Search Results

Search found 361 results on 15 pages for 'inter'.

Page 12/15 | < Previous Page | 8 9 10 11 12 13 14 15  | Next Page >

• New to Linux Kernel/Driver development...

  - by CVS-2600Hertz-wordpress-com

  Recently, i began developing a driver of an embedded device running linux. Until now i have only read about linux internals. Having no prior experience in driver devlopment, i am finding it a tad difficult to land my first step. I have downloaded the kernel source-code (v2.6.32). I have read (skimped) Linux Device Drivers (3e) I read a few related posts here on StackOverflow. I understand that linux has a "monolithic" approach. I have built kernel (included existing driver in menuconfig etc.) I know the basics of kconfig and makefile files so that should not be a problem. Can someone describe the structure (i.e. the inter-links) of the various folders in the kernel-source code. In other words given a source-code file, which other files would it refer to for related code (The "#include"-s provide a partial idea) Could someone please help me in getting a better idea? Any help will be greatly appreciated Thank You.

  Read the article

• Does anyone knows any Train-table-api service?

  - by DaNieL

  Hi guys, im wondering if there is any online service who provide API about the train timetables (arrivals, departure, etch..), at least for the european stations. I know www.bahn.de, who provide the accurated timetables for many european countries, but i didin't find any similar to a api service. My goal (well, just a future-project) is to develope an application like gmaps, but instead of giving the car-trip i would like to give the train-trip.. you know, the user set the departure day, time and station, then the first arrival, maybe then add another one, and so on. So, there is something like, that can be queryed by php/python/javascript? Edit: if can help, im wondering to build a service to plan an inter-rail trip! (and any help will be really appreciate) Im stuck. Google's public-service api rely on the information that every local company makes avaiable, much branches are missing (for example, is almost impossible to use it to build an itinerary that touches two or more regions of Europe. As i said before, the only service that i know doing it good is the bahn.de, they really have all the data.. but no api. I tryed to parse theyre result page (in order to use them as API), but seem like the markup is been build exactly to avoid that.. maybe they have business plans behind that or whatever, but i dont think they will ever release some API.. so, my project is going on without this function (p.s: my project is about non-profit cultural organizations, we wont make war to anyone ;P) @El Goorf: if you find a way, and consider the idea of sharing it, count on my hand if need help!

  Read the article

• Format for storing contacts in a database

  - by Gart

  I'm thinking of the best way to store personal contacts in a database for a business application. The traditional and straightforward approach would be to create a table with columns for each element, i.e. Name, Telephone Number, Job title, Address, etc... However, there are known industry standards for this kind of data, like for example vCard, or hCard, or vCard-RDF/XML or even Windows Contacts XML Schema. Utilizing an standard format would offer some benefits, like inter-operablilty with other systems. But how can I decide which method to use? The requirements are mainly to store the data. Search and ordering queries are highly unlikely but possible. The volume of the data is 100,000 records at maximum. My database engine supports native XML columns. I have been thinking to use some XML-based format to store the personal contacts. Then it will be possible to utilize XML indexes on this data, if searching and ordering is needed. Is this a good approach? Which contacts format and schema would you recommend for this?

  Read the article

• Bulletin board - Database optimisation

  - by andrew

  This question is a follow on from this Question The project and problem The project I am currently working on is a bulletin board for a large non-profit organisation. The bulletin board will be used to allow inter-office communication within the organisation. I am building the application and have been having trouble extracting the results that I need from my database because I don't think it is properly normalized and because of limitations in my knowledge of relational database theory and mysql. I would appreciate input into the design of the board in general and in particular, ways that the database structure can be improved to facilitate efficient queries and help me develop this application and future application faster Business Logic The bulletin board will be used in the following way Posting bulletins and responses to bulletins Employees or 'users' in offices around the country will be able to post messages to the bulletin board.Bulletins must be posted to a location and categorised- i'll call these "bulletins". Users will be able to post any number of replies to any one bulletin and users will be able to reply to their own bulletin - i'll call these 'replies'. Rating bulletins and replies Users will be able to either 'like' or 'dislike' a bulletin or a reply and the total number of likes or dislikes will be shown for each bulletin or reply. Viewing the bulletin board and responses Bulletins can be displayed chronologically. Users can sort bulletins chronologically or chronologically by the latest reply to that bulletin(let me know if you need more explanation) When a particular bulletin is selected, replies to that bulletin will be displayed chronologically @PerformanceDBA - edited 10:34 est 28/12/10I have begun implementing the data model. I assume that the 6th data model is the physical model because it contains the associative tables. I am going to post any questions that I have below. I will put up a database dump once I am done. I will then put up a list of all the queries that I need to run on the database and begin writing them. I hope you had a good Christmas. I'm in Canada and there's snow! Implementation of Physical model

  Read the article

• What does it mean for an OS to "execute within user processes"? Do any modern OS's use that approach

  - by Chris Cooper

  I have recently become interested in operating system, and a friend of mine lent me a book called Operating Systems: Internals and Design Principles (I have the third edition), published in 1998. It's been a very interesting book so far, but I have come to the part dealing with process control, and it's using UNIX System V as one of its examples of an operating system that executes within user processes. This concept has struck me as a little strange. First of all, does this mean that OS instructions and data are stored in each user of the processes? Probably not, because that would be an absurdly redundant scheme. But if not, then what does it mean to "execute within" a user process? Do any modern operating systems use this approach? It seems much more logical to have the operating system execute as its own process, or even independently of all processes, if you're short on memory. All the inter-accessiblilty of process data required for this layout seems to greatly complicate things. (But maybe that's just because I don't quite get the concept ;D) Here is what the book says: "Execution within User Processes: An alternative that is common with operation systems on smaller machines is to execute virtually all operating system software in the context of a user process. ... "

  Read the article

• C# Minimize all running windows when application runs

  - by Derek

  I am working on a C# windows form application. How can i edit my code in a way that when more than 2 faces is being detected by my webcam. More information: When "FaceDetectedLabel.Text = "Faces Detected : " + cam.facesdetected.ToString();" becomes Face Detected: 2 or more... How can i do the following: Minimize all program running except my application. Log out of my computer Here is my code: namespace PBD { public partial class MainPage : Form { //declaring global variables private Capture capture; //takes images from camera as image frames public MainPage() { InitializeComponent(); } private void ProcessFrame(object sender, EventArgs arg) { Wrapper cam = new Wrapper(); //show the image in the EmguCV ImageBox WebcamPictureBox.Image = cam.start_cam(capture).Resize(390, 243, Emgu.CV.CvEnum.INTER.CV_INTER_CUBIC).ToBitmap(); FaceDetectedLabel.Text = "Faces Detected : " + cam.facesdetected.ToString(); } private void MainPage_Load(object sender, EventArgs e) { #region if capture is not created, create it now if (capture == null) { try { capture = new Capture(); } catch (NullReferenceException excpt) { MessageBox.Show(excpt.Message); } } #endregion Application.Idle += ProcessFrame; }

