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  • AsyncTask not do onPostExecute()

    - by brian
    I write a AsyncTask as below: class Load extends AsyncTask<String, String, String> { @Override protected void onPreExecute() { super.onPreExecute(); } @Override protected String doInBackground(String... aurl) { //do job seconds //stop at here, and does not run onPostExecute } @Override protected void onPostExecute(String unused) { super.onPostExecute(unused); wait = false; new Load().execute(); } } And the other method as below: public void click() { new Load().execute(); while(wait) { ; } } The wait is a global boolean value.

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  • Issue with TurnBased Multiplayer Game in Game-kit

    - by Nirav
    I am working with cocos2d game in which i am implementing Game-kit. My game supports multiplayer option. Actually as given example Raywenderlich link. I am GKTurnBasedMultiplayer class from Game-kit. But now the issue when first player connected to game center and will select option of "Play Now" it automatches for another player. but issue is it directly connects and starts the match, and doesn't wait for another player. I am using [[GCTurnBasedMatchHelper sharedInstance] findMatchWithMinPlayers:2 maxPlayers:4 viewController:viewConroller]; for connecting and playing with other players but directly connects the match. I want to wait for another player. That is the issue. I am also using GCTurnBasedMatchHelper Class.

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  • L2TP connection fails!

    - by a.toraby
    I've installed l2tp-ipsec-vpn but when I try to connect to the vpn server I get error 500. Here are the logs: Jun 17 12:54:37.449 ipsec_setup: Stopping Openswan IPsec... Jun 17 12:54:38.858 Stopping xl2tpd: xl2tpd. Jun 17 12:54:38.859 xl2tpd[1511]: death_handler: Fatal signal 15 received Jun 17 12:54:38.872 ipsec_setup: Starting Openswan IPsec U2.6.37/K3.2.0-23-generic... Jun 17 12:54:39.027 ipsec__plutorun: Starting Pluto subsystem... Jun 17 12:54:39.033 ipsec__plutorun: adjusting ipsec.d to /etc/ipsec.d Jun 17 12:54:39.037 recvref[30]: Protocol not available Jun 17 12:54:39.038 xl2tpd[2442]: This binary does not support kernel L2TP. Jun 17 12:54:39.038 xl2tpd[2444]: xl2tpd version xl2tpd-1.3.1 started on atp-ThinkPad-SL410 PID:2444 Jun 17 12:54:39.038 xl2tpd[2444]: Written by Mark Spencer, Copyright (C) 1998, Adtran, Inc. Jun 17 12:54:39.038 xl2tpd[2444]: Forked by Scott Balmos and David Stipp, (C) 2001 Jun 17 12:54:39.038 xl2tpd[2444]: Inherited by Jeff McAdams, (C) 2002 Jun 17 12:54:39.039 xl2tpd[2444]: Forked again by Xelerance (www.xelerance.com) (C) 2006 Jun 17 12:54:39.039 xl2tpd[2444]: Listening on IP address 0.0.0.0, port 1701 Jun 17 12:54:39.040 Starting xl2tpd: xl2tpd. Jun 17 12:54:39.062 ipsec__plutorun: 002 added connection description "L2TP" Jun 17 12:55:30.753 104 "L2TP" #1: STATE_MAIN_I1: initiate Jun 17 12:55:30.754 010 "L2TP" #1: STATE_MAIN_I1: retransmission; will wait 20s for response Jun 17 12:55:30.754 010 "L2TP" #1: STATE_MAIN_I1: retransmission; will wait 40s for response Jun 17 12:55:30.754 003 "L2TP" #1: ignoring Vendor ID payload [MS NT5 ISAKMPOAKLEY 00000008] Jun 17 12:55:30.754 003 "L2TP" #1: received Vendor ID payload [RFC 3947] method set to=109 Jun 17 12:55:30.754 003 "L2TP" #1: received Vendor ID payload [draft-ietf-ipsec-nat-t-ike-02_n] meth=106, but already using method 109 Jun 17 12:55:30.755 003 "L2TP" #1: ignoring Vendor ID payload [FRAGMENTATION] Jun 17 12:55:30.755 003 "L2TP" #1: ignoring Vendor ID payload [MS-Negotiation Discovery Capable] Jun 17 12:55:30.755 003 "L2TP" #1: ignoring Vendor ID payload [IKE CGA version 1] Jun 17 12:55:30.755 106 "L2TP" #1: STATE_MAIN_I2: sent MI2, expecting MR2 Jun 17 12:55:30.755 010 "L2TP" #1: STATE_MAIN_I2: retransmission; will wait 20s for response Jun 17 12:55:30.755 003 "L2TP" #1: NAT-Traversal: Result using RFC 3947 (NAT-Traversal): i am NATed Jun 17 12:55:30.755 108 "L2TP" #1: STATE_MAIN_I3: sent MI3, expecting MR3 Jun 17 12:55:30.756 004 "L2TP" #1: STATE_MAIN_I4: ISAKMP SA established {auth=OAKLEY_PRESHARED_KEY cipher=oakley_3des_cbc_192 prf=oakley_sha group=modp1024} Jun 17 12:55:30.756 117 "L2TP" #2: STATE_QUICK_I1: initiate Jun 17 12:55:30.756 010 "L2TP" #2: STATE_QUICK_I1: retransmission; will wait 20s for response Jun 17 12:55:30.756 003 "L2TP" #2: ignoring informational payload, type IPSEC_RESPONDER_LIFETIME msgid=6b03ff69 Jun 17 12:55:30.756 003 "L2TP" #2: NAT-Traversal: received 2 NAT-OA. ignored because peer is not NATed Jun 17 12:55:30.756 003 "L2TP" #2: our client subnet returned doesn't match my proposal - us:192.168.1.3/32 vs them:109.162.174.235/32 Jun 17 12:55:30.757 003 "L2TP" #2: Allowing questionable proposal anyway [ALLOW_MICROSOFT_BAD_PROPOSAL] Jun 17 12:55:30.757 004 "L2TP" #2: STATE_QUICK_I2: sent QI2, IPsec SA established transport mode {ESP=>0x23af21f8 <0xdb4a87b6 xfrm=AES_128-HMAC_SHA1 NATOA=none NATD=none DPD=none} Jun 17 12:55:31.759 xl2tpd[2444]: Connecting to host x.x.x.x, port 1701 Jun 17 12:55:32.021 xl2tpd[2444]: Connection established to x.x.x.x, 1701. Local: 4720, Remote: 200 (ref=0/0). Jun 17 12:55:32.023 xl2tpd[2444]: Calling on tunnel 4720 Jun 17 12:55:32.454 xl2tpd[2444]: Call established with x.x.x.x, Local: 9667, Remote: 3, Serial: 1 (ref=0/0) Jun 17 12:55:32.456 xl2tpd[2444]: start_pppd: I'm running: Jun 17 12:55:32.456 xl2tpd[2444]: "/usr/sbin/pppd" Jun 17 12:55:32.457 xl2tpd[2444]: "passive" Jun 17 12:55:32.458 xl2tpd[2444]: "nodetach" Jun 17 12:55:32.458 xl2tpd[2444]: ":" Jun 17 12:55:32.459 xl2tpd[2444]: "file" Jun 17 12:55:32.459 xl2tpd[2444]: "/etc/ppp/L2TP.options.xl2tpd" Jun 17 12:55:32.460 xl2tpd[2444]: "ipparam" Jun 17 12:55:32.461 xl2tpd[2444]: "x.x.x.x" Jun 17 12:55:32.462 xl2tpd[2444]: "/dev/pts/1" Jun 17 12:55:32.583 pppd[2711]: Plugin passprompt.so loaded. Jun 17 12:55:32.583 pppd[2711]: pppd 2.4.5 started by root, uid 0 Jun 17 12:55:32.619 pppd[2711]: Using interface ppp0 Jun 17 12:55:32.620 pppd[2711]: Connect: ppp0 <--> /dev/pts/1 Jun 17 12:55:33.693 pppd[2711]: /usr/bin/L2tpIPsecVpn exited with code 0 Jun 17 12:55:34.454 [ERROR 404] Authentication failed: closing connection to 'L2TP' Jun 17 12:55:34.456 pppd[2711]: MS-CHAP authentication failed: E=691 Authentication failure Jun 17 12:55:34.457 pppd[2711]: CHAP authentication failed Jun 17 12:55:34.461 Stopping xl2tpd: xl2tpd. Jun 17 12:55:34.462 xl2tpd[2444]: death_handler: Fatal signal 15 received Jun 17 12:55:34.463 pppd[2711]: Modem hangup Jun 17 12:55:34.463 pppd[2711]: Connection terminated. Jun 17 12:55:34.474 ipsec_setup: Stopping Openswan IPsec... Jun 17 12:55:34.482 pppd[2711]: Exit. Jun 17 12:55:35.587 ipsec_setup: ERROR: Module xfrm4_mode_transport is in use Jun 17 12:55:35.665 ipsec_setup: ERROR: Module esp4 is in use I had this problem by ubuntu 11.10 though I can easily connect to the server from windows. I use ubuntu 12.0 64bit

