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• Your First Graphics Web Application in GDI+

  In this application we will draw a few simple graphics objects, including lines and rectangles.

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• Keeping application backend and UI synchronised

  - by Deanna

  Hi all. I have an app that works with a list of objects so has one central keyed list. The main window has a tree containing these object with some information, which is easy enough to populate as a one off event after loading. Now, the complicated part, any part of the application can add, remove, and more importantly change the details of those objects at any time (all in the same process) and I'd like the tree to update to suit. I have a few options including passing events back down from the object to the list to the form which seems to be the most flexible way. I can also do it lazily and repopulate the tree each time or periodically (very hackish). Does anyone have any better thoughts on how to structure this? This is being done in C# 2.0 but the concepts apply to any environment. Thanks

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• C++ game architecture

  - by rxc

  I'm trying to make a game, but I'm not sure of the best way to set up the main loop and classes. For really small games, I could put everything in the main() loop, including event handling, collision checking, etc. However, for large games, that's seems like a highly inefficient way to get things done. The architecture I want is kind like the way the Minecraft coders did it (I quote Minecraft code because I've seen the source code when downloading MCP). They have objects entity classes EntityCow and EntityChicken and they have methods like onDeath(), onLivingUpdate(); and item classes like ItemSword have methods like onItemUse(). I've never seen these methods get called directly, but apparently, they get stored in a class called DataWatcher, which, I think "watches" all the data (as the name implies) and calls the appropriate methods in the objects. Is that how most games do it? If so, how is the DataWatcher class implemented? Any help or alternate suggestions is really appreciated.

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• Working with Object Context in the Entity Framework

  Learn about how to work with the object context of the Entity Framework including how to detach and attach objects.

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• Providing a generic framework to windows(MFC) applications to fetch custom properties from any GUI o

  This is a framework that allows application developers or automation architects to use to expose custom properties on GUI objects

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• Entity framework architecture

  - by user1741807

  I want to make a entity framework application in Winforms C#. I'm new to entity framework, and don't know how to make the architecture. I want to have the model in a class library, and a GUI layer, and maybe a controller layer. I'm used to that architecture, but don't know have to handle the objects in other layers than the model. Have do I manage objects in the gui layer, when I can't have a reference to the model? I'm used to have some kind of dto, but what's the best way?

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• What is the correct pattern to use in this case?

  - by nulliusinverba

  I'm sure this scenario has arisen before, and I want to know what experience has taught to be the best solution. I have a number of classes that are all of a kind. Say all the objects are "Content". They may be "Article", or "Book" for example. The reason I want the "Content" abstraction is because I want to define a number of behaviours for all "Content" objects and not have to build a new DB Table and 10 classes of essentially the same code for each type of "Content". For example, to attach a "Tag" or a "Premise" to a content object would be much nicer if, say, I just had two columns one for ContentID and one for TagID. A solution I've played around with is to have a Content table with a unique ID, and then to have foreign key references on all the other tables (Book, Article, etc). This has actually proven quite solid, but I'm just not sure about it. Do you know how to call this described pattern?

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• How do I convert a partially transparent image into polygons?

  - by user82779

  I'm using GLEE2D, a level editor allowing me to import images, scale them, rotate them, and position them onto layers and export the data into XML format. However, it does not tell me objects' boundaries. I can calculate them, but only given the original image's polygons. How do I get polygons of objects in a transparent image? An example object (I outlined it): How would I turn the object, knowing the scaled size of the image, into polygons? Is there an algorithm for this? I'll use OpenGL to draw them.

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• Java game applet development

  - by RomZes

  I'm getting 4 sec delay when sending objects over UDP. Working on small game and trying to implement multiplayer. For now just trying to synchronize movements of 2 balls on the screen. StartingPoint.java is my server(first player), that receiving serialized objects (coordinates). SecondPlayer.java is client that sending serialized objects to server. When I'm moving my first object it appears 4 seconds later on different screen. StartingPoint.java @Override public void run() { byte[] receiveData = new byte[256]; byte[] sendData = new byte[256]; // DatagramSocket socketS; try { socket = new DatagramSocket(5000); System.out.println("Socket created on "+ port + " port"); } catch (SocketException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } while(true){ b1.update(this); b3.update(); System.out.println("Starting server..."); //// Receiving and deserializing object try { //socket.setSoTimeout(1000); DatagramPacket packet = new DatagramPacket(buf, buf.length); socket.receive(packet); byte[] data = packet.getData(); ByteArrayInputStream in = new ByteArrayInputStream(data); ObjectInputStream is = new ObjectInputStream(in); // socket.setSoTimeout(300); b1 = (Ball) is.readObject(); } catch (IOException | ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } repaint(); try { Thread.sleep(17); } catch (InterruptedException e) { e.printStackTrace(); } SecondPlayer.java @Override public void run() { while(true){ b.update(); networkSend(); repaint(); try { Thread.sleep(17); } catch (InterruptedException e) { e.printStackTrace(); } } public void networkSend(){ // Serialize to a byte array try { ByteArrayOutputStream bStream = new ByteArrayOutputStream(); ObjectOutputStream oo; oo = new ObjectOutputStream(bStream); oo.writeObject(b); oo.flush(); oo.close(); byte[] bufCar = bStream.toByteArray(); //socket = new DatagramSocket(); //socket.setSoTimeout(1000); InetAddress address = InetAddress.getByName("localhost"); DatagramPacket packet = new DatagramPacket(bufCar, bufCar.length, address, port); socket.send(packet); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }

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• Providing a generic framework to windows(MFC) applications to fetch custom properties from any GUI o

  This is a framework that allows application developers or automation architects to use to expose custom properties on GUI objects

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• How can I find the closest vector to another in a specific direction?

  - by Sniper

  Perhaps I am not phrasing it incorrectly in my searches, but I can not find anything on this. I have a vector3 with a specific direction that it is facing, I want to get the closest object to that position in that specific direction. Basically I want to get the object that is being aimed at. I have thought about finding all objects within a box and then finding the closest object to my vector from them results, but I am sure that there is a more efficient way. The Z axis is optional, the objects are most likely within a few meters of the search vector. http://i.stack.imgur.com/FafAu.jpg

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• ?RAC??????(Rolling)??/????????

  - by JaneZhang(???)

