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• Java CORBA Client Disconnects Immediately

  - by Benny

  I have built a Java CORBA application that subscribes to an event server. The application narrows and logs on just fine, but as soon as an event is sent to the client, it breaks with the error below. Please advise. 2010/04/25!13.00.00!E00555!enserver!EventServiceIF_i.cpp!655!PID(7390)!enserver - e._info=system exception, ID 'IDL:omg.org/CORBA/TRANSIENT:1.0' TAO exception, minor code = 54410093 (invocation connect failed; ECONNRESET), completed = NO EDIT: Please note, this only happens when running on some machines. It works on some, but not others. Even on the same platform (I've tried Windows XP/7 and CentOS linux) Some work, some don't... Here is the WireShark output...looks like the working PC is much more interactive with the network compared to the non-working PC. Working PC No. Time Source Destination Protocol Info 62 28.837255 10.10.10.209 10.10.10.250 TCP 50169 > 23120 [SYN] Seq=0 Win=8192 Len=0 MSS=1260 WS=8 63 28.907068 fe80::5de0:8d21:937e:c649 ff02::1:3 LLMNR Standard query A isatap 64 28.907166 10.10.10.209 224.0.0.252 LLMNR Standard query A isatap 65 29.107259 10.10.10.209 10.255.255.255 NBNS Name query NB ISATAP<00> 66 29.227000 10.10.10.250 10.10.10.209 TCP 23120 > 50169 [SYN, ACK] Seq=0 Ack=1 Win=32768 Len=0 MSS=1260 WS=0 67 29.227032 10.10.10.209 10.10.10.250 TCP 50169 > 23120 [ACK] Seq=1 Ack=1 Win=66560 Len=0 68 29.238063 10.10.10.209 10.10.10.250 GIOP GIOP 1.1 Request s=326 id=5 (two-way): op=logon 69 29.291765 10.10.10.250 10.10.10.209 GIOP GIOP 1.1 Reply s=420 id=5: No Exception 70 29.301395 10.10.10.209 10.10.10.250 GIOP GIOP 1.1 Request s=369 id=6 (two-way): op=registerEventStat 71 29.348275 10.10.10.250 10.10.10.209 GIOP GIOP 1.1 Reply s=60 id=6: No Exception 72 29.405250 10.10.10.209 10.10.10.250 TCP 50170 > telnet [SYN] Seq=0 Win=8192 Len=0 MSS=1260 WS=8 73 29.446055 10.10.10.250 10.10.10.209 TCP telnet > 50170 [SYN, ACK] Seq=0 Ack=1 Win=32768 Len=0 MSS=1260 WS=0 74 29.446128 10.10.10.209 10.10.10.250 TCP 50170 > telnet [ACK] Seq=1 Ack=1 Win=66560 Len=0 75 29.452021 10.10.10.209 10.10.10.250 TELNET Telnet Data ... 76 29.483537 10.10.10.250 10.10.10.209 TELNET Telnet Data ... 77 29.483651 10.10.10.209 10.10.10.250 TELNET Telnet Data ... 78 29.523463 10.10.10.250 10.10.10.209 TCP telnet > 50170 [ACK] Seq=4 Ack=5 Win=32768 Len=0 79 29.554954 10.10.10.209 10.10.10.250 TCP 50169 > 23120 [ACK] Seq=720 Ack=505 Win=66048 Len=0 Non-working PC No. Time Source Destination Protocol Info 1 0.000000 10.10.10.209 10.10.10.250 TCP 64161 > 23120 [SYN] Seq=0 Win=8192 Len=0 MSS=1260 WS=8 2 2.999847 10.10.10.209 10.10.10.250 TCP 64161 > 23120 [SYN] Seq=0 Win=8192 Len=0 MSS=1260 WS=8 3 4.540773 Cisco_3c:78:00 Cisco-Li_55:87:72 ARP Who has 10.0.0.1? Tell 10.10.10.209 4 4.540843 Cisco-Li_55:87:72 Cisco_3c:78:00 ARP 10.0.0.1 is at 00:1a:70:55:87:72 5 8.992284 10.10.10.209 10.10.10.250 TCP 64161 > 23120 [SYN] Seq=0 Win=8192 Len=0 MSS=1260

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• Limiting TCP sends with a "to-be-sent" queue and other design issues.

  - by Poni

  Hello all! This question is the result of two other questions I've asked in the last few days. I'm creating a new question because I think it's related to the "next step" in my understanding of how to control the flow of my send/receive, something I didn't get a full answer to yet. The other related questions are: http://stackoverflow.com/questions/3028376/an-iocp-documentation-interpretation-question-buffer-ownership-ambiguity http://stackoverflow.com/questions/3028998/non-blocking-tcp-buffer-issues In summary, I'm using Windows I/O Completion Ports. I have several threads that process notifications from the completion port. I believe the question is platform-independent and would have the same answer as if to do the same thing on a *nix, *BSD, Solaris system. So, I need to have my own flow control system. Fine. So I send send and send, a lot. How do I know when to start queueing the sends, as the receiver side is limited to X amount? Let's take an example (closest thing to my question): FTP protocol. I have two servers; One is on a 100Mb link and the other is on a 10Mb link. I order the 100Mb one to send to the other one (the 10Mb linked one) a 1GB file. It finishes with an average transfer rate of 1.25MB/s. How did the sender (the 100Mb linked one) knew when to hold the sending, so the slower one wouldn't be flooded? Another way to ask this: Can I get a "hold-your-sendings" notification from the remote side? Is it built-in in TCP or the so called "reliable network protocol" needs me to do so? Again, I have a loop with many sends to a remote server, and at some point, within that loop I'll have to determine if I should queue that send or I can pass it on to the transport layer (TCP). How do I do that? What would you do? Of course that when I get a completion notification from IOCP that the send was done I'll issue other pending sends, that's clear. Another design question related to this: Since I am to use a custom buffers with a send queue, and these buffers are being freed to be reused (thus not using the "delete" keyword) when a "send-done" notification has been arrived, I'll have to use a mutual exlusion on that buffer pool. Using a mutex slows things down, so I've been thinking; Why not have each thread have its own buffers pool, thus accessing it , at least when getting the required buffers for a send operation, will require no mutex, because it belongs to that thread only. The buffers pool is located at the thread local storage (TLS) level. No mutual pool implies no lock needed, implies faster operations BUT also implies more memory used by the app, because even if one thread already allocated 1000 buffers, the other one that is sending right now and need 1000 buffers to send something will need to allocated these to its own. This is a long question and I hope none got hurt (: Thank you all!

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• Devise / Rails 4 Windows mobile authentication failure

  - by Nic Willemse

  Im using devise with a rails 4 application. Authentication works fine on most devices, including some old feature phones. I am however running into problems with the Nokia Lumia. Please see log snippet below. By the looks of things this appears to be a rails issue rather than a devise problem. Please Help! 014-05-30T09:47:38.668478+00:00 app[web.1]: Started POST "/users/sign_in" for 197.111.223.249 at 2014-05-30 09:47:38 +0000 2014-05-30T09:47:38.668505+00:00 app[web.1]: Started POST "/users/sign_in" for 197.111.223.249 at 2014-05-30 09:47:38 +0000 2014-05-30T09:47:38.672961+00:00 app[web.1]: Processing by Devise::SessionsController#create as HTML 2014-05-30T09:47:38.672968+00:00 app[web.1]: Processing by Devise::SessionsController#create as HTML 2014-05-30T09:47:38.674163+00:00 app[web.1]: Can't verify CSRF token authenticity 2014-05-30T09:47:38.673021+00:00 app[web.1]: Parameters: {"utf8"="?", "authenticity_token"="Ckyw9vAfxbgksugLMainfWoG2jRdq7GB5xBBGxqYhCs=", "user"={"email"="", "password"="[FILTERED]", "remember_me"="0"}, "commit"="Sign in"} 2014-05-30T09:47:38.673027+00:00 app[web.1]: Parameters: {"utf8"="?", "authenticity_token"="Ckyw9vAfxbgksugLMainfWoG2jRdq7GB5xBBGxqYhCs=", "user"={"email"="", "password"="[FILTERED]", "remember_me"="0"}, "commit"="Sign in"} 2014-05-30T09:47:38.674170+00:00 app[web.1]: Can't verify CSRF token authenticity 2014-05-30T09:47:38.677792+00:00 app[web.1]: Completed 422 Unprocessable Entity in 5ms 2014-05-30T09:47:38.677799+00:00 app[web.1]: Completed 422 Unprocessable Entity in 5ms 2014-05-30T09:47:38.683294+00:00 app[web.1]: ActionController::InvalidAuthenticityToken (ActionController::InvalidAuthenticityToken): 2014-05-30T09:47:38.683299+00:00 app[web.1]: vendor/bundle/ruby/2.0.0/gems/actionpack-4.0.1/lib/action_controller/metal/request_forgery_protection.rb:170:in handle_unverified_request' 2014-05-30T09:47:38.683289+00:00 app[web.1]: 2014-05-30T09:47:38.683298+00:00 app[web.1]: vendor/bundle/ruby/2.0.0/gems/actionpack-4.0.1/lib/action_controller/metal/request_forgery_protection.rb:163:inhandle_unverified_request' 2014-05-30T09:47:38.683303+00:00 app[web.1]: vendor/bundle/ruby/2.0.0/gems/actionpack-4.0.1/lib/action_controller/metal/request_forgery_protection.rb:177:in verify_authenticity_token' 2014-05-30T09:47:38.683305+00:00 app[web.1]: vendor/bundle/ruby/2.0.0/gems/activesupport-4.0.1/lib/active_support/callbacks.rb:417:in_run__3672081613755604432__process_action__callbacks' Form : <%= form_for(resource, :as => resource_name, :url => session_path(resource_name), :html => {:class => "form-signin"}) do |f| %> <h2 class="form-signin-heading">Sign in</h2> <%= devise_error_messages! %> <div><%= f.label :email %><br /> <%= f.email_field :email, :autofocus => true, :class=> "form-control" %></div> <div><%= f.label :password %><br /> <%= f.password_field :password , :class=> "form-control"%></div> <% if devise_mapping.rememberable? -%> <div><%= f.check_box :remember_me, :class=> "form-control"%> <%= f.label :remember_me %></div> <% end -%> <div><%= f.submit "Sign in" ,:class => "btn btn-lg btn-primary btn-block"%></div> <input name="authenticity_token" type="hidden" value="<%= form_authenticity_token %>"/> <%= render "devise/shared/links" %> <% end %>

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• How to revert-back from SSL to non-SSL in Tomcat 6 ?