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  • NVIDIA graphics driver on Macbook Pro 10,1

    - by Boatzart
    I just installed 14.04 over my old 12.04 partition on my Macbook Pro 10,1 (which is dual-booting with OS X) by following the instructions here. The only difference is that I'm using rEFInd instead of rEFIt. The proprietary NVIDIA drivers worked great with 12.04, but now I'm unable to boot into Unity with it in 14.04. Generally, I just get a black screen after the Grub menu, though occasionally I get some kind of panic screen like this, where I see errors like: [drm: __gen6_gt_force_wake_mt_get] *ERROR* Timed out waiting for forcewake old ack to clear. [drm: __gen6_gt_wait_for_thread_c0] *ERROR* GT thread status wait timed out [drm: __intel_ring_setup_status_page] *ERROR* render ring: wait for SyncFlush to complete for TLB invalidation timed out etc. Using the nouveau drivers works fine, but everything feels sluggish so I would really like to get the NVIDIA drivers working. Has anyone successfully gotten the NVIDIA drivers working with the GT-650M Mac Edition?

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  • SQL Server Scripts I Use

    - by Bill Graziano
    When I get to a new client I usually find myself using the same set of scripts for maintenance and troubleshooting.  These are all drop in solutions for various maintenance issues. Reindexing.  I use Michelle Ufford’s (SQLFool) re-indexing script.  I like that it has a throttle and only re-indexes when needed.  She also has a variety of other interesting scripts on her blog too. Server Activity.  Adam Machanic is up to version 10 of sp_WhoIsActive.  It’s a great replacement for the sp_who* stored procedures and does so much more.  If a server is acting funny this is one of the first tools I use. Backups.  Tara Kizer has a great little T-SQL script for SQL Server backups.  Wait Stats.  Paul Randal has a great script to display wait stats.  The biggest benefit for me is that his script filters out at least three dozen wait stats that I just don’t care about (for example LAZYWRITER_SLEEP). Update Statistics.  I didn’t find anything I liked so I wrote a simple script to update stats myself.  The big need for me was that it had to run inside a time window and update the oldest statistics first.  Is there a better one? Diagnostic Queries.  Glenn Berry has a huge collection of DMV queries available.  He also just highlighted five of them including two I really like dealing with unused indexes and suggested indexes. Single Use Query Plans.  Kim Tripp has a script that counts the number of single-use query plans.  This should guide you in whether to enable the Optimize for Adhoc Workloads option in SQL Server 2008. Granting Permissions to Developers.  This is one of those scripts I didn’t even know I needed until I needed it.  Kendra Little wrote it to grant a login read-only permission to all the databases.  It also grants view server state and a few other handy permissions.   What else do you use?  What should I add to my list?

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  • Oracle OpenWorld Preview: Oracle Social Network Technical Tour

    - by kellsey.ruppel
      Originally posted by Jake Kuramoto on The Apps Lab blog. Yesterday, I told you about the Oracle Social Network Developer Challenge we’ll be hosting at OpenWorld (@oracleopenworld) next week. If you’re attending OpenWorld or JavaOne (@javaoneconf) and want to get hands-on experience with Oracle Social Network and show off your coding chops, this is the event for you. Go ahead and register. I’ll wait. But wait, there’s more. If you’re not sure you’ll have the time for the Challenge, don’t want to embarrass anyone with your awesome skills, have a hectic schedule and can’t commit, or just want to learn more about Oracle Social Network and how to extend it, then the Oracle Social Network Technical Tour is for you. Read Jake's originally entry to learn more about The Tour!