     ?RAC??????????,???????,???????????(Rolling),????,???????,??????????,???????????,????????,???????????????,?????????????????,???????   ?????????????????Rolling???,???????????Rolling?,?????????? ????,???Rolling???????:1. ?????2. ?????,????????????3. ????????????????????4. ??????,????????????????5. ?????????Readme????????????:1). ?oracle???????????????????.2). ??????:3). ??1????ORACLE_HOME?????????+ASM??(???);4). ?1?????:$cd $ORACLE_HOME/OPatch/10082277$opatch apply5). ??opatch????????????,??????????:6). ??1????ORACLE_HOME?????????+ASM??(???);7). ??2????ORACLE_HOME?????????+ASM??(???);8). ?????????????,??????????;9). ??2????ORACLE_HOME?????????+ASM??(???);10).???????,????? ????10.2.0.4 RAC???(Rolling)????8575528???:1).?oracle???????????????????,??:$ORACLE_HOME/OPatch??.$ pwd/u01/app/oracle/OPatch$ lsdocs  emdpatch.pl  jlib  opatch  opatch.ini  opatch.pl  opatchprereqs  p8575528_10204_Linux-x86.zip2).??????:su - oracle$ unzip p8575528_10204_Linux-x86.zipArchive:  p8575528_10204_Linux-x86.zip  creating: 8575528/  creating: 8575528/files/  creating: 8575528/files/lib/  creating: 8575528/files/lib/libserver10.a/ inflating: 8575528/files/lib/libserver10.a/kks1.o inflating: 8575528/files/lib/libserver10.a/kksc.o inflating: 8575528/files/lib/libserver10.a/kksh.o inflating: 8575528/files/lib/libserver10.a/ksmp.o  creating: 8575528/etc/  creating: 8575528/etc/config/ inflating: 8575528/etc/config/inventory inflating: 8575528/etc/config/actions  creating: 8575528/etc/xml/ inflating: 8575528/etc/xml/GenericActions.xml inflating: 8575528/etc/xml/ShiphomeDirectoryStructure.xml inflating: 8575528/README.txt    $ ls8575528  docs  emdpatch.pl  jlib  opatch  opatch.ini  opatch.pl  opatchprereqs  p8575528_10204_Linux-x86.zip3).????????????RAC?????(rolling)?$ $ORACLE_HOME/OPatch/opatch query -all /u01/app/oracle/OPatch/8575528|grep rollingPatch is a rolling patch: true <=====??????4).??1??????ORACLE_HOME?????????(???ASM,????):$srvctl stop instance -d <dbname> -i <instance_name>$srvctl stop asm -n <nodename>??:$srvctl stop instance -d ONEPIECE -i ONEPIECE1$srvctl stop asm -n nascds14$ crs_stat -tName           Type           Target    State     Host      ------------------------------------------------------------ora....E1.inst application    OFFLINE   OFFLINE            ora....SM1.asm application    OFFLINE   OFFLINE5). ?1?????:??:$su - oracle$cd /u01/app/oracle/OPatch/8575528$opatch applyInvoking OPatch 10.2.0.4.2Oracle Interim Patch Installer version 10.2.0.4.2Copyright (c) 2007, Oracle Corporation.  All rights reserved.Oracle Home       : /u01/app/oracleCentral Inventory : /home/oracle/oraInventory  from           : /etc/oraInst.locOPatch version    : 10.2.0.4.2OUI version       : 10.2.0.4.0OUI location      : /u01/app/oracle/ouiLog file location : /u01/app/oracle/cfgtoollogs/opatch/opatch2012-06-13_01-27-38AM.logApplySession applying interim patch '8575528' to OH '/u01/app/oracle'Running prerequisite checks...OPatch detected the node list and the local node from the inventory.  OPatch will patch the local system thenpropagate the patch to the remote nodes.This node is part of an Oracle Real Application Cluster.Remote nodes: 'nascds15'Local node: 'nascds14'Please shutdown Oracle instances running out of this ORACLE_HOME on the local system.(Oracle Home = '/u01/app/oracle')Is the local system ready for patching? [y|n]y <======??yUser Responded with: YBacking up files and inventory (not for auto-rollback) for the Oracle HomeBacking up files affected by the patch '8575528' for restore. This might take a while...Backing up files affected by the patch '8575528' for rollback. This might take a while...Patching component oracle.rdbms, 10.2.0.4.0...Updating archive file "/u01/app/oracle/lib/libserver10.a"  with "lib/libserver10.a/kks1.o"Updating archive file "/u01/app/oracle/lib/libserver10.a"  with "lib/libserver10.a/kksc.o"Updating archive file "/u01/app/oracle/lib/libserver10.a"  with "lib/libserver10.a/kksh.o"Updating archive file "/u01/app/oracle/lib/libserver10.a"  with "lib/libserver10.a/ksmp.o"Running make for target ioracleApplySession adding interim patch '8575528' to inventoryVerifying the update...Inventory check OK: Patch ID 8575528 is registered in Oracle Home inventory with proper meta-data.Files check OK: Files from Patch ID 8575528 are present in Oracle Home.The local system has been patched.  You can restart Oracle instances on it.Patching in rolling mode.The node 'nascds15' will be patched next.Please shutdown Oracle instances running out of this ORACLE_HOME on 'nascds15'.(Oracle Home = '/u01/app/oracle')Is the node ready for patching? [y|n]6). ??opatch????????????????????????7). ??1???ASM ????????:$srvctl start asm -n <nodename>$srvctl start instance -d <dbname> -i <instance_name>??:$srvctl start asm -n nascds14$srvctl start instance -d ONEPIECE -i ONEPIECE1$crs_stat -tora....E1.inst application    ONLINE    ONLINE    nascds14  ora....SM1.asm application    ONLINE    ONLINE    nascds148).??2???ASM????????:$srvctl stop instance -d <dbname> -i <instance_name>$srvctl stop asm -n <nodename>$srvctl stop instance -d ONEPIECE -i ONEPIECE2$srvctl stop asm -n nascds15$crs_statora....E2.inst application    OFFLINE   OFFLINE            ora....SM2.asm application    OFFLINE   OFFLINE9). ?????????????,???????????Is the node ready for patching? [y|n] y <====??yUser Responded with: YUpdating nodes 'nascds15'  Apply-related files are:    FP = "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_files.txt"    DP = "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_dirs.txt"    MP = "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/make_cmds.txt"    RC = "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/remote_cmds.txt"Instantiating the file "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_files.txt.instantiated"by replacing $ORACLE_HOME in "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_files.txt" withactual path.Propagating files to remote nodes...Instantiating the file "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_dirs.txt.instantiated"by replacing $ORACLE_HOME in "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_dirs.txt" withactual path.Propagating directories to remote nodes...Instantiating the file "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/make_cmds.txt.instantiated"by replacing $ORACLE_HOME in "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/make_cmds.txt" withactual path.Running command on remote node 'nascds15':cd /u01/app/oracle/rdbms/lib; /usr/bin/make -f ins_rdbms.mk ioracle ORACLE_HOME=/u01/app/oracle || echoREMOTE_MAKE_FAILED::>&2The node 'nascds15' has been patched.  You can restart Oracle instances on it.There were relinks on remote nodes.  Remember to check the binary size and timestamp on the nodes 'nascds15' .The following make commands were invoked on remote nodes:'cd /u01/app/oracle/rdbms/lib; /usr/bin/make -f ins_rdbms.mk ioracle ORACLE_HOME=/u01/app/oracle'OPatch succeeded.10). ??2???ASM????????:$srvctl start asm -n <nodename>$srvctl start instance -d <dbname> -i <instance_name>??:$srvctl start asm -n nascds15$srvctl start instance -d ONEPIECE -i ONEPIECE211).??????????????????????????$ORACLE_HOME/OPatch/opatch lsinventory[oracle@nascds14 8575528]$ $ORACLE_HOME/OPatch/opatch lsinventoryInvoking OPatch 10.2.0.4.2Oracle Interim Patch Installer version 10.2.0.4.2Copyright (c) 2007, Oracle Corporation.  All rights reserved.Oracle Home       : /u01/app/oracleCentral Inventory : /home/oracle/oraInventory  from           : /etc/oraInst.locOPatch version    : 10.2.0.4.2OUI version       : 10.2.0.4.0OUI location      : /u01/app/oracle/ouiLog file location : /u01/app/oracle/cfgtoollogs/opatch/opatch2012-06-13_01-44-11AM.logLsinventory Output file location : /u01/app/oracle/cfgtoollogs/opatch/lsinv/lsinventory2012-06-13_01-44-11AM.txt--------------------------------------------------------------------------------Installed Top-level Products (2):Oracle Database 10g                                                  10.2.0.1.0Oracle Database 10g Release 2 Patch Set 3                            10.2.0.4.0There are 2 products installed in this Oracle Home.Interim patches (1) :Patch  8575528      : applied on Wed Jun 13 01:28:24 CST 2012<<<<<<<<<<<<<<<<<<<  Created on 17 Aug 2010, 07:56:36 hrs PST8PDT  Bugs fixed:    8575528Rac system comprising of multiple nodes Local node = nascds14 Remote node = nascds15--------------------------------------------------------------------------------OPatch succeeded.Rac system comprising of multiple nodes Local node = nascds14 Remote node = nascds15--------------------------------------------------------------------------------OPatch succeeded. ????10.2.0.4 RAC???(Rolling)????8575528???: 1).??1?????ORACLE_HOME?????????(???ASM,????):$srvctl stop instance -d <dbname> -i <instance_name>$srvctl stop asm -n <nodename>??:$srvctl stop instance -d ONEPIECE -i ONEPIECE1$srvctl stop asm -n nascds14$crs_stat -tName           Type           Target    State     Host        ------------------------------------------------------------ora....E1.inst application    OFFLINE   OFFLINE              ora....SM1.asm application    OFFLINE   OFFLINE  2). ?1??????:??:$su - oracle$cd $ORACLE_HOME/OPatch/8575528$opatch rollback -id 8575528Invoking OPatch 10.2.0.4.2Oracle Interim Patch Installer version 10.2.0.4.2Copyright (c) 2007, Oracle Corporation.  All rights reserved.Oracle Home       : /u01/app/oracleCentral Inventory : /home/oracle/oraInventory  from           : /etc/oraInst.locOPatch version    : 10.2.0.4.2OUI version       : 10.2.0.4.0OUI location      : /u01/app/oracle/ouiLog file location : /u01/app/oracle/cfgtoollogs/opatch/opatch2012-06-13_18-22-10PM.logRollbackSession rolling back interim patch '8575528' from OH '/u01/app/oracle'Running prerequisite checks...OPatch detected the node list and the local node from the inventory.  OPatch will patch the local system thenpropagate the patch to the remote nodes.This node is part of an Oracle Real Application Cluster.Remote nodes: 'nascds15'Local node: 'nascds14'Please shut down Oracle instances running out of this ORACLE_HOME on all the nodes.(Oracle Home = '/u01/app/oracle')Are all the nodes ready for patching? [y|n]y <=========??yUser Responded with: YBacking up files affected by the patch '8575528' for restore. This might take a while...Patching component oracle.rdbms, 10.2.0.4.0...Updating archive file "/u01/app/oracle/lib/libserver10.a"  with "lib/libserver10.a/kks1.o"Updating archive file "/u01/app/oracle/lib/libserver10.a"  with "lib/libserver10.a/kksc.o"Updating archive file "/u01/app/oracle/lib/libserver10.a"  with "lib/libserver10.a/kksh.o"Updating archive file "/u01/app/oracle/lib/libserver10.a"  with "lib/libserver10.a/ksmp.o"Running make for target ioracleRollbackSession removing interim patch '8575528' from inventoryPatching in rolling mode.The node 'nascds15' will be patched next.Please shutdown Oracle instances running out of this ORACLE_HOME on 'nascds15'.(Oracle Home = '/u01/app/oracle')Is the node ready for patching? [y|n]3). ??opatch????????????????????????????4). ??1??ASM ????????:$srvctl start asm -n <nodename>$srvctl start instance -d <dbname> -i <instance_name>??:$srvctl start asm -n nascds14$srvctl start instance -d ONEPIECE -i ONEPIECE1$crs_stat -tora....E1.inst application    ONLINE    ONLINE    nascds14    ora....SM1.asm application    ONLINE    ONLINE    nascds145).??2???ASM????????:$srvctl stop instance -d <dbname> -i <instance_name>$srvctl stop asm -n <nodename>$srvctl stop instance -d ONEPIECE -i ONEPIECE2$srvctl stop asm -n nascds15$crs_stat -tora....E2.inst application    OFFLINE   OFFLINE              ora....SM2.asm application    OFFLINE   OFFLINE  6). ??????????????,??????????The node 'nascds15' will be patched next.Please shutdown Oracle instances running out of this ORACLE_HOME on 'nascds15'.(Oracle Home = '/u01/app/oracle')Is the node ready for patching? [y|n]y <=========??yUser Responded with: YUpdating nodes 'nascds15'  Rollback-related files are:    FR = "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/remove_files.txt"    DR = "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/remove_dirs.txt"    FP = "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_files.txt"    MP = "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/make_cmds.txt"    RC = "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/remote_cmds.txt"Instantiating the file "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/remove_dirs.txt.instantiated"by replacing $ORACLE_HOME in "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/remove_dirs.txt" withactual path.Removing directories on remote nodes...Instantiating the file "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_files.txt.instantiated"by replacing $ORACLE_HOME in "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_files.txt" withactual path.Propagating files to remote nodes...Instantiating the file "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_dirs.txt.instantiated"by replacing $ORACLE_HOME in "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/copy_dirs.txt" withactual path.Propagating directories to remote nodes...Instantiating the file "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/make_cmds.txt.instantiated"by replacing $ORACLE_HOME in "/u01/app/oracle/.patch_storage/8575528_Aug_17_2010_07_56_36/rac/make_cmds.txt" withactual path.Running command on remote node 'nascds15':cd /u01/app/oracle/rdbms/lib; /usr/bin/make -f ins_rdbms.mk ioracle ORACLE_HOME=/u01/app/oracle || echoREMOTE_MAKE_FAILED::>&2The node 'nascds15' has been patched.  You can restart Oracle instances on it.There were relinks on remote nodes.  Remember to check the binary size and timestamp on the nodes 'nascds15' .The following make commands were invoked on remote nodes:'cd /u01/app/oracle/rdbms/lib; /usr/bin/make -f ins_rdbms.mk ioracle ORACLE_HOME=/u01/app/oracle'OPatch succeeded.7). ??2???ASM????????:$srvctl start asm -n <nodename>$srvctl start instance -d <dbname> -i <instance_name>??:$srvctl start asm -n nascds15$srvctl start instance -d ONEPIECE -i ONEPIECE28).??????????????????????????$ $ORACLE_HOME/OPatch/opatch lsinventoryInvoking OPatch 10.2.0.4.2Oracle Interim Patch Installer version 10.2.0.4.2Copyright (c) 2007, Oracle Corporation.  All rights reserved.Oracle Home       : /u01/app/oracleCentral Inventory : /home/oracle/oraInventory  from           : /etc/oraInst.locOPatch version    : 10.2.0.4.2OUI version       : 10.2.0.4.0OUI location      : /u01/app/oracle/ouiLog file location : /u01/app/oracle/cfgtoollogs/opatch/opatch2012-06-13_19-40-41PM.logLsinventory Output file location : /u01/app/oracle/cfgtoollogs/opatch/lsinv/lsinventory2012-06-13_19-40-41PM.txt--------------------------------------------------------------------------------Installed Top-level Products (2):Oracle Database 10g                                                  10.2.0.1.0Oracle Database 10g Release 2 Patch Set 3                            10.2.0.4.0There are 2 products installed in this Oracle Home.There are no Interim patches installed in this Oracle Home.Rac system comprising of multiple nodes Local node = nascds14 Remote node = nascds15--------------------------------------------------------------------------------OPatch succeeded.

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• ?Exadata??????DBFS

  - by Liu Maclean(???)

