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• Low Throughput on Windows Named Pipe Over WAN

  - by MichaelB76

  I'm having problems with low performance using a Windows named pipe. The throughput drops off rapidly as the network latency increases. There is a roughly linear relationship between messages sent per second and round trip time. It seems that the client must ack each message before the server will send the next one. This leads to very poor performance, I can only send 5 (~100 byte) messages per second over a link with an RTT of 200 ms. The pipe is asynchronous, using multiple overlapped write operations (and multiple overlapped reads at the client end), but this is not improving throughput. Is it possible to send messages in parallel over a named pipe? The pipe is created using PIPE_TYPE_MESSAGE, would PIPE_READMODE_BYTE work better? Is there any other way I can improve performance? This is a deployed solution, so I can't simply replace the pipe with a socket connection (I've read that Windows named pipe aren't recommended for use over a WAN, and I'm wondering if this is why). I'd be grateful for any help with this matter.

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• please help me for performing serch in my program

  - by Abid

  i want to perform searching in my programe.. i have my class in which i have made a function i.e. public DataTable Search() { string SQL = "Select * from Customer where " + mField + " like '%" + mValue + "%'"; DataTable dt = new DataTable(); dt = dm.GetData(SQL); return (dt); } in which i have made setters and getters for mField and mValue.. where dm is the object of class Datamanagement in which i have made a function GetData i.e. public DataTable GetData(string SQL) { SqlCommand command = new SqlCommand(); SqlDataAdapter dbAdapter = new SqlDataAdapter(); DataTable DataTable = new DataTable(); command.Connection = clsConnection.GetConnection(); command.CommandText = SQL; dbAdapter.SelectCommand = command; dbAdapter.Fill(DataTable); return (DataTable); } and behind the search button, i have written.. private void btnfind_Click(object sender, EventArgs e) { //cust is the object of class customer// if (tbCustName.Text != "") { cust.Field="CustName"; cust.Value = tbCustName.Text; } else if (tbAddress.Text != "") { cust.Value = tbAddress.Text; cust.Field="Address"; } else if (tbEmail.Text != "") { cust.Value = tbEmail.Text; cust.Field="Email"; } else if (tbCell.Text != "") { cust.Value = tbCell.Text; cust.Field = "Cell"; } DataTable dt = new DataTable(); dt = cust.Search(); dgCustomer.DataSource = dt; RefreshGrid(); } where my referesh grid fuction does that : private void RefreshGrid() { DataTable dt = new DataTable(); dt = cust.GetCustomers(); dgCustomer.DataSource = dt; } but this is not working.. i dont knw y.. please help..

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• Is this use of PreparedStatements in a Thread in JAVA correct?

  - by Gormcito

  I'm still an undergrad just working part time and so I'm always trying to be aware of better ways to do things. Recently I had to write a program for work where the main thread of the program would spawn "task" threads (for each db "task" record) which would perform some operations and then update the record to say that it has finished. Therefore I needed a database connection object and PreparedStatement objects in or available to the ThreadedTask objects. This is roughly what I ended up writing, is creating a PreparedStatement object per thread a waste? I thought static PreparedStatments could create race conditions... Thread A stmt.setInt(); Thread B stmt.setInt(); Thread A stmt.execute(); Thread B stmt.execute(); A´s version never gets execed.. Is this thread safe? Is creating and destroying PreparedStatement objects that are always the same not a huge waste? public class ThreadedTask implements runnable { private final PreparedStatement taskCompleteStmt; public ThreadedTask() { //... taskCompleteStmt = Main.db.prepareStatement(...); } public run() { //... taskCompleteStmt.executeUpdate(); } } public class Main { public static final db = DriverManager.getConnection(...); }

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• How to send XML data through socket InputStream

  - by THeK3nger

  Hi, I'm trying to write a client-server application in Java with an XML-based protocol. But I have a great problem! See this part of client code: InputStream incoming = skt.getInputStream(); //I get Stream from Socket. OutputStream out = skt.getOutputStream(); [...] XMLSerializer serializer = new XMLSerializer(); //This create an XML document. tosend = WUTPClientWriter.createMessage100(projectid, cpuclock, cpunumber); serializer.setOutputByteStream(out); serializer.serialize(tosend); At this point server fall in deadlock. It wait for EOF but I can't send it because if I use out.close(); or skt.shutdownOutput(); I close Socket and I must keep alive this connection. I can't send '\0' becouse I get Parse Error in the server. How can I do? Can I "close" output stream without close socket? RESOLVED I've created new class XMLStreamOutput and XMLStreamInput with advanced Stream gesture.

