Stampor

  I have a DataGridView that is set to EditOnF2. I do some special processing of data in the CellEndEdit eventhandler that sets the value of the cell. I still want the functionality of the EditOnKeystrokeOrF2 of reverting to the original value when the Esc key is pressed. Unfortunately, at the CellEndEdit eventhandler, I don't see a way to tell what caused the CellEndEdit event to be fired. I only want to change the value of the cell if the Esc key is not pressed. How can I tell if it was or not? Edit: It is worth noting that the KeyDown event does not get fired when the cell is being edited, nor for the final ending keystroke. Edit2: I have tried the KeyPreview suggestion, but the form still does not capture the Escape key being pressed. Edit3: I've been experimenting with trying to get this working. I originally posted some of the following as a separate post, but feel it might be more relevant to include it here. I have a cell in a DataGridView that is now set to EditProgrammatically. To capture the keystroke that starts an edit, I am setting the cell.Value equal to the keystroke. However, this ruins the "Escape" functionality of the cell - when you press escape, instead of reverting to the original value, it reverts to the keystroke that I programmatically inserted into the cell. I believe that if I could set the "EditedFormattedValue" on a cell, this would be where I want to put my keystroke value, however this appears to be read only. How can I accomplish what I am attempting? An example to clarify: If the cell has a value of "54.3" in it, and I press the "9" key, it begins editing the cell and places a "9" there. If I hit Escape, instead of reverting to "54.3" it reverts to "9". What I want is for it to return to its original value of "54.3". So, I am trying to tackle this issue from both the beginning and the end. I think the real problem is that I am overwriting the original value and have no way to determine if I should revert it or not. Edit4: It looks like CellValidating might be worth using, but I am seeing strange behavior when I experiment with it. In a new project, I create the DataGridView and register for the various events and see that CellValidating is fired before the CellEndEdit. However, in my project where I am trying to get this to work, CellEndEdit is firing BEFORE CellValidating. Any ideas on what the difference might be?

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• Is it a oop good design ?

  - by remi bourgarel

  Hi all, I'd like to know what you think about this part of our program is realized : We have in our database a list of campsite. Partners call us to get all the campsites near a GPS location or all the campsites which provide a bar (we call it a service). So how I realized it ? Here is our database : Campsite - ID - NAME - GPS_latitude - GPS_longitude CampsiteServices -Campsite_ID -Services_ID So my code (c# but it's not relevant, let say it's an OO language) looks like this public class SqlCodeCampsiteFilter{ public string SqlCode; public Dictionary<string, object> Parameters; } interface ISQLCampsiteFilter{ SqlCodeEngineCore CreateSQLCode(); } public class GpsLocationFilter : ISQLCampsiteFilter{ public float? GpsLatitude; public float? GpsLongitude; public SqlCodeEngineCore CreateSQLCode() { --return an sql code to filter on the gps location like dbo.getDistance(@gpsLat,@gpsLong,campsite.GPS_latitude,campsite.GPS_longitude) with the parameters } } public class ServiceFilter : : ISQLCampsiteFilter{ public int[] RequiredServicesID; public SqlCodeEngineCore CreateSQLCode() { --return an sql code to filter on the services "where ID IN (select CampsiteServices.Service_ID FROm CampsiteServices WHERE Service_ID in ...) } } So in my webservice code : List<ISQLFilterEngineCore> filters = new List<ISQLFilterEngineCore>(); if(gps_latitude.hasvalue && gps_longitude.hasvalue){ filters.Add (new GpsLocationFilter (gps_latitude.value,gps_longitude.value)); } if(required_services_id != null){ filters.Add (new ServiceFilter (required_services_id )); } string sql = "SELECT ID,NAME FROM campsite where 1=1" foreach(ISQLFilterEngineCore aFilter in filters){ SqlCodeCampsiteFilter code = aFilter.CreateSQLCode(); sql += code.SqlCode; mySqlCommand.AddParameters(code.Parameters);//add all the parameters to the sql command } return mySqlCommand.GetResults(); 1/ I don't use ORM for the simple reason that the system exists since 10 years and the only dev who is here since the beginning is starting to learn about difference between public and private. 2/ I don't like SP because : we can do override, and t-sql is not so funny to use :) So what do you think ? Is it clear ? Do you have any pattern that I should have a look to ? If something is not clear please ask

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• Issue with parsed text with HTMLCleaner - spaces at the begining of text