  ?Exadata???DBFS ??????? 1. ??fuse RPM  [root@dm01db01 ~]# yum install fuse Loaded plugins: rhnplugin, security This system is not registered with ULN. ULN support will be disabled. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package fuse.x86_64 0:2.7.4-8.0.1.el5 set to be updated --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================  Package                            Arch                                 Version                                         Repository                                Size ======================================================================================================================================================================== Installing:  fuse                               x86_64                               2.7.4-8.0.1.el5                                 el5_latest                                85 k Transaction Summary ======================================================================================================================================================================== Install       1 Package(s) Upgrade       0 Package(s) Total download size: 85 k Is this ok [y/N]: y Downloading Packages: fuse-2.7.4-8.0.1.el5.x86_64.rpm                                                                                                                  |  85 kB     00:00      Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction   Installing     : fuse                                                                                                                                             1/1  Installed:   fuse.x86_64 0:2.7.4-8.0.1.el5                                                                                                                                          [root@dm01db01 ~]# yum install fuse-libs Loaded plugins: rhnplugin, security This system is not registered with ULN. ULN support will be disabled. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package fuse-libs.i386 0:2.7.4-8.0.1.el5 set to be updated ---> Package fuse-libs.x86_64 0:2.7.4-8.0.1.el5 set to be updated --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================  Package                                Arch                                Version                                       Repository                               Size ======================================================================================================================================================================== Installing:  fuse-libs                              i386                                2.7.4-8.0.1.el5                               el5_latest                               71 k  fuse-libs                              x86_64                              2.7.4-8.0.1.el5                               el5_latest                               70 k Transaction Summary ======================================================================================================================================================================== Install       2 Package(s) Upgrade       0 Package(s) Total download size: 141 k Is this ok [y/N]: y Downloading Packages: (1/2): fuse-libs-2.7.4-8.0.1.el5.x86_64.rpm                                                                                                      |  70 kB     00:00      (2/2): fuse-libs-2.7.4-8.0.1.el5.i386.rpm                                                                                                        |  71 kB     00:00      ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Total                                                                                                                                    71 kB/s | 141 kB     00:01      Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction   Installing     : fuse-libs                                                                                                                                        1/2    Installing     : fuse-libs                                                                                                                                        2/2  Installed:   fuse-libs.i386 0:2.7.4-8.0.1.el5                                                  fuse-libs.x86_64 0:2.7.4-8.0.1.el5                                                  Complete! [root@dm01db01 ~]# yum install fuse-devel Loaded plugins: rhnplugin, security This system is not registered with ULN. ULN support will be disabled. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package fuse-devel.i386 0:2.7.4-8.0.1.el5 set to be updated ---> Package fuse-devel.x86_64 0:2.7.4-8.0.1.el5 set to be updated --> Finished Dependency Resolution Dependencies Resolved ========================================================================================================================================================================  Package                                 Arch                                Version                                      Repository                               Size ======================================================================================================================================================================== Installing:  fuse-devel                              i386                                2.7.4-8.0.1.el5                              el5_latest                               28 k  fuse-devel                              x86_64                              2.7.4-8.0.1.el5                              el5_latest                               28 k Transaction Summary ======================================================================================================================================================================== Install       2 Package(s) Upgrade       0 Package(s) Total download size: 57 k Is this ok [y/N]: y Downloading Packages: (1/2): fuse-devel-2.7.4-8.0.1.el5.x86_64.rpm                                                                                                     |  28 kB     00:00      (2/2): fuse-devel-2.7.4-8.0.1.el5.i386.rpm                                                                                                       |  28 kB     00:00      ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Total                                                                                                                                    21 kB/s |  57 kB     00:02      Running rpm_check_debug Running Transaction Test Finished Transaction Test Transaction Test Succeeded Running Transaction   Installing     : fuse-devel                                                                                                                                       1/2    Installing     : fuse-devel                                                                                                                                       2/2  Installed:   fuse-devel.i386 0:2.7.4-8.0.1.el5                                                 fuse-devel.x86_64 0:2.7.4-8.0.1.el5                                                 Complete! 2. ?? DBFS??? ?????? cd $ORACLE_HOME/rdbms/admin sqlplus / as sysdba Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP, Data Mining and Real Application Testing options SQL> @prvtfspi.plb Package body created. No errors. Package body created. No errors. ?????dbms_dbfs_sfs package  SQL> create tablespace dbfstbs datafile size 20g; Tablespace created. SQL> create user maclean_dbfs identified by oracle; User created. SQL> grant dba to maclean_dbfs; Grant succeeded. @@!!! SQL> grant  dbfs_role to maclean_dbfs; Grant succeeded. 3. ??DBFS SQL> conn maclean_dbfs/oracle Connected. SQL> @?/rdbms/admin/dbfs_create_filesystem.sql  dbfstbs mac_dbfs   No errors. -------- CREATE STORE: begin dbms_dbfs_sfs.createFilesystem(store_name => 'FS_MAC_DBFS', tbl_name => 'T_MAC_DBFS', tbl_tbs => 'dbfstbs', lob_tbs => 'dbfstbs', do_partition => false, partition_key => 1, do_compress => false, compression => '', do_dedup => false, do_encrypt => false); end; -------- REGISTER STORE: begin dbms_dbfs_content.registerStore(store_name=> 'FS_MAC_DBFS', provider_name => 'sample1', provider_package => 'dbms_dbfs_sfs'); end; -------- MOUNT STORE: begin dbms_dbfs_content.mountStore(store_name=>'FS_MAC_DBFS', store_mount=>'mac_dbfs'); end; -------- CHMOD STORE: declare m integer; begin m := dbms_fuse.fs_chmod('/mac_dbfs', 16895); end; No errors. 4.  ??mount point  [root@dm01db01 ~]# mkdir /dbfs [root@dm01db01 ~]# chown oracle:oinstall /dbfs 5. ??library path ?OS  # echo "/usr/local/lib" >> /etc/ld.so.conf.d/usr_local_lib.conf 6. ?????? export ORACLE_HOME=/s01/orabase/product/11.2.0/dbhome_1 [root@dm01db01 ~]# ln -s $ORACLE_HOME/lib/libclntsh.so.11.1 /usr/local/lib/libclntsh.so.11.1 [root@dm01db01 ~]#  ln -s $ORACLE_HOME/lib/libnnz11.so /usr/local/lib/libnnz11.so [root@dm01db01 ~]#  ln -s /lib64/libfuse.so.2 /usr/local/lib/libfuse.so.2 7. ??ldconfig  [root@dm01db01 ~]# ldconfig [root@dm01db01 ~]#  8. ??fusermount??????? [root@dm01db01 ~]#  chmod +x /usr/bin/fusermount [root@dm01db01 ~]#  ls -l /usr/bin/fusermount lrwxrwxrwx 1 root root 15 Sep  7 03:06 /usr/bin/fusermount -> /bin/fusermount [root@dm01db01 ~]#  ls -l /bin/fusermount -rwsr-x--x 1 root fuse 27072 Oct 17  2011 /bin/fusermount 9. ???????OS  dbfs_client maclean_dbfs@dm01db01:1521/orcl  /dbfs 10. ????nohup + &?????mount DBFS,???????????? [oracle@dm01db01 ~]$ echo "oracle"  >> dbfs_pw [oracle@dm01db01 ~]$ nohup dbfs_client maclean_dbfs@dm01db01:1521/orcl /dbfs < dbfs_pw & [oracle@dm01db01 ~]$ df -h Filesystem            Size  Used Avail Use% Mounted on /dev/mapper/VGExaDb-LVDbSys1                        30G   15G   14G  53% / /dev/sda1             502M   30M  447M   7% /boot /dev/mapper/VGExaDb-LVDbOra1                        99G   20G   75G  21% /u01 tmpfs                  81G     0   81G   0% /dev/shm dbfs-maclean_dbfs@orcl:/                        20G  120K   20G   1% /dbfs [oracle@dm01db01 ~]$ mount /dev/mapper/VGExaDb-LVDbSys1 on / type ext3 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) /dev/sda1 on /boot type ext3 (rw,nodev) /dev/mapper/VGExaDb-LVDbOra1 on /u01 type ext3 (rw,nodev) tmpfs on /dev/shm type tmpfs (rw,size=82052m) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) dbfs-maclean_dbfs@orcl:/ on /dbfs type fuse (rw,nosuid,nodev,max_read=1048576,default_permissions,user=oracle) [oracle@dm01db01 ~]$ ls -l /dbfs/ total 0 drwxrwxrwx 3 root root 0 Sep 14 05:11 mac_dbfs [oracle@nas ~]$ dbfs_client  --------MOUNT mode: usage: dbfs_client <db_user>@<db_server> [options] <mountpoint>   db_user:              Name of Database user that owns DBFS content repository filesystem(s)   db_server:            A valid connect string for Oracle database server                         (for example, hrdb_host:1521/hrservice)   mountpoint:           Path to mount Database File System(s)                         All the file systems owned by the database user will be seen at the mountpoint. DBFS options:   -o direct_io          Bypass the Linux page cache. Gives much better performance for large files.                         Programs in the file system cannot be executed with this option.                         This option is recommended when DBFS is used as an ETL staging area.   -o wallet             Run dbfs_client in background.                         Wallet must be configured to get credentials.   -o failover           dbfs_client fails over to surviving database instance with no data loss.                         Some performance cost on writes, especially for small files.   -o allow_root         Allows root access to the filesystem.                         This option requires setting 'user_allow_other' parameter in '/etc/fuse.conf'.   -o allow_other        Allows other users access to the file system.                         This option requires setting 'user_allow_other' parameter in '/etc/fuse.conf'.   -o rw                 Mount the filesystem read-write. [Default]   -o ro                 Mount the filesystem read-only. Files cannot be modified.   -o trace_file=STR     Tracing <filename> | 'syslog'   -o trace_level=N      Trace Level: 1->DEBUG, 2->INFO, 3->WARNING, 4->ERROR, 5->CRITICAL [Default: 4]   -h                    help   -V                    version --------COMMAND mode: Usage:     dbfs_client <db_user>@<db_server> --command command [switches] [arguments]             command:          Command to be executed, e.g., ls, cp, mkdir, rm            switches:         Switches are described below for each command.            arguments:        File names or directory names NOTE:      All database pathnames must be absolute and preceded by dbfs:/ Commands   ls            dbfs_client <db_user>@<db_server> --command ls [switches] target      Switches:              -a         Show all files including those starting with '.'            -l         Use a long listing format. In addition to the name of each file                       print the file type, permissions, size, user and group information            -R         List subdirectories recursively cp                     dbfs_client <db_user>@<db_server> --command cp [switches] source destination      Switches:              -r, -R      Copy a directory and its contents recursively into the destination directory rm                     dbfs_client <db_user>@<db_server> --command rm [switches] target      Switches:              -r, -R      Removes a directory and its contents recursively mkdir                  dbfs_client <db_user>@<db_server> --command mkdir directory_name Examples                     dbfs_client ETLUser@DBConnectString --command ls -l -a dbfs:/staging_area/directory1            dbfs_client ETLUser@DBConnectString --command cp -R  /tmp/1-Jan-2009-dump dbfs:/staging_area            dbfs_client ETLUser@DBConnectString --command rm dbfs:/staging_area/hello.txt            dbfs_client ETLUser@DBConnectString --command mkdir dbfs:/staging_area/directory2 [oracle@dm01db01 ~]$ ls -lh /tmp/largefile -rw-r--r-- 1 oracle oinstall 2.0G Sep 14 08:50 /tmp/largefile [oracle@dm01db01 ~]$ time dbfs_client  maclean_dbfs@dm01db01:1521/orcl --command cp /tmp/largefile dbfs:/mac_dbfs Password: /tmp/largefile -> dbfs:/mac_dbfs/largefile real    0m11.802s user    0m0.580s sys     0m2.375s ?Exadata?????2G?????? DBFS???11s => 200MB/s 

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• FluentNHibernate Unit Of Work / Repository Design Pattern Questions

  - by Echiban

  Hi all, I think I am at a impasse here. I have an application I built from scratch using FluentNHibernate (ORM) / SQLite (file db). I have decided to implement the Unit of Work and Repository Design pattern. I am at a point where I need to think about the end game, which will start as a WPF windows app (using MVVM) and eventually implement web services / ASP.Net as UI. Now I already created domain objects (entities) for ORM. And now I don't know how should I use it outside of ORM. Questions about it include: Should I use ORM entity objects directly as models in MVVM? If yes, do I put business logic (such as certain values must be positive and be greater than another Property) in those entity objects? It is certainly the simpler approach, and one I am leaning right now. However, will there be gotchas that would trash this plan? If the answer above is no, do I then create a new set of classes to implement business logic and use those as Models in MVVM? How would I deal with the transition between model objects and entity objects? I guess a type converter implementation would work well here. Now I followed this well written article to implement the Unit Of Work pattern. However, due to the fact that I am using FluentNHibernate instead of NHibernate, I had to bastardize the implementation of UnitOfWorkFactory. Here's my implementation: using System; using FluentNHibernate.Cfg; using FluentNHibernate.Cfg.Db; using NHibernate; using NHibernate.Cfg; using NHibernate.Tool.hbm2ddl; namespace ELau.BlindsManagement.Business { public class UnitOfWorkFactory : IUnitOfWorkFactory { private static readonly string DbFilename; private static Configuration _configuration; private static ISession _currentSession; private ISessionFactory _sessionFactory; static UnitOfWorkFactory() { // arbitrary default filename DbFilename = "defaultBlindsDb.db3"; } internal UnitOfWorkFactory() { } #region IUnitOfWorkFactory Members public ISession CurrentSession { get { if (_currentSession == null) { throw new InvalidOperationException(ExceptionStringTable.Generic_NotInUnitOfWork); } return _currentSession; } set { _currentSession = value; } } public ISessionFactory SessionFactory { get { if (_sessionFactory == null) { _sessionFactory = BuildSessionFactory(); } return _sessionFactory; } } public Configuration Configuration { get { if (_configuration == null) { Fluently.Configure().ExposeConfiguration(c => _configuration = c); } return _configuration; } } public IUnitOfWork Create() { ISession session = CreateSession(); session.FlushMode = FlushMode.Commit; _currentSession = session; return new UnitOfWorkImplementor(this, session); } public void DisposeUnitOfWork(UnitOfWorkImplementor adapter) { CurrentSession = null; UnitOfWork.DisposeUnitOfWork(adapter); } #endregion public ISession CreateSession() { return SessionFactory.OpenSession(); } public IStatelessSession CreateStatelessSession() { return SessionFactory.OpenStatelessSession(); } private static ISessionFactory BuildSessionFactory() { ISessionFactory result = Fluently.Configure() .Database( SQLiteConfiguration.Standard .UsingFile(DbFilename) ) .Mappings(m => m.FluentMappings.AddFromAssemblyOf<UnitOfWorkFactory>()) .ExposeConfiguration(BuildSchema) .BuildSessionFactory(); return result; } private static void BuildSchema(Configuration config) { // this NHibernate tool takes a configuration (with mapping info in) // and exports a database schema from it _configuration = config; new SchemaExport(_configuration).Create(false, true); } } } I know that this implementation is flawed because a few tests pass when run individually, but when all tests are run, it would fail for some unknown reason. Whoever wants to help me out with this one, given its complexity, please contact me by private message. I am willing to send some $$$ by Paypal to someone who can address the issue and provide solid explanation. I am new to ORM, so any assistance is appreciated.