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  • Cannot install .NET Framework 4.0 on Windows XP SP3

    - by Bob
    I'm using Windows XP SP3 logged in as the administrator. I had RAID Mirroring running. The motherboard broke earlier in the year. When I got a new battery I did not resync. I just use the disks as two separate disks. I searched Google for the errors but I didn't find anything detailed enough. The following Microsoft components are in Add/Remove programs: .NET Framework 1.1 .NET Framework 2.0 Service Pack 2 .NET Framework 3.0 Service Pack 2 .NET Framework 3.5 SP1 Microsoft Compression Client Pack 1.0 for Windows XP Microsoft Office Enterprise 2007 Microsoft Silverlight Microsoft USB Flash Driver Manager Micrsoft User-mode Driver Framework Feature Pack 1.0 Microsoft Visual C++ 2005 ATL Update KB 973923 x86 8.050727.4053 Microsoft Visual C++ 2005 Redistributable This is the installation log: Exists: evaluating... [10/21/2011, 22:17:14]MsiGetProductInfo with product code {3C3901C5-3455-3E0A-A214-0B093A5070A6} found no matches [10/21/2011, 22:17:14] Exists evaluated to false [10/21/2011, 22:15:50]calling PerformAction on an installing performer [10/21/2011, 22:15:50] Action: Performing actions on all Items... [10/21/2011, 22:15:50]Wait for Item (clr_optimization_v2.0.50727_32) to be available [10/21/2011, 22:15:50]clr_optimization_v2.0.50727_32 is now available to install [10/21/2011, 22:15:50]Creating new Performer for ServiceControl item [10/21/2011, 22:15:50] Action: ServiceControl - Stop clr_optimization_v2.0.50727_32... [10/21/2011, 22:15:50]ServiceControl operation succeeded! [10/21/2011, 22:15:50] Action complete [10/21/2011, 22:15:50]Error 0 is mapped to Custom Error: [10/21/2011, 22:15:50]Wait for Item (Windows6.0-KB956250-v6001-x86.msu) to be available [10/21/2011, 22:15:51]Windows6.0-KB956250-v6001-x86.msu is now available to install [10/21/2011, 22:15:51]Created new DoNothingPerformer for File item [10/21/2011, 22:15:51]No CustomError defined for this item. [10/21/2011, 22:15:51]Wait for Item (Windows6.1-KB958488-v6001-x86.msu) to be available [10/21/2011, 22:15:51]Windows6.1-KB958488-v6001-x86.msu is now available to install [10/21/2011, 22:15:51]Created new DoNothingPerformer for File item [10/21/2011, 22:15:51]No CustomError defined for this item. [10/21/2011, 22:15:51]Wait for Item (netfx_Core.mzz) to be available [10/21/2011, 22:15:52]netfx_Core.mzz is now available to install [10/21/2011, 22:15:52]Created new DoNothingPerformer for File item [10/21/2011, 22:15:52]No CustomError defined for this item. [10/21/2011, 22:15:52]Wait for Item (netfx_Core_x86.msi) to be available [10/21/2011, 22:15:52]netfx_Core_x86.msi is now available to install [10/21/2011, 22:15:52]Creating new Performer for MSI item [10/21/2011, 22:15:52] Action: Performing Action on MSI at F:\DOCUME~1\Owner\LOCALS~1\Temp\Microsoft .NET Framework 4 Client Profile Setup_4.0.30319\netfx_Core_x86.msi... [10/21/2011, 22:15:52]Log File F:\DOCUME~1\Owner\LOCALS~1\Temp\Microsoft .NET Framework 4 Client Profile Setup_20111021_221545515-MSI_netfx_Core_x86.msi.txt does not yet exist but may do at Watson upload time [10/21/2011, 22:15:52]Calling MsiInstallProduct(F:\DOCUME~1\Owner\LOCALS~1\Temp\Microsoft .NET Framework 4 Client Profile Setup_4.0.30319\netfx_Core_x86.msi, EXTUI=1 [10/21/2011, 22:17:14]MSI (F:\DOCUME~1\Owner\LOCALS~1\Temp\Microsoft .NET Framework 4 Client Profile Setup_4.0.30319\netfx_Core_x86.msi) Installation failed. Msi Log: Microsoft .NET Framework 4 Client Profile Setup_20111021_221545515-MSI_netfx_Core_x86.msi.txt [10/21/2011, 22:17:14]PerformOperation returned 1603 (translates to HRESULT = 0x80070643) [10/21/2011, 22:17:14] Action complete [10/21/2011, 22:17:14]OnFailureBehavior for this item is to Rollback. [10/21/2011, 22:17:14] Action: Performing actions on all Items... [10/21/2011, 22:17:14] Action complete [10/21/2011, 22:17:14] Action complete [10/21/2011, 22:17:14]Final Result: Installation failed with error code: (0x80070643), "Fatal error during installation. " (Elapsed time: 0 00:01:29). [10/21/2011, 22:17:41]WM_ACTIVATEAPP: Focus stealer's windows WAS visible, NOT taking back focus SECOND LOG REQUESTED BELOW: MSI (s) (6C:EC) [22:17:13:828]: Invoking remote custom action. DLL: F:\WINDOWS\Installer\MSIBB4.tmp, Entrypoint: NgenUpdateHighestVersionRollback MSI (s) (6C:64) [22:17:13:984]: Executing op: ActionStart(Name=CA_NgenRemoveNicPFROs_I_DEF_x86.3643236F_FC70_11D3_A536_0090278A1BB8,,) MSI (s) (6C:64) [22:17:13:984]: Executing op: ActionStart(Name=CA_NgenRemoveNicPFROs_I_RB_x86.3643236F_FC70_11D3_A536_0090278A1BB8,,) MSI (s) (6C:64) [22:17:13:984]: Executing op: CustomActionRollback(Action=CA_NgenRemoveNicPFROs_I_RB_x86.3643236F_FC70_11D3_A536_0090278A1BB8,ActionType=17729,Source=BinaryData,Target=NgenRemoveNicPFROs,) MSI (s) (6C:AC) [22:17:13:984]: Invoking remote custom action. DLL: F:\WINDOWS\Installer\MSIBB5.tmp, Entrypoint: NgenRemoveNicPFROs MSI (s) (6C:64) [22:17:14:000]: Executing op: End(Checksum=0,ProgressTotalHDWord=0,ProgressTotalLDWord=0) MSI (s) (6C:64) [22:17:14:000]: Error in rollback skipped. Return: 5 MSI (s) (6C:64) [22:17:14:015]: No System Restore sequence number for this installation. MSI (s) (6C:64) [22:17:14:015]: Unlocking Server MSI (s) (6C:64) [22:17:14:015]: PROPERTY CHANGE: Deleting UpdateStarted property. Its current value is '1'. MSI (s) (6C:64) [22:17:14:031]: Note: 1: 1708 MSI (s) (6C:64) [22:17:14:031]: Product: Microsoft .NET Framework 4 Client Profile -- Installation failed. MSI (s) (6C:64) [22:17:14:078]: Cleaning up uninstalled install packages, if any exist MSI (s) (6C:64) [22:17:14:078]: MainEngineThread is returning 1603 MSI (s) (6C:EC) [22:17:14:171]: Destroying RemoteAPI object. MSI (s) (6C:9C) [22:17:14:171]: Custom Action Manager thread ending. MSI (c) (F4:C4) [22:17:14:203]: Decrementing counter to disable shutdown. If counter >= 0, shutdown will be denied. Counter after decrement: -1 MSI (c) (F4:C4) [22:17:14:203]: MainEngineThread is returning 1603 === Verbose logging stopped: 10/21/2011 22:17:14 ===