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• Threading in client-server socket program - proxy sever

  - by crazyTechie

  I am trying to write a program that acts as a proxy server. Proxy server basically listens to a given port (7575) and sends the request to the server. As of now, I did not implement caching the response. The code looks like ServerSocket socket = new ServerSocket(7575); Socket clientSocket = socket.accept(); clientRequestHandler(clientSocket); I changed the above code as below: //calling the same clientRequestHandler method from inside another method. Socket clientSocket = socket.accept(); Thread serverThread = new Thread(new ConnectionHandler(client)); serverThread.start(); class ConnectionHandler implements Runnable { Socket clientSocket = null; ConnectionHandler(Socket client){ this.clientSocket = client; } @Override public void run () { try { PrxyServer.clientRequestHandler(clientSocket); } catch (Exception ex) { ex.printStackTrace(); } } } Using the code, I am able to open a webpage like google. However, if I open another web page even I completely receive the first response, I get connection reset by peer expection. 1. How can I handle this issue Can i use threading to handle different requests. Can someone give a reference where I look for example code that implements threading. Thanks. Thanks.

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• Accessing a broken mdadm raid

  - by CarstenCarsten

  Hi! I used a western digital mybookworld (SOHO NAS storage using Linux) as backup for my Linux box. Suddenly, the mybookworld does not boot up any more. So I opened the box, removed the hard disk and put the hard disk into an external USB HDD case, and connected it to my Linux box. [ 530.640301] usb 2-1: new high speed USB device using ehci_hcd and address 3 [ 530.797630] scsi7 : usb-storage 2-1:1.0 [ 531.794844] scsi 7:0:0:0: Direct-Access WDC WD75 00AAKS-00RBA0 PQ: 0 ANSI: 2 [ 531.796490] sd 7:0:0:0: Attached scsi generic sg3 type 0 [ 531.797966] sd 7:0:0:0: [sdc] 1465149168 512-byte logical blocks: (750 GB/698 GiB) [ 531.800317] sd 7:0:0:0: [sdc] Write Protect is off [ 531.800327] sd 7:0:0:0: [sdc] Mode Sense: 38 00 00 00 [ 531.800333] sd 7:0:0:0: [sdc] Assuming drive cache: write through [ 531.803821] sd 7:0:0:0: [sdc] Assuming drive cache: write through [ 531.803836] sdc: sdc1 sdc2 sdc3 sdc4 [ 531.815831] sd 7:0:0:0: [sdc] Assuming drive cache: write through [ 531.815842] sd 7:0:0:0: [sdc] Attached SCSI disk The dmesg output looks normal, but I was wondering why the hardisk was not mounted at all. And why there are 4 different partitions on it. fdisk showed the following: root@ubuntu:/home/ubuntu# fdisk /dev/sdc WARNING: DOS-compatible mode is deprecated. It's strongly recommended to switch off the mode (command 'c') and change display units to sectors (command 'u'). Command (m for help): p Disk /dev/sdc: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00007c00 Device Boot Start End Blocks Id System /dev/sdc1 4 369 2939895 fd Linux raid autodetect /dev/sdc2 370 382 104422+ fd Linux raid autodetect /dev/sdc3 383 505 987997+ fd Linux raid autodetect /dev/sdc4 506 91201 728515620 fd Linux raid autodetect Oh no! Everything seems to be created as a mdadm software raid. Calling mdadm --examine with the different partitions seems to affirm that. I think the only partition I am interested in, is /dev/sdc4 (because it is the largest). But nevertheless I called mdadm --examine with every partition. root@ubuntu:/home/ubuntu# mdadm --examine /dev/sdc1 /dev/sdc1: Magic : a92b4efc Version : 00.90.00 UUID : 5626a2d8:070ad992:ef1c8d24:cd8e13e4 Creation Time : Wed Feb 20 00:57:49 2002 Raid Level : raid1 Used Dev Size : 2939776 (2.80 GiB 3.01 GB) Array Size : 2939776 (2.80 GiB 3.01 GB) Raid Devices : 2 Total Devices : 1 Preferred Minor : 1 Update Time : Sun Nov 21 11:05:27 2010 State : clean Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 Checksum : 4c90bc55 - correct Events : 16682 Number Major Minor RaidDevice State this 0 8 