  - by mohamida

  I'm using jsf 2 + jaas + ssl + tomcat 6.0.26 I have in my web site 2 paths: /faces/protected/* which uses SSL /faces/unprotected/* which don't uses SSL. I've put this in my web.xml: <login-config> <auth-method>FORM</auth-method> <form-login-config> <form-login-page>/faces/login.jsp</form-login-page> <form-error-page>/faces/error.jsp</form-error-page> </form-login-config> </login-config> <security-constraint> <web-resource-collection> <web-resource-name>Secure Resource</web-resource-name> <description/> <url-pattern>/faces/unprotected/*</url-pattern> <http-method>GET</http-method> <http-method>POST</http-method> <http-method>HEAD</http-method> <http-method>PUT</http-method> <http-method>OPTIONS</http-method> <http-method>TRACE</http-method> <http-method>DELETE</http-method> </web-resource-collection> <auth-constraint> <role-name>C</role-name> </auth-constraint> </security-constraint> <security-constraint> <web-resource-collection> <web-resource-name>Secure Resource</web-resource-name> <description /> <url-pattern>/faces/protected/*</url-pattern> <http-method>GET</http-method> <http-method>POST</http-method> <http-method>HEAD</http-method> <http-method>PUT</http-method> <http-method>OPTIONS</http-method> <http-method>TRACE</http-method> <http-method>DELETE</http-method> </web-resource-collection> <auth-constraint> <role-name>C</role-name> </auth-constraint> <user-data-constraint> <transport-guarantee>CONFIDENTIAL</transport-guarantee> </user-data-constraint> </security-constraint> <security-role> <description> Role Client </description> <role-name>C</role-name> </security-role> and this is my server.xml: <Connector port="8080" protocol="HTTP/1.1" maxThreads="400" maxKeepAliveRequests="1" acceptCount="100" connectionTimeout="3000" redirectPort="8443" compression="on" compressionMinSize="2048" noCompressionUserAgents="gozilla, traviata" compressableMimeType="text/javascript,text/css,text/html, text/xml,text/plain,application/x-javascript,application/javascript,application/xhtml+xml" /> <Connector port="8443" protocol="org.apache.coyote.http11.Http11AprProtocol" SSLEnabled="true" maxThreads="400" scheme="https" secure="true" clientAuth="optional" sslProtocol="TLS" SSLCertificateFile="path/to/crt" SSLCertificateKeyFile="path/to/pem"/> when i enter to protected paths, it switches to HTTPS (port 8443), but when i enter to path /faces/unprotected/somthing... it stays using HTTPS. what i want is when i enter to unprotected paths, it revert-back to non-SSL communications ( otherwise, i have to re-login again when i set the exact adress in my browser). What's wrong with my configurations ? Is there a way so i can do such a thing ?

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• Advantage database throws an exception when attempting to delete a record with a like statement used

  - by ChrisR

  The code below shows that a record is deleted when the sql statement is: select * from test where qty between 50 and 59 but the sql statement: select * from test where partno like 'PART/005%' throws the exception: Advantage.Data.Provider.AdsException: Error 5072: Action requires read-write access to the table How can you reliably delete a record with a where clause applied? Note: I'm using Advantage Database v9.10.1.9, VS2008, .Net Framework 3.5 and WinXP 32 bit using System.IO; using Advantage.Data.Provider; using AdvantageClientEngine; using NUnit.Framework; namespace NetworkEidetics.Core.Tests.Dbf { [TestFixture] public class AdvantageDatabaseTests { private const string DefaultConnectionString = @"data source={0};ServerType=local;TableType=ADS_CDX;LockMode=COMPATIBLE;TrimTrailingSpaces=TRUE;ShowDeleted=FALSE"; private const string TestFilesDirectory = "./TestFiles"; [SetUp] public void Setup() { const string createSql = @"CREATE TABLE [{0}] (ITEM_NO char(4), PARTNO char(20), QTY numeric(6,0), QUOTE numeric(12,4)) "; const string insertSql = @"INSERT INTO [{0}] (ITEM_NO, PARTNO, QTY, QUOTE) VALUES('{1}', '{2}', {3}, {4})"; const string filename = "test.dbf"; var connectionString = string.Format(DefaultConnectionString, TestFilesDirectory); using (var connection = new AdsConnection(connectionString)) { connection.Open(); using (var transaction = connection.BeginTransaction()) { using (var command = connection.CreateCommand()) { command.CommandText = string.Format(createSql, filename); command.Transaction = transaction; command.ExecuteNonQuery(); } transaction.Commit(); } using (var transaction = connection.BeginTransaction()) { for (var i = 0; i < 1000; ++i) { using (var command = connection.CreateCommand()) { var itemNo = string.Format("{0}", i); var partNumber = string.Format("PART/{0:d4}", i); var quantity = i; var quote = i * 10; command.CommandText = string.Format(insertSql, filename, itemNo, partNumber, quantity, quote); command.Transaction = transaction; command.ExecuteNonQuery(); } } transaction.Commit(); } connection.Close(); } } [TearDown] public void TearDown() { File.Delete("./TestFiles/test.dbf"); } [Test] public void CanDeleteRecord() { const string sqlStatement = @"select * from test"; Assert.AreEqual(1000, GetRecordCount(sqlStatement)); DeleteRecord(sqlStatement, 3); Assert.AreEqual(999, GetRecordCount(sqlStatement)); } [Test] public void CanDeleteRecordBetween() { const string sqlStatement = @"select * from test where qty between 50 and 59"; Assert.AreEqual(10, GetRecordCount(sqlStatement)); DeleteRecord(sqlStatement, 3); Assert.AreEqual(9, GetRecordCount(sqlStatement)); } [Test] public void CanDeleteRecordWithLike() { const string sqlStatement = @"select * from test where partno like 'PART/005%'"; Assert.AreEqual(10, GetRecordCount(sqlStatement)); DeleteRecord(sqlStatement, 3); Assert.AreEqual(9, GetRecordCount(sqlStatement)); } public int GetRecordCount(string sqlStatement) { var connectionString = string.Format(DefaultConnectionString, TestFilesDirectory); using (var connection = new AdsConnection(connectionString)) { connection.Open(); using (var command = connection.CreateCommand()) { command.CommandText = sqlStatement; var reader = command.ExecuteExtendedReader(); return reader.GetRecordCount(AdsExtendedReader.FilterOption.RespectFilters); } } } public void DeleteRecord(string sqlStatement, int rowIndex) { var connectionString = string.Format(DefaultConnectionString, TestFilesDirectory); using (var connection = new AdsConnection(connectionString)) { connection.Open(); using (var command = connection.CreateCommand()) { command.CommandText = sqlStatement; var reader = command.ExecuteExtendedReader(); reader.GotoBOF(); reader.Read(); if (rowIndex != 0) { ACE.AdsSkip(reader.AdsActiveHandle, rowIndex); } reader.DeleteRecord(); } connection.Close(); } } } }

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• method is not called from xhtml

  - by Amlan Karmakar

  Whenever I am clicking the h:commandButton,the method associated with the action is not called.action="${statusBean.update}" is not working, the update is not being called. 1) Here is my xhtml page <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:p="http://primefaces.org/ui"> <h:head></h:head> <h:body> <h:form > <p:dataList value="#{statusBean.statusList}" var="p"> <h:outputText value="#{p.statusId}-#{p.statusmsg}"/><br/> <p:inputText value="#{statusBean.comment.comment}"/> <h:commandButton value="comment" action="${statusBean.update}"></h:commandButton> </p:dataList> </h:form> </h:body> </html> 2)Here is my statusBean package com.bean; import java.util.List; import javax.faces.context.FacesContext; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; import javax.servlet.http.HttpSession; import com.entity.Album; import com.entity.Comment; import com.entity.Status; import com.entity.User; public class StatusBean { Comment comment; Status status; private EntityManager em; public Comment getComment() { return comment; } public void setComment(Comment comment) { this.comment = comment; } public Status getStatus() { return status; } public void setStatus(Status status) { this.status = status; } public StatusBean(){ comment = new Comment(); status=new Status(); EntityManagerFactory emf=Persistence.createEntityManagerFactory("FreeBird"); em =emf.createEntityManager(); } public String save(){ FacesContext context = FacesContext.getCurrentInstance(); HttpSession session = (HttpSession) context.getExternalContext().getSession(true); User user = (User) session.getAttribute("userdet"); status.setEmail(user.getEmail()); System.out.println("status save called"); em.getTransaction().begin(); em.persist(status); em.getTransaction().commit(); return "success"; } public List<Status> getStatusList(){ FacesContext context = FacesContext.getCurrentInstance(); HttpSession session = (HttpSession) context.getExternalContext().getSession(true); User user=(User) session.getAttribute("userdet"); Query query = em.createQuery("SELECT s FROM Status s WHERE s.email='"+user.getEmail()+"'", Status.class); List<Status> results =query.getResultList(); return results; } public String update(){ System.out.println("Update Called..."); //comment.setStatusId(Integer.parseInt(statusId)); em.getTransaction().begin(); em.persist(comment); em.getTransaction().commit(); return "success"; } }