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  • SEOs: mobile version using AJAX: how to be properly read by SEOs?

    - by Olivier Pons
    Before anything else, I'd like to emphasize that I've already read this and this. Here's what I can do: Choice (1): create classical Web version with all products in that page - http://www.myweb.com. create mobile Web version with all products in the page and use jQuery Mobile to format all nicely. But this may be long to (load + format), and may provide bad user experience - http://m.myweb.com. Choice (2): create classical Web version with all products in that page create mobile Web version with almost nothing but a Web page showing "wait", then download all products in the page using AJAX and use jQuery Mobile to format all nicely. Showing a "wait, loading" message gives far more time to do whatever I want and may provide better user experience - http://m.myweb.com. Question: if I choose solution (2), google won't read anything on the mobile version (because all products will be downloaded in the page using AJAX), so it wont be properly read by SEOs. What / how shall I do?

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  • How to create scripts that create another scripts

    - by sfrj
    I am writing an script that needs to generate another script that will be used to shutdown an appserver... This is how my code looks like: echo "STEP 8: CREATE STOP SCRIPT" stopScriptContent="echo \"STOPING GLASSFISH PLEASE WAIT...\"\n cd glassfish4/bin\n chmod +x asadmin\n ./asadmin stop-domain\n #In order to work it is required that the original folder of glassfish don't contain already any #project, otherwise, there will be a conflict\n" ${stopScriptContent} > stop.sh chmod +x stop.sh But it is not being created correctly, this is how the output stop.sh looks like: "STOPING GLASSFISH PLEASE WAIT..."\n cd glassfish4/bin\n chmod +x asadmin\n ./asadmin stop-domain\n #In order to work it is required that the original folder of glassfish don't contain already any #project, otherwise, there will be a conflict\n As you see, lots of things are wrong: there is no echo command is taking the \n literaly so there is no new line My doubts are: What is the correct way of making an .sh script create another .sh script. What do you thing I am doing wrong?

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  • SEOs: mobile version using AJAX: how to be properly read by crawlers?

    - by Olivier Pons
    Before anything else, I'd like to emphasize that I've already read this and this. Here's what I can do: First choice: create classical web version with all products in that page - http://www.myweb.com. create mobile web version with all products in the page and use jQuery Mobile to format all nicely but this may be long to (load + format), and may provide bad user experience - http://m.myweb.com. Second choice: create classical web version with all products in that page create mobile web version with almost nothing but a Web page showing wait, then download all products in the page using AJAX and use jQuery Mobile to format all nicely. Showing a wait, loading message gives far more time to do whatever I want and may provide better user experience - http://m.myweb.com. Question: if I choose the second solution, Google won't read anything on the mobile version (because all products will be downloaded in the page using AJAX), so it wont be properly read by crawlers. What / how shall I do?

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  • What's the better user experience: Waiting once at startup for a long time or waiting frequently for a short time?

    - by Roflcoptr
    I'm currently design an application that involves a lot of calculation. Now I have generally two possibilities which I have both tested: 1) During startup of the application I calculated only the most important values and these values that consume a lot of time. So the user has to wait approximately 15 seconds during startup. But on the other hand a lot of user interactions require recalculation so that the user often has to wait 2-3 seconds after clicking somewhere until the application has calculated and loaded all values 2) I load everything during startup. This takes from 90 to 120 seconds... This is quite a long time, but the big advantage is that all the user interactions are executed immediately. So what would you generally consider the better approach? Loading all time-consuming operations during startup or when needed?

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  • C#: Handling Notifications: inheritance, events, or delegates?