1 0 active sync /dev/sda1 0 0 8 1 0 active sync /dev/sda1 1 1 0 0 1 faulty removed root@ubuntu:/home/ubuntu# mdadm --examine /dev/sdc2 /dev/sdc2: Magic : a92b4efc Version : 00.90.00 UUID : 9734b3ee:2d5af206:05fe3413:585f7f26 Creation Time : Wed Feb 20 00:57:54 2002 Raid Level : raid1 Used Dev Size : 104320 (101.89 MiB 106.82 MB) Array Size : 104320 (101.89 MiB 106.82 MB) Raid Devices : 2 Total Devices : 1 Preferred Minor : 2 Update Time : Wed Oct 27 20:19:08 2010 State : clean Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 Checksum : 55560b40 - correct Events : 9884 Number Major Minor RaidDevice State this 0 8 2 0 active sync /dev/sda2 0 0 8 2 0 active sync /dev/sda2 1 1 0 0 1 faulty removed root@ubuntu:/home/ubuntu# mdadm --examine /dev/sdc3 /dev/sdc3: Magic : a92b4efc Version : 00.90.00 UUID : 08f30b4f:91cca15d:2332bfef:48e67824 Creation Time : Wed Feb 20 00:57:54 2002 Raid Level : raid1 Used Dev Size : 987904 (964.91 MiB 1011.61 MB) Array Size : 987904 (964.91 MiB 1011.61 MB) Raid Devices : 2 Total Devices : 1 Preferred Minor : 3 Update Time : Sun Nov 21 11:05:27 2010 State : clean Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 Checksum : 39717874 - correct Events : 73678 Number Major Minor RaidDevice State this 0 8 3 0 active sync 0 0 8 3 0 active sync 1 1 0 0 1 faulty removed root@ubuntu:/home/ubuntu# mdadm --examine /dev/sdc4 /dev/sdc4: Magic : a92b4efc Version : 00.90.00 UUID : febb75ca:e9d1ce18:f14cc006:f759419a Creation Time : Wed Feb 20 00:57:55 2002 Raid Level : raid1 Used Dev Size : 728515520 (694.77 GiB 746.00 GB) Array Size : 728515520 (694.77 GiB 746.00 GB) Raid Devices : 2 Total Devices : 1 Preferred Minor : 4 Update Time : Sun Nov 21 11:05:27 2010 State : clean Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 Checksum : 2f36a392 - correct Events : 519320 Number Major Minor RaidDevice State this 0 8 4 0 active sync 0 0 8 4 0 active sync 1 1 0 0 1 faulty removed If I read the output correctly everything was removed, because it was faulty. Is there ANY way to see the contents of the largest partition? Or seeing somehow which files are broken? I see that everything is raid1 which is only mirroring, so this should be a normal partition. I am anxious to do anything with mdadm, in fear that I destroy the data on the hard disk. I would be very thankful for any help.

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• cURL/PHP Request Executes 50% of the Time

  - by makavelli

  After searching all over, I can't understand why cURL requests issued to a remote SSL-enabled host are successful only 50% or so of the time in my case. Here's the situation: I have a sequence of cURL requests, all of them issued to a HTTPS remote host, within a single PHP script that I run using the PHP CLI. Occasionally when I run the script the requests execute successfully, but for some reason most of the times I run it I get the following error from cURL: * About to connect() to www.virginia.edu port 443 (#0) * Trying 128.143.22.36... * connected * Connected to www.virginia.edu (128.143.22.36) port 443 (#0) * successfully set certificate verify locations: * CAfile: none CApath: /etc/ssl/certs * error:140943FC:SSL routines:SSL3_READ_BYTES:sslv3 alert bad record mac * Closing connection #0 If I try again a few times I get the same result, but then after a few tries the requests will go through successfully. Running the script after that again results in an error, and the pattern continues. Researching the error 'alert bad record mac' didn't give me anything helpful, and I hesitate to blame it on an SSL issue since the script still runs occasionally. I'm on Ubuntu Server 10.04, with php5 and php5-curl installed, as well as the latest version of openssl. In terms of cURL specific options, CURLOPT_SSL_VERIFYPEER is set to false, and both CURLOPT_TIMEOUT and CURLOPT_CONNECTTIMEOUT are set to 4 seconds. Further illustrating this problem is the fact that the same exact situation occurs on my Mac OS X dev machine - the requests only go through ~50% of the time.