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• Problem detaching entire object graph in GAE-J with JDO

  - by tempy

  I am trying to load the full object graph for User, which contains a collection of decks, which then contains a collection of cards, as such: User: @PersistenceCapable(detachable = "true") @Inheritance(strategy = InheritanceStrategy.SUBCLASS_TABLE) @FetchGroup(name = "decks", members = { @Persistent(name = "_Decks") }) public abstract class User { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) protected Key _ID; @Persistent protected String _UniqueIdentifier; @Persistent(mappedBy = "_Owner") @Element(dependent = "true") protected Set<Deck> _Decks; protected User() { } } Each Deck has a collection of Cards, as such: @PersistenceCapable(detachable = "true") @FetchGroup(name = "cards", members = { @Persistent(name = "_Cards") }) public class Deck { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key _ID; @Persistent String _Name; @Persistent(mappedBy = "_Parent") @Element(dependent = "true") private Set<Card> _Cards = new HashSet<Card>(); @Persistent private Set<String> _Tags = new HashSet<String>(); @Persistent private User _Owner; } And finally, each card: @PersistenceCapable public class Card { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key _ID; @Persistent private Text _Question; @Persistent private Text _Answer; @Persistent private Deck _Parent; } I am trying to retrieve and then detach the entire object graph. I can see in the debugger that it loads fine, but then when I get to detaching, I can't make anything beyond the User object load. (No Decks, no Cards). At first I tried without a transaction to simply "touch" all the fields on the attached object before detaching, but that didn't help. Then I tried adding everything to the default fetch group, but that just generated warnings about GAE not supporting joins. I tried setting the fetch plan's max fetch depth to -1, but that didn't do it. Finally, I tried using FetchGroups as you can see above, and then retrieving with the following code: PersistenceManager pm = _pmf.getPersistenceManager(); pm.setDetachAllOnCommit(true); pm.getFetchPlan().setGroup("decks"); pm.getFetchPlan().setGroup("cards"); Transaction tx = pm.currentTransaction(); Query query = null; try { tx.begin(); query = pm.newQuery(GoogleAccountsUser.class); //Subclass of User query.setFilter("_UniqueIdentifier == TheUser"); query.declareParameters("String TheUser"); List<User> results = (List<User>)query.execute(ID); //ID = Supplied parameter //TODO: Test for more than one result and throw if(results.size() == 0) { tx.commit(); return null; } else { User usr = (User)results.get(0); //usr = pm.detachCopy(usr); tx.commit(); return usr; } } finally { query.closeAll(); if (tx.isActive()) { tx.rollback(); } pm.close(); } This also doesn't work, and I'm running out of ideas...

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• "FOR UPDATE" v/s "LOCK IN SHARE MODE" : Allow concurrent threads to read updated "state" value of locked row

  - by shadesco

  I have the following scenario: User X logs in to the application from location lc1: call it Ulc1 User X (has been hacked, or some friend of his knows his login credential, or he just logs in from a different browser on his machine,etc.. u got the point) logs in at the same time from location lc2: call it Ulc2 I am using a main servlet which : - gets a connection from database pooling - sets autocommit to false - executes a command that goes through app layers: if all successful, set autocommit to true in a "finally" statement, and closes connection. Else if an exception happens, rollback(). In my database (mysql/innoDb) i have a "history" table, with row columns: id(primary key) |username | date | topic | locked The column "locked" has by default value "false" and it serves as a flag that marks if a specific row is locked or not. Each row is specific to a user (as u can see from the username column) So back to the scenario: --Ulc1 sends the command to update his history from the db for date "D" and topic "T". --Ulc2 sends the same command to update history from the db for the same date "D" and same topic "T" at the exact same time. I want to implement an mysql/innoDB locking system that will enable whichever thread arriving to do the following check: Is column "locked" for this row true or not? if true, return a message to the user that " he is already updating the same data from another location" if not true (ie not locked) : flag it as locked and update then reset locked to false once finished. Which of these two mysql locking techniques, will actually allow the 2nd arriving thread from reading the "updated" value of the locked column to decide wt action to take?Should i use "FOR UPDATE" or "LOCK IN SHARE MODE"? This scenario explains what i want to accomplish: - Ulc1 thread arrives first: column "locked" is false, set it to true and continue updating process - Ulc2 thread arrives while Ulc1's transaction is still in process, and even though the row is locked through innoDb functionalities, it doesn't have to wait but in fact reads the "new" value of column locked which is "true", and so doesn't in fact have to wait till Ulc1 transaction commits to read the value of the "locked" column(anyway by that time the value of this column will already have been reset to false). I am not very experienced with the 2 types of locking mechanisms, what i understand so far is that LOCK IN SHARE MODE allow other transaction to read the locked row while FOR UPDATE doesn't even allow reading. But does this read gets on the updated value? or the 2nd arriving thread has to wait the first thread to commit to then read the value? Any recommendations about which locking mechanism to use for this scenario is appreciated. Also if there's a better way to "check" if the row has been locked (other than using a true/false column flag) please let me know about it. thank you SOLUTION (Jdbc pseudocode example based on @Darhazer's answer) Table : [ id(primary key) |username | date | topic | locked ] connection.setautocommit(false); //transaction-1 PreparedStatement ps1 = "Select locked from tableName for update where id="key" and locked=false); ps1.executeQuery(); //transaction 2 PreparedStatement ps2 = "Update tableName set locked=true where id="key"; ps2.executeUpdate(); connection.setautocommit(true);// here we allow other transactions threads to see the new value connection.setautocommit(false); //transaction 3 PreparedStatement ps3 = "Update tableName set aField="Sthg" where id="key" And date="D" and topic="T"; ps3.executeUpdate(); // reset locked to false PreparedStatement ps4 = "Update tableName set locked=false where id="key"; ps4.executeUpdate(); //commit connection.setautocommit(true);

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• Ajax using Rails

  - by Steve

  Hi, I have a favourite and un-favourite functionality in my application and I am using jQuery. This functionality works partially. The page gets loaded, and when I click the 'favourite' button(it is inside add_favourite_div element), it sends a XHR request and the post is set as favourite. Then a new div called "remove_favourite_div" replaces its place.Now when I click the remove favourite(which is part of remove_favourite_div), it sends a normal http request inside of xhr. The structure when the page gets loaded first time <div id="favourite"> <div id="add_favourite_div"> <form method="post" id="add_favourite" action="/viewpost/add_favourite"> <div style="margin: 0pt; padding: 0pt; display: inline;"> <input type="hidden" value="w873BgYHLxQmadUalzMRUC+1ql4AtP3U7f78dT8x9ho=" name="authenticity_token"> </div> <input type="hidden" value="3" name="Favourite[post_id]" id="Favourite_place_id"> <input type="hidden" value="2" name="Favourite[user_id]" id="Favourite_user_id"> <input type="submit" value="Favourite" name="commit"><br> </form> </div> </div> DOM after clicking on the unfavourite button <div id="favourite"> <div id="remove_favourite_div"> <form method="post" id="remove_favourite" action="/viewpost/remove_favourite"> <div style="margin: 0pt; padding: 0pt; display: inline;"> <input type="hidden" value="w873BgYHLxQmadUalzMRUC+1ql4AtP3U7f78dT8x9ho=" name="authenticity_token"> </div> <input type="hidden" value="3" name="Favourite[post_id]" id="Favourite_place_id"> <input type="hidden" value="2" name="Favourite[user_id]" id="Favourite_user_id"> <input type="submit" value="UnFavourite" name="commit"><br> </form> </div> </div> In my application.js, I have two functions to trigger the xhr request $("#add_favourite").submit(function(){ alert("add favourite"); action = $(this).attr("action") $.post(action,$(this).serialize(),null,"script"); return false; }); $("#remove_favourite").submit(function(){ alert("remove favourite"); action = $(this).attr("action"); $.post(action,$(this).serialize(),null,"script"); return false; }); Here, when the post is initially not a favourite, favourite button is displayed and when i clicked on the button, $("#add_favourite").submit gets called and unfavourite form is displayed correctly, but now when I click on the un-favourite button, $("#remove_favourite").submit does not get called. The whole scenario is true in both ways, I mean favourite-Unfavourite and Unfavourite-favourite Can someone please help me to solve this Thanks

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• form_for called in a loop overloads IDs and associates fields and labels incorrectly