  Read the article

• Seeking suggestions on redesigning the interface

  - by ratkok

  As a part of maintaining large piece of legacy code, we need to change part of the design mainly to make it more testable (unit testing). One of the issues we need to resolve is the existing interface between components. The interface between two components is a class that contains static methods only. Simplified example: class ABInterface { static methodA(); static methodB(); ... static methodZ(); }; The interface is used by component A so that different methods can use ABInterface::methodA() in order to prepare some input data and then invoke appropriate functions within component B. Now we are trying to redesign this interface for various reasons: Extending our unit test coverage - we need to resolve this dependency between the components and stubs/mocks are to be introduced The interface between these components diverged from the original design (ie. a lots of newer functions, used for the inter-component i/f are created outside this interface class). The code is old, changed a lot over the time and needs to be refactored. The change should not be disruptive for the rest of the system. We try to limit leaving many test-required artifacts in the production code. Performance is very important and should be no (or very minimal) degradation after the redesign. Code is OO in C++. I am looking for some ideas what approach to take. Any suggestions on how to do this efficiently?

  Read the article

• using spring, hibernate and scala, is there a better way to load test data than dbunit?

  - by egervari

  Here are some things I really dislike about dbunit: 1) You cannot specify the exact ordering the inserts because dbunit likes to group your inserts by table name, and not by the order you define them in the XML file. This is a problem when you have records depending on other records in other tables, so you have to disable foreign key constraints during your tests... which actually sucks because these foreign key constraints will get fired in production while your tests won't be aware of them! 2) They seem hellbent on forcing you to use an xml namespace to define your xml... and I honestly can't be bothered to do this. I like the data.xml without any namespace. It works. But they are so hellbent on deprecating it. 3) Creating different xml files is hard on a per test basis, so it actually encourages creating data for your entire app. Unfortunately, this process is a little bloated too once the data grows in size and things get inter tangled. There has got to be a better way to split up your test data into chunks without having to copy/paste a lot of the test data across all of your tests. 4) Keeping track of id references in a big xml file is just impossible. If you have 130 domain classes, it just gets bewildering. This model simply does not scale. Is there something less bloated and better in the Spring/Hibernate space? db unit has worn out its welcome and I'm really looking for something better.

  Read the article

• Problem finding the difference in days between two dates

  - by James

  I have been using a tidy little routine that I found here to calculate the difference in days between two dates in AS3. I am getting some strange results and I am wondering if any of you inter-codal-mega-lords can shed some light? Why is Q1 of 2010 coming up one day short, when in all other cases the routine is performing fine? Many thanks in advance to anyone who can help! function countDays( startDate:Date, endDate:Date ):int { var oneDay:int = 24*60*60*1000; // hours*minutes*seconds*milliseconds var diffDays:int = Math.abs((startDate.getTime() - endDate.getTime())/(oneDay)); return diffDays; } countDays( new Date( 2010, 00, 01 ), new Date( 2011, 00, 01 ) ); // returns 365, which is correct countDays( new Date( 2010, 00, 01 ), new Date( 2010, 03, 01 ) ); // returns 89, which is 1 day short countDays( new Date( 2010, 03, 01 ), new Date( 2010, 06, 01 ) ); // returns 91, which is correct countDays( new Date( 2010, 06, 01 ), new Date( 2010, 09, 01 ) ); // returns 92, which is correct countDays( new Date( 2010, 09, 01 ), new Date( 2011, 00, 01 ) ); // returns 92, which is correct

  Read the article

• Proper API Design for Version Independence?

  - by Justavian

  I've inherited an enormous .NET solution of about 200 projects. There are now some developers who wish to start adding their own components into our application, which will require that we begin exposing functionality via an API. The major problem with that, of course, is that the solution we've got on our hands contains such a spider web of dependencies that we have to be careful to avoid sabotaging the API every time there's a minor change somewhere in the app. We'd also like to be able to incrementally expose new functionality without destroying any previous third party apps. I have a way to solve this problem, but i'm not sure it's the ideal way - i was looking for other ideas. My plan would be to essentially have three dlls. APIServer_1_0.dll - this would be the dll with all of the dependencies. APIClient_1_0.dll - this would be the dll our developers would actual refer to. No references to any of the mess in our solution. APISupport_1_0.dll - this would contain the interfaces which would allow the client piece to dynamically load the "server" component and perform whatever functions are required. Both of the above dlls would depend upon this. It would be the only dll that the "client" piece refers to. I initially arrived at this design, because the way in which we do inter process communication between windows services is sort of similar (except that the client talks to the server via named pipes, rather than dynamically loading dlls). While i'm fairly certain i can make this work, i'm curious to know if there are better ways to accomplish the same task.

  Read the article

• How to allow all except part 1 and part 2 ?

  - by Stackfan

  This allows me to get easyly dynamic input variables instead of putting a static prefix like /en/etcetcetc, but the problem is all controllers are blocked. Everything goes to index/index. Question: How can i tell this rule allow evertying as it is now, but do not track if it contains http://site.com/donotcatch/me and http://site.com/iamnotbelongstodynamic1/blabla protected function _initRoutes() { ... $dynamic1 = new Zend_Controller_Router_Route( '/:variable0/:variable1', array( 'controller' => 'index', 'action' => 'index'), array( 'variable0' => '^[a-zA-Z0-9_]*$', 'variable1' => '^[a-zA-Z0-9_]*$', ) ); Follow up: Normally, i always belive yes we can, so, we can do that like this where dynamic1 does not the inter-fare with my other static controllers: // http://site/yeswecan/blabla // variable0 = yeswecan // variable1 = blabla $dynamic1 = new Zend_Controller_Router_Route( '/:variable0/:variable1', array( 'controller' => 'index', 'action' => 'index'), array( 'variable0' => '^[a-zA-Z]*$', 'variable1' => '^[a-z0-9_]*$', ) ); // http://site/ajax/whatever... // solves it $dynamic2 = new Zend_Controller_Router_Route( '/ajax/:variable0', array( 'controller' => 'ajax', 'action' => '' ), array( 'variable0' => '^[a-zA-Z0-9_]*$', ) ); // http://site/order/whatever... // solves it $dynamic3 = new Zend_Controller_Router_Route( '/order/:variable0', array( 'controller' => 'order', 'action' => ''), array( 'variable0' => '^[a-zA-Z0-9_]*$', ) ); Note: Still the controllers are getting failed for example http://site/ajax/whatever always goes to /ajax/index where i wanted to send it as /ajax/user-inserted-value How can i fix the $dynamic2 and $dynamic3 by keeping $dynamic1 ??