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• Need help getting buttons to work...

  - by Mike Droid

  I am trying to get my first button to update a display number in my view when clicked. This view will have several buttons and "outputs" displayed. After reading examples and Q's here, I finally put something together that runs, but my first button is still not working; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.ship_layout); mSwitcher = (TextSwitcher) findViewById(R.id.eng_val); } private TextSwitcher mSwitcher; // Will be connected with the buttons via XML void onClick(View v){ switch (v.getId()) { case R.id.engplus: engcounter++; updateCounter(); break; case R.id.engneg: engcounter--; updateCounter(); break; } } private void updateCounter() { mSwitcher.setText(String.valueOf(engcounter)); } The .xml for this button is; <TextSwitcher android:id="@+id/eng_val" android:visibility="visible" android:paddingTop="9px" android:paddingLeft="50px" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/build" android:layout_toRightOf="@+id/engeq" android:textColor="#DD00ff00" android:textSize="24sp"/> This is within a Relative Layout that appears otherwise OK. When I had set the view to have a TextView with the number set as a string , the number displayed, but I could not figure out how to update the text with a numerical field. That may be my real problem. I have gone through many examples generally referenced from the dev. site (UI, Common Tasks, various samples), and I am still not seeing the connection here... Again, this is simply a try at getting variables to respond to buttons and update on the view. So, a few Q's for anyone that can help; 1) Is there any easier way of doing this (ie. send numerical value to View) ? 2) Why isn't my TextSwitcher displaying the number? 3) Should I be using a TextSwitcher here? 4) Any examples of this you can point me to?

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• how to change uibutton title at runtime in objective c?

  - by Sarah

  Hello, I know this question is asked many a times,and i am also implementing the same funda for chanding the title of the uibutton i guess. Let me clarify my problem first. I have one uibutton named btnType, on clicking of what one picker pops up and after selecting one value,i am hitting done button to hide the picker and at the same time i am changing the the title of the uibutton with code [btnType setTitle:btnTitle forState:UIControlEventTouchUpInside]; [btnType setTitleColor:[UIColor redColor] forState:UIControlEventAllEvents]; But with my surpriaze,it is not changed and application crashes with signal EXC_BAD_ACCESS. I am not getting where i am making mistake.I have allocated memory to the btnType at viewdidLoad. Also I am using -(IBAction)pressAddType { toolBar.hidden = FALSE; dateTypePicker.hidden = FALSE; } event on pressing the button to open the picker. Also i would like to mention that i have made connection with IB with event TouchUpInside for pressAddType. Any guesses? I will be grateful if you could help me. Thanks.

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• Empty Datagrid problem in VB6

  - by Hybrid SyntaX

  Hello Recently, i encountered a problem; when I bind a recordset to datagrid ,and run the application the datagrid is not populated even though recordset has data I use the following code Option Explicit Dim conn As New ADODB.Connection Dim cmd As New ADODB.Command Dim recordset As New ADODB.recordset Private Sub InitializeConnection() Dim str As String str = _ "Provider=Microsoft.Jet.OLEDB.4.0;" & _ "Data Source=" + App.Path + "\phonebook.mdb;" & _ "Persist Security Info=False" conn.CursorLocation = adUseClient conn.ConnectionString = str conn.Open (conn.ConnectionString) End Sub Private Sub AbandonConnection() If conn.State <> 0 Then conn.Close End If End Sub Private Sub Persons_Read() Dim qry_all As String ' qry_all = "select * from person,web,phone Where web.personid = person.id And phone.personid = person.id" qry_all = "SELECT * FROM person" Call InitializeConnection cmd.CommandText = qry_all cmd.CommandType = adCmdText Set cmd.ActiveConnection = conn If conn.State = 1 Then Set recordset = cmd.Execute() End If Call BindDatagrid Call AbandonConnection End Sub Private Function Person_Add() End Function Private Function Person_Delete() End Function Private Function Person_Update() End Function Private Sub BindDatagrid() Set dg_Persons.DataSource = recordset dg_Persons.Refresh End Sub Private Sub cmd_Add_Click() Person_Add End Sub Private Sub cmd_Delete_Click() Person_Delete End Sub Private Sub cmd_Update_Click() Person_Update End Sub Private Sub Form_Load() Call Persons_Read End Sub Private Sub mnu_About_Click() frm_About.Show End Sub Thanks in advance

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• How do you send email from IMAP account with PHP?