  - by Katy Levinson

  Rails likes giving all of my fields the same IDs when they are generated in a loop, and this causes trouble. <% current_user.subscriptions.each do |s| %> <div class="subscription_listing"> <%= link_to_function s.product.name, "toggle_delay(this)"%> in <%= s.calc_time_to_next_arrival %> days. <div class="modify_subscription"> <%= form_for s, :url => change_subscription_path(s) do |f| %> <%= label_tag(:q, "Days to delay:") %> <%= text_field_tag(:query) %> <%= check_box_tag(:always) %> <%= label_tag(:always, "Apply delay to all future orders") %> <%= submit_tag("Change") %> <% end %> <%= link_to 'Destroy', s, :confirm => 'Are you sure?', :method => :delete %> </div> </div> <% end %> Produces <div class="subscription_listing"> <a href="#" onclick="toggle_delay(this); return false;">Pasta</a> in 57 days. <div class="modify_subscription"> <form accept-charset="UTF-8" action="/subscriptions/7/change" class="edit_subscription" id="edit_subscription_7" method="post"><div style="margin:0;padding:0;display:inline"><input name="utf8" type="hidden" value="&#x2713;" /><input name="_method" type="hidden" value="put" /><input name="authenticity_token" type="hidden" value="s5LJffuzmbEMkSrez8b3KLVmDWN/PGmDryXhp25+qc4=" /></div> <label for="q">Days to delay:</label> <input id="query" name="query" type="text" /> <input id="always" name="always" type="checkbox" value="1" /> <label for="always">Apply delay to all future orders</label> <input name="commit" type="submit" value="Change" /> </form> <a href="/subscriptions/7" data-confirm="Are you sure?" data-method="delete" rel="nofollow">Destroy</a> </div> </div> <div class="subscription_listing"> <a href="#" onclick="toggle_delay(this); return false;">Gummy Bears</a> in 57 days. <div class="modify_subscription"> <form accept-charset="UTF-8" action="/subscriptions/8/change" class="edit_subscription" id="edit_subscription_8" method="post"><div style="margin:0;padding:0;display:inline"><input name="utf8" type="hidden" value="&#x2713;" /><input name="_method" type="hidden" value="put" /><input name="authenticity_token" type="hidden" value="s5LJffuzmbEMkSrez8b3KLVmDWN/PGmDryXhp25+qc4=" /></div> <label for="q">Days to delay:</label> <input id="query" name="query" type="text" /> <input id="always" name="always" type="checkbox" value="1" /> <label for="always">Apply delay to all future orders</label> <input name="commit" type="submit" value="Change" /> </form> <a href="/subscriptions/8" data-confirm="Are you sure?" data-method="delete" rel="nofollow">Destroy</a> </div> </div> And that's a problem because now no matter which "Apply delay to all future orders" I select it always very helpfully checks the first box for me. How can I override the ID without doing something ugly and un-rails-like?

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• xf86OpenConsole: Cannot find a free VT: Invalid argument

  - by Oliver Seeliger

  I'v set up an Ubuntu 12.04 from the precreated OpenVZ template. The host system is configured as follows: # $ cat /etc/issue Debian GNU/Linux 6.0 # $ uname -a Linux openvz-02 2.6.32-16-pve #1 SMP Fri Nov 9 11:42:51 CET 2012 x86_64 GNU/Linux # $ apt-cache showpkg proxmox-ve-2.6.32 Package: proxmox-ve-2.6.32 # $ tail -n 3 /etc/apt/sources.list # PVE packages provided by proxmox.com deb http://download.proxmox.com/debian squeeze pve For a software project I need a minimal xserver and followed the instructions at https://help.ubuntu.com/community/ServerGUI. I simply installed the package xorg (xorg 1:7.6+7ubuntu7.1). Now when I 'startx' I get an error message Fatal server error: xf86OpenConsole: Cannot find a free VT: Invalid argument The complete output of startx # startx X.Org X Server 1.11.3 Release Date: 2011-12-16 X Protocol Version 11, Revision 0 Build Operating System: Linux 2.6.42-23-generic x86_64 Ubuntu Current Operating System: Linux www 2.6.32-16-pve #1 SMP Fri Nov 9 11:42:51 CET 2012 x86_64 Kernel command line: quiet Build Date: 29 August 2012 12:12:33AM xorg-server 2:1.11.4-0ubuntu10.8 (For technical support please see http://www.ubuntu.com/support) Current version of pixman: 0.24.4 Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. (==) Log file: "/var/log/Xorg.0.log", Time: Tue Nov 20 08:46:04 2012 (==) Using system config directory "/usr/share/X11/xorg.conf.d" Fatal server error: xf86OpenConsole: Cannot find a free VT: Invalid argument Please consult the The X.Org Foundation support at http://wiki.x.org for help. Please also check the log file at "/var/log/Xorg.0.log" for additional information. ddxSigGiveUp: Closing log Server terminated with error (1). Closing log file.

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• Netflix, jQuery, JSONP, and OData

  - by Stephen Walther

  At the last MIX conference, Netflix announced that they are exposing their catalog of movie information using the OData protocol. This is great news! This means that you can take advantage of all of the advanced OData querying features against a live database of Netflix movies. In this blog entry, I’ll demonstrate how you can use Netflix, jQuery, JSONP, and OData to create a simple movie lookup form. The form enables you to enter a movie title, or part of a movie title, and display a list of matching movies. For example, Figure 1 illustrates the movies displayed when you enter the value robot into the lookup form.   Using the Netflix OData Catalog API You can learn about the Netflix OData Catalog API at the following website: http://developer.netflix.com/docs/oData_Catalog The nice thing about this website is that it provides plenty of samples. It also has a good general reference for OData. For example, the website includes a list of OData filter operators and functions. The Netflix Catalog API exposes 4 top-level resources: Titles – A database of Movie information including interesting movie properties such as synopsis, BoxArt, and Cast. People – A database of people information including interesting information such as Awards, TitlesDirected, and TitlesActedIn. Languages – Enables you to get title information in different languages. Genres – Enables you to get title information for specific movie genres. OData is REST based. This means that you can perform queries by putting together the right URL. For example, if you want to get a list of the movies that were released after 2010 and that had an average rating greater than 4 then you can enter the following URL in the address bar of your browser: http://odata.netflix.com/Catalog/Titles?$filter=ReleaseYear gt 2010&AverageRating gt 4 Entering this URL returns the movies in Figure 2. Creating the Movie Lookup Form The complete code for the Movie Lookup form is contained in Listing 1. Listing 1 – MovieLookup.htm <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Netflix with jQuery</title> <style type="text/css"> #movieTemplateContainer div { width:400px; padding: 10px; margin: 10px; border: black solid 1px; } </style> <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js" type="text/javascript"></script> <script src="App_Scripts/Microtemplates.js" type="text/javascript"></script> </head> <body> <label>Search Movies:</label> <input id="movieName" size="50" /> <button id="btnLookup">Lookup</button> <div id="movieTemplateContainer"></div> <script id="movieTemplate" type="text/html"> <div> <img src="<%=BoxArtSmallUrl %>" /> <strong><%=Name%></strong> <p> <%=Synopsis %> </p> </div> </script> <script type="text/javascript"> $("#btnLookup").click(function () { // Build OData query var movieName = $("#movieName").val(); var query = "http://odata.netflix.com/Catalog" // netflix base url + "/Titles" // top-level resource + "?$filter=substringof('" + escape(movieName) + "',Name)" // filter by movie name + "&$callback=callback" // jsonp request + "&$format=json"; // json request // Make JSONP call to Netflix $.ajax({ dataType: "jsonp", url: query, jsonpCallback: "callback", success: callback }); }); function callback(result) { // unwrap result var movies = result["d"]["results"]; // show movies in template var showMovie = tmpl("movieTemplate"); var html = ""; for (var i = 0; i < movies.length; i++) { // flatten movie movies[i].BoxArtSmallUrl = movies[i].BoxArt.SmallUrl; // render with template html += showMovie(movies[i]); } $("#movieTemplateContainer").html(html); } </script> </body> </html> The HTML page in Listing 1 includes two JavaScript libraries: <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js" type="text/javascript"></script> <script src="App_Scripts/Microtemplates.js" type="text/javascript"></script> The first script tag retrieves jQuery from the Microsoft Ajax CDN. You can learn more about the Microsoft Ajax CDN by visiting the following website: http://www.asp.net/ajaxLibrary/cdn.ashx The second script tag is used to reference Resig’s micro-templating library. Because I want to use a template to display each movie, I need this library: http://ejohn.org/blog/javascript-micro-templating/ When you enter a value into the Search Movies input field and click the button, the following JavaScript code is executed: // Build OData query var movieName = $("#movieName").val(); var query = "http://odata.netflix.com/Catalog" // netflix base url + "/Titles" // top-level resource + "?$filter=substringof('" + escape(movieName) + "',Name)" // filter by movie name + "&$callback=callback" // jsonp request + "&$format=json"; // json request // Make JSONP call to Netflix $.ajax({ dataType: "jsonp", url: query, jsonpCallback: "callback", success: callback }); This code Is used to build a query that will be executed against the Netflix Catalog API. For example, if you enter the search phrase King Kong then the following URL is created: http://odata.netflix.com/Catalog/Titles?$filter=substringof(‘King%20Kong’,Name)&$callback=callback&$format=json This query includes the following parameters: $filter – You assign a filter expression to this parameter to filter the movie results. $callback – You assign the name of a JavaScript callback method to this parameter. OData calls this method to return the movie results. $format – you assign either the value json or xml to this parameter to specify how the format of the movie results. Notice that all of the OData parameters -- $filter, $callback, $format -- start with a dollar sign $. The Movie Lookup form uses JSONP to retrieve data across the Internet. Because WCF Data Services supports JSONP, and Netflix uses WCF Data Services to expose movies using the OData protocol, you can use JSONP when interacting with the Netflix Catalog API. To learn more about using JSONP with OData, see Pablo Castro’s blog: http://blogs.msdn.com/pablo/archive/2009/02/25/adding-support-for-jsonp-and-url-controlled-format-to-ado-net-data-services.aspx The actual JSONP call is performed by calling the $.ajax() method. When this call successfully completes, the JavaScript callback() method is called. The callback() method looks like this: function callback(result) { // unwrap result var movies = result["d"]["results"]; // show movies in template var showMovie = tmpl("movieTemplate"); var html = ""; for (var i = 0; i < movies.length; i++) { // flatten movie movies[i].BoxArtSmallUrl = movies[i].BoxArt.SmallUrl; // render with template html += showMovie(movies[i]); } $("#movieTemplateContainer").html(html); } The movie results from Netflix are passed to the callback method. The callback method takes advantage of Resig’s micro-templating library to display each of the movie results. A template used to display each movie is passed to the tmpl() method. The movie template looks like this: <script id="movieTemplate" type="text/html"> <div> <img src="<%=BoxArtSmallUrl %>" /> <strong><%=Name%></strong> <p> <%=Synopsis %> </p> </div> </script>   This template looks like a server-side ASP.NET template. However, the template is rendered in the client (browser) instead of the server. Summary The goal of this blog entry was to demonstrate how well jQuery works with OData. We managed to use a number of interesting open-source libraries and open protocols while building the Movie Lookup form including jQuery, JSONP, JSON, and OData.