  - by ansol90

  Im able to get text using HTMLCleaner from website. The problem is that when I set the text to a TextView it shows the beginning of the text with a big space on it. Here is the screenshot of what im talking about. I have tried android:gravity but nothing happened. Please help. Here is my Code: private class SiteParser extends AsyncTask<String, Void, String> { protected String doInBackground(String... arg) { String output = null; try { HtmlHelper hh = new HtmlHelper(new URL(arg[0])); List<TagNode> news = hh.getnewsByClass("TextoPrint"); for (Iterator<TagNode> iterator = newss.iterator(); iterator .hasNext();) { TagNode divElement = (TagNode) iterator.next(); output = divElement.getText().toString(); } } catch (Exception e) { e.printStackTrace(); } return output; } protected void onPostExecute(String output) { Bundle bundle=new Bundle(); bundle.putString("body",output); Intent mainIntent = new Intent(act, MyView.class); mainIntent.putExtras(bundle); startActivity(mainIntent); act.finish(); } } public class HtmlHelper { TagNode rootNode; public HtmlHelper(URL htmlPage) throws IOException, XPatherException { HtmlCleaner cleaner = new HtmlCleaner(); rootNode = cleaner.clean(htmlPage); } List<TagNode> getnewsByClass(String Classname){ List<TagNode> newsList = new ArrayList<TagNode>(); TagNode divElements[] = rootNode.getElementsByName("div", true); for (int i = 0; divElements != null && i < divElements.length; i++) { String classType = divElements[i].getAttributeByName("id"); if (classType != null && classType.equals(Classname)) { newsList.add(divElements[i]); } } return newsList; } }

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• AJAX response not valid in C++ but Apache

  - by fehergeri

  I want to make a server written in C++ to power my game. I learned the basics of sockets and wrote a basic chat program that worked well. Now I want to create an HTTP server like Apache, but only for the AJAX request-response part. I think just for the beginning i copied one Apache response text, and i sent the exact response with the C++ server program. The problem that is that the browser (Firefox) connnects to the apache and everything works fine, except all of the requests get a correct response. But if i send this with the C++ client, then FireBug tells me that the response status is OK (200) but there is no actual response text. (How is this possible?) This response-text is exactly the same what apache sends. I made a bit-bit comparison and they were the same. The php file wich is the original response <?php echo "AS";echo rand(0,9); ?> And the origional source code: Socket.h http://pastebin.com/bW9qxtrR Socket.cpp http://pastebin.com/S3c8RFM7 main.cpp http://pastebin.com/ckExuXsR index.html http://pastebin.com/mcfEEqPP < this is the requester file. ajax.js http://pastebin.com/uXJe9hVC benchmark.js http://pastebin.com/djSYtKg9 jQuery is not needed. The main.cpp there is lot of trash code like main3 and main4 functions, these do not affect the result. I know that the response stuff in the C++ code is not really good because the connection closing is not the best; I will fix that later now I want to send a success response first. UPDATE: now i tested today a lot again and i find out there is no problem with the socket. I used the fiddler program to capture the the good answer and to capture the bad. They were the same. After this i turned off my socket application, and forced fiddler to auto respond, and the answer from the 'bad' answer still bat. So after that i replaced the bad with the good and nothing happedned. The bad answer with the good text still bad on the :8888 port but the other on the original :80 port was good, but they were absolutly the same and the same program sended it (fiddler) i think there is something missing if the response is not on the same server address (even not the same port). UPDATE: oh my god! i cant send ajax request to a remote server. now i know this.

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• Performance tuning of a Hibernate+Spring+MySQL project operation that stores images uploaded by user

  - by Umar

  Hi I am working on a web project that is Spring+Hibernate+MySQL based. I am stuck at a point where I have to store images uploaded by a user into the database. Although I have written some code that works well for now, but I believe that things will mess up when the project would go live. Here's my domain class that carries the image bytes: @Entity public class Picture implements java.io.Serializable{ long id; byte[] data; ... // getters and setters } And here's my controller that saves the file on submit: public class PictureUploadFormController extends AbstractBaseFormController{ ... protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception{ MutlipartFile file; // getting MultipartFile from the command object ... // beginning hibernate transaction ... Picture p=new Picture(); p.setData(file.getBytes()); pictureDAO.makePersistent(p); // this method simply calls getSession().saveOrUpdate(p) // committing hiernate transaction ... } ... } Obviously a bad piece of code. Is there anyway I could use InputStream or Blob to save the data, instead of first loading all the bytes from the user into the memory and then pushing them into the database? I did some research on hibernate's support for Blob, and found this in Hibernate In Action book: java.sql.Blob and java.sql.Clob are the most efficient way to handle large objects in Java. Unfortunately, an instance of Blob or Clob is only useable until the JDBC transaction completes. So if your persistent class defines a property of java.sql.Clob or java.sql.Blob (not a good idea anyway), you’ll be restricted in how instances of the class may be used. In particular, you won’t be able to use instances of that class as detached objects. Furthermore, many JDBC drivers don’t feature working support for java.sql.Blob and java.sql.Clob. Therefore, it makes more sense to map large objects using the binary or text mapping type, assuming retrieval of the entire large object into memory isn’t a performance killer. Note you can find up-to-date design patterns and tips for large object usage on the Hibernate website, with tricks for particular platforms. Now apparently the Blob cannot be used, as it is not a good idea anyway, what else could be used to improve the performance? I couldn't find any up-to-date design pattern or any useful information on Hibernate website. So any help/recommendations from stackoverflowers will be much appreciated. Thanks

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