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• Django manager for _set in model

  - by Daniel Johansson

  Hello, I'm in the progress of learning Django at the moment but I can't figure out how to solve this problem on my own. I'm reading the book Developers Library - Python Web Development With Django and in one chapter you build a simple CMS system with two models (Story and Category), some generic and custom views together with templates for the views. The book only contains code for listing stories, story details and search. I wanted to expand on that and build a page with nested lists for categories and stories. - Category1 -- Story1 -- Story2 - Category2 - Story3 etc. I managed to figure out how to add my own generic object_list view for the category listing. My problem is that the Story model have STATUS_CHOICES if the Story is public or not and a custom manager that'll only fetch the public Stories per default. I can't figure out how to tell my generic Category list view to also use a custom manager and only fetch the public Stories. Everything works except that small problem. I'm able to create a list for all categories with a sub list for all stories in that category on a single page, the only problem is that the list contains non public Stories. I don't know if I'm on the right track here. My urls.py contains a generic view that fetches all Category objects and in my template I'm using the *category.story_set.all* to get all Story objects for that category, wich I then loop over. I think it would be possible to add a if statement in the template and use the VIEWABLE_STATUS from my model file to check if it should be listed or not. The problem with that solution is that it's not very DRY compatible. Is it possible to add some kind of manager for the Category model too that only will fetch in public Story objects when using the story_set on a category? Or is this the wrong way to attack my problem? Related code urls.py (only category list view): urlpatterns += patterns('django.views.generic.list_detail', url(r'^categories/$', 'object_list', {'queryset': Category.objects.all(), 'template_object_name': 'category' }, name='cms-categories'), models.py: from markdown import markdown import datetime from django.db import models from django.db.models import permalink from django.contrib.auth.models import User VIEWABLE_STATUS = [3, 4] class ViewableManager(models.Manager): def get_query_set(self): default_queryset = super(ViewableManager, self).get_query_set() return default_queryset.filter(status__in=VIEWABLE_STATUS) class Category(models.Model): """A content category""" label = models.CharField(blank=True, max_length=50) slug = models.SlugField() class Meta: verbose_name_plural = "categories" def __unicode__(self): return self.label @permalink def get_absolute_url(self): return ('cms-category', (), {'slug': self.slug}) class Story(models.Model): """A hunk of content for our site, generally corresponding to a page""" STATUS_CHOICES = ( (1, "Needs Edit"), (2, "Needs Approval"), (3, "Published"), (4, "Archived"), ) title = models.CharField(max_length=100) slug = models.SlugField() category = models.ForeignKey(Category) markdown_content = models.TextField() html_content = models.TextField(editable=False) owner = models.ForeignKey(User) status = models.IntegerField(choices=STATUS_CHOICES, default=1) created = models.DateTimeField(default=datetime.datetime.now) modified = models.DateTimeField(default=datetime.datetime.now) class Meta: ordering = ['modified'] verbose_name_plural = "stories" def __unicode__(self): return self.title @permalink def get_absolute_url(self): return ("cms-story", (), {'slug': self.slug}) def save(self): self.html_content = markdown(self.markdown_content) self.modified = datetime.datetime.now() super(Story, self).save() admin_objects = models.Manager() objects = ViewableManager() category_list.html (related template): {% extends "cms/base.html" %} {% block content %} <h1>Categories</h1> {% if category_list %} <ul id="category-list"> {% for category in category_list %} <li><a href="{{ category.get_absolute_url }}">{{ category.label }}</a></li> {% if category.story_set %} <ul> {% for story in category.story_set.all %} <li><a href="{{ story.get_absolute_url }}">{{ story.title }}</a></li> {% endfor %} </ul> {% endif %} {% endfor %} </ul> {% else %} <p> Sorry, no categories at the moment. </p> {% endif %} {% endblock %}

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• Linking LLVM JIT Code to Static LLVM Libraries?

  - by inflector

  I'm in the process of implementing a cross-platform (Mac OS X, Windows, and Linux) application which will do lots of CPU intensive analysis of financial data. The bulk of the analysis engine will be written in C++ for speed reasons, with a user-accessible scripting engine interfacing with the C++ testing engine. I want to write several scripting front-ends over time to emulate other popular software with existing large user bases. The first front will be a VisualBasic-like scripting language. I'm thinking that LLVM would be perfect for my needs. Performance is very important because of the sheer amount of data; it can take hours or days to run a single run of tests to get an answer. I believe that using LLVM will also allow me to use a single back-end solution while I implement different front-ends for different flavors of the scripting language over time. The testing engine itself will be separated from the interface and testing will even take place in a separate process with progress and results being reported to the testing management interface. Tests will consist of scripting code integrated with the testing engine code. In a previous implementation of a similar commercial testing system I wrote, I built a fast interpreter which easily interfaced with the testing library because it was written in C++ and linked directly to the testing engine library. Callbacks from scripting code to testing library objects involved translating between the formats with significant overhead. I'm imagining that with LLVM, I could implement the callbacks into C++ directly so that I could make the scripting code work almost as if it had been written in C++. Likewise, if all the code was compiled to LLVM byte-code format, it seems like the LLVM optimizers could optimize across the boundaries between the scripting language and the testing engine code that was written in C++. I don't want to have to compile the testing engine every time. Ideally, I'd like to JIT compile only the scripting code. For small tests, I'd skip some optimization passes, while for large tests, I'd perform full optimizations during the link. So is this possible? Can I precompile the testing engine to a .o object file or .a library file and then link in the scripting code using the JIT? Finally, ideally, I'd like to have the scripting code implement specific methods as subclasses for a specific C++ class. So the C++ testing engine would only see C++ objects while the JIT setup code compiled scripting code that implemented some of the methods for the objects. It seems that if I used the right name mangling algorithm it would be relatively easy to set up the LLVM generation for the scripting language to look like a C++ method call which could then be linked into the testing engine. Thus the linking stage would go in two directions, calls from the scripting language into the testing engine objects to retrieve pricing information and test state information and calls from the testing engine of methods of some particular C++ objects where the code was supplied not from C++ but from the scripting language. In summary: 1) Can I link in precompiled (either .bc, .o, or .a) files as part of the JIT compilation, code-generation process? 2) Can I link in code using that the process in 1) above in such a way that I am able to create code that acts as if it was all written in C++?

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• Overriding Object.Equals() instance method in C#; now Code Analysis / FxCop warning CA2218: "should

  - by Chris W. Rea

  I've got a complex class in my C# project on which I want to be able to do equality tests. It is not a trivial class; it contains a variety of scalar properties as well as references to other objects and collections (e.g. IDictionary). For what it's worth, my class is sealed. To enable a performance optimization elsewhere in my system (an optimization that avoids a costly network round-trip), I need to be able to compare instances of these objects to each other for equality – other than the built-in reference equality – and so I'm overriding the Object.Equals() instance method. However, now that I've done that, Visual Studio 2008's Code Analysis a.k.a. FxCop, which I keep enabled by default, is raising the following warning: warning : CA2218 : Microsoft.Usage : Since 'MySuperDuperClass' redefines Equals, it should also redefine GetHashCode. I think I understand the rationale for this warning: If I am going to be using such objects as the key in a collection, the hash code is important. i.e. see this question. However, I am not going to be using these objects as the key in a collection. Ever. Feeling justified to suppress the warning, I looked up code CA2218 in the MSDN documentation to get the full name of the warning so I could apply a SuppressMessage attribute to my class as follows: [SuppressMessage("Microsoft.Naming", "CA2218:OverrideGetHashCodeOnOverridingEquals", Justification="This class is not to be used as key in a hashtable.")] However, while reading further, I noticed the following: How to Fix Violations To fix a violation of this rule, provide an implementation of GetHashCode. For a pair of objects of the same type, you must ensure that the implementation returns the same value if your implementation of Equals returns true for the pair. When to Suppress Warnings ----- Do not suppress a warning from this rule. [arrow & emphasis mine] So, I'd like to know: Why shouldn't I suppress this warning as I was planning to? Doesn't my case warrant suppression? I don't want to code up an implementation of GetHashCode() for this object that will never get called, since my object will never be the key in a collection. If I wanted to be pedantic, instead of suppressing, would it be more reasonable for me to override GetHashCode() with an implementation that throws a NotImplementedException? Update: I just looked this subject up again in Bill Wagner's good book Effective C#, and he states in "Item 10: Understand the Pitfalls of GetHashCode()": If you're defining a type that won't ever be used as the key in a container, this won't matter. Types that represent window controls, web page controls, or database connections are unlikely to be used as keys in a collection. In those cases, do nothing. All reference types will have a hash code that is correct, even if it is very inefficient. [...] In most types that you create, the best approach is to avoid the existence of GetHashCode() entirely. ... that's where I originally got this idea that I need not be concerned about GetHashCode() always.

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• What's my best approach on this simple hierarchy Java Problem?

  - by Nazgulled

  First, I'm sorry for the question title but I can't think of a better one to describe my problem. Feel free to change it :) Let's say I have this abstract class Box which implements a couple of constructors, methods and whatever on some private variables. Then I have a couple of sub classes like BoxA and BoxB. Both of these implement extra things. Now I have another abstract class Shape and a few sub classes like Square and Circle. For both BoxA and BoxB I need to have a list of Shape objects but I need to make sure that only Square objects go into BoxA's list and only Circle objects go into BoxB's list. For that list (on each box), I need to have a get() and set() method and also a addShape() and removeShape() methods. Another important thing to know is that for each box created, either BoxA or BoxB, each respectively Shape list is exactly the same. Let's say I create a list of Square's named ls and two BoxA objects named boxA1 and boxA2. No matter what, both boxA1 and boxA2 must have the same ls list. This is my idea: public abstract class Box { // private instance variables public Box() { // constructor stuff } // public instance methods } public class BoxA extends Box { // private instance variables private static List<Shape> list; public BoxA() { // constructor stuff } // public instance methods public static List<Square> getList() { List<Square> aux = new ArrayList<Square>(); for(Square s : list.values()) { aux.add(s.clone()); // I know what I'm doing with this clone, don't worry about it } return aux; } public static void setList(List<Square> newList) { list = new ArrayList<Square>(newList); } public static void addShape(Square s) { list.add(s); } public static void removeShape(Square s) { list.remove(list.indexOf(s)); } } As the list needs to be the same for that type of object, I declared as static and all methods that work with that list are also static. Now, for BoxB the class would be almost the same regarding the list stuff. I would only replace Square by Triangle and the problem was solved. So, for each BoxA object created, the list would be only one and the same for each BoxB object created, but a different type of list of course. So, what's my problem you ask? Well, I don't like the code... The getList(), setList(), addShape() and removeShape() methods are basically repeated for BoxA and BoxB, only the type of the objects that the list will hold is different. I can't think of way to do it in the super class Box instead. Doing it statically too, using Shape instead of Square and Triangle, wouldn't work because the list would be only one and I need it to be only one but for each sub class of Box. How could I do this differently and better? P.S: I could not describe my real example because I don't know the correct words in English for the stuff I'm doing, so I just used a box and shapes example, but it's basically the same.