  Read the article

• Mocking non-virtual methods in C++ without editing production code?

  - by wk1989

  Hello, I am a fairly new software developer currently working adding unit tests to an existing C++ project that started years ago. Due to a non-technical reason, I'm not allowed to modify any existing code. The base class of all my modules has a bunch of methods for Setting/Getting data and communicating with other modules. Since I just want to unit testing each individual module, I want to be able to use canned values for all my inter-module communication methods. I.e. for a method Ping() which checks if another module is active, I want to have it return true or false based on what kind of test I'm doing. I've been looking into Google Test and Google Mock, and it does support mocking non-virtual methods. However the approach described (http://code.google.com/p/googlemock/wiki/CookBook#Mocking_Nonvirtual_Methods) requires me to "templatize" the original methods to take in either real or mock objects. I can't go and templatize my methods in the base class due to the requirement mentioned earlier, so I need some other way of mocking these virtual methods Basically, the methods I want to mock are in some base class, the modules I want to unit test and create mocks of are derived classes of that base class. There are intermediate modules in between my base Module class and the modules that I want to test. I would appreciate any advise! Thanks, JW EDIT: A more concrete examples My base class is lets say rootModule, the module I want to test is leafModule. There is an intermediate module which inherits from rootModule, leafModule inherits from this intermediate module. In my leafModule, I want to test the doStuff() method, which calls the non virtual GetStatus(moduleName) defined in the rootModule class. I need to somehow make GetStatus() to return a chosen canned value. Mocking is new to me, so is using mock objects even the right approach?

  Read the article

• What do you call a generalized (non-GUI-related) "Model-View-Controller" architecture?

  - by dcuccia

  I am currently refactoring code that coordinates multiple hardware components for data acquisition, and feeling a bit like I'm recreating the wheel. In particular, an MVC-like pattern seems to be emerging. Except, this has nothing to do with a GUI and I'm worried that I'm forcing this particular pattern where another might be more appropriate. Here's my scenario: Individual hardware "component" classes obey interface contracts for each hardware type. Previously, component instances were orchestrated by a single monolithic InstrumentController class, which relied heavily on configuration + branching logic for executing a specific acquisition sequence. After an iteration, I have a separate controller for each component, with these controllers all managed by a small InstrumentControllerBase (or its derivatives). The composite system will receive "input" either programmatically or via inter-hardware component triggering - in either case these interactions are routed to, and handled by, the appropriate controller. So, I have something that feels MVC-esque, but I don't know if that's because I'm forcing the point. With little direct MVC experience in application development, it's hard to know if I'm just trying to make my scenario fit MVC, where another pattern might be a good alternative or complimentary. My problem is, search results and wiki documentation of these family of patterns seems to immediately drop me into GUI-specific discussions. I understand "M means Model data and the V means View" - but do you call the superset pattern? Component-Commander-Controller? Whence can I exhume examples exemplary?

  Read the article

• Python: need to get energies of charge pairs.

  - by Two786

  I am new to python. I have to make a program for a project that takes a PDB format file as input and returns a list of all the intra-chain and inter-chain charge pairs and their energies (using coulomb’s law assuming a dielectric constant of (?) of 40.0). For simplicity, the charged residues for this program are just Arg (CZ), Lys (NZ), Asp (CG) and Glu (CD) with the charge bearing atoms for each indicated in parentheses. The program should report any attractive or repulsive interactions within 8.0 Å. Here is some additional information needed for the program. Eij = energy of interaction between atoms i and j in kilocalories/mole (kcals/mol) qi = charge for atom i (+1 for Lys or Arg, -1 for Glu or Asp) rij = distance between atoms i and j in angstroms using the distance formula The output should adhere to the following format: First residue : Second residue Distance Energy Lys 10 Chain A: ASP 46 Chain A D= 4.76 ang E= -2.32 kcals/mol (For some reason I can't organize the top two rows, but the first row should be lables and below it the corresponding values.) I really have no idea how to tackle this problem, any and all help is greatly appreciated. I hope this is the right place to ask. Thank you in advance. Using python 2.5

  Read the article

• Web services or shared database for (game) server communication?

  - by jaaronfarr

  We have 2 server clusters: the first is made up of typical web applications backed by SQL databases. The second are highly optimized multiplayer game servers which keep all data in memory. Both clusters communicate with clients via HTTP (Ajax with JSON). There are a few cases in which we need to share data between the two server types, for example, reporting back and storing the results of a game (should ultimately end up in the database). We're considering several approaches for inter-server communication: Just share the MySQL databases between clusters (introduce SQL to the game servers) Sharing data in a distributed key-value store like Memcache, Redis, etc. Use an RPC technology like Google ProtoBufs or Apache Thrift Using RESTful web services (the game server would POST back to the web servers, for example) At the moment, we're leaning towards web services or just sharing the database. Sharing the database seems easy, but we're concerned this adds extra memory and a new dependency into the game servers. Web services provide good separation of concerns and fit with the existing Ajax we use, but add complexity, overhead and many more ways for communication to fail. Are there any other good reasons not to use one or the other approach? Which would be easier to scale?