  - by arthurakay

  I'm having an issue sending email via PHP/IMAP - and I don't know if it's because: I don't correctly understand IMAP, or there's an issue with my server My application opens an IMAP connection to an email account to read messages in the inbox. It does this successfully. The problem I have is that I want to send messages from this account and have them display in the outbox/sent folder. As far as I can tell, the PHP imap_mail() function doesn't in any way hook into the IMAP stream I currently have open. My code executes without throwing an error. However, the email never arrives to the recipient and never displays in my sent folder. private function createHeaders() { return "MIME-Version: 1.0" . "\r\n" . "Content-type: text/html; charset=iso-8859-1" . "\r\n" . "From: " . $this->accountEmail . "\r\n"; } private function notifyAdminForCompleteSet($urlToCompleteSet) { $message = " <p> In order to process the latest records, you must visit <a href='$urlToCompleteSet'>the website</a> and manually export the set. </p> "; try { imap_mail( $this->adminEmail, "Alert: Manual Export of Records Required", wordwrap($message, 70), $this->createHeaders() ); echo(" ---> Admin notified via email!\n"); } catch (Exception $e) { throw new Exception("Error in notifyAdminForCompleteSet()"); } } I'm guessing I need to copy the message into the IMAP account manually... or is there a different solution to this problem? Also, does it matter if the domain in the "from" address is different than that of the server on whicn this script is running? I can't explain why the message is never sent.

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• Socket stops communicating

  - by user1392992

  I'm running python 2.7 code on a Raspberry Pi that receives serial data from an Arduino, processes it, and sends it to a Windows box over a wifi link. The Pi is wired to a Linksys router running in client bridge mode and that router connects over wifi to another Linksys router to which the Windows box is wired. The code in the Pi runs fine for some (apparently) random interval, and then the Pi becomes unreachable from the Windows box. I'm running PUTTY on the the Windows machine to connect to the Pi and when the fail occurs I get a message saying there's been a network error and the Pi is not reachable. Pinging the Pi from the Windows machine works fine until the error, at which time it produces "Reply from 192.168.0.129: Destination host unreachable." The client bridge router to which the Pi is connected remains reachable. I've got the networking code on the Pi wrapped in an exception handler, and when it fails it shows the following: Ethernet problem: Traceback (most recent call last): File "garage.py", line 108, in module s.connect((host, port)) File "/usr/lib/python2.7/socket.py", line 224, in meth return getattr(self._sock,name)(*args) error: [Errno 113] No route to host None The relevant python code looks like: import socket import traceback host = '192.168.0.129' port = 31415 in the setup, and after serial data has been processed: try: bline = strline.encode('utf-8') s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((host, port)) s.send(bline) s.close() except: print "Ethernet problem: " print traceback.print_exc() Where strline contains the processed data. As I said, this runs fine for a few hours more or less before failing. Any ideas? EDIT: When PUTTY fails its error message is :Network Error: Software caused connection abort."

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• Peculiar JRE behaviour running RMI server under load, should I worry?

  - by darri

  I've been developing a minimalistic Java rich client CRUD application framework for the past few years, mostly as a hobby but also actively using it to write applications for my current employer. The framework provides database access to clients either via a local JDBC based connection or a lightweight RMI server. Last night I started a load testing application, which ran 100 headless clients, bombarding the server with requests, each client waiting only 1 - 2 seconds between running simple use cases, consisting of selecting records along with associated detail records from a simple e-store database (Chinook). This morning when I looked at the telemetry results from the server profiling session I noticed something which to me seemed strange (and made me keep the setup running for the remainder of the day), I don't really know what conclusions to draw from it. Here are the results: Memory GC activity Threads CPU load Interesting, right? So the question is, is this normal or erratic? Is this simply the JRE (1.6.0_03 on Windows XP) doing it's thing (perhaps related to the JRE configuration) or is my framework design somehow causing this? Running the server against MySQL as opposed to an embedded H2 database does not affect the pattern. I am leaving out the details of my server design, but I'll be happy to elaborate if this behaviour is deemed erratic.

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• APC decreasing php performance??? (php 5.3, apache 2.2, windows vista 64bit)

  - by M.M.