    - by James Michael Hare
    Often times as developers we have to design a class where we get notification when certain things happen. In older object-oriented code this would often be implemented by overriding methods -- with events, delegates, and interfaces, however, we have far more elegant options. So, when should you use each of these methods and what are their strengths and weaknesses? Now, for the purposes of this article when I say notification, I'm just talking about ways for a class to let a user know that something has occurred. This can be through any programmatic means such as inheritance, events, delegates, etc. So let's build some context. I'm sitting here thinking about a provider neutral messaging layer for the place I work, and I got to the point where I needed to design the message subscriber which will receive messages from the message bus. Basically, what we want is to be able to create a message listener and have it be called whenever a new message arrives. Now, back before the flood we would have done this via inheritance and an abstract class: 1:  2: // using inheritance - omitting argument null checks and halt logic 3: public abstract class MessageListener 4: { 5: private ISubscriber _subscriber; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber) 11: { 12: _subscriber = subscriber; 13: _messageThread = new Thread(MessageLoop); 14: _messageThread.Start(); 15: } 16:  17: // user will override this to process their messages 18: protected abstract void OnMessageReceived(Message msg); 19:  20: // handle the looping in the thread 21: private void MessageLoop() 22: { 23: while(!_isHalted) 24: { 25: // as long as processing, wait 1 second for message 26: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 27: if(msg != null) 28: { 29: OnMessageReceived(msg); 30: } 31: } 32: } 33: ... 34: } It seems so odd to write this kind of code now. Does it feel odd to you? Maybe it's just because I've gotten so used to delegation that I really don't like the feel of this. To me it is akin to saying that if I want to drive my car I need to derive a new instance of it just to put myself in the driver's seat. And yet, unquestionably, five years ago I would have probably written the code as you see above. To me, inheritance is a flawed approach for notifications due to several reasons: Inheritance is one of the HIGHEST forms of coupling. You can't seal the listener class because it depends on sub-classing to work. Because C# does not allow multiple-inheritance, I've spent my one inheritance implementing this class. Every time you need to listen to a bus, you have to derive a class which leads to lots of trivial sub-classes. The act of consuming a message should be a separate responsibility than the act of listening for a message (SRP). Inheritance is such a strong statement (this IS-A that) that it should only be used in building type hierarchies and not for overriding use-specific behaviors and notifications. Chances are, if a class needs to be inherited to be used, it most likely is not designed as well as it could be in today's modern programming languages. So lets look at the other tools available to us for getting notified instead. Here's a few other choices to consider. Have the listener expose a MessageReceived event. Have the listener accept a new IMessageHandler interface instance. Have the listener accept an Action<Message> delegate. Really, all of these are different forms of delegation. Now, .NET events are a bit heavier than the other types of delegates in terms of run-time execution, but they are a great way to allow others using your class to subscribe to your events: 1: // using event - ommiting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private bool _isHalted = false; 6: private Thread _messageThread; 7:  8: // assign the subscriber and start the messaging loop 9: public MessageListener(ISubscriber subscriber) 10: { 11: _subscriber = subscriber; 12: _messageThread = new Thread(MessageLoop); 13: _messageThread.Start(); 14: } 15:  16: // user will override this to process their messages 17: public event Action<Message> MessageReceived; 18:  19: // handle the looping in the thread 20: private void MessageLoop() 21: { 22: while(!_isHalted) 23: { 24: // as long as processing, wait 1 second for message 25: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 26: if(msg != null && MessageReceived != null) 27: { 28: MessageReceived(msg); 29: } 30: } 31: } 32: } Note, now we can seal the class to avoid changes and the user just needs to provide a message handling method: 1: theListener.MessageReceived += CustomReceiveMethod; However, personally I don't think events hold up as well in this case because events are largely optional. To me, what is the point of a listener if you create one with no event listeners? So in my mind, use events when handling the notification is optional. So how about the delegation via interface? I personally like this method quite a bit. Basically what it does is similar to inheritance method mentioned first, but better because it makes it easy to split the part of the class that doesn't change (the base listener behavior) from the part that does change (the user-specified action after receiving a message). So assuming we had an interface like: 1: public interface IMessageHandler 2: { 3: void OnMessageReceived(Message receivedMessage); 4: } Our listener would look like this: 1: // using delegation via interface - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private IMessageHandler _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler.OnMessageReceived(msg); 28: } 29: } 30: } 31: } And they would call it by creating a class that implements IMessageHandler and pass that instance into the constructor of the listener. I like that this alleviates the issues of inheritance and essentially forces you to provide a handler (as opposed to events) on construction. Well, this is good, but personally I think we could go one step further. While I like this better than events or inheritance, it still forces you to implement a specific method name. What if that name collides? Furthermore if you have lots of these you end up either with large classes inheriting multiple interfaces to implement one method, or lots of small classes. Also, if you had one class that wanted to manage messages from two different subscribers differently, it wouldn't be able to because the interface can't be overloaded. This brings me to using delegates directly. In general, every time I think about creating an interface for something, and if that interface contains only one method, I start thinking a delegate is a better approach. Now, that said delegates don't accomplish everything an interface can. Obviously having the interface allows you to refer to the classes that implement the interface which can be very handy. In this case, though, really all you want is a method to handle the messages. So let's look at a method delegate: 1: // using delegation via delegate - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler(msg); 28: } 29: } 30: } 31: } Here the MessageListener now takes an Action<Message>.  For those of you unfamiliar with the pre-defined delegate types in .NET, that is a method with the signature: void SomeMethodName(Message). The great thing about delegates is it gives you a lot of power. You could create an anonymous delegate, a lambda, or specify any other method as long as it satisfies the Action<Message> signature. This way, you don't need to define an arbitrary helper class or name the method a specific thing. Incidentally, we could combine both the interface and delegate approach to allow maximum flexibility. Doing this, the user could either pass in a delegate, or specify a delegate interface: 1: // using delegation - give users choice of interface or delegate 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // passes the interface method as a delegate using method group 19: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 20: : this(subscriber, handler.OnMessageReceived) 21: { 22: } 23:  24: // handle the looping in the thread 25: private void MessageLoop() 26: { 27: while(!_isHalted) 28: { 29: // as long as processing, wait 1 second for message 30: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 31: if(msg != null) 32: { 33: _handler(msg); 34: } 35: } 36: } 37: } } This is the method I tend to prefer because it allows the user of the class to choose which method works best for them. You may be curious about the actual performance of these different methods. 1: Enter iterations: 2: 1000000 3:  4: Inheritance took 4 ms. 5: Events took 7 ms. 6: Interface delegation took 4 ms. 7: Lambda delegate took 5 ms. Before you get too caught up in the numbers, however, keep in mind that this is performance over over 1,000,000 iterations. Since they are all < 10 ms which boils down to fractions of a micro-second per iteration so really any of them are a fine choice performance wise. As such, I think the choice of what to do really boils down to what you're trying to do. Here's my guidelines: Inheritance should be used only when defining a collection of related types with implementation specific behaviors, it should not be used as a hook for users to add their own functionality. Events should be used when subscription is optional or multi-cast is desired. Interface delegation should be used when you wish to refer to implementing classes by the interface type or if the type requires several methods to be implemented. Delegate method delegation should be used when you only need to provide one method and do not need to refer to implementers by the interface name.