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• SVN: Working with branches using the same working copy

  - by uXuf

  We've just moved to SVN from CVS. We have a small team and everyone checks in code on the trunk and we have never ever used branches for development. We each have directories on a remote dev server with the codebase checked out. Each developer works on their own sandbox with an associated URL to pull up the app in a browser (something like the setup here: Trade-offs of local vs remote development workflows for a web development team). I've decided that for my current project, I'll use a branch because it would span multiple releases. I've already cut a branch out, but I am using the same directory as the one originally checked out (i.e. for the trunk). Since it's the same directory (or working copy) for both the branch and the trunk, if for e.g. a bug pops up in the app I switch to the trunk and commit the change there, and then switch back to my branch for my project development. My questions are: Is this a sane way to work with branches? Are there any pitfalls that I need to be aware of? What would be the optimal way to work with branches if separate working copies are out of the question? I haven't had issues yet as I have just started doing this way but all the tutorials/books/blog posts I have seen about branching with SVN imply working with different working copies (or perhaps I haven't come across an explanation of mixed working copies in plain English). I just don't want to be sorry three months down the road when its time to integrate the branch back to the trunk.

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• Making Sense of ASP.NET Paths

  - by Rick Strahl

  ASP.Net includes quite a plethora of properties to retrieve path information about the current request, control and application. There's a ton of information available about paths on the Request object, some of it appearing to overlap and some of it buried several levels down, and it can be confusing to find just the right path that you are looking for. To keep things straight I thought it a good idea to summarize the path options along with descriptions and example paths. I wrote a post about this a long time ago in 2004 and I find myself frequently going back to that page to quickly figure out which path I’m looking for in processing the current URL. Apparently a lot of people must be doing the same, because the original post is the second most visited even to this date on this blog to the tune of nearly 500 hits per day. So, I decided to update and expand a bit on the original post with a little more information and clarification based on the original comments. Request Object Paths Available Here's a list of the Path related properties on the Request object (and the Page object). Assume a path like http://www.west-wind.com/webstore/admin/paths.aspx for the paths below where webstore is the name of the virtual. .blackborder td { border-bottom: solid 1px silver; border-left: solid 1px silver; } Request Property Description and Value ApplicationPath Returns the web root-relative logical path to the virtual root of this app. /webstore/ PhysicalApplicationPath Returns local file system path of the virtual root for this app. c:\inetpub\wwwroot\webstore PhysicalPath Returns the local file system path to the current script or path. c:\inetpub\wwwroot\webstore\admin\paths.aspx Path FilePath CurrentExecutionFilePath All of these return the full root relative logical path to the script page including path and scriptname. CurrentExcecutionFilePath will return the ‘current’ request path after a Transfer/Execute call while FilePath will always return the original request’s path. /webstore/admin/paths.aspx AppRelativeCurrentExecutionFilePath Returns an ASP.NET root relative virtual path to the script or path for the current request. If in  a Transfer/Execute call the transferred Path is returned. ~/admin/paths.aspx PathInfo Returns any extra path following the script name. If no extra path is provided returns the root-relative path (returns text in red below). string.Empty if no PathInfo is available. /webstore/admin/paths.aspx/ExtraPathInfo RawUrl Returns the full root relative URL including querystring and extra path as a string. /webstore/admin/paths.aspx?sku=wwhelp40 Url Returns a fully qualified URL including querystring and extra path. Note this is a Uri instance rather than string. http://www.west-wind.com/webstore/admin/paths.aspx?sku=wwhelp40 UrlReferrer The fully qualified URL of the page that sent the request. This is also a Uri instance and this value is null if the page was directly accessed by typing into the address bar or using an HttpClient based Referrer client Http header. http://www.west-wind.com/webstore/default.aspx?Info Control.TemplateSourceDirectory Returns the logical path to the folder of the page, master or user control on which it is called. This is useful if you need to know the path only to a Page or control from within the control. For non-file controls this returns the Page path. /webstore/admin/ As you can see there’s a ton of information available there for each of the three common path formats: Physical Path is an OS type path that points to a path or file on disk. Logical Path is a Web path that is relative to the Web server’s root. It includes the virtual plus the application relative path. ~/ (Root-relative) Path is an ASP.NET specific path that includes ~/ to indicate the virtual root Web path. ASP.NET can convert virtual paths into either logical paths using Control.ResolveUrl(), or physical paths using Server.MapPath(). Root relative paths are useful for specifying portable URLs that don’t rely on relative directory structures and very useful from within control or component code. You should be able to get any necessary format from ASP.NET from just about any path or script using these mechanisms. ~/ Root Relative Paths and ResolveUrl() and ResolveClientUrl() ASP.NET supports root-relative virtual path syntax in most of its URL properties in Web Forms. So you can easily specify a root relative path in a control rather than a location relative path: <asp:Image runat="server" ID="imgHelp" ImageUrl="~/images/help.gif" /> ASP.NET internally resolves this URL by using ResolveUrl("~/images/help.gif") to arrive at the root-relative URL of /webstore/images/help.gif which uses the Request.ApplicationPath as the basepath to replace the ~. By convention any custom Web controls also should use ResolveUrl() on URL properties to provide the same functionality. In your own code you can use Page.ResolveUrl() or Control.ResolveUrl() to accomplish the same thing: string imgPath = this.ResolveUrl("~/images/help.gif"); imgHelp.ImageUrl = imgPath; Unfortunately ResolveUrl() is limited to WebForm pages, so if you’re in an HttpHandler or Module it’s not available. ASP.NET Mvc also has it’s own more generic version of ResolveUrl in Url.Decode: <script src="<%= Url.Content("~/scripts/new.js") %>" type="text/javascript"></script> which is part of the UrlHelper class. In ASP.NET MVC the above sort of syntax is actually even more crucial than in WebForms due to the fact that views are not referencing specific pages but rather are often path based which can lead to various variations on how a particular view is referenced. In a Module or Handler code Control.ResolveUrl() unfortunately is not available which in retrospect seems like an odd design choice – URL resolution really should happen on a Request basis not as part of the Page framework. Luckily you can also rely on the static VirtualPathUtility class: string path = VirtualPathUtility.ToAbsolute("~/admin/paths.aspx"); VirtualPathUtility also many other quite useful methods for dealing with paths and converting between the various kinds of paths supported. One thing to watch out for is that ToAbsolute() will throw an exception if a query string is provided and doesn’t work on fully qualified URLs. I wrote about this topic with a custom solution that works fully qualified URLs and query strings here (check comments for some interesting discussions too). Similar to ResolveUrl() is ResolveClientUrl() which creates a fully qualified HTTP path that includes the protocol and domain name. It’s rare that this full resolution is needed but can be useful in some scenarios. Mapping Virtual Paths to Physical Paths with Server.MapPath() If you need to map root relative or current folder relative URLs to physical URLs or you can use HttpContext.Current.Server.MapPath(). Inside of a Page you can do the following: string physicalPath = Server.MapPath("~/scripts/ww.jquery.js")); MapPath is pretty flexible and it understands both ASP.NET style virtual paths as well as plain relative paths, so the following also works. string physicalPath = Server.MapPath("scripts/silverlight.js"); as well as dot relative syntax: string physicalPath = Server.MapPath("../scripts/jquery.js"); Once you have the physical path you can perform standard System.IO Path and File operations on the file. Remember with physical paths and IO or copy operations you need to make sure you have permissions to access files and folders based on the Web server user account that is active (NETWORK SERVICE, ASPNET typically). Note the Server.MapPath will not map up beyond the virtual root of the application for security reasons. Server and Host Information Between these settings you can get all the information you may need to figure out where you are at and to build new Url if necessary. If you need to build a URL completely from scratch you can get access to information about the server you are accessing: Server Variable Function and Example SERVER_NAME The of the domain or IP Address wwww.west-wind.com or 127.0.0.1 SERVER_PORT The port that the request runs under. 80 SERVER_PORT_SECURE Determines whether https: was used. 0 or 1 APPL_MD_PATH ADSI DirectoryServices path to the virtual root directory. Note that LM typically doesn’t work for ADSI access so you should replace that with LOCALHOST or the machine’s NetBios name. /LM/W3SVC/1/ROOT/webstore Request.Url and Uri Parsing If you still need more control over the current request URL or  you need to create new URLs from an existing one, the current Request.Url Uri property offers a lot of control. Using the Uri class and UriBuilder makes it easy to retrieve parts of a URL and create new URLs based on existing URL. The UriBuilder class is the preferred way to create URLs – much preferable over creating URIs via string concatenation. Uri Property Function Scheme The URL scheme or protocol prefix. http or https Port The port if specifically specified. DnsSafeHost The domain name or local host NetBios machine name www.west-wind.com or rasnote LocalPath The full path of the URL including script name and extra PathInfo. /webstore/admin/paths.aspx Query The query string if any ?id=1 The Uri class itself is great for retrieving Uri parts, but most of the properties are read only if you need to modify a URL in order to change it you can use the UriBuilder class to load up an existing URL and modify it to create a new one. Here are a few common operations I’ve needed to do to get specific URLs: Convert the Request URL to an SSL/HTTPS link For example to take the current request URL and converted  it to a secure URL can be done like this: UriBuilder build = new UriBuilder(Request.Url); build.Scheme = "https"; build.Port = -1; // don't inject port Uri newUri = build.Uri; string newUrl = build.ToString(); Retrieve the fully qualified URL without a QueryString AFAIK, there’s no native routine to retrieve the current request URL without the query string. It’s easy to do with UriBuilder however: UriBuilder builder = newUriBuilder(Request.Url); builder.Query = ""; stringlogicalPathWithoutQuery = builder.ToString(); What else? I took a look through the old post’s comments and addressed as many of the questions and comments that came up in there. With a few small and silly exceptions this update post handles most of these. But I’m sure there are a more things that go in here. What else would be useful to put onto this post so it serves as a nice all in one place to go for path references? If you think of something leave a comment and I’ll try to update the post with it in the future.© Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• Envista: Coordinating Utilities with Oracle Spatial 11g