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• unexplainable packet drops with 5 ethernet NICs and low traffic on Ubuntu

  - by jon

  I'm stuck on problem where my machine started to drops packets with no sign of ANY system load or high interrupt usage after an upgrade to Ubuntu 12.04. My server is a network monitoring sensor, running Ubuntu LTS 12.04, it passively collects packets from 5 interfaces doing network intrusion type stuff. Before the upgrade I managed to collect 200+GB of packets a day while writing them to disk with around 0% packet loss depending on the day with the help of CPU affinity and NIC IRQ to CPU bindings. Now I lose a great deal of packets with none of my applications running and at very low PPS rate which a modern workstation NIC would have no trouble with. Specs: x64 Xeon 4 cores 3.2 Ghz 16 GB RAM NICs: 5 Intel Pro NICs using the e1000 driver (NAPI). [1] eth0 and eth1 are integrated NICs (in the motherboard) There are 2 other PCI-X network cards, each with 2 Ethernet ports. 3 of the interfaces are running at Gigabit Ethernet, the others are not because they're attached to hubs. Specs: [2] http://support.dell.com/support/edocs/systems/pe2850/en/ug/t1390aa.htm uptime 17:36:00 up 1:43, 2 users, load average: 0.00, 0.01, 0.05 # uname -a Linux nms 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux I also have the CPU governor set to performance mode and irqbalance off. The problem still occurs with them on. # lspci -t -vv -[0000:00]-+-00.0 Intel Corporation E7520 Memory Controller Hub +-02.0-[01-03]--+-00.0-[02]----0e.0 Dell PowerEdge Expandable RAID controller 4 | \-00.2-[03]-- +-04.0-[04]-- +-05.0-[05-07]--+-00.0-[06]----07.0 Intel Corporation 82541GI Gigabit Ethernet Controller | \-00.2-[07]----08.0 Intel Corporation 82541GI Gigabit Ethernet Controller +-06.0-[08-0a]--+-00.0-[09]--+-04.0 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) | | \-04.1 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) | \-00.2-[0a]--+-02.0 Digium, Inc. Wildcard TE210P/TE212P dual-span T1/E1/J1 card 3.3V | +-03.0 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) | \-03.1 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) +-1d.0 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #1 +-1d.1 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #2 +-1d.2 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #3 +-1d.7 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB2 EHCI Controller +-1e.0-[0b]----0d.0 Advanced Micro Devices [AMD] nee ATI RV100 QY [Radeon 7000/VE] +-1f.0 Intel Corporation 82801EB/ER (ICH5/ICH5R) LPC Interface Bridge \-1f.1 Intel Corporation 82801EB/ER (ICH5/ICH5R) IDE Controller I believe the NIC nor the NIC drivers are dropping the packets because ethtool reports 0 under rx_missed_errors and rx_no_buffer_count for each interface. On the old system, if it couldn't keep up this is where the drops would be. I drop packets on multiple interfaces just about every second, usually in small increments of 2-4. I tried all these sysctl values, I'm currently using the uncommented ones. # cat /etc/sysctl.conf # high net.core.netdev_max_backlog = 3000000 net.core.rmem_max = 16000000 net.core.rmem_default = 8000000 # defaults #net.core.netdev_max_backlog = 1000 #net.core.rmem_max = 131071 #net.core.rmem_default = 163480 # moderate #net.core.netdev_max_backlog = 10000 #net.core.rmem_max = 33554432 #net.core.rmem_default = 33554432 Here's an example of an interface stats report with ethtool. They are all the same, nothing is out of the ordinary ( I think ), so I'm only going to show one: ethtool -S eth2 NIC statistics: rx_packets: 7498 tx_packets: 0 rx_bytes: 2722585 tx_bytes: 0 rx_broadcast: 327 tx_broadcast: 0 rx_multicast: 1504 tx_multicast: 0 rx_errors: 0 tx_errors: 0 tx_dropped: 0 multicast: 1504 collisions: 0 rx_length_errors: 0 rx_over_errors: 0 rx_crc_errors: 0 rx_frame_errors: 0 rx_no_buffer_count: 0 rx_missed_errors: 0 tx_aborted_errors: 0 tx_carrier_errors: 0 tx_fifo_errors: 0 tx_heartbeat_errors: 0 tx_window_errors: 0 tx_abort_late_coll: 0 tx_deferred_ok: 0 tx_single_coll_ok: 0 tx_multi_coll_ok: 0 tx_timeout_count: 0 tx_restart_queue: 0 rx_long_length_errors: 0 rx_short_length_errors: 0 rx_align_errors: 0 tx_tcp_seg_good: 0 tx_tcp_seg_failed: 0 rx_flow_control_xon: 0 rx_flow_control_xoff: 0 tx_flow_control_xon: 0 tx_flow_control_xoff: 0 rx_long_byte_count: 2722585 rx_csum_offload_good: 0 rx_csum_offload_errors: 0 alloc_rx_buff_failed: 0 tx_smbus: 0 rx_smbus: 0 dropped_smbus: 01 # ifconfig eth0 Link encap:Ethernet HWaddr 00:11:43:e0:e2:8c UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:373348 errors:16 dropped:95 overruns:0 frame:16 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:356830572 (356.8 MB) TX bytes:0 (0.0 B) eth1 Link encap:Ethernet HWaddr 00:11:43:e0:e2:8d UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:13616 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:8690528 (8.6 MB) TX bytes:0 (0.0 B) eth2 Link encap:Ethernet HWaddr 00:04:23:e1:77:6a UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:7750 errors:0 dropped:471 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2780935 (2.7 MB) TX bytes:0 (0.0 B) eth3 Link encap:Ethernet HWaddr 00:04:23:e1:77:6b UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:5112 errors:0 dropped:206 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:639472 (639.4 KB) TX bytes:0 (0.0 B) eth4 Link encap:Ethernet HWaddr 00:04:23:b6:35:6c UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:961467 errors:0 dropped:935 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:958561305 (958.5 MB) TX bytes:0 (0.0 B) eth5 Link encap:Ethernet HWaddr 00:04:23:b6:35:6d inet addr:192.168.1.6 Bcast:192.168.1.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:4264 errors:0 dropped:16 overruns:0 frame:0 TX packets:699 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:572228 (572.2 KB) TX bytes:124456 (124.4 KB) I tried the defaults, then started to play around with settings. I wasn't using any flow control and I increased the RxDescriptor count to 4096 before the upgrade as well without any problems. # cat /etc/modprobe.d/e1000.conf options e1000 XsumRX=0,0,0,0,0 RxDescriptors=4096,4096,4096,4096,4096 FlowControl=0,0,0,0,0 debug=16 Here's my network configuration file, I turned off checksumming and various offloading mechanisms along with setting CPU affinity with heavy use interfaces getting an entire CPU and light use interfaces sharing a CPU. I used these settings prior to the upgrade without problems. # cat /etc/network/interfaces # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet manual pre-up /sbin/ethtool -G eth0 rx 4096 tx 0 pre-up /sbin/ethtool -K eth0 gro off gso off rx off pre-up /sbin/ethtool -A eth0 rx off autoneg off up ifconfig eth0 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "4" > /proc/irq/48/smp_affinity down ifconfig eth0 down post-down /sbin/ethtool -G eth0 rx 256 tx 256 post-down /sbin/ethtool -K eth0 gro on gso on rx on post-down /sbin/ethtool -A eth0 rx on autoneg on auto eth1 iface eth1 inet manual pre-up /sbin/ethtool -G eth1 rx 4096 tx 0 pre-up /sbin/ethtool -K eth1 gro off gso off rx off pre-up /sbin/ethtool -A eth1 rx off autoneg off up ifconfig eth1 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "4" > /proc/irq/49/smp_affinity down ifconfig eth1 down post-down /sbin/ethtool -G eth1 rx 256 tx 256 post-down /sbin/ethtool -K eth1 gro on gso on rx on post-down /sbin/ethtool -A eth1 rx on autoneg on auto eth2 iface eth2 inet manual pre-up /sbin/ethtool -G eth2 rx 4096 tx 0 pre-up /sbin/ethtool -K eth2 gro off gso off rx off pre-up /sbin/ethtool -A eth2 rx off autoneg off up ifconfig eth2 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "1" > /proc/irq/82/smp_affinity down ifconfig eth2 down post-down /sbin/ethtool -G eth2 rx 256 tx 256 post-down /sbin/ethtool -K eth2 gro on gso on rx on post-down /sbin/ethtool -A eth2 rx on autoneg on auto eth3 iface eth3 inet manual pre-up /sbin/ethtool -G eth3 rx 4096 tx 0 pre-up /sbin/ethtool -K eth3 gro off gso off rx off pre-up /sbin/ethtool -A eth3 rx off autoneg off up ifconfig eth3 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "2" > /proc/irq/83/smp_affinity down ifconfig eth3 down post-down /sbin/ethtool -G eth3 rx 256 tx 256 post-down /sbin/ethtool -K eth3 gro on gso on rx on post-down /sbin/ethtool -A eth3 rx on autoneg on auto eth4 iface eth4 inet manual pre-up /sbin/ethtool -G eth4 rx 4096 tx 0 pre-up /sbin/ethtool -K eth4 gro off gso off rx off pre-up /sbin/ethtool -A eth4 rx off autoneg off up ifconfig eth4 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "4" > /proc/irq/77/smp_affinity down ifconfig eth4 down post-down /sbin/ethtool -G eth4 rx 256 tx 256 post-down /sbin/ethtool -K eth4 gro on gso on rx on post-down /sbin/ethtool -A eth4 rx on autoneg on auto eth5 iface eth5 inet static pre-up /etc/fw.conf address 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255 gateway 192.168.1.1 dns-nameservers 192.168.1.2 192.168.1.3 up ifconfig eth5 up post-up echo "8" > /proc/irq/77/smp_affinity down ifconfig eth5 down Here's a few examples of packet drops, i ran one after another, probabling totaling 3 or 4 seconds. You can see increases in the drops from the 1st and 3rd. This was a non-busy time, very little traffic. # awk '{ print $1,$5 }' /proc/net/dev Inter-| face drop eth3: 225 lo: 0 eth2: 505 eth1: 0 eth5: 17 eth0: 105 eth4: 1034 # awk '{ print $1,$5 }' /proc/net/dev Inter-| face drop eth3: 225 lo: 0 eth2: 507 eth1: 0 eth5: 17 eth0: 105 eth4: 1034 # awk '{ print $1,$5 }' /proc/net/dev Inter-| face drop eth3: 227 lo: 0 eth2: 512 eth1: 0 eth5: 17 eth0: 105 eth4: 1039 I tried the pci=noacpi options. With and without, it's the same. This is what my interrupt stats looked like before the upgrade, after, with ACPI on PCI it showed multiple NICs bound to an interrupt and shared with other devices such as USB drives which I didn't like so I think i'm going to keep it with ACPI off as it's easier to designate sole purpose interrupts. Is there any advantage I would have using the default i.e. ACPI w/ PCI. ? # cat /etc/default/grub | grep CMD_LINE GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 noacpi pci=noacpi" GRUB_CMDLINE_LINUX="" # cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 0: 45 0 0 16 IO-APIC-edge timer 1: 1 0 0 7936 IO-APIC-edge i8042 2: 0 0 0 0 XT-PIC-XT-PIC cascade 6: 0 0 0 3 IO-APIC-edge floppy 8: 0 0 0 1 IO-APIC-edge rtc0 9: 0 0 0 0 IO-APIC-edge acpi 12: 0 0 0 1809 IO-APIC-edge i8042 14: 1 0 0 4498 IO-APIC-edge ata_piix 15: 0 0 0 0 IO-APIC-edge ata_piix 16: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb2 18: 0 0 0 1350 IO-APIC-fasteoi uhci_hcd:usb4, radeon 19: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb3 23: 0 0 0 4099 IO-APIC-fasteoi ehci_hcd:usb1 38: 0 0 0 61963 IO-APIC-fasteoi megaraid 48: 0 0 1002319 4 IO-APIC-fasteoi eth0 49: 0 0 38772 3 IO-APIC-fasteoi eth1 77: 0 0 130076 432159 IO-APIC-fasteoi eth4 78: 0 0 0 23917 IO-APIC-fasteoi eth5 82: 1329033 0 0 4 IO-APIC-fasteoi eth2 83: 0 4886525 0 6 IO-APIC-fasteoi eth3 NMI: 5 6 4 5 Non-maskable interrupts LOC: 61409 57076 64257 114764 Local timer interrupts SPU: 0 0 0 0 Spurious interrupts IWI: 0 0 0 0 IRQ work interrupts RES: 17956 25333 13436 14789 Rescheduling interrupts CAL: 22436 607 539 478 Function call interrupts TLB: 1525 1458 4600 4151 TLB shootdowns TRM: 0 0 0 0 Thermal event interrupts THR: 0 0 0 0 Threshold APIC interrupts MCE: 0 0 0 0 Machine check exceptions MCP: 16 16 16 16 Machine check polls ERR: 0 MIS: 0 Here's sample output of vmstat, showing the system. Barebones system right now. root@nms:~# vmstat -S m 1 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 14992 192 1029 0 0 56 2 419 29 1 0 99 0 0 0 0 14992 192 1029 0 0 0 0 922 27 0 0 100 0 0 0 0 14991 192 1029 0 0 0 36 763 50 0 0 100 0 0 0 0 14991 192 1029 0 0 0 0 646 35 0 0 100 0 0 0 0 14991 192 1029 0 0 0 0 722 54 0 0 100 0 0 0 0 14991 192 1029 0 0 0 0 793 27 0 0 100 0 ^C Here's dmesg output. I can't figure out why my PCI-X slots are negotiated as PCI. The network cards are all PCI-X with the exception of the integrated NICs that came with the server. In the output below it looks as if eth3 and eth2 negotiated at PCI-X speeds rather than PCI:66Mhz. Wouldn't they all drop to PCI:66Mhz? If your integrated NICs are PCI, as labeled below (eth0,eth1), then wouldn't all devices on your bus speed drop down to that slower bus speed? If not, I still don't know why only one of my NICs ( each has two ethernet ports) is labeled as PCI-X in the output below. Does that mean it is running at PCI-X speeds are is it showing that it's capable? # dmesg | grep e1000 [ 3678.349337] e1000: Intel(R) PRO/1000 Network Driver - version 7.3.21-k8-NAPI [ 3678.349342] e1000: Copyright (c) 1999-2006 Intel Corporation. [ 3678.349394] e1000 0000:06:07.0: PCI->APIC IRQ transform: INT A -> IRQ 48 [ 3678.409725] e1000 0000:06:07.0: Receive Descriptors set to 4096 [ 3678.409730] e1000 0000:06:07.0: Checksum Offload Disabled [ 3678.409734] e1000 0000:06:07.0: Flow Control Disabled [ 3678.586409] e1000 0000:06:07.0: eth0: (PCI:66MHz:32-bit) 00:11:43:e0:e2:8c [ 3678.586419] e1000 0000:06:07.0: eth0: Intel(R) PRO/1000 Network Connection [ 3678.586642] e1000 0000:07:08.0: PCI->APIC IRQ transform: INT A -> IRQ 49 [ 3678.649854] e1000 0000:07:08.0: Receive Descriptors set to 4096 [ 3678.649859] e1000 0000:07:08.0: Checksum Offload Disabled [ 3678.649863] e1000 0000:07:08.0: Flow Control Disabled [ 3678.826436] e1000 0000:07:08.0: eth1: (PCI:66MHz:32-bit) 00:11:43:e0:e2:8d [ 3678.826444] e1000 0000:07:08.0: eth1: Intel(R) PRO/1000 Network Connection [ 3678.826627] e1000 0000:09:04.0: PCI->APIC IRQ transform: INT A -> IRQ 82 [ 3679.093266] e1000 0000:09:04.0: Receive Descriptors set to 4096 [ 3679.093271] e1000 0000:09:04.0: Checksum Offload Disabled [ 3679.093275] e1000 0000:09:04.0: Flow Control Disabled [ 3679.130239] e1000 0000:09:04.0: eth2: (PCI-X:133MHz:64-bit) 00:04:23:e1:77:6a [ 3679.130246] e1000 0000:09:04.0: eth2: Intel(R) PRO/1000 Network Connection [ 3679.130449] e1000 0000:09:04.1: PCI->APIC IRQ transform: INT B -> IRQ 83 [ 3679.397312] e1000 0000:09:04.1: Receive Descriptors set to 4096 [ 3679.397318] e1000 0000:09:04.1: Checksum Offload Disabled [ 3679.397321] e1000 0000:09:04.1: Flow Control Disabled [ 3679.434350] e1000 0000:09:04.1: eth3: (PCI-X:133MHz:64-bit) 00:04:23:e1:77:6b [ 3679.434360] e1000 0000:09:04.1: eth3: Intel(R) PRO/1000 Network Connection [ 3679.434553] e1000 0000:0a:03.0: PCI->APIC IRQ transform: INT A -> IRQ 77 [ 3679.704072] e1000 0000:0a:03.0: Receive Descriptors set to 4096 [ 3679.704077] e1000 0000:0a:03.0: Checksum Offload Disabled [ 3679.704081] e1000 0000:0a:03.0: Flow Control Disabled [ 3679.738364] e1000 0000:0a:03.0: eth4: (PCI:33MHz:64-bit) 00:04:23:b6:35:6c [ 3679.738371] e1000 0000:0a:03.0: eth4: Intel(R) PRO/1000 Network Connection [ 3679.738538] e1000 0000:0a:03.1: PCI->APIC IRQ transform: INT B -> IRQ 78 [ 3680.046060] e1000 0000:0a:03.1: eth5: (PCI:33MHz:64-bit) 00:04:23:b6:35:6d [ 3680.046067] e1000 0000:0a:03.1: eth5: Intel(R) PRO/1000 Network Connection [ 3682.132415] e1000: eth0 NIC Link is Up 100 Mbps Half Duplex, Flow Control: None [ 3682.224423] e1000: eth1 NIC Link is Up 100 Mbps Half Duplex, Flow Control: None [ 3682.316385] e1000: eth2 NIC Link is Up 100 Mbps Half Duplex, Flow Control: None [ 3682.408391] e1000: eth3 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None [ 3682.500396] e1000: eth4 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None [ 3682.708401] e1000: eth5 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX At first I thought it was the NIC drivers but I'm not so sure. I really have no idea where else to look at the moment. Any help is greatly appreciated as I'm struggling with this. If you need more information just ask. Thanks! [1]http://www.cs.fsu.edu/~baker/devices/lxr/http/source/linux/Documentation/networking/e1000.txt?v=2.6.11.8 [2] http://support.dell.com/support/edocs/systems/pe2850/en/ug/t1390aa.htm