  Hi, I have an Apache/2.2.15 (VC9) and PHP/5.3.2 (VC9 thread safe) running as an apache module on Vista 64bit machine. All running fine. Project that I'm benchmarking (with apache's ab utility) is basically standard Zend Framework project with no db connection involved. Average (median) apache response is about 0.15 seconds. After I've installed APC (3.1.4-dev VC9 thread safe) with standard settings suddenly the request response time raised to 1.3 seconds (!), which is unacceptable... All apc settings looked always good (through the apc.php script: enough shm memory, no cache full, fragmentation 0%). Only difference was to disable the stats lookup (apc.stat = 0). Then the response dropped to 0.09 seconds which was finally better than without the apc. IIRC, it's expected and obvious that the stat lookup creates some overhead, but shouldn't it still be far more performant compared to running wihout the apc extension at all? Or put it differently why is the apc.stat creating so much overhead? Apparently, something is not working as it should, I don't really know where to start looking. Thank you for your time/answers/direction in advance. Cheers, m.

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• Run SQL Scripts from C# application across domains

  - by Saravanan AR

  To run sql script files from my C# application, I referred this. http://social.msdn.microsoft.com/Forums/en/adodotnetdataproviders/thread/43e8bc3a-1132-453b-b950-09427e970f31 it works perfectly when my machine and DB server are in the same domain. my problem now is, i'm executing this console application from a machine (name: X, user id: abc, domain D1). the SQL server is in another machine (name: Y, domain: D2). I use VPN to connect to machine Y with user id 'abc' and work on SQL in remote desktop. how can i run sql scripts across domains? I use this in a custom activity in my TFS build template as the last step to run the scripts in the target database which is in domain D2. i'm getting this error: "A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)" is it possible to connect to the DB using the admin user ID of machine Y in domain D2?

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• Can anyone give me a sample java socket programming for doing a peer to peer for 3 systems?

  - by Sadesh Kumar N

  I am doing an university project. I need some sample programs on peer to peer programs in java socket programming. Every where people are telling to add a server socket in the client program. I am in a confusion. Can a single program having server socket and client socket will do or i have to create two programs of one initiating a system and another peer program running thrice to solve the problem. or i need to create three programs for three peer systems. I am not clear on the architecture of building peer to peer programs using java sockets. Can some one help me giving a simple program on how to create a peer to peer connection between three systems. I know how to do a socket program for client server model and clear on the concept. But creating a peer to peer architecture sounds complex for me to understand. I also referred this thread. developing peer to peer in java The person commented second says" To make peer2peer app each client opens server socket too. When client A wishes to connect to client B it just connects to its socket. " Need some more sample and an explanation on how peer to peer java socket program works I dont want any external api like jxta to do this task. I need a clear picture on how it works alone with an example.

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• A very interesting MYSQL problem (related to indexing, million records, algorithm.)

  - by terence410

  This problem is pretty hard to describe and therefore difficult to search the answer. I hope some expert could share you opinions on that. I have a table with around 1 million of records. The table structure is similar to something like this: items{ uid (primary key, bigint, 15) updated (indexed, int, 11) enabled (indexed, tinyint, 1) } The scenario is like this. I have to select all of the records everyday and do some processing. It takes around 3 second to handle each item. I have written a PHP script to fetch 200 items each time using the following. select * from items where updated unix_timestamp(now()) - 86400 and enabled = 1 limit 200; I will then update the "updated" field of the selected items to make sure that it wont' be selected again within one day. The selected query is something like that. update items set updated = unix_timestamp(now()) where uid in (1,2,3,4,...); Then, the PHP will continue to run and process the data which doesn't require any MYSQL connection anymore. Since I have million records and each record take 3 seconds to process, it's definitely impossible to do it sequentially. Therefore, I will execute the PHP in every 10 seconds. However, as time goes by and the table growth, the select getting much slower. Sometimes, it take more than 100 seconds to run! Do you guys have any suggestion how may I solve this problem?

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• How can I use Qt to get html code of this NCBI page??