  - by stephen.garth

  It's annoying when the same streets seem to be perpetually dug up for utility construction or maintenance by your water or sewer department, electric utility, gas company or telephone company. Can't they do a better job of coordinating these activities? In this podcast, Marc Fagan, Executive VP of Product Management from Envista describes a Software-as-a-Service solution that Envista provides for utilities and public works departments to coordinate upcoming construction work, using Oracle Database 11g with Oracle Spatial. Each participating utility enters key data into the Web-based application, including when and where their work is to take place, and who to contact for more information. The data is then available on a common base map, enabling all participants to coordinate their activities, save money, and minimize inconvenience to their customers. Listen to the podcast Find out more about Oracle Spatial 11g var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); try { var pageTracker = _gat._getTracker("UA-13185312-1"); pageTracker._trackPageview(); } catch(err) {}

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• Video Recording Not Working in ICS

  - by Nirav Ranpara

  I have implement code Record video in Android Phone . This code is working in 2.2 , 2.3 . not in ICS But when I checked in ICS code is not working ? here I posted code and xml file. videorecord.java import java.io.File; import java.io.IOException; import android.app.Activity; import android.app.AlertDialog; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.content.SharedPreferences; import android.hardware.Camera; import android.media.CamcorderProfile; import android.media.MediaRecorder; import android.os.Bundle; import android.os.CountDownTimer; import android.os.Environment; import android.util.Log; import android.view.Display; import android.view.KeyEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.widget.EditText; import android.widget.FrameLayout; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.TextView; import android.widget.Toast; public class videorecord extends Activity{ SharedPreferences.Editor pre; String filename; CountDownTimer t; private Camera myCamera; private MyCameraSurfaceView myCameraSurfaceView; private MediaRecorder mediaRecorder; Integer cnt=0; LinearLayout myButton; TextView myButton1; SurfaceHolder surfaceHolder; boolean recording; private TextView txtcount; private ImageView btnplay; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); recording = false; setContentView(R.layout.videorecord); init(); myCamera = getCameraInstance(); if(myCamera == null){ } myCameraSurfaceView = new MyCameraSurfaceView(this, myCamera); FrameLayout myCameraPreview = (FrameLayout)findViewById(R.id.videoview); Display display = getWindowManager().getDefaultDisplay(); int width = display.getWidth(); int height = display.getHeight(); myCameraSurfaceView.setLayoutParams(new LinearLayout.LayoutParams(width, height-60)); myCameraPreview.addView(myCameraSurfaceView); myButton = (LinearLayout)findViewById(R.id.mybutton); btnplay.setOnClickListener(myButtonOnClickListener); } private void init() { txtcount = (TextView) findViewById(R.id.txtcounter); //myButton1 = (TextView) findViewById(R.id.mybutton1); btnplay = (ImageView)findViewById(R.id.btnplay); t = new CountDownTimer( Long.MAX_VALUE , 1000) { @Override public void onTick(long millisUntilFinished) { cnt++; String time = new Integer(cnt).toString(); long millis = cnt; int seconds = (int) (millis / 60); int minutes = seconds / 60; seconds = seconds % 60; txtcount.setText(String.format("%d:%02d:%02d", minutes, seconds,millis)); } @Override public void onFinish() { } }; } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if ((keyCode == KeyEvent.KEYCODE_BACK)) { if(recording) { new AlertDialog.Builder(videorecord.this).setTitle("Do you want to save Video ?") .setPositiveButton("OK", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { filename(); //finish(); } }).setNegativeButton("Cancle", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub } }).show(); } else { if ((keyCode == KeyEvent.KEYCODE_BACK)) { //Intent homeIntent= new Intent(Intent.ACTION_MAIN); //homeIntent.addCategory(Intent.CATEGORY_HOME); //homeIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); //startActivity(homeIntent); //this.finishActivity(1); finish(); } //moveTaskToBack(true); // finish(); return super.onKeyDown(keyCode, event); } } else { // Toast.makeText(getApplicationContext(), "asd", Toast.LENGTH_LONG).show(); android.os.Process.killProcess(android.os.Process.myPid()) ; } return super.onKeyDown(keyCode, event); } ImageView.OnClickListener myButtonOnClickListener = new ImageView.OnClickListener(){ public void onClick(View v) { if(recording){ Log.e("Record error", "error in recording ."); mediaRecorder.stop(); t.cancel(); filename(); releaseMediaRecorder(); }else{ releaseCamera(); Log.e("Record Stop error", "error in recording ."); // if(!prepareMediaRecorder()){ prepareMediaRecorder(); finish(); } mediaRecorder.start(); recording = true; // myButton1.setText("STOP Recording"); // btnplay.setImageResource(android.R.drawable.ic_media_pause); btnplay.setImageResource(R.drawable.stoprec); t.start(); } }}; private Camera getCameraInstance(){ Camera c = null; try { c = Camera.open(); } catch (Exception e){ } return c; } private void filename() { AlertDialog.Builder alert = new AlertDialog.Builder(this); alert.setTitle("Save Video"); alert.setMessage("Enter File Name"); final EditText input = new EditText(this); alert.setView(input); alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { if(input.getText().length()>=1) { filename = input.getText().toString(); File sdcard = new File(Environment.getExternalStorageDirectory() + "/VideoRecord"); File from = new File(sdcard,"null.mp4"); File to = new File(sdcard,filename+".mp4"); from.renameTo(to); SharedPreferences sp = videorecord.this.getSharedPreferences("data", MODE_WORLD_WRITEABLE); pre = sp.edit(); pre.clear(); pre.commit(); pre.putString("lastvideo", filename+".mp4"); pre.commit(); //btnplay.setImageResource(android.R.drawable.ic_media_play); btnplay.setImageResource(R.drawable.startrec); // Intent intent = new Intent(videorecord.this,StopVidoWatch_Activity.class); // startActivity(intent); Intent myIntent = new Intent(getApplicationContext(), StopVidoWatch_Activity.class).setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); startActivity(myIntent); } else { filename(); } } }); alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { // Intent intent = new Intent(videorecord.this,StopVidoWatch_Activity.class); // startActivity(intent); File file = new File(Environment.getExternalStorageDirectory() + "/VideoRecord/null.mp4"); //boolean deleted = file.delete(); file.delete(); finish(); } }); alert.show(); } private boolean prepareMediaRecorder(){ myCamera = getCameraInstance(); mediaRecorder = new MediaRecorder(); myCamera.unlock(); mediaRecorder.setCamera(myCamera); mediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER); mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA); mediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH)); File folder = new File(Environment.getExternalStorageDirectory() + "/VideoRecord"); boolean success = false; if (!folder.exists()) { success = folder.mkdir(); } if (!success) { } else { } mediaRecorder.setOutputFile("/sdcard/VideoRecord/"+filename+".mp4"); mediaRecorder.setMaxDuration(60000); mediaRecorder.setMaxFileSize(5000000); Display display = getWindowManager().getDefaultDisplay(); int width = display.getHeight(); int height = display.getWidth(); String s = new String(); s= s.valueOf(width); String s1 = new String(); s1= s1.valueOf(height); // Toast.makeText(videorecord.this, "Width : " + s , Toast.LENGTH_LONG).show(); // Toast.makeText(videorecord.this, "Height : " + s1 , Toast.LENGTH_LONG).show(); mediaRecorder.setVideoSize(height, width); mediaRecorder.setPreviewDisplay(myCameraSurfaceView.getHolder().getSurface()); try { mediaRecorder.prepare(); } catch (IllegalStateException e) { releaseMediaRecorder(); return false; } catch (IOException e) { releaseMediaRecorder(); return false; } return true; } @Override protected void onPause() { super.onPause(); releaseMediaRecorder(); releaseCamera(); } private void releaseMediaRecorder() { if (mediaRecorder != null) { mediaRecorder.reset(); mediaRecorder.release(); mediaRecorder = null; myCamera.lock(); } } private void releaseCamera(){ if (myCamera != null){ myCamera.release(); myCamera = null; } } public class MyCameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback{ private SurfaceHolder mHolder; private Camera mCamera; public MyCameraSurfaceView(Context context, Camera camera) { super(context); mCamera = camera; mHolder = getHolder(); mHolder.addCallback(this); mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } public void surfaceChanged(SurfaceHolder holder, int format, int weight, int height) { if (mHolder.getSurface() == null){ return; } try { mCamera.stopPreview(); } catch (Exception e){ } try { mCamera.setPreviewDisplay(mHolder); mCamera.startPreview(); } catch (Exception e){ } } public void surfaceCreated(SurfaceHolder holder) { try { mCamera.setPreviewDisplay(holder); mCamera.startPreview(); } catch (IOException e) { } } public void surfaceDestroyed(SurfaceHolder holder) { } } } videorecord.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <FrameLayout android:layout_width="fill_parent" android:layout_height="fill_parent" > <FrameLayout android:id="@+id/videoview" android:layout_width="fill_parent" android:layout_height="fill_parent"></FrameLayout> <LinearLayout android:id="@+id/mybutton" android:layout_width="fill_parent" android:layout_marginBottom="0dip" android:layout_height="wrap_content" android:orientation="horizontal" android:layout_weight="0" > <!-- <TextView android:text="START Recording" android:id="@+id/mybutton1" android:layout_height="wrap_content" android:layout_width="wrap_content" style="@style/savestyle" android:layout_weight="1" android:gravity="left" > </TextView> --> <ImageView android:layout_height="wrap_content" android:id="@+id/btnplay" android:padding="5dip" android:background="#A0000000" android:textColor="#ffffffff" android:layout_width="wrap_content" android:src="@drawable/startrec" /> </LinearLayout> <TextView android:text="00:00:00" android:id="@+id/txtcounter" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="right|bottom" android:padding="5dip" android:background="#A0000000" android:textColor="#ffffffff" /> </FrameLayout> <RelativeLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@color/bgcolor" > <LinearLayout android:layout_above="@+id/mybutton" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="fill_parent" > </LinearLayout> </RelativeLayout> </LinearLayout>