  Read the article

• TPROXY Not working with HAProxy, Ubuntu 14.04

  - by Nyxynyx

  I'm trying to use HAProxy as a fully transparent proxy using TPROXY in Ubuntu 14.04. HAProxy will be setup on the first server with eth1 111.111.250.250 and eth0 10.111.128.134. The single balanced server has eth1 and eth0 as well. eth1 is the public facing network interface while eth0 is for the private network which both servers are in. Problem: I'm able to connect to the balanced server's port 1234 directly (via eth1) but am not able to reach the balanced server via Haproxy port 1234 (which redirects to 1234 via eth0). Am I missing out something in this configuration? On the HAProxy server The current kernel is: Linux extremehash-lb2 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10 19:11:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux The kernel appears to have TPROXY support: # grep TPROXY /boot/config-3.13.0-24-generic CONFIG_NETFILTER_XT_TARGET_TPROXY=m HAProxy was compiled with TPROXY support: haproxy -vv HA-Proxy version 1.5.3 2014/07/25 Copyright 2000-2014 Willy Tarreau <[email protected]> Build options : TARGET = linux26 CPU = x86_64 CC = gcc CFLAGS = -g -fno-strict-aliasing OPTIONS = USE_LINUX_TPROXY=1 USE_LIBCRYPT=1 USE_STATIC_PCRE=1 Default settings : maxconn = 2000, bufsize = 16384, maxrewrite = 8192, maxpollevents = 200 Encrypted password support via crypt(3): yes Built without zlib support (USE_ZLIB not set) Compression algorithms supported : identity Built without OpenSSL support (USE_OPENSSL not set) Built with PCRE version : 8.31 2012-07-06 PCRE library supports JIT : no (USE_PCRE_JIT not set) Built with transparent proxy support using: IP_TRANSPARENT IPV6_TRANSPARENT IP_FREEBIND Available polling systems : epoll : pref=300, test result OK poll : pref=200, test result OK select : pref=150, test result OK Total: 3 (3 usable), will use epoll. In /etc/haproxy/haproxy.cfg, I've configured a port to have the following options: listen test1235 :1234 mode tcp option tcplog balance leastconn source 0.0.0.0 usesrc clientip server balanced1 10.111.163.76:1234 check inter 5s rise 2 fall 4 weight 4 On the balanced server In /etc/networking/interfaces I've set the gateway for eth0 to be the HAProxy box 10.111.128.134 and restarted networking. auto eth0 eth1 iface eth0 inet static address 111.111.250.250 netmask 255.255.224.0 gateway 111.131.224.1 dns-nameservers 8.8.4.4 8.8.8.8 209.244.0.3 iface eth1 inet static address 10.111.163.76 netmask 255.255.0.0 gateway 10.111.128.134 ip route gives: default via 111.111.224.1 dev eth0 10.111.0.0/16 dev eth1 proto kernel scope link src 10.111.163.76 111.111.224.0/19 dev eth0 proto kernel scope link src 111.111.250.250

  Read the article

• networking tunnel adapter connections?

  - by Karthik Balaguru

  I understand that Tunnel Adapter LAN is for encapsulating IPv6 packets with an IPv4 header so that they can be sent across an IPv4 network. Few queries popped up in my mind based on this :- If i do 'ipconfig', Apart from ethernet adapter LAN details, I get a series of statments as below - Tunnel adapter Local Area Connection* 6 Tunnel adapter Local Area Connection* 7 Tunnel adapter Local Area Connection* 12 Tunnel adapter Local Area Connection* 13 Tunnel adapter Local Area Connection* 14 Tunnel adapter Local Area Connection* 15 Tunnel adapter Local Area Connection* 16 Except for the *16, all the other Tunnel Adapter Local Area Connections show Media Disconnected. Why is the numbering for the Tunnel adapter LAN not sequential? It is like 6, 7, 12, 13, 14, 15, 16. A strange numbering scheme! I tried to figure it out by thinking of some arithmetic series. But, it does not seem to fit in. There is a huge gap between 7 and 12. Any ideas? What is the need for so many Tunnel Adapter LAN connections? Can you tell me a scenario that requires all of those ? I did ipconfig /all to get more information. From the listing, I understand that: 16, 15, 14, 12 are Microsoft 6to4 Adapters 13, 6 are isatap Adapters 7 is Teredo Tunneling Pseudo-interface I understand that the above are for automatic tunneling so that the tunnel endpoints are determined automatically by the routing infrastructure. 6to4 is recommended by RFC3056 for automatic tunneling that uses protocol 41 for encapsulation. It is typically used when an end-user wants to connect to the IPv6 Internet using their existing IPv4 connection. Teredo is an automatic tunneling technique that uses UDP encapsulation across multiple NATs. That is, It is to grant IPv6 connectivity to nodes that are located behind IPv6-unaware NAT devices ISATAP treats the IPv4 network as a virtual IPv6 local link, with mappings from each IPv4 address to a link-local IPv6 address. That is to transmit IPv6 packets between dual-stack nodes on top of an IPv4 network. That is, to put in simple words, ISATAP is an intra-site mechanism, while the 6to4 and Teredo are for inter-site tunnelling mechanisms. It seems that Teredo should alone enabled by default in Vista, But my system does not show it to be enabled by default. Interestingly, it shows a 6to4 tunnel adapter (Tunnel adapter LAN connection 16) to be enabled by default? Any specific reasons for it? If i do ipconfig /all, why is only one Teredo present while four 6to4 are present ? I searched the internet for answers to the above queries, but I am unable to find clear answers.

  Read the article

• networking tunnel adapter connections?

  - by Karthik Balaguru

  I understand that Tunnel Adapter LAN is for encapsulating IPv6 packets with an IPv4 header so that they can be sent across an IPv4 network. Few queries popped up in my mind based on this :- If i do 'ipconfig', Apart from ethernet adapter LAN details, I get a series of statments as below - Tunnel adapter Local Area Connection* 6 Tunnel adapter Local Area Connection* 7 Tunnel adapter Local Area Connection* 12 Tunnel adapter Local Area Connection* 13 Tunnel adapter Local Area Connection* 14 Tunnel adapter Local Area Connection* 15 Tunnel adapter Local Area Connection* 16 Except for the *16, all the other Tunnel Adapter Local Area Connections show Media Disconnected. Why is the numbering for the Tunnel adapter LAN not sequential? It is like 6, 7, 12, 13, 14, 15, 16. A strange numbering scheme! I tried to figure it out by thinking of some arithmetic series. But, it does not seem to fit in. There is a huge gap between 7 and 12. Any ideas? What is the need for so many Tunnel Adapter LAN connections? Can you tell me a scenario that requires all of those ? I did ipconfig /all to get more information. From the listing, I understand that: 16, 15, 14, 12 are Microsoft 6to4 Adapters 13, 6 are isatap Adapters 7 is Teredo Tunneling Pseudo-interface I understand that the above are for automatic tunneling so that the tunnel endpoints are determined automatically by the routing infrastructure. 6to4 is recommended by RFC3056 for automatic tunneling that uses protocol 41 for encapsulation. It is typically used when an end-user wants to connect to the IPv6 Internet using their existing IPv4 connection. Teredo is an automatic tunneling technique that uses UDP encapsulation across multiple NATs. That is, It is to grant IPv6 connectivity to nodes that are located behind IPv6-unaware NAT devices ISATAP treats the IPv4 network as a virtual IPv6 local link, with mappings from each IPv4 address to a link-local IPv6 address. That is to transmit IPv6 packets between dual-stack nodes on top of an IPv4 network. That is, to put in simple words, ISATAP is an intra-site mechanism, while the 6to4 and Teredo are for inter-site tunnelling mechanisms. It seems that Teredo should alone enabled by default in Vista, But my system does not show it to be enabled by default. Interestingly, it shows a 6to4 tunnel adapter (Tunnel adapter LAN connection 16) to be enabled by default? Any specific reasons for it? If i do ipconfig /all, why is only one Teredo present while four 6to4 are present ? I searched the internet for answers to the above queries, but I am unable to find clear answers.