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  • Downloading large files hangs system

    - by Igor
    When Im trying to download large files, i.e. 1gb or more under FireFox, first of all it starts with very big download speed and in few seconds in almost get up to max (~11 MBps). It is downloading very fast, but when downloaded size becomes near 700-800mb and more, my system almost completely hangs, so I can do nothing - I just have to wait until it finishes downloading. Also when it hangs, I can't see the download progress - it looks like it completely hangs. Sometimes, however, if the file size is near 1gb, the system comes back from hang, finishing download, but sometimes I just cant wait before system comes back and have to kill FF from top (it takes me 2 minutes to do this, because of very slow system performance). I use Firefox as primary browser. If I use wget with direct link to file - everything is fine. Speed at max, no performance decrease. So what can I do?

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  • SQL SERVER – Weekly Series – Memory Lane – #007

    - by pinaldave
    Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 Find Stored Procedure Related to Table in Database – Search in All Stored Procedure In 2006 I wrote a small script which will help user  find all the Stored Procedures (SP) which are related to one or more specific tables. This was quite a popular script however, in SQL Server 2012 the same can be achieved using new DMV sys.sql-expression_dependencies. I recently blogged about it over Find Referenced or Referencing Object in SQL Server using sys.sql_expression_dependencies. 2007 SQL SERVER – Versions, CodeNames, Year of Release 1993 – SQL Server 4.21 for Windows NT 1995 – SQL Server 6.0, codenamed SQL95 1996 – SQL Server 6.5, codenamed Hydra 1999 – SQL Server 7.0, codenamed Sphinx 1999 – SQL Server 7.0 OLAP, codenamed Plato 2000 – SQL Server 2000 32-bit, codenamed Shiloh (version 8.0) 2003 – SQL Server 2000 64-bit, codenamed Liberty 2005 – SQL Server 2005, codenamed Yukon (version 9.0) 2008 – SQL Server 2008, codenamed Katmai (version 10.0) 2011 – SQL Server 2008, codenamed Denali (version 11.0) Search String in Stored Procedure Searching sting in the stored procedure is one of the most frequent task developer do. They might be searching for a table, view or any other details. I have written a script to do the same in SQL Server 2000 and SQL Server 2005. This is worth bookmarking blog post. There is an alternative way to do the same as well here is the example. 2008 SQL SERVER – Refresh Database Using T-SQL NO! Some of the questions have a single answer NO! You may want to read the question in the original blog post. I had a great time saying No! SQL SERVER – Delete Backup History – Cleanup Backup History SQL Server stores history of all the taken backup forever. History of all the backup is stored in the msdb database. Many times older history is no more required. Following Stored Procedure can be executed with a parameter which takes days of history to keep. In the following example 30 is passed to keep a history of month. 2009 Stored Procedure are Compiled on First Run – SP taking Longer to Run First Time Is stored procedure pre-compiled? Why the Stored Procedure takes a long time to run for the first time?  This is a very common questions often discussed by developers and DBAs. There is an absolutely definite answer but the question has been discussed forever. There is a misconception that stored procedures are pre-compiled. They are not pre-compiled, but compiled only during the first run. For every subsequent runs, it is for sure pre-compiled. Read the entire article for example and demonstration. Removing Key Lookup – Seek Predicate – Predicate – An Interesting Observation Related to Datatypes This is one of the most important performance tuning lesson on my blog. I suggest this weekend you spend time reading them and let me know what you think about the concepts which I have demonstrated in the four part series. Part 1 | Part 2 | Part 3 | Part 4 Seek Predicate is the operation that describes the b-tree portion of the Seek. Predicate is the operation that describes the additional filter using non-key columns. Based on the description, it is very clear that Seek Predicate is better than Predicate as it searches indexes whereas in Predicate, the search is on non-key columns – which implies that the search is on the data in page files itself. Policy Based Management – Create, Evaluate and Fix Policies This article will cover the most spectacular feature of SQL Server – Policy-based management and how the configuration of SQL Server with policy-based management architecture can make a powerful difference. Policy based management is loaded with several advantages. It can help you implement various policies for reliable configuration of the system. It also provides additional administration assistance to DBAs and helps them effortlessly manage various tasks of SQL Server across the enterprise. 2010 Recycle Error Log – Create New Log file without Server Restart Once I observed a DBA to restaring the SQL Server when he needed new error log file. This was funny and sad both at the same time. There is no need to restart the server to create a new log file or recycle the log file. You can run sp_cycle_errorlog and achieve the same result. Get Database Backup History for a Single Database Simple but effective script! Reducing CXPACKET Wait Stats for High Transactional Database The subject is very complex and I have done my best to simplify the concept. In simpler words, when a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. Threads which came first have to wait for the slower thread to finish. The Wait by a specific completed thread is called CXPACKET Wait Stat. Information Related to DATETIME and DATETIME2 There are quite a lot of confusion with DATETIME and DATETIME2. DATETIME2 is also one of the underutilized datatype of SQL Server.  In this blog post I have written a follow up of the my earlier datetime series where I clarify a few of the concepts related to datetime. Difference Between GETDATE and SYSDATETIME Difference Between DATETIME and DATETIME2 – WITH GETDATE Difference Between DATETIME and DATETIME2 2011 Introduction to CUME_DIST – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function CUME_DIST(). This function provides cumulative distribution value. It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. Introduction to FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical functions FIRST_VALUE() and LAST_VALUE(). This function returns first and last value from the list. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. OVER clause with FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 – ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING “Don’t you think there is bug in your first example where FIRST_VALUE is remain same but the LAST_VALUE is changing every line. I think the LAST_VALUE should be the highest value in the windows or set of result.” Puzzle – Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY You can see that row number 2, 3, 4, and 5 has same SalesOrderID = 43667. The FIRST_VALUE is 78 and LAST_VALUE is 77. Now if these function was working on maximum and minimum value they should have given answer as 77 and 80 respectively instead of 78 and 77. Also the value of FIRST_VALUE is greater than LAST_VALUE 77. Why? Explain in detail. Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function LEAD() and LAG(). This functions accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. A Real Story of Book Getting ‘Out of Stock’ to A 25% Discount Story Available Our book was out of stock in 48 hours of it was arrived in stock! We got call from the online store with a request for more copies within 12 hours. But we had printed only as many as we had sent them. There were no extra copies. We finally talked to the printer to get more copies. However, due to festivals and holidays the copies could not be shipped to the online retailer for two days. We knew for sure that they were going to be out of the book for 48 hours. This is the story of how we overcame that situation! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Are there deprecated practices for multithread and multiprocessor programming that I should no longer use?