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• SQL SERVER – Difference Between ROLLBACK IMMEDIATE and WITH NO_WAIT during ALTER DATABASE

  - by pinaldave

  Today, we are going to discuss about something very simple, but quite commonly confused two options of ALTER DATABASE. The first one is ALTER DATABASE …ROLLBACK IMMEDIATE and the second one is WITH NO_WAIT. Many people think they are the same or are not sure of the difference between these two options. Before we continue our explaination, let us go through the explanation given by Book On Line. ROLLBACK AFTER integer [SECONDS] | ROLLBACK IMMEDIATE Specifies whether to roll back after a specified number of seconds or immediately. NO_WAIT Specifies that if the requested database state or option change cannot complete immediately without waiting for transactions to commit or roll back on their own, then the request will fail. If you have understood the difference by now, there is no need to proceed further. If you are still confused, continue with the rest of the post. There is one big difference between ROLLBACK and NO_WAIT. In case incomplete Transaction ALTER DATABASE … ROLLBACK rollbacks those incomplete transaction immediately, where as ALTER DATABASE … NO_WAIT will terminate and rollback the transaction of ALTER DATABASE … NO_WAIT itself. I think it can be clearly explained with the help of the following images. Option 1: ALTER DATABASE … ROLLBACK Connection 1 – Simulating some operation using WAITFOR DELAY WAITFOR DELAY '1:00:00' Connection 2 ALTER DATABASE TestDb SET SINGLE_USER WITH ROLLBACK IMMEDIATE; Option 2: ALTER DATABASE … NO_WAIT Connection 1 – Simulating some operation using WAITFOR DELAY WAITFOR DELAY '1:00:00' Connection 2 ALTER DATABASE TestDb SET SINGLE_USER WITH NO_WAIT; Let me know if this example was simple enough. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Documentation, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Free Webinar Featuring Oracle Spatial and MapViewer, Oracle Business Intelligence, and Oracle Utilities

  - by stephen.garth

  Maps, BI and Network Management: Together At Last Date: Thursday, January 20 | Time: 11:00 a.m. PDT | 2:00 p.m. EDT | Duration: 1 hour Cost: FREE For years, utilities have wrestled with the challenge of providing executive management and other decision makers with maps and business intelligence during outages without compromising the performance of their real-time network operations and control systems. Join experts from Directions Media, Oracle and ThinkHuddle in this webinar for a discussion on how Oracle has addressed this challenge by incorporating Oracle Spatial data and the dashboard capabilities of Oracle Business Intelligence into a new application, Oracle Utilities Advanced Spatial Outage Analytics. Jim Steiner, Vice President of Spatial Product Management at Oracle, will provide an overview of Oracle's spatial and location technology, including Oracle Spatial 11g and Oracle Fusion Middleware MapViewer, and describe how Oracle is using this technology to spatially-enable many of its own enterprise applications. Brad Williams, Vice President of Oracle Utilities, will describe why and how the company developed Oracle Utilities Advanced Spatial Outage Analytics, how it works with Oracle Utilities Network Management System, and how this can deliver improved decision support and operational benefits to utilities. Steve Pierce, Spatial Systems Consultant with ThinkHuddle, will discuss architectural aspects and best practices in the integration of Oracle's spatial and BI technology. Following the presentation, attendees will have an opportunity to engage the panelists in a live Q&A session. Who Should Attend Executives, decision makers and analysts from IT, customer service, operations, engineering and marketing - especially in utilities, but also any business where location is important. Don't miss this webinar - Register Now. Find out more: Oracle Spatial on oracle.com More technical information on Oracle Technology Network Information on Oracle Utilities applications var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); try { var pageTracker = _gat._getTracker("UA-13185312-1"); pageTracker._trackPageview(); } catch(err) {}

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• Quotas - Using quotas on ZFSSA shares and projects and users

  - by Steve Tunstall

  So you don't want your users to fill up your entire storage pool with their MP3 files, right? Good idea to make some quotas. There's some good tips and tricks here, including a helpful workflow (a script) that will allow you to set a default quota on all of the users of a share at once. Let's start with some basics. I mad a project called "small" and inside it I made a share called "Share1". You can set quotas on the project level, which will affect all of the shares in it, or you can do it on the share level like I am here. Go the the share's General property page. First, I'm using a Windows client, so I need to make sure I have my SMB mountpoint. Do you know this trick yet? Go to the Protocol page of the share. See the SMB section? It needs a resource name to make the UNC path for the SMB (Windows) users. You do NOT have to type this name in for every share you make! Do this at the Project level. Before you make any shares, go to the Protocol properties of the Project, and set the SMB Resource name to "On". This special code will automatically make the SMB resource name of every share in the project the same as the share name. Note the UNC path name I got below. Since I did this at the Project level, I didn't have to lift a finger for it to work on every share I make in this project. Simple. So I have now mapped my Windows "Z:" drive to this Share1. I logged in as the user "Joe". Note that my computer shows my Z: drive as 34GB, which is the entire size of my Pool that this share is in. Right now, Joe could fill this drive up and it would fill up my pool.  Now, go back to the General properties of Share1. In the "Space Usage" area, over on the right, click on the "Show All" text under the Users & Groups section. Sure enough, Joe and some other users are in here and have some data. Note this is also a handy window to use just to see how much space your users are using in any given share.  Ok, Joe owes us money from lunch last week, so we want to give him a quota of 100MB. Type his name in the Users box. Notice how it now shows you how much data he's currently using. Go ahead and give him a 100M quota and hit the Apply button. If I go back to "Show All", I can see that Joe now has a quota, and no one else does. Sure enough, as soon as I refresh my screen back on Joe's client, he sees that his Z: drive is now only 100MB, and he's more than half way full.  That was easy enough, but what if you wanted to make the whole share have a quota, so that the share itself, no matter who uses it, can only grow to a certain size? That's even easier. Just use the Quota box on the left hand side. Here, I use a Quota on the share of 300MB.  So now I log off as Joe, and log in as Steve. Even though Steve does NOT have a quota, it is showing my Z: drive as 300MB. This would effect anyone, INCLUDING the ROOT user, becuase you specified the Quota to be on the SHARE, not on a person.  Note that back in the Share, if you click the "Show All" text, the window does NOT show Steve, or anyone else, to have a quota of 300MB. Yet we do, because it's on the share itself, not on any user, so this panel does not see that. Ok, here is where it gets FUN.... Let's say you do NOT want a quota on the SHARE, because you want SOME people, like Root and yourself, to have FULL access to it and you want the ability to fill the whole thing up if you darn well feel like it. HOWEVER, you want to give the other users a quota. HOWEVER you have, say, 200 users, and you do NOT feel like typing in each of their names and giving them each a quota, and they are not all members of a AD global group you could use or anything like that.  Hmmmmmm.... No worries, mate. We have a handy-dandy script that can do this for us. Now, this script was written a few years back by Tim Graves, one of our ZFSSA engineers out of the UK. This is not my script. It is NOT supported by Oracle support in any way. It does work fine with the 2011.1.4 code as best as I can tell, but Oracle, and I, are NOT responsible for ANYTHING that you do with this script. Furthermore, I will NOT give you this script, so do not ask me for it. You need to get this from your local Oracle storage SC. I will give it to them. I want this only going to my fellow SCs, who can then work with you to have it and show you how it works.  Here's what it does...Once you add this workflow to the Maintenance-->Workflows section, you click it once to run it. Nothing seems to happen at this point, but something did.   Go back to any share or project. You will see that you now have four new, custom properties on the bottom.  Do NOT touch the bottom two properties, EVER. Only touch the top two. Here, I'm going to give my users a default quota of about 40MB each. The beauty of this script is that it will only effect users that do NOT already have any kind of personal quota. It will only change people who have no quota at all. It does not effect the Root user.  After I hit Apply on the Share screen. Nothing will happen until I go back and run the script again. The first time you run it, it creates the custom properties. The second and all subsequent times you run it, it checks the shares for any users, and applies your quota number to each one of them, UNLESS they already have one set. Notice in the readout below how it did NOT apply to my Joe user, since Joe had a quota set.  Sure enough, when I go back to the "Show All" in the share properties, all of the users who did not have a quota, now have one for 39.1MB. Hmmm... I did my math wrong, didn't I?    That's OK, I'll just change the number of the Custom Default quota again. Here, I am adding a zero on the end.  After I click Apply, and then run the script again, all of my users, except Joe, now have a quota of 391MB  You can customize a person at any time. Here, I took the Steve user, and specifically gave him a Quota of zero. Now when I run the script again, he is different from the rest, so he is no longer effected by the script. Under Show All, I see that Joe is at 100, and Steve has no Quota at all. I can do this all day long. es, you will have to re-run the script every time new users get added. The script only applies the default quota to users that are present at the time the script is ran. However, it would be a simple thing to schedule the script to run each night, or to make an alert to run the script when certain events occur.  For you power users, if you ever want to delete these custom properties and remove the script completely, you will find these properties under the "Schema" section under the Shares section. You can remove them here. There's no need to, however, they don't hurt a thing if you just don't use them.  I hope these tips have helped you out there. Quotas can be fun. 