  Read the article

• HAProxy + Percona XtraDB Cluster

  - by rottmanj

  I am attempting to setup HAproxy in conjunction with Percona XtraDB Cluster on a series of 3 EC2 instances. I have found a few tutorials online dealing with this specific issue, but I am a bit stuck. Both the Percona servers and the HAproxy servers are running ubuntu 12.04. The HAProxy version is 1.4.18, When I start HAProxy I get the following error: Server pxc-back/db01 is DOWN, reason: Socket error, check duration: 2ms. I am not really sure what the issue could be. I have verified the following: EC2 security groups ports are open Poured over my config files looking for issues. I currently do not see any. Ensured that xinetd was installed Ensured that I am using the correct ip address of the mysql server. Any help with this is greatly appreciated. Here are my current config Load Balancer /etc/haproxy/haproxy.cfg global log 127.0.0.1 local0 log 127.0.0.1 local1 notice maxconn 4096 user haproxy group haproxy debug #quiet daemon defaults log global mode http option tcplog option dontlognull retries 3 option redispatch maxconn 2000 contimeout 5000 clitimeout 50000 srvtimeout 50000 frontend pxc-front bind 0.0.0.0:3307 mode tcp default_backend pxc-back frontend stats-front bind 0.0.0.0:22002 mode http default_backend stats-back backend pxc-back mode tcp balance leastconn option httpchk server db01 10.86.154.105:3306 check port 9200 inter 12000 rise 3 fall 3 backend stats-back mode http balance roundrobin stats uri /haproxy/stats MySql Server /etc/xinetd.d/mysqlchk # default: on # description: mysqlchk service mysqlchk { # this is a config for xinetd, place it in /etc/xinetd.d/ disable = no flags = REUSE socket_type = stream port = 9200 wait = no user = nobody server = /usr/bin/clustercheck log_on_failure += USERID #only_from = 0.0.0.0/0 # recommended to put the IPs that need # to connect exclusively (security purposes) per_source = UNLIMITED } MySql Server /etc/services Added the line mysqlchk 9200/tcp # mysqlchk MySql Server /usr/bin/clustercheck # GNU nano 2.2.6 File: /usr/bin/clustercheck #!/bin/bash # # Script to make a proxy (ie HAProxy) capable of monitoring Percona XtraDB Cluster nodes properly # # Author: Olaf van Zandwijk <[email protected]> # Documentation and download: https://github.com/olafz/percona-clustercheck # # Based on the original script from Unai Rodriguez # MYSQL_USERNAME="testuser" MYSQL_PASSWORD="" ERR_FILE="/dev/null" AVAILABLE_WHEN_DONOR=0 # # Perform the query to check the wsrep_local_state # WSREP_STATUS=`mysql --user=${MYSQL_USERNAME} --password=${MYSQL_PASSWORD} -e "SHOW STATUS LIKE 'wsrep_local_state';" 2>${ERR_FILE} | awk '{if (NR!=1){print $2}}' 2>${ERR_FILE}` if [[ "${WSREP_STATUS}" == "4" ]] || [[ "${WSREP_STATUS}" == "2" && ${AVAILABLE_WHEN_DONOR} == 1 ]] then # Percona XtraDB Cluster node local state is 'Synced' => return HTTP 200 /bin/echo -en "HTTP/1.1 200 OK\r\n" /bin/echo -en "Content-Type: text/plain\r\n" /bin/echo -en "\r\n" /bin/echo -en "Percona XtraDB Cluster Node is synced.\r\n" /bin/echo -en "\r\n" else # Percona XtraDB Cluster node local state is not 'Synced' => return HTTP 503 /bin/echo -en "HTTP/1.1 503 Service Unavailable\r\n" /bin/echo -en "Content-Type: text/plain\r\n" /bin/echo -en "\r\n" /bin/echo -en "Percona XtraDB Cluster Node is not synced.\r\n" /bin/echo -en "\r\n" fi

  Read the article

• IPv6 routing to another interface

  - by Robert

  I'm trying to get an IPv6 enabled router to forward data from one interface to the other and I'm having issues. When following this example (http://www.cisco.com/en/US/tech/tk872/technologies_configuration_example09186a0080ba6106.shtml) I am able to get full connectivity between all 3 routers in my simulator. However when I try to use only 1 router; I can't get connectivity to the other interfacs on the same router. My PC is directly attached to FA 0/1 and it can ping the router's interface. However it can not ping any other interface on the router(which unless I'm missing something it should be able to do). The router on the other hand can ping everything. I thought static routes might help; but the router already has routes for everything. I'm thinking the packet should come in; router looks up the destination in it's ipv6 routing table and then realizes it's for itself, and should respond. I thought maybe it couldn't respond directly; so I tried pinging a device like 2001:0000:0000:1000::2, but i don't get a response. I'm running on IOS 12.4. I'm missing something(hopefully simple), but I just can't see what it is. With only 1 router; how do I enable my PC to talk to the other subnets? Thank you in advance, Robert Topology: R1 FA 0/0: 2001:0000:0000:0000::1/52 FA 0/1: 2001:0000:0000:1000::1/52 FA 1/0: 2001:0000:0000:2000::1/52 Loopback 0: 2001:0000:0000:3000::1/52 PC: 2001:0000:0000:2000::2/52 PC plugs directly into FA 1/0 on the router. --- Configuration --- ipv6 cef ipv6 unicast routing interface Loopback0 no ip address ipv6 address 2001:0000:0000:3000::1/52 ipv6 enable ! interface FastEthernet0/0 no ip address duplex auto speed auto ipv6 address 2001:0000:0000::1/52 ipv6 enable ! interface FastEthernet0/1 no ip address duplex auto speed auto ipv6 address 2001:0000:0000:1000::1/52 ipv6 enable ! interface FastEthernet1/0 no ip address duplex auto speed auto ipv6 address 2001:0000:0000:2000::1/52 ipv6 enable --- end of config --- --- routing table --- IPV6Lab#show ipv6 route IPv6 Routing Table - 10 entries Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP U - Per-user Static route I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2 ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2 C 2001:0000:0000::/52 [0/0] via ::, FastEthernet0/0 L 2001:0000:0000::1/128 [0/0] via ::, FastEthernet0/0 C 2001:0000:0000:1000::/52 [0/0] via ::, FastEthernet0/1 L 2001:0000:0000:1000::1/128 [0/0] via ::, FastEthernet0/1 C 2001:0000:0000:2000::/52 [0/0] via ::, FastEthernet1/0 L 2001:0000:0000:2000::1/128 [0/0] via ::, FastEthernet1/0 C 2001:0000:0000:3000::/52 [0/0] via ::, Loopback0 L 2001:0000:0000:3000::1/128 [0/0] via ::, Loopback0 L FE80::/10 [0/0] via ::, Null0 L FF00::/8 [0/0] via ::, Null0 --- end of routing table ---