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• What are good design practices when working with Entity Framework

  - by AD

  This will apply mostly for an asp.net application where the data is not accessed via soa. Meaning that you get access to the objects loaded from the framework, not Transfer Objects, although some recommendation still apply. This is a community post, so please add to it as you see fit. Applies to: Entity Framework 1.0 shipped with Visual Studio 2008 sp1. Why pick EF in the first place? Considering it is a young technology with plenty of problems (see below), it may be a hard sell to get on the EF bandwagon for your project. However, it is the technology Microsoft is pushing (at the expense of Linq2Sql, which is a subset of EF). In addition, you may not be satisfied with NHibernate or other solutions out there. Whatever the reasons, there are people out there (including me) working with EF and life is not bad.make you think. EF and inheritance The first big subject is inheritance. EF does support mapping for inherited classes that are persisted in 2 ways: table per class and table the hierarchy. The modeling is easy and there are no programming issues with that part. (The following applies to table per class model as I don't have experience with table per hierarchy, which is, anyway, limited.) The real problem comes when you are trying to run queries that include one or many objects that are part of an inheritance tree: the generated sql is incredibly awful, takes a long time to get parsed by the EF and takes a long time to execute as well. This is a real show stopper. Enough that EF should probably not be used with inheritance or as little as possible. Here is an example of how bad it was. My EF model had ~30 classes, ~10 of which were part of an inheritance tree. On running a query to get one item from the Base class, something as simple as Base.Get(id), the generated SQL was over 50,000 characters. Then when you are trying to return some Associations, it degenerates even more, going as far as throwing SQL exceptions about not being able to query more than 256 tables at once. Ok, this is bad, EF concept is to allow you to create your object structure without (or with as little as possible) consideration on the actual database implementation of your table. It completely fails at this. So, recommendations? Avoid inheritance if you can, the performance will be so much better. Use it sparingly where you have to. In my opinion, this makes EF a glorified sql-generation tool for querying, but there are still advantages to using it. And ways to implement mechanism that are similar to inheritance. Bypassing inheritance with Interfaces First thing to know with trying to get some kind of inheritance going with EF is that you cannot assign a non-EF-modeled class a base class. Don't even try it, it will get overwritten by the modeler. So what to do? You can use interfaces to enforce that classes implement some functionality. For example here is a IEntity interface that allow you to define Associations between EF entities where you don't know at design time what the type of the entity would be. public enum EntityTypes{ Unknown = -1, Dog = 0, Cat } public interface IEntity { int EntityID { get; } string Name { get; } Type EntityType { get; } } public partial class Dog : IEntity { // implement EntityID and Name which could actually be fields // from your EF model Type EntityType{ get{ return EntityTypes.Dog; } } } Using this IEntity, you can then work with undefined associations in other classes // lets take a class that you defined in your model. // that class has a mapping to the columns: PetID, PetType public partial class Person { public IEntity GetPet() { return IEntityController.Get(PetID,PetType); } } which makes use of some extension functions: public class IEntityController { static public IEntity Get(int id, EntityTypes type) { switch (type) { case EntityTypes.Dog: return Dog.Get(id); case EntityTypes.Cat: return Cat.Get(id); default: throw new Exception("Invalid EntityType"); } } } Not as neat as having plain inheritance, particularly considering you have to store the PetType in an extra database field, but considering the performance gains, I would not look back. It also cannot model one-to-many, many-to-many relationship, but with creative uses of 'Union' it could be made to work. Finally, it creates the side effet of loading data in a property/function of the object, which you need to be careful about. Using a clear naming convention like GetXYZ() helps in that regards. Compiled Queries Entity Framework performance is not as good as direct database access with ADO (obviously) or Linq2SQL. There are ways to improve it however, one of which is compiling your queries. The performance of a compiled query is similar to Linq2Sql. What is a compiled query? It is simply a query for which you tell the framework to keep the parsed tree in memory so it doesn't need to be regenerated the next time you run it. So the next run, you will save the time it takes to parse the tree. Do not discount that as it is a very costly operation that gets even worse with more complex queries. There are 2 ways to compile a query: creating an ObjectQuery with EntitySQL and using CompiledQuery.Compile() function. (Note that by using an EntityDataSource in your page, you will in fact be using ObjectQuery with EntitySQL, so that gets compiled and cached). An aside here in case you don't know what EntitySQL is. It is a string-based way of writing queries against the EF. Here is an example: "select value dog from Entities.DogSet as dog where dog.ID = @ID". The syntax is pretty similar to SQL syntax. You can also do pretty complex object manipulation, which is well explained [here][1]. Ok, so here is how to do it using ObjectQuery< string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); The first time you run this query, the framework will generate the expression tree and keep it in memory. So the next time it gets executed, you will save on that costly step. In that example EnablePlanCaching = true, which is unnecessary since that is the default option. The other way to compile a query for later use is the CompiledQuery.Compile method. This uses a delegate: static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => ctx.DogSet.FirstOrDefault(it => it.ID == id)); or using linq static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet where dog.ID == id select dog).FirstOrDefault()); to call the query: query_GetDog.Invoke( YourContext, id ); The advantage of CompiledQuery is that the syntax of your query is checked at compile time, where as EntitySQL is not. However, there are other consideration... Includes Lets say you want to have the data for the dog owner to be returned by the query to avoid making 2 calls to the database. Easy to do, right? EntitySQL string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)).Include("Owner"); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); CompiledQuery static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet.Include("Owner") where dog.ID == id select dog).FirstOrDefault()); Now, what if you want to have the Include parametrized? What I mean is that you want to have a single Get() function that is called from different pages that care about different relationships for the dog. One cares about the Owner, another about his FavoriteFood, another about his FavotireToy and so on. Basicly, you want to tell the query which associations to load. It is easy to do with EntitySQL public Dog Get(int id, string include) { string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)) .IncludeMany(include); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); } The include simply uses the passed string. Easy enough. Note that it is possible to improve on the Include(string) function (that accepts only a single path) with an IncludeMany(string) that will let you pass a string of comma-separated associations to load. Look further in the extension section for this function. If we try to do it with CompiledQuery however, we run into numerous problems: The obvious static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.Include(include) where dog.ID == id select dog).FirstOrDefault()); will choke when called with: query_GetDog.Invoke( YourContext, id, "Owner,FavoriteFood" ); Because, as mentionned above, Include() only wants to see a single path in the string and here we are giving it 2: "Owner" and "FavoriteFood" (which is not to be confused with "Owner.FavoriteFood"!). Then, let's use IncludeMany(), which is an extension function static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.IncludeMany(include) where dog.ID == id select dog).FirstOrDefault()); Wrong again, this time it is because the EF cannot parse IncludeMany because it is not part of the functions that is recognizes: it is an extension. Ok, so you want to pass an arbitrary number of paths to your function and Includes() only takes a single one. What to do? You could decide that you will never ever need more than, say 20 Includes, and pass each separated strings in a struct to CompiledQuery. But now the query looks like this: from dog in ctx.DogSet.Include(include1).Include(include2).Include(include3) .Include(include4).Include(include5).Include(include6) .[...].Include(include19).Include(include20) where dog.ID == id select dog which is awful as well. Ok, then, but wait a minute. Can't we return an ObjectQuery< with CompiledQuery? Then set the includes on that? Well, that what I would have thought so as well: static readonly Func<Entities, int, ObjectQuery<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, ObjectQuery<Dog>>((ctx, id) => (ObjectQuery<Dog>)(from dog in ctx.DogSet where dog.ID == id select dog)); public Dog GetDog( int id, string include ) { ObjectQuery<Dog> oQuery = query_GetDog(id); oQuery = oQuery.IncludeMany(include); return oQuery.FirstOrDefault; } That should have worked, except that when you call IncludeMany (or Include, Where, OrderBy...) you invalidate the cached compiled query because it is an entirely new one now! So, the expression tree needs to be reparsed and you get that performance hit again. So what is the solution? You simply cannot use CompiledQueries with parametrized Includes. Use EntitySQL instead. This doesn't mean that there aren't uses for CompiledQueries. It is great for localized queries that will always be called in the same context. Ideally CompiledQuery should always be used because the syntax is checked at compile time, but due to limitation, that's not possible. An example of use would be: you may want to have a page that queries which two dogs have the same favorite food, which is a bit narrow for a BusinessLayer function, so you put it in your page and know exactly what type of includes are required. Passing more than 3 parameters to a CompiledQuery Func is limited to 5 parameters, of which the last one is the return type and the first one is your Entities object from the model. So that leaves you with 3 parameters. A pitance, but it can be improved on very easily. public struct MyParams { public string param1; public int param2; public DateTime param3; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where dog.Age == myParams.param2 && dog.Name == myParams.param1 and dog.BirthDate > myParams.param3 select dog); public List<Dog> GetSomeDogs( int age, string Name, DateTime birthDate ) { MyParams myParams = new MyParams(); myParams.param1 = name; myParams.param2 = age; myParams.param3 = birthDate; return query_GetDog(YourContext,myParams).ToList(); } Return Types (this does not apply to EntitySQL queries as they aren't compiled at the same time during execution as the CompiledQuery method) Working with Linq, you usually don't force the execution of the query until the very last moment, in case some other functions downstream wants to change the query in some way: static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public IEnumerable<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name); } public void DataBindStuff() { IEnumerable<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } What is going to happen here? By still playing with the original ObjectQuery (that is the actual return type of the Linq statement, which implements IEnumerable), it will invalidate the compiled query and be force to re-parse. So, the rule of thumb is to return a List< of objects instead. static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public List<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name).ToList(); //<== change here } public void