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• SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

  - by pinaldave

  This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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• Favorite Programmer Quotes…

  - by SGWellens

    "A computer once beat me at chess, but it was no match for me at kick boxing." — Emo Philips   "There are only 10 types of people in the world, those who understand binary and those who don't. " – Unknown.   "Premature optimization is the root of all evil." — Donald Knuth   "I should have become a doctor; then I could bury my mistakes." — Unknown   "Code softly and carry a large backup thumb drive." — Me   "Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live." — Martin Golding   "DDE…the protocol from hell"— Charles Petzold   "Just because a thing is new don't mean that it's better" — Will Rogers   "The mark of a mature programmer is willingness to throw out code you spent time on when you realize it's pointless." — Bram Cohen   "A good programmer is someone who looks both ways before crossing a one-way street." — Doug Linder   "The early bird may get the worm but it's the second mouse that gets the cheese." — Unknown   I hope someone finds this amusing. Steve Wellens CodeProject

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• Google Analytics and Whos.amung.us in realtime visitors, why such an enormous discrepancy?

  - by jacouh

  Since years I use in a site both Google Analytics and Whos.amung.us, both Google analytics and whos.amung.us javascripts are inserted in the same pages in the tracked part of the site. In real-time visitors, why such an enormous discrepancy ? for example at the moment, Google analytics gives me 9 visitors, whos.amung.us indicates 59, a ratio of 6 times? Why whos.amung.us is 6 times optimistic than Google Analytics in terms of the realtime visitors? Google whos.amung.us My question is: whos.amung.us does not detect robots while Google does? GA ignores visitors from some countries, not whos.amung.us? Some robots/bots execute whos.amung.us javascript for tracking? While no robots/bots can execute the tracking javascript provided by Google Analytics? To facilitate your analysis, I copy JS code used below: Google analytics: <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'MyGaAccountNo']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script> Whos.amung.us: <script>var _wau = _wau || []; _wau.push(["tab", "MyWAUAccountNo", "c6x", "right-upper"]);(function() { var s=document.createElement("script"); s.async=true; s.src="http://widgets.amung.us/tab.js";document.getElementsByTagName("head")[0].appendChild(s);})();</script> I've aleady signaled this to WAU staff some time ago, NR, I've not done this to Google as they don't handle this kind of feedback. Thank you for your explanations.

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• CodePlex Daily Summary for Tuesday, April 27, 2010

  CodePlex Daily Summary for Tuesday, April 27, 2010New ProjectsActive Directory User Properties Change: A complete application in VS 2005 and VB.NET, for Request Request in User Details in Active Directory, with flow to HR and then to IT for approval ...AVR Terminal: A Windows application for connecting to an AVR via RS232 serial or USB-to-COM FTDI ports. Works on Arduino, Bare Bones Board, and any custom board...Battle Droids: AVR-based Network Combat!: A Battle Droid is an AVR® microcontroller running the BattleDroid firmware. This firmware turns your AVR into a lean, mean, fighting machine, and ...Camp Foundation: Camp Foundationchakma: chakma is a question - answer based web application to make people get questions from anybody around the world and being able to answer them. c...Document.Editor: Document.Editor is a multitab text editor for Windows. It includes plain and rich text format support, multi tab interface so you can edit multiple...Dot Net Marche Music Store Demo Application: This is a demo application that the DotNetMarche user gorup (www.dotnetmarche.org) use to make experiments and prepare demos for our workshopselivators: a monitor which enables the user to view the movement of the elivators in a buildingExtended SSIS Package Execute: The SSIS package execute task is flawed as it does not support passing variables. Here we have a custom task that will pass items in a dataflow as...File tools: File toolsFileExplorer.NET: FileExplorer.NET is a .net usercontrol which tries to mimic the Windows FileExplorer treeview.Kazuku: ASP.NET MVC 2 Content Management SystemKSharp Ajax Control Toolkit Library: Built ontop of the Microsoft ASP.NET Ajax Control Toolkit, this library offers enhanced versions of the controls found in the Ajax Control Toolkit....Nitrous - An Aspx ViewEngine for ASP.NET MVC: Near drop-in replacement ASP.NET ViewEngine for MVC.Open Data Protocol - Client Libraries: This is an Open Source release of the .NET and Silverlight Client Libraries for the Open Data Protocol (OData). For more information on odata, see ...ORAYLIS BI.SmartDiff: BI.SmartDiff is a helper to connect the functionality of BIDS Helper – SmartDiff to TortoiseSVN. BIDS Helper – SmartDiff helps you to get more read...RicciWebSiteSystem: soon websiteSynapse:Silverlight A Simple Silverlight Framework: Synapse:Silverlight is a simplified framework for Silverlight. It's purpose is to help developers and designers produce basic LOB solutions that do...TestProjectMB: Testing Team Foundation ServerThoughtWorks Cruise Notification Interceptor: Cruise notification interceptorThreadSafeControls: ThreadSafeControls is a C# project that greatly simplifies the process of transitioning Windows Forms applications to a multithreaded environment b...Unscrambler: Unscrambler is a multitouch WPF word game built with MVVM Light in order to show how to use the touch maniupation and inertia features included in ...Web Utilities: web utilitiesNew Releases7zbackup - PowerShell Script to Backup Files with 7zip: 7zBackup v. 1.7.1 Stable: Bug Solved : Presence of junction.exe is wrongly referred to 7z.exeAVR Terminal: AVR Terminal v0.2: Here is an Alpha-almost-BETA release of the AVR Terminal. That being said, I use it almost daily and it shouldn't break anything on your system, b...Bistro FSharp Extensions: 0.9.7.0: This is the VS 2010 release of BistroFS extensions. This release focused on usability, adding key functionality such as resource aliasing and secur...Bojinx: Bojinx Dialog Management V1.0: Stable release of the Bojinx Dialog Management library.BOWIE: BOWIE 2010: This new version works on Outlook 2007/2010 and TFS 2008/2010 RTM. Details about all features in this version on the Home Page : http://bowie.code...Catharsis: Catharsis 2.5 on catarsa.com: The Catharsis framework has finally its own portal http://catarsa.com Example - documented steps to create Web-Application http://catarsa.com/Arti...Colorful Expression: Expression Blend 3: Alpha Version, Read Issues and Installing! Colorful Expression is an add-in for Expression Blend and Expression Design that brings you the Adobe K...Colorful Expression: Expression Blend 4: Read Issues and Installing! Colorful Expression is an add-in for Expression Blend and Expression Design that brings you the Adobe Kuler and ColorLo...Courier: Version 1.0: This release includes integration with the Reactive Framework for more elegant message handling and allowing more succinct client code. Full suite...CRM 4.0 Contract Utilities: Release 1.0: Project Description List of Contract Utilities (i.e. custom workflow actions) 1. Change contract status from Active to Draft 2. Copy Contract (with...Document.Editor: 0.9.0: Whats New?: New icon set Bug fix'sDotNetNuke® Blog: 04.00.00: Minimum Required DNN Version: 4.06.02General Code organization * Converted project to .NET 3.5 * Converted solution to Visual Stud...EPiAbstractions: EPiAbstractions 1.2: Updated for EPiServer CMS 6. Only features abstractions for EPiServer CMS. For abstractions for EPiServer.Common and EPiServer.Community use versio...Fluent ViewModel Configuration for WPF (MVVM): FluentViewModel Alpha2: Added support for view model validation using FluentValidation (http://fluentvalidation.codeplex.com/) Fixed exception from Blend while in design...GArphics: Beta v0.9: Beta v0.9. Practically all of the planned features have been implemented and are available to the users. For the version 1.0 mainly just some minor...HTML Ruby: 6.22.2.1: Fixed a bug where HTML Ruby's options window will generate entries in the error log when applying option changes (regression from 6.21.8)HTML Ruby: 6.22.3: Add/remove stop spacing event listener as needed for possible fix to 4620iTuner - The iTunes Companion: iTuner 1.2.3768 Beta 3b: Beta 3 requires iTunes 9.1.0.79 or later A Librarian status panel showing active and queued Librarian scanners. This will be hidden behind the "bi...LiveUpload to Facebook: LiveUpload to Facebook 3.2.3: Version 3.2.3Become a fan on Facebook! Features Quickly and easily upload your photos and videos to Facebook, including any people tags added in W...Maintainance Schedule: Maintenance Scheduler: The first Alpha release of the project.NetSockets: NetSockets (1.2): The NetSockets library (DLL)NSIS Autorun: NSIS Autorun 0.1.2: NSIS Autorun 0.1.1 This release includes source code, application binary, and example materials.OpenSceneGraph glsl samples: OsgGlslSamples Win32 binaries: Project binary release for Windows. The effects shown are: Ambient Occlusion, Depth of Field, DoF with alpha channel, Fire effects, HDR, Light Ma...ORAYLIS BI.SmartDiff: ORAYLIS BI.SmartDiff 0.6.1: First public versionpatterns & practices - Windows Azure Guidance: Code Drop 4 - Content Complete: This release includes documentation and all code samples intended for this first guide. As before, this code release builds on the previous one an...Pex Custom Arithmetic Solver: Custom Solver Package: This is the custom solvers packaged together. To use simply include the dll in your project and add [assembly: PexCustomArithmeticSolver] to your P...PokeIn Comet Ajax Library: PokeIn v08 x86: New FeatureFrom this version forward, PokeIn will define a way between the main page and client side automaticly based to security level. Add "pub...