  Read the article

• How To Switch Back to Outlook 2007 After the 2010 Beta Ends

  - by Matthew Guay

  Are you switching back to Outlook 2007 after trying out Office 2010 beta?  Here’s how you can restore your Outlook data and keep everything working fine after the switch. Whenever you install a newer version of Outlook, it will convert your profile and data files to the latest format.  This makes them work the best in the newer version of Outlook, but may cause problems if you decide to revert to an older version.  If you installed Outlook 2010 beta, it automatically imported and converted your profile from Outlook 2007.  When the beta expires, you will either have to reinstall Office 2007 or purchase a copy of Office 2010. If you choose to reinstall Office 2007, you may notice an error message each time you open Outlook. Outlook will still work fine and all of your data will be saved, but this error message can get annoying.  Here’s how you can create a new profile, import all of your old data, and get rid of this error message. Banish the Error Message with a New Profile To get rid of this error message, we need to create a new Outlook profile.  First, make sure your Outlook data files are backed up.  Your messages, contacts, calendar, and more are stored in a .pst file in your appdata folder.  Enter the following in the address bar of an Explorer window to open your Outlook data folder, and replace username with your user name: C:\Users\username\AppData\Local\Microsoft\Outlook Copy the Outlook Personal Folders (.pst) files that contain your data. Its name is usually your email address, though it may have a different name.  If in doubt, select all of the Outlook Personal Folders files, copy them, and save them in another safe place (such as your Documents folder). Now, let’s remove your old profile.  Open Control Panel, and select Mail.  In Windows Vista or 7, simply enter “Mail” in the search box and select the first entry. Click the “Show Profiles…” button. Now, select your Outlook profile, and click Remove.  This will not delete your data files, but will remove them from Outlook. Press Yes to confirm that you wish to remove this profile. Open Outlook, and you will be asked to create a new profile.  Enter a name for your new profile, and press Ok. Now enter your email account information to setup Outlook as normal. Outlook will attempt to automatically configure your account settings.  This usually works for accounts with popular email systems, but if it fails to find your information you can enter it manually.  Press finish when everything’s done. Outlook will now go ahead and download messages from your email account.  In our test, we used a Gmail account that still had all of our old messages online.  Those files are backed up in our old Outlook data files, so we can save time and not download them.  Click the Send/Receive button on the bottom of the window, and select “Cancel Send/Receive”. Restore Your Old Outlook Data Let’s add our old Outlook file back to Outlook 2007.  Exit Outlook, and then go back to Control Panel, and select Mail as above.  This time, click the Data Files button. Click the Add button on the top left. Select “Office Outlook Personal Folders File (.pst)”, and click Ok. Now, select your old Outlook data file.  It should be in the folder that opens by default; if not, browse to the backup copy we saved earlier, and select it. Press Ok at the next dialog to accept the default settings. Now, select the data file we just imported, and click “Set as Default”. Now, all of your old messages, appointments, contacts, and everything else will be right in Outlook ready for you.  Click Ok, and then open Outlook to see the change. All of the data that was in Outlook 2010 is now ready to use in Outlook 2007.  You won’t have to wait to re-download all of your emails from the server since everything’s still here ready to be used.  And when you open Outlook, you won’t see any error messages, either! Conclusion Migrating your Outlook profile back to Outlook 2007 is fairly easy, and with these steps, you can avoid seeing an error message every time you open Outlook.  With all your data in tact, you’re ready to get back to work instead of getting frustrated with Outlook.  Many of us use webmail and keep all of our messages in the cloud, but even on broadband connections it can take a long time to download several gigabytes of emails. Similar Articles Productive Geek Tips Opening Attachments in Outlook 2007 by KeyboardQuickly Create Appointments from Tasks with Outlook 2007’s To-Do BarFix For Outlook 2007 Constantly Asking for Password on VistaPin Microsoft Outlook to the Desktop BackgroundOur Look at the LinkedIn Social Connector for Outlook TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Download Free MP3s from Amazon Awe inspiring, inter-galactic theme (Win 7) Case Study – How to Optimize Popular Wordpress Sites Restore Hidden Updates in Windows 7 & Vista Iceland an Insurance Job? Find Downloads and Add-ins for Outlook