  - by user308503

  I'm trying to use Qt to download the html code from the following url: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=nucleotide&cmd=search&term=AB100362 this url will re-direct to www.ncbi.nlm.nih.gov/nuccore/27884304 I try to do it by following way, but I cannot get anything. it works for some webpage such as www.google.com, but not for this NCBI page. is there any way to get this page?? QNetworkReply::NetworkError downloadURL(const QUrl &url, QByteArray &data) { QNetworkAccessManager manager; QNetworkRequest request(url); QNetworkReply *reply = manager.get(request); QEventLoop loop; QObject::connect(reply, SIGNAL(finished()), &loop, SLOT(quit())); loop.exec(); if (reply->error() != QNetworkReply::NoError) { return reply->error(); } data = reply->readAll(); delete reply; return QNetworkReply::NoError; } void GetGi() { int pos; QString sGetFromURL = "http://www.ncbi.nlm.nih.gov/entrez/query.fcgi"; QUrl url(sGetFromURL); url.addQueryItem("db", "nucleotide"); url.addQueryItem("cmd", "search"); url.addQueryItem("term", "AB100362"); QByteArray InfoNCBI; int errorCode = downloadURL(url, InfoNCBI); if (errorCode != 0 ) { QMessageBox::about(0,tr("Internet Error "), tr("Internet Error %1: Failed to connect to NCBI.\t\nPlease check your internect connection.").arg(errorCode)); return "ERROR"; } }

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• How can I set paperclip's storage mechanism based on the current Rails environment?

  - by John Reilly

  I have a rails application that has multiple models with paperclip attachments that are all uploaded to S3. This app also has a large test suite that is run quite often. The downside with this is that a ton of files are uploaded to our S3 account on every test run, making the test suite run slowly. It also slows down development a bit, and requires you to have an internet connection in order to work on the code. Is there a reasonable way to set the paperclip storage mechanism based on the Rails environment? Ideally, our test and development environments would use the local filesystem storage, and the production environment would use S3 storage. I'd also like to extract this logic into a shared module of some kind, since we have several models that will need this behavior. I'd like to avoid a solution like this inside of every model: ### We don't want to do this in our models... if Rails.env.production? has_attached_file :image, :styles => {...}, :storage => :s3, # ...etc... else has_attached_file :image, :styles => {...}, :storage => :filesystem, # ...etc... end Any advice or suggestions would be greatly appreciated! :-)

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• Help with HTTP Intercepting Proxy in Ruby?

  - by Philip

  I have the beginnings of an HTTP Intercepting Proxy written in Ruby: require 'socket' # Get sockets from stdlib server = TCPServer.open(8080) # Socket to listen on port 8080 loop { # Servers run forever Thread.start(server.accept) do |client| puts "** Got connection!" @output = "" @host = "" @port = 80 while line = client.gets line.chomp! if (line =~ /^(GET|CONNECT) .*(\.com|\.net):(.*) (HTTP\/1.1|HTTP\/1.0)$/) @port = $3 elsif (line =~ /^Host: (.*)$/ && @host == "") @host = $1 end print line + "\n" @output += line + "\n" # This *may* cause problems with not getting full requests, # but without this, the loop never returns. break if line == "" end if (@host != "") puts "** Got host! (#{@host}:#{@port})" out = TCPSocket.open(@host, @port) puts "** Got destination!" out.print(@output) while line = out.gets line.chomp! if (line =~ /^<proxyinfo>.*<\/proxyinfo>$/) # Logic is done here. end print line + "\n" client.print(line + "\n") end out.close end client.close end } This simple proxy that I made parses the destination out of the HTTP request, then reads the HTTP response and performs logic based on special HTML tags. The proxy works for the most part, but seems to have trouble dealing with binary data and HTTPS connections. How can I fix these problems?

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• JDBC with JSP fails to insert

  - by StrykeR

  I am having some issues right now with JDBC in JSP. I am trying to insert username/pass ext into my MySQL DB. I am not getting any error or exception, however nothing is being inserted into my DB either. Below is my code, any help would be greatly appreciated. <% String uname=request.getParameter("userName"); String pword=request.getParameter("passWord"); String fname=request.getParameter("firstName"); String lname=request.getParameter("lastName"); String email=request.getParameter("emailAddress"); %> <% try{ String dbURL = "jdbc:mysql:localhost:3306/assi1"; String user = "root"; String pwd = "password"; String driver = "com.mysql.jdbc.Driver"; String query = "USE Users"+"INSERT INTO User (UserName, UserPass, FirstName, LastName, EmailAddress) " + "VALUES ('"+uname+"','"+pword+"','"+fname+"','"+lname+"','"+email+"')"; Class.forName(driver); Connection conn = DriverManager.getConnection(dbURL, user, pwd); Statement statement = conn.createStatement(); statement.executeUpdate(query); out.println("Data is successfully inserted!"); } catch(SQLException e){ for (Throwable t : e) t.printStackTrace(); } %> DB script here: CREATE DATABASE Users; use Users; CREATE TABLE User ( UserID INT NOT NULL AUTO_INCREMENT, UserName VARCHAR(20), UserPass VARCHAR(20), FirstName VARCHAR(30), LastName VARCHAR(35), EmailAddress VARCHAR(50), PRIMARY KEY (UserID) );