DataBindStuff() { List<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } When you call ToList(), the query gets executed as per the compiled query and then, later, the OrderBy is executed against the objects in memory. It may be a little bit slower, but I'm not even sure. One sure thing is that you have no worries about mis-handling the ObjectQuery and invalidating the compiled query plan. Once again, that is not a blanket statement. ToList() is a defensive programming trick, but if you have a valid reason not to use ToList(), go ahead. There are many cases in which you would want to refine the query before executing it. Performance What is the performance impact of compiling a query? It can actually be fairly large. A rule of thumb is that compiling and caching the query for reuse takes at least double the time of simply executing it without caching. For complex queries (read inherirante), I have seen upwards to 10 seconds. So, the first time a pre-compiled query gets called, you get a performance hit. After that first hit, performance is noticeably better than the same non-pre-compiled query. Practically the same as Linq2Sql When you load a page with pre-compiled queries the first time you will get a hit. It will load in maybe 5-15 seconds (obviously more than one pre-compiled queries will end up being called), while subsequent loads will take less than 300ms. Dramatic difference, and it is up to you to decide if it is ok for your first user to take a hit or you want a script to call your pages to force a compilation of the queries. Can this query be cached? { Dog dog = from dog in YourContext.DogSet where dog.ID == id select dog; } No, ad-hoc Linq queries are not cached and you will incur the cost of generating the tree every single time you call it. Parametrized Queries Most search capabilities involve heavily parametrized queries. There are even libraries available that will let you build a parametrized query out of lamba expressions. The problem is that you cannot use pre-compiled queries with those. One way around that is to map out all the possible criteria in the query and flag which one you want to use: public struct MyParams { public string name; public bool checkName; public int age; public bool checkAge; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where (myParams.checkAge == true && dog.Age == myParams.age) && (myParams.checkName == true && dog.Name == myParams.name ) select dog); protected List<Dog> GetSomeDogs() { MyParams myParams = new MyParams(); myParams.name = "Bud"; myParams.checkName = true; myParams.age = 0; myParams.checkAge = false; return query_GetDog(YourContext,myParams).ToList(); } The advantage here is that you get all the benifits of a pre-compiled quert. The disadvantages are that you most likely will end up with a where clause that is pretty difficult to maintain, that you will incur a bigger penalty for pre-compiling the query and that each query you run is not as efficient as it could be (particularly with joins thrown in). Another way is to build an EntitySQL query piece by piece, like we all did with SQL. protected List<Dod> GetSomeDogs( string name, int age) { string query = "select value dog from Entities.DogSet where 1 = 1 "; if( !String.IsNullOrEmpty(name) ) query = query + " and dog.Name == @Name "; if( age > 0 ) query = query + " and dog.Age == @Age "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); if( !String.IsNullOrEmpty(name) ) oQuery.Parameters.Add( new ObjectParameter( "Name", name ) ); if( age > 0 ) oQuery.Parameters.Add( new ObjectParameter( "Age", age ) ); return oQuery.ToList(); } Here the problems are: - there is no syntax checking during compilation - each different combination of parameters generate a different query which will need to be pre-compiled when it is first run. In this case, there are only 4 different possible queries (no params, age-only, name-only and both params), but you can see that there can be way more with a normal world search. - Noone likes to concatenate strings! Another option is to query a large subset of the data and then narrow it down in memory. This is particularly useful if you are working with a definite subset of the data, like all the dogs in a city. You know there are a lot but you also know there aren't that many... so your CityDog search page can load all the dogs for the city in memory, which is a single pre-compiled query and then refine the results protected List<Dod> GetSomeDogs( string name, int age, string city) { string query = "select value dog from Entities.DogSet where dog.Owner.Address.City == @City "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); oQuery.Parameters.Add( new ObjectParameter( "City", city ) ); List<Dog> dogs = oQuery.ToList(); if( !String.IsNullOrEmpty(name) ) dogs = dogs.Where( it => it.Name == name ); if( age > 0 ) dogs = dogs.Where( it => it.Age == age ); return dogs; } It is particularly useful when you start displaying all the data then allow for filtering. Problems: - Could lead to serious data transfer if you are not careful about your subset. - You can only filter on the data that you returned. It means that if you don't return the Dog.Owner association, you will not be able to filter on the Dog.Owner.Name So what is the best solution? There isn't any. You need to pick the solution that works best for you and your problem: - Use lambda-based query building when you don't care about pre-compiling your queries. - Use fully-defined pre-compiled Linq query when your object structure is not too complex. - Use EntitySQL/string concatenation when the structure could be complex and when the possible number of different resulting queries are small (which means fewer pre-compilation hits). - Use in-memory filtering when you are working with a smallish subset of the data or when you had to fetch all of the data on the data at first anyway (if the performance is fine with all the data, then filtering in memory will not cause any time to be spent in the db). Singleton access The best way to deal with your context and entities accross all your pages is to use the singleton pattern: public sealed class YourContext { private const string instanceKey = "On3GoModelKey"; YourContext(){} public static YourEntities Instance { get { HttpContext context = HttpContext.Current; if( context == null ) return Nested.instance; if (context.Items[instanceKey] == null) { On3GoEntities entity = new On3GoEntities(); context.Items[instanceKey] = entity; } return (YourEntities)context.Items[instanceKey]; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly YourEntities instance = new YourEntities(); } } NoTracking, is it worth it? When executing a query, you can tell the framework to track the objects it will return or not. What does it mean? With tracking enabled (the default option), the framework will track what is going on with the object (has it been modified? Created? Deleted?) and will also link objects together, when further queries are made from the database, which is what is of interest here. For example, lets assume that Dog with ID == 2 has an owner which ID == 10. Dog dog = (from dog in YourContext.DogSet where dog.ID == 2 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Person owner = (from o in YourContext.PersonSet where o.ID == 10 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == true; If we were to do the same with no tracking, the result would be different. ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog = oDogQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>) (from o in YourContext.PersonSet where o.ID == 10 select o); oPersonQuery.MergeOption = MergeOption.NoTracking; Owner owner = oPersonQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Tracking is very useful and in a perfect world without performance issue, it would always be on. But in this world, there is a price for it, in terms of performance. So, should you use NoTracking to speed things up? It depends on what you are planning to use the data for. Is there any chance that the data your query with NoTracking can be used to make update/insert/delete in the database? If so, don't use NoTracking because associations are not tracked and will causes exceptions to be thrown. In a page where there are absolutly no updates to the database, you can use NoTracking. Mixing tracking and NoTracking is possible, but it requires you to be extra careful with updates/inserts/deletes. The problem is that if you mix then you risk having the framework trying to Attach() a NoTracking object to the context where another copy of the same object exist with tracking on. Basicly, what I am saying is that Dog dog1 = (from dog in YourContext.DogSet where dog.ID == 2).FirstOrDefault(); ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog2 = oDogQuery.FirstOrDefault(); dog1 and dog2 are 2 different objects, one tracked and one not. Using the detached object in an update/insert will force an Attach() that will say "Wait a minute, I do already have an object here with the same database key. Fail". And when you Attach() one object, all of its hierarchy gets attached as well, causing problems everywhere. Be extra careful. How much faster is it with NoTracking It depends on the queries. Some are much more succeptible to tracking than other. I don't have a fast an easy rule for it, but it helps. So I should use NoTracking everywhere then? Not exactly. There are some advantages to tracking object. The first one is that the object is cached, so subsequent call for that object will not hit the database. That cache is only valid for the lifetime of the YourEntities object, which, if you use the singleton code above, is the same as the page lifetime. One page request == one YourEntity object. So for multiple calls for the same object, it will load only once per page request. (Other caching mechanism could extend that). What happens when you are using NoTracking and try to load the same object multiple times? The database will be queried each time, so there is an impact there. How often do/should you call for the same object during a single page request? As little as possible of course, but it does happens. Also remember the piece above about having the associations connected automatically for your? You don't have that with NoTracking, so if you load your data in multiple batches, you will not have a link to between them: ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>)(from dog in YourContext.DogSet select dog); oDogQuery.MergeOption = MergeOption.NoTracking; List<Dog> dogs = oDogQuery.ToList(); ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>)(from o in YourContext.PersonSet select o); oPersonQuery.MergeOption = MergeOption.NoTracking; List<Person> owners = oPersonQuery.ToList(); In this case, no dog will have its .Owner property set. Some things to keep in mind when you are trying to optimize the performance. No lazy loading, what am I to do? This can be seen as a blessing in disguise. Of course it is annoying to load everything manually. However, it decreases the number of calls to the db and forces you to think about when you should load data. The more you can load in one database call the better. That was always true, but it is enforced now with this 'feature' of EF. Of course, you can call if( !ObjectReference.IsLoaded ) ObjectReference.Load(); if you want to, but a better practice is to force the framework to load the objects you know you will need in one shot. This is where the discussion about parametrized Includes begins to make sense. Lets say you have you Dog object public class Dog { public Dog Get(int id) { return YourContext.DogSet.FirstOrDefault(it => it.ID == id ); } } This is the type of function you work with all the time. It gets called from all over the place and once you have that Dog object, you will do very different things to it in different functions. First, it should be pre-compiled, because you will call that very often. Second, each different pages will want to have access to a different subset of the Dog data. Some will want the Owner, some the FavoriteToy, etc. Of course, you could call Load() for each reference you need anytime you need one. But that will generate a call to the database each time. Bad idea. So instead, each page will ask for the data it wants to see when it first request for the Dog object: static public Dog Get(int id) { return GetDog(entity,"");} static public Dog Get(int id, string includePath) { string query = "select value o " + " from YourEntities.DogSet as o " +

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• Windows 7 intermittently drops wired internet/lan connection.