  Read the article

• WordPress SEO Plugins to make your Blog Search Engine Friendly

  - by Vaibhav

  WordPress is the most common blogging system in use today and its use as a CMS is also wide spread. With hundreds of millions of sites using wordpress, getting correct SEO for your WordPress based Blog or Site is very important. We get regular queries from people who want Search Engine Optimisation for their site or blog which is made using wordpress. Here is a list of 16 of the best WordPress Plug-ins That can help you achieve better rankings: All in one SEO Pack This is most popular plugin among all SEO plugins for WordPress. It is easy to use and is compatible with most of the WordPress plugins. It works as a complete package of SEO plugin – automatically generating META tags and optimizing search engines for your titles and avoiding duplicate content. You can also include META tags manually (Met title, Meta description and Met keywords) for all pages and post in your website. HeadSpace2 HeasSpace2 is available in different languages , you can manage a wide range of SEO Tasks related with meta data, you can tag your posts, Custom descriptions and titles. So your page can rank the created relevancy on Search engines and you can load different settings for different pages. Platinum SEO plugin Automatic 301 redirects permalink changes, META tags generation, avoids duplicate content, and does SEO optimization of post and page titles and a lots of other features. TGFI.net SEO WordPress Plugin It’s a modified version of all-in-one SEO Pack. It has some unique feature over All-in-one SEO plugin, It generate titles, meta descriptions and meta keywords automatically when overrides are not present. Google XML Sitemaps Sitemaps Generated by this tool are supported by  Google,  Yahoo,  Bing, and Ask. We all know Sitemaps make indexing of web pages easier for web crawlers. Crawlers can retrieve complete structure of site and more information by sitemaps. They notify all major search engines about new posts every time you create a new post. Sitemap Generator You can generate highly customizable sitemap for your WordPress page. You can choose what to show and what not to show, you can list the items in your choice of orde. It supports pages and permalinks and multi-level categories. SEO Slugs They can generate more search engine friendly URLs for your site. Slugs are filename assigned to your post , this plugin removes all  common words like ‘a’, ‘the’, ‘in’, ‘what’, ‘you’ from slug which are assigned automatically to your post. SEO Post Links This is a similar plugin to SEO Slug, it removes unnecessary keywords from slug to make it short and SEO friendly and you can fix the number of characters in your post. Automatic SEO links With this tool you can create auto linking in your post. You can use this tool for inter linking or external linking too. Just select your words, anchor text target URL nature of links ( Do fallow / No follow ). This plugin will replace the matches found in post, WP Backlinks A helpful plugin for link exchange , whenever any webmaster submits a link for link exchange, the plugin will spider webmasters site for reciprocal link, and if everything is found good , your link will be exchanged. SEO Title Tag You can optimize your Title  tags of  Word press blog through this plugin . You can also override the title tag with custom titles , mass editing and title tags for 404 pages which are the main feature of this plugin. 404 SEO plugin With this Plugin you can customize 404 page of your site; you can give customized error message and links to relevant pages of your site. Redirection A powerful plugins to manage 301 redirection and logs related with redirection, with this plugin you can track 404 errors and track the log of all redirected URLs , this plugin can redirect  post automatically when URL changes for that post. AddToAny This plugin helps your readers to share, save, email and bookmark your posts and pages. It supports more than a hundred social bookmarking , networking and sharing sites. SEO Friendly Images You can make SEO friendly images available on your site with the help of this tool. It updates images with proper titles and ALT tags. Robots Meta A plugin which prevents Search engines to index comments on your post, login and admin pages. It also allows to add tags for individual pages.

  Read the article

• A Graduate&rsquo;s Journey at Oracle &ndash; Bhaskar Ghosh From Oracle India

  - by david.talamelli

  I am Bhaskar Ghosh, and I work as an Applications Engineer with Oracle. Well, it was three years ago when my journey with one of the largest software companies started. It was a fine day and a decisive moment, when I was placed in Oracle as a campus recruit from College of Engineering Guindy, Anna University, Chennai! I always thought of looking back, the time that helped me learn beyond my boundaries, think broader and ahead, and grow – technically, professionally and personally. Hmmn! Let me recall the eventful moments once again. My first day as an intern at Oracle started in late 2007. I met one of the Oracle Managers at the Oracle Campus in Hyderabad and on the same day I also met another Oracle employee who was to later to become my first manager. I was charged and thrilled with the environment and the wonderful people around me! I was joined by two other interns, who also had a Masters in Computer Applications. We formed a very friendly group with all the interns and the new hires, and shared our excitement and learning. Myself and one of the other Graduates started working on a very interesting project on Semantic technology. We finally had our names added as co-developers for this very project. This phase of five months was the time and we learnt tremendously and worked very hard, partly because we had to travel back and forth to our colleges to submit reports and present for the Masters in Computer Applications final year project reviews. After completing my MCA, I joined as a full-time employee in 2008. During the next year, we worked on interesting and bleeding edge technologies - OWL, RDF, SPARQL, Visualization, J2EE, Social Web features, Semantic Web technologies, Web Services and many more! We developed cool, rich internet and desktop applications. Little did I know at that time, that this learning would help me tremendously for my the next project in Oracle. The following year saw me being assigned a role in a different project that my other team members were working on for the last two years. It took me two months to understand and get into a flow with this new task. I was fortunate that this phase helped me enhance my inter-personal and communication skills, as much as it helped me grow professionally with better ability to tackle multiple priorities and switch between tasks based on the team’s requirements. I was made the POC for all communications with our team and other product teams. I personally feel that this time enhanced me tremendously in technologies like Oracle Forms, J2EE, and Java and Web Services. The last six months, saw myself becoming an Institute of Electrical and Electronics Engineer member, and continuing my higher education International Institute of Information Technology, Hyderabad. Oracle supports its employees becoming members of professional bodies, and higher studies are supported by management, I think it is tremendously helpful in the professional and technical growth of the employees. Last three months, I have been working on great and useful enhancements to our product. Ah beautiful! All these years, there have been other moments and events of fun that are too worth mentioning. Clubs and groups at Oracle such as Employee Club, Oracle Volunteers, Football Club, etc. have always kept on organizing numerous events and competitions, full of fun and entertainment. I really enjoyed participating, even if it was small, in the intra-Oracle football tourney, Oracle Volunteer Days, OraFora, OraOvations, and a few more. Those ‘Seasons of Sharing’, those ‘Blood Donation camps’, those ‘Diwali and Christmas gifts and events’, those ‘fun events at the annual function called OraOvations’, those ‘books and cycle stalls’, and those so many other things… It only fills my mind with pleasure. The last three years have been very eventful:they have been full of learning and growth, and under the very able and encouraging guidance of my manager. I have got the opportunity to know about and/or interact with many wonderful personalities, and learn from them, here at Oracle. The environment, the people, and the fellow developers have been so friendly, and always ever ready to help, when we were in doubt.. I really love the big office space, and the flexible timings, and the caring people around. I look forward to a beautiful, learning and motivating journey with Oracle.