    - by DeveloperDon
    In the early days of FORTRAN and BASIC, essentially all programs were written with GOTO statements. The result was spaghetti code and the solution was structured programming. Similarly, pointers can have difficult to control characteristics in our programs. C++ started with plenty of pointers, but use of references are recommended. Libraries like STL can reduce some of our dependency. There are also idioms to create smart pointers that have better characteristics, and some version of C++ permit references and managed code. Programming practices like inheritance and polymorphism use a lot of pointers behind the scenes (just as for, while, do structured programming generates code filled with branch instructions). Languages like Java eliminate pointers and use garbage collection to manage dynamically allocated data instead of depending on programmers to match all their new and delete statements. In my reading, I have seen examples of multi-process and multi-thread programming that don't seem to use semaphores. Do they use the same thing with different names or do they have new ways of structuring protection of resources from concurrent use? For example, a specific example of a system for multithread programming with multicore processors is OpenMP. It represents a critical region as follows, without the use of semaphores, which seem not to be included in the environment. th_id = omp_get_thread_num(); #pragma omp critical { cout << "Hello World from thread " << th_id << '\n'; } This example is an excerpt from: http://en.wikipedia.org/wiki/OpenMP Alternatively, similar protection of threads from each other using semaphores with functions wait() and signal() might look like this: wait(sem); th_id = get_thread_num(); cout << "Hello World from thread " << th_id << '\n'; signal(sem); In this example, things are pretty simple, and just a simple review is enough to show the wait() and signal() calls are matched and even with a lot of concurrency, thread safety is provided. But other algorithms are more complicated and use multiple semaphores (both binary and counting) spread across multiple functions with complex conditions that can be called by many threads. The consequences of creating deadlock or failing to make things thread safe can be hard to manage. Do these systems like OpenMP eliminate the problems with semaphores? Do they move the problem somewhere else? How do I transform my favorite semaphore using algorithm to not use semaphores anymore?

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  • Should tests be in the same ruby file or in separeted ruby files?

    - by Junior Mayhé
    While using Selenium and Ruby to do some functional tests, I am worried with the performance. So is it better to add all test methods in the same ruby file, or I should put each one in separated code files? Below a sample with all tests in the same file: # encoding: utf-8 require "selenium-webdriver" require "test/unit" class Tests < Test::Unit::TestCase def setup @driver = Selenium::WebDriver.for :firefox @base_url = "http://mysite" @driver.manage.timeouts.implicit_wait = 30 @verification_errors = [] @wait = Selenium::WebDriver::Wait.new :timeout => 10 end def teardown @driver.quit assert_equal [], @verification_errors end def element_present?(how, what) @driver.find_element(how, what) true rescue Selenium::WebDriver::Error::NoSuchElementError false end def verify(&blk) yield rescue Test::Unit::AssertionFailedError => ex @verification_errors << ex end def test_1 @driver.get(@base_url + "/") # a huge test here end def test_2 @driver.get(@base_url + "/") # a huge test here end def test_3 @driver.get(@base_url + "/") # a huge test here end def test_4 @driver.get(@base_url + "/") # a huge test here end def test_5 @driver.get(@base_url + "/") # a huge test here end end

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  • Temporary dimming of desktop in 12.04

    - by deshmukh
    I am running Ubuntu 12.04 (almost default install regularly updated) Unity interface on ASUS X53U (AMD Brazos Dual Core C60 with 2GB RAM). On launching Thunderbird and Firefox, the application dims and the cursor changes to wait mode. In case of Thunderbird, this is most pronounced with the wait time of up to a minute. Memory status checked with free indicates around 500MB of free memory on such occasions. The OS is stable and I can switch to a different work-space, etc. What could this be? Is this something normal?

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  • Wubi 12.04 boot error message

    - by Leandro
    Im having a boot problem with my Wubi 12.04 system. When Ubuntu starts to boot up, a message will appear in my screen and it's something like: T#s..... does not exist Sorry, I couldn't read all the message. Then another message pop-out after Ubuntu loading screen this time the message is this: Gave up waiting for root device. Common problems: -Boot args (cat /proc/cmdline) -check rootdelay= (did the system wait long enough?) -check root= (did the system wait for the right device?) -missing module (cat /proc/module: ls /dev) ALERT! /dev/disk/by/by_uuid/EODC2345DC231576 does not exist. Dropping to a shell

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  • 12.04 64 bit: Keybord not responding for about 20 seconds at startup/beginning of session

    - by Danilo
    I am running Ubuntu 12.04 64bit. When I get at the login screen and try to type the password for my user, I cannot type anything for about 20 seconds. After that, the keyboard starts responding and everything works fine. Mouse is responding normally as well as all buttons of the login interface (time/calendar, session selection (Unity/Unity 2D), etc.). What could be the reason for this behavior? How can I solve this temporary freeze of the keyboard so that I can type my password immediately without having to wait each time? Thanks for your time. EDIT: I tried auto login, but the problem is still there: the Desktop loads but even there, if I try to type something in the dash or anywhere else, I must wait about 20 seconds before I can actually start typing. Can the issue be related to some keyboard modules that get loaded little bit "too late"?

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  • wireless driver error after install

    - by James
    after following this command to update wifi drivers:1- Boot into Ubuntu 2- Open a terminal by pressing Ctrl+Alt+T 3- Type in the following (verbatim!) sudo apt-get update && sudo apt-get upgrade press Enter, the command will prompt for your password (the one you use to login into Ubuntu), type it and press Enter. Wait for it to finish updating your system. Now type: sudo apt-get remove bcmwl-kernel-source sudo apt-get install firmware-b43-installer Wait for the command to finish installing the driver, when done restart your computer. i get a message after the first command when installing has done saying not enough space so it aborts! what do i do to fix this

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  • Should tests be in the same Ruby file or in separated Ruby files?