  - by CraigTP

  In a nutshell, my Windows 7 Ultimate PC intermittently drops it's internet connection. Why? Background: My PC is wired to my ADSL modem/router which is directly connected to the phone line. I also have wireless connectivity turned on within the router for a laptop to connect wirelessly. Every few hours or so, when using my PC, I find I cannot access the internet and pages will not load. Eventually, Windows7 will update the network icon in the task-tray to show the exclamation mark symbol on the network icon. Opening up the Network And Sharing Centre will show the red cross between the "Multiple Networks" and "The Internet". Here's a picture of the "Network And Sharing Centre" (grabbed when everything was working!) As you can see, I'm running Sun's VirtualBox on this machine and that creates a Network connection for itself. This doesn't seem to affect the intermittent dropping (i.e. the intermittent drops occur whether the VirtualBox connection is in use or not). When the connection does drop, I cannot access any internet pages, nor can I access the router's web admin page at http://192.168.1.1/, so I'm assuming I've lost all local LAN access too. It's definitely not the router (or the internet connection itself) as my laptop, using the wireless connection (and running Vista Home Premium) continues to be able to access the internet (and the router's web admin pages) just fine. Every time this happens, I can immediately restore all internet and LAN access by opening Network Adapter page, disabling the "Local Area Connection" and then re-enabling it. Give it a few seconds and everything is fine again. I assume this is because, beneath the GUI, it's effectively doing an "ipconfig /release" then "ipconfig /renew". Why does this happen in the first place, though? I've googled for this and seen quite a few other people (even on MSDN/Technet forums) experiencing the same or almost the same problem, but with no clear resolution. Suggestions of turning off IPv6 on the LAN adapter, and ensuring there's no power management "sleeping" the network adapter have been tried but do not cure the problem. There does not seem to be any particular sequence of events that cause it to happen either. I've had it go twice in 20 minutes when just randomly browsing the web with no other traffic, and I've also had it go once then not go again for 2-3 hours with the same sort of usage. Can anyone tell me why this is happening and how to make it stop? EDIT: Additional information based upon the answer provided so far: Firstly, I forgot the mention that this is Windows 7 64 bit if that makes any difference at all. I mentioned that I don't think the VirtualBox network adpater is causing this problem in any way, and I also have VirtualBox installed on two other machines, one running Vista Home Premium and the other running XP. Neither of these machine experience the same network connectivity issues as the Windows 7 machine. The IP assignment for the Windows 7 machine is the same both before and after the "drop". I have a DHCP server on the router issuing IP Addresses, however my Windows 7 machine uses a static address. Here's the output from "ipconfig": Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.1.2(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.1.1 DNS Servers . . . . . . . . . . . : 192.168.1.1 NetBIOS over Tcpip. . . . . . . . : Enabled Within the system's event logs, the only event that relates to the connection dropping is a "DNS Client Event" and this is generated after the connection has dropped and is an event detailing that DNS information can't be found for whatever website I may be trying to access, just as the connection drops: Log Name: System Source: Microsoft-Windows-DNS-Client Event ID: 1014 Task Category: None Level: Warning Keywords: User: NETWORK SERVICE Description: Name resolution for the name weather.service.msn.com timed out after none of the configured DNS servers responded. The network adapter chipset is Realtek PCIe GBE Family Controller and I have confirmed that this is the correct chipset for the motherboard (Asus M4A77TD PRO), and in fact, Windows Update installed an updated driver for this on 12/Jan/2009. The details of the update say that it's a Realtek software update from December 2009. Incidentally, I was still having the same intermittent problems prior to this update. It seems to have made no difference at all. EDIT 2 (1 Feb 2010): In my quest to solve this problem, I have discovered some more interesting information. On another forum, someone suggested that I should try running Windows in "Safe Mode With Networking" and see if the problem continues to occur. This was a fantastic suggestion and I don't know why I didn't think of it sooner myself. So, I proceeded to run in Safe Mode with Networking for a number of hours, and amazingly, the "drops" didn't occur once. It was a positive discovery, however, due to the intermittent nature of the original problem, I wasn't completely convinced that the problem was cured. One thing I did note is that the fan on my GFX card was running alot louder than normal. This is due to the fact that I have an ASUS ENGTS250 graphics card (http://www.asus.com/product.aspx?P_ID=B6imcoax3MRY42f3) which had a known problem with a noisy fan until a BIOS update fixed the issue. (See the "Manufacturer Response" here: http://www.newegg.com/Product/Product.aspx?Item=N82E16814121334 for details). Well, running in safe mode had the fan running (incorrectly) at full speed (as it did before the BIOS update), but with an (apparently) stable network connection. Obviously some driver was not loaded for the GFX card when in Safe Mode so this got me thinking about the GFX card (since the very noisy fan was quite obvious when running in Safe Mode). I rebooted into normal mode, and found that Nvidia had a very up-to-date new driver for my GFX card (only about 1 week old), so I downloaded the appropriate driver and installed it. After installation and a reboot, I was able to use my PC for an entire day with NO NETWORK DROPS!!! This was on Saturday. However, on the Sunday, I also had my PC for pretty much the entire day and experienced 2 network drops. No other changes have been made to my PC in this time. So, the story seems to be that updating my graphics card drivers seems to have improved (if not completely fixed) the issue, however, I'm still searching for a proper fix for this problem. Hopefully, this information may help anyone who may have additional ideas as to why this problem is occuring in the first place. (And why does new GFX card drivers have anything to do with the network?) I appreciate everyone's feedback so far. However, I'll have to ask once more if anyone has any further ideas of how to fix this particular problem? Thanks in advance.

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• Cannot delete a SharePoint web application

  - by Vijay

  What I have? I have normal web application and it has 3 site collections with name, "PDirectory". Other than this I have only Central administration web application in the farm. What I want? I want to delete that web application, "PDirectory". What problem am I facing? I am not able to delete the web application. I get below error when I try to delete it but, the site collections got deleted! Error: An object in the SharePoint administrative framework, "SPWebApplication Name=XXX Parent=SPWebService", could not be deleted because other objects depend on it. Update all of these dependants to point to null or different objects and retry this operation. The dependant objects are as follows: SPFarm Name=SharePoint_Config SPFarm Name=SharePoint_Config at Microsoft.SharePoint.Administration.SPConfigurationDatabase.DeleteObject(Guid id) at Microsoft.SharePoint.Administration.SPConfigurationDatabase.DeleteObject(SPPersistedObject obj) at Microsoft.SharePoint.Administration.SPPersistedObject.Delete() at Microsoft.SharePoint.Administration.SPWebApplication.Delete() at Microsoft.SharePoint.ApplicationPages.DeleteWebApplicationPage.BtnSubmit_Click(Object sender, EventArgs e) at System.Web.UI.WebControls.Button.OnClick(EventArgs e) at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) Can somebody tell me how I can delete this web application? Thanks in advance!

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• unlinked libraries in a makefile?

  - by wyatt

  I'm trying to install a libspopc, but when I run the make I get the following output: cc -Wall -Wextra -pedantic -pipe -fPIC -Os -DUSE_SSL -c session.c cc -Wall -Wextra -pedantic -pipe -fPIC -Os -DUSE_SSL -c queries.c cc -Wall -Wextra -pedantic -pipe -fPIC -Os -DUSE_SSL -c parsing.c cc -Wall -Wextra -pedantic -pipe -fPIC -Os -DUSE_SSL -c format.c cc -Wall -Wextra -pedantic -pipe -fPIC -Os -DUSE_SSL -c objects.c cc -Wall -Wextra -pedantic -pipe -fPIC -Os -DUSE_SSL -c libspopc.c rm -f libspopc*.a ar r libspopc-0.9n.a session.o queries.o parsing.o format.o objects.o libspopc.o ar: creating libspopc-0.9n.a ranlib libspopc-0.9n.a ln -s libspopc-0.9n.a libspopc.a rm -f libspopc*.so cc -o libspopc-0.9n.so -shared session.o queries.o parsing.o format.o objects.o libspopc.o ln -s libspopc-0.9n.so libspopc.so cc -o poptest1 -Wall -Wextra -pedantic -pipe -fPIC -Os -DUSE_SSL examples/poptest1.c -L. -lspopc -lssl -lcrypto /usr/local/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_globallookup': dso_dlfcn.c:(.text+0x2d): undefined reference to `dlopen' dso_dlfcn.c:(.text+0x43): undefined reference to `dlsym' dso_dlfcn.c:(.text+0x4d): undefined reference to `dlclose' /usr/local/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_pathbyaddr': dso_dlfcn.c:(.text+0x8f): undefined reference to `dladdr' dso_dlfcn.c:(.text+0xe9): undefined reference to `dlerror' /usr/local/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_func': dso_dlfcn.c:(.text+0x491): undefined reference to `dlsym' dso_dlfcn.c:(.text+0x570): undefined reference to `dlerror' /usr/local/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_var': dso_dlfcn.c:(.text+0x5f1): undefined reference to `dlsym' dso_dlfcn.c:(.text+0x6d0): undefined reference to `dlerror' /usr/local/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_unload': dso_dlfcn.c:(.text+0x735): undefined reference to `dlclose' /usr/local/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_load': dso_dlfcn.c:(.text+0x817): undefined reference to `dlopen' dso_dlfcn.c:(.text+0x88e): undefined reference to `dlclose' dso_dlfcn.c:(.text+0x8d5): undefined reference to `dlerror' collect2: ld returned 1 exit status make: *** [poptest1] Error 1 A quick search suggested that this was due to libdl being unlinked, though this seems unlikely in a distributed library, particularly a seemingly relatively popular one. Could anything else be causing this? And if it is due to an unlinked library, how would I go about fixing it? Thanks

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• Files built with a makefile are disapearing (including the binary)

  - by Reid

  I am building a program on a TS-7800(SBC), and when I run make (show below), it appears to go through all of the steps normally, but in the end i do not get a binary file. Why is this, and how can I get my file. makefile CC= /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc # compiler options #CFLAGS= -O2 CFLAGS= -mcpu=arm9 #CFLAGS= -pg -Wall # linker LN= $(CC) # linker options LNFLAGS= #LNFLAGS= -pg # extra libraries used in linking (use -l command) LDLIBS= -lpthread # source files SOURCES= HMITelem.c Cpacket.c GPS.c ADC.c Wireless.c Receivers.c CSVReader.c RPM.c RS485.c # include files INCLUDES= Cpacket.h HMITelem.h CSVReader.h RS485.h # object files OBJECTS= HMITelem.o Cpacket.o GPS.o ADC.o Wireless.o Receivers.o CSVReader.o RPM.o RS485.o HMITelem: $(OBJECTS) $(LN) $(LNFLAGS) -o $@ $(OBJECTS) $(LDLIBS) .c.o: $*.c $(CC) $(CFLAGS) -c $*.c RUN : ./HMITelem #clean: # rm -f *.o # rm -f *~ Output root@ts7800:ReidTest# make /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -mcpu=arm9 -c HMITelem.c /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -mcpu=arm9 -c Cpacket.c /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -mcpu=arm9 -c GPS.c /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -mcpu=arm9 -c ADC.c /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -mcpu=arm9 -c Wireless.c /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -mcpu=arm9 -c Receivers.c /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -mcpu=arm9 -c CSVReader.c /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -mcpu=arm9 -c RPM.c /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -mcpu=arm9 -c RS485.c /home/eclipse/ReidTest/cc/cross-toolchains/arm-none-linux-gnueabi/bin/arm-none-linux-gnueabi-gcc -o HMITelem HMITelem.o Cpacket.o GPS.o ADC.o Wireless.o Receivers.o CSVReader.o RPM.o RS485.o -lpthread Thank you.

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• Git fails to push with error 'out of memory'

  - by jwir3

  I'm using gitosis on a server that has a low amount of memory, specifically around 512 MB. When I try to push a large folder (happens to be a backup from an android phone), I get: me@corellia:~/Configs/$ git push origin master Counting objects: 18, done. Delta compression using up to 8 threads. Compressing objects: 100% (14/14), done. fatal: Out of memory, malloc failed MiB | 685 KiB/s error: pack-objects died of signal 13 error: failed to push some refs to 'git@dagobah:Configs' I've been searching the web, and notably found: http://www.mail-archive.com/[email protected]/msg01747.html as well as http://git.661346.n2.nabble.com/Out-of-memory-error-during-git-push-td5443705.html but these don't seem to help me for two reasons: 1) I am not actually out of memory when I push. When I run 'top' during the push, I get: 24262 git 18 0 16204 6084 1096 S 2 1.2 0:00.12 git-unpack-obje Also, during the push if I run /head/meminfo, I get: MemTotal: 524288 kB MemFree: 289408 kB Buffers: 0 kB Cached: 0 kB SwapCached: 0 kB Active: 0 kB Inactive: 0 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 524288 kB So, it seems that I have enough memory free, but it's actually still failing, and I'm not enough of a git guru to figure out what is happening. I would appreciate it if someone could give me a hand here and tell me what could be causing this problem, and what I can do to solve it. Thanks! EDIT: The output of running the ulimit -a command: scottj@dagobah:~$ ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 204800 max locked memory (kbytes, -l) 32 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 10240 cpu time (seconds, -t) unlimited max user processes (-u) 204800 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited

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