  Read the article

• Frameskipping in Android gameloop causing choppy sprites (Open GL ES 2.0)

  - by user22241

  I have written a simple 2d platform game for Android and am wondering how one deals with frame-skipping? Are there any alternatives? Let me explain further. So, my game loop allows for the rendering to be skipped if game updates and rendering do not fit into my fixed time-slice (16.667ms). This allows my game to run at identically perceived speeds on different devices. And this works great, things do run at the same speed. However, when the gameloop skips a render call for even one frame, the sprite glitches. And thinking about it, why wouldn't it? You're seeing a sprite move say, an average of 10 pixels every 1.6 seconds, then suddenly, there is a pause of 3.2ms, and the sprite then appears to jump 20 pixels. When this happens 3 or 4 times in close succession, the result is very ugly and not something I want in my game. Therfore, my question is how does one deal with these 'pauses' and 'jumps' - I've read every article on game loops I can find (see below) and my loops are even based off of code from these articles. The articles specifically mention frame skipping but they don't make any reference to how to deal with visual glitches that result from it. I've attempted various game-loops. My loop must have a mechanism in-place to allow rendering to be skipped to keep game-speed constant across multiple devices (or alternative, if one exists) I've tried interpolation but this doesn't eliminate this specific problem (although it looks like it may mitigate the issue slightly as when it eventually draws the sprite it 'moves it back' between the old and current positions so the 'jump' isn't so big. I've also tried a form of extrapolation which does seem to keep things smooth considerably, but I find it to be next to completely useless because it plays havoc with my collision detection (even when drawing with a 'display only' coordinate - see extrapolation-breaks-collision-detection) I've tried a loop that uses Thread.sleep when drawing / updating completes with time left over, no frame skipping in this one, again fairly smooth, but runs differently on different devices so no good. And I've tried spawning my own, third thread for logic updates, but this, was extremely messy to deal with and the performance really wasn't good. (upon reading tons of forums, most people seem to agree a 2 thread loops ( so UI and GL threads) is safer / easier). Now if I remove frame skipping, then all seems to run nice and smooth, with or without inter/extrapolation. However, this isn't an option because the game then runs at different speeds on different devices as it falls behind from not being able to render fast enough. I'm running logic at 60 Ticks per second and rendering as fast as I can. I've read, as far as I can see every article out there, I've tried the loops from My Secret Garden and Fix your timestep. I've also read: Against the grain deWITTERS Game Loop Plus various other articles on Game-loops. A lot of the others are derived from the above articles or just copied word for word. These are all great, but they don't touch on the issues I'm experiencing. I really have tried everything I can think of over the course of a year to eliminate these glitches to no avail, so any and all help would be appreciated. A couple of examples of my game loops (Code follows): From My Secret Room public void onDrawFrame(GL10 gl) { //Rre-set loop back to 0 to start counting again loops=0; while(System.currentTimeMillis() > nextGameTick && loops < maxFrameskip) { SceneManager.getInstance().getCurrentScene().updateLogic(); nextGameTick += skipTicks; timeCorrection += (1000d / ticksPerSecond) % 1; nextGameTick += timeCorrection; timeCorrection %= 1; loops++; } extrapolation = (float)(System.currentTimeMillis() + skipTicks - nextGameTick) / (float)skipTicks; render(extrapolation); } And from Fix your timestep double t = 0.0; double dt2 = 0.01; double currentTime = System.currentTimeMillis()*0.001; double accumulator = 0.0; double newTime; double frameTime; @Override public void onDrawFrame(GL10 gl) { newTime = System.currentTimeMillis()*0.001; frameTime = newTime - currentTime; if ( frameTime > (dt*5)) //Allow 5 'skips' frameTime = (dt*5); currentTime = newTime; accumulator += frameTime; while ( accumulator >= dt ) { SceneManager.getInstance().getCurrentScene().updateLogic(); previousState = currentState; accumulator -= dt; } interpolation = (float) (accumulator / dt); render(interpolation); }

  Read the article

• Developing Schema Compare for Oracle (Part 3): Ghost Objects

  - by Simon Cooper

  In the previous blog post, I covered how we solved the problem of dependencies between objects and between schemas. However, that isn’t the end of the issue. The dependencies algorithm I described works when you’re querying live databases and you can get dependencies for a particular schema direct from the server, and that’s all well and good. To throw a (rather large) spanner in the works, Schema Compare also has the concept of a snapshot, which is a read-only compressed XML representation of a selection of schemas that can be compared in the same way as a live database. This can be useful for keeping historical records or a baseline of a database schema, or comparing a schema on a computer that doesn’t have direct access to the database. So, how do snapshots interact with dependencies? Inter-database dependencies don't pose an issue as we store the dependencies in the snapshot. However, comparing a snapshot to a live database with cross-schema dependencies does cause a problem; what if the live database has a dependency to an object that does not exist in the snapshot? Take a basic example schema, where you’re only populating SchemaA: SOURCE   TARGET (using snapshot) CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100)); In this case, we want to generate a sync script to synchronize SchemaA.Table1 on the database represented by the snapshot. When taking a snapshot, database dependencies are followed, but because you’re not comparing it to anything at the time, the comparison dependencies algorithm described in my last post cannot be used. So, as you only take a snapshot of SchemaA on the target database, SchemaB.Table1 will not be in the snapshot. If this snapshot is then used to compare against the above source schema, SchemaB.Table1 will be included in the source, but the object will not be found in the target snapshot. This is the same problem that was solved with comparison dependencies, but here we cannot use the comparison dependencies algorithm as the snapshot has not got any information on SchemaB! We've now hit quite a big problem - we’re trying to include SchemaB.Table1 in the target, but we simply do not know the status of this object on the database the snapshot was taken from; whether it exists in the database at all, whether it’s the same as the target, whether it’s different... What can we do about this sorry state of affairs? Well, not a lot, it would seem. We can’t query the original database, as it may not be accessible, and we cannot assume any default state as it could be wrong and break the script (and we currently do not have a roll-back mechanism for failed synchronizes). The only way to fix this properly is for the user to go right back to the start and re-create the snapshot, explicitly including the schemas of these 'ghost' objects. So, the only thing we can do is flag up dependent ghost objects in the UI, and ask the user what we should do with it – assume it doesn’t exist, assume it’s the same as the target, or specify a definition for it. Unfortunately, such functionality didn’t make the cut for v1 of Schema Compare (as this is very much an edge case for a non-critical piece of functionality), so we simply flag the ghost objects up in the sync wizard as unsyncable, and let the user sort out what’s going on and edit the sync script as appropriate. There are some things that we do do to alleviate somewhat this rather unhappy situation; if a user creates a snapshot from the source or target of a database comparison, we include all the objects registered from the database, not just the ones in the schemas originally selected for comparison. This includes any extra dependent objects registered through the comparison dependencies algorithm. If the user then compares the resulting snapshot against the same database they were comparing against when it was created, the extra dependencies will be included in the snapshot as required and everything will be good. Fortunately, this problem will come up quite rarely, and only when the user uses snapshots and tries to sync objects with unknown cross-schema dependencies. However, the solution is not an easy one, and lead to some difficult architecture and design decisions within the product. And all this pain follows from the simple decision to allow schema pre-filtering! Next: why adding a column to a table isn't as easy as you would think...

  Read the article

< Previous Page | 8 9 10 11 12 13 14 15  | Next Page >