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• Testing for a closed socket

  - by Robert S. Barnes

  I'm trying to test for a closed socket that has been gracefully closed by the peer without incurring the latency hit of a double send to induce a SIGPIPE. One of the assumptions here is that the socket if closed was gracefully closed by the peer immediately after it's last write / send. Actual errors like a premature close are dealt with else where in the code. If the socket is still open, there will be 0 or more bytes data which I don't actually want to pull out of the socket buffer yet. I was thinking that I could call int ret = recv(sockfd, buf, 1, MSG_DONTWAIT | MSG_PEEK); to determine if the socket is still connected. If it's connected but there's no data in the buffer I'll get a return of -1 with errno == EAGAIN and return the sockfd for reuse. If it's been gracefully closed by the peer I'll get ret == 0 and open a new connection. I've tested this and it seems to work. However, I suspect there is a small window between when I recv the last bit of my data and when the peer FIN arrives in which I could get a false-positive EAGAIN from my test recv. Is this going to bite me, or is there a better way of doing this?

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• [java] tcp socket communication [send and recieve help]

  - by raven

  hello, I am creating a Chat in java. I have a method (onMouseRelease) inside an object that creates a tcp server and waits for a socket ServerSocket server = new ServerSocket(port); Socket channel = server.accept(); now I want to make a thread that will loop and read data from the socket, so that once the user on the other side sent me a string, I will extract the data from the socket [or is it called packet? sry I am new to this], and update a textbox to add the additional string from the socket [or packet?]. I have no idea how to READ (extract) the information from the scoket [/packet] and then update it into a JTextArea which is called userOutput. And how to Send a string to the other client, so that it will also could read the new data and update its JTextArea. (from what I know, for a 2 sided tcp communication you need one computer to host a server and the other to connect [as a client] and once the connection is set the client can also recieve new information from the socket. Is that true? and please tell me how ) Any help appreciated !! I know this is abit long but I have searched allot and didn't understand [I saw something like printwriter but failed to understand].

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• Error in inserting data into database

  - by Matthew

  When I try to run this code it will not insert the data into the database? <?php class Database { private $dsn; function __construct($dbname, $host, $user, $password, $enckey) { $this->dsn = "mysql:dbname=" . $dbname . ';host=' . $host; $this->user = $user; $this->password = $password; } private function createDSN() { return $this->dsn; } public function createConnection() { try { $dbh = new PDO(self::createDSN(), $this->user, $this->password); } catch (PDOException $e) { echo 'Connection failed: ' . $e->getMessage(); } return $dbh; } } $db = new Database('mytest', 'localhost', 'root', 'hashedpassword', null); $dbh = $db->createConnection(); $sql = $dbh->prepare("INSERT INTO contacts (firstname, lastname) VALUES (?,?)"); $sql->execute(array("abc", "xyz")); ?>

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• VB.Net Memory Issue

  - by Skulmuk

  We have an application that has some interesting memory usage issues. When it first opens, the program uses aroun 50-60MB of memory. This stays consistent on 32-bit machines. On 64-bit machines, however, re-activating the form in any way (clicking, dragging, alt-tabbing, etc.) adds around another 50MB to it's memory usage. It repeats this process several times before resetting back to around 45MB, at which point the cycle begins again. I've done some research and a lot of people have said that VB in general has pretty poor garbage collection, which could be affecting the software in some way. However, I've yet to find a solution. There are no events fired when the application is activated (as shown by 32-bit usage) - the applications is merely sitting awaiting the user's actions. At load, the system pulls some data into a tree view, but that's the only external connection, and it only re-fires the routine when the user makes a change to something and saves the change. Has anyone else experienced anything this strange, and if so, does anyone know of what might fix it? It seems strange that it only occurs under x64 systems. Thanks

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