    - by Junior Mayhé
    While using Selenium and Ruby to do some functional tests, I am worried with the performance. So is it better to add all test methods in the same Ruby file, or I should put each one in separated code files? Below a sample with all tests in the same file: # encoding: utf-8 require "selenium-webdriver" require "test/unit" class Tests < Test::Unit::TestCase def setup @driver = Selenium::WebDriver.for :firefox @base_url = "http://mysite" @driver.manage.timeouts.implicit_wait = 30 @verification_errors = [] @wait = Selenium::WebDriver::Wait.new :timeout => 10 end def teardown @driver.quit assert_equal [], @verification_errors end def element_present?(how, what) @driver.find_element(how, what) true rescue Selenium::WebDriver::Error::NoSuchElementError false end def verify(&blk) yield rescue Test::Unit::AssertionFailedError => ex @verification_errors << ex end def test_1 @driver.get(@base_url + "/") # a huge test here end def test_2 @driver.get(@base_url + "/") # a huge test here end def test_3 @driver.get(@base_url + "/") # a huge test here end def test_4 @driver.get(@base_url + "/") # a huge test here end def test_5 @driver.get(@base_url + "/") # a huge test here end end

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  • When was sys.dm_os_wait_stats last cleared?

    - by SQLOS Team
    The sys.dm_os_wait_stats DMV provides essential metrics for diagnosing SQL Server performance problems. Returning incrementally accumulating information about all the completed waits encountered by executing threads it is a useful way to identify bottlenecks such as IO latency issues or waits on locks. The counters are reset each time SQL server is restarted, or when the following command is run: DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR); To make sense out of these wait values you need to know how they change over time. Suppose you are asked to troubleshoot a system and you don't know when the wait stats were last zeroed. Is there any way to find the elapsed time since this happened? If the wait stats were not cleared using the DBCC SQLPERF command then you can simply correlate the stats with the time SQL Server was started using the sqlserver_start_time column introduced in SQL Server 2008 R2: SELECT sqlserver_start_time from sys.dm_os_sys_info However how do you tell if someone has run DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR) since the server was started, and if they did, when? Without this information the initial, or historical, wait_stats have less value until you can measure deltas over time. There is a way to at least estimate when the stats were last cleared, by using the wait stats themselves and choosing a thread that spends most of its time sleeping. A good candidate is the SQL Trace incremental flush task, which mostly sleeps (in 4 second intervals) and in between it attempts to flush (if there are new events – which is rare when only default trace is running) – so it pretty much sleeps all the time. Hence the time it has spent waiting is very close to the elapsed time since the counter was reset. Credit goes to Ivan Penkov in the SQLOS dev team for suggesting this. Here's an example (excuse formatting): 144 seconds after the server was started: select top 10 wait_type, wait_time_ms from sys.dm_os_wait_stats order by wait_time_ms desc wait_type                                                               wait_time_ms--------------------------------------------------------------------------------------------------------------- XE_DISPATCHER_WAIT                                      242273LAZYWRITER_SLEEP                                          146010LOGMGR_QUEUE                                                145412DIRTY_PAGE_POLL                                             145411XE_TIMER_EVENT                                               145216REQUEST_FOR_DEADLOCK_SEARCH             145194SQLTRACE_INCREMENTAL_FLUSH_SLEEP    144325SLEEP_TASK                                                        73359BROKER_TO_FLUSH                                           73113PREEMPTIVE_OS_AUTHENTICATIONOPS       143 (10 rows affected) Reset: DBCC SQLPERF('sys.dm_os_wait_stats', CLEAR)" DBCC execution completed. If DBCC printed error messages, contact your system administrator. After 8 seconds: select top 10 wait_type, wait_time_ms from sys.dm_os_wait_stats order by wait_time_ms desc wait_type                                                                 wait_time_ms--------------------------------------------------------------------------------------------------------------------- REQUEST_FOR_DEADLOCK_SEARCH              10013LAZYWRITER_SLEEP                                           8124SQLTRACE_INCREMENTAL_FLUSH_SLEEP     8017LOGMGR_QUEUE                                                 7579DIRTY_PAGE_POLL                                              7532XE_TIMER_EVENT                                                5007BROKER_TO_FLUSH                                            4118SLEEP_TASK                                                         3089PREEMPTIVE_OS_AUTHENTICATIONOPS        28SOS_SCHEDULER_YIELD                                   27 (10 rows affected)   After 12 seconds: select top 10 wait_type, wait_time_ms from sys.dm_os_wait_stats order by wait_time_ms desc wait_type                                                                  wait_time_ms------------------------------------------------------------------------------------------------------ REQUEST_FOR_DEADLOCK_SEARCH               15020LAZYWRITER_SLEEP                                            14206LOGMGR_QUEUE                                                  14036DIRTY_PAGE_POLL                                               13973SQLTRACE_INCREMENTAL_FLUSH_SLEEP      12026XE_TIMER_EVENT                                                 10014SLEEP_TASK                                                          7207BROKER_TO_FLUSH                                             7207PREEMPTIVE_OS_AUTHENTICATIONOPS         57SOS_SCHEDULER_YIELD                                     28 (10 rows affected) It may not be accurate to the millisecond, but it can provide a useful data point, and give an indication whether the wait stats were manually cleared after startup, and if so approximately when. - Guy     Originally posted at http://blogs.msdn.com/b/sqlosteam/

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  • SQL Azure Security: DoS Part II

    - by Herve Roggero
    Ah!  When you shoot yourself in the foot... a few times... it hurts! That's what I did on Sunday, to learn more about the behavior of the SQL Azure Denial Of Service prevention feature. This article is a short follow up to my last post on this feature. In this post, I will outline some of the lessons learned that were the result of testing the behavior of SQL Azure from two machines. From the standpoint of SQL Azure, they look like one machine since they are behind a NAT. All logins affected The first thing to note is that all the logins are affected. If you lock yourself out to a specific database, none of the logins will work on that database. In fact the database size becomes "--" in the SQL Azure Portal.   Less than 100 sessions I was able to see 50+ sessions being made in SQL Azure (by looking at sys.dm_exec_sessions) before being locked out. The the DoS feature appears to be triggered in part by the number of open sessions. I could not determine if the lockout is triggered by the speed at which connection requests are made however.   Other Databases Unaffected This was interesting... the DoS feature works at the database level. Other databases were available for me to use.   Just Wait Initially I thought that going through SQL Azure and connecting from there would reset the database and allow me to connect again. Unfortunately this doesn't seem to be the case. You will have to wait. And the more you lock yourself out, the more you will have to wait... The first time the database became available again within 30 seconds or so; the second time within 2-3 minutes and the third time... within 2-3 hours...   Successful Logins The DoS feature appears to engage only for valid logins. If you have a login failure, it doesn't seem to count. I ran a test with over 100 login failures without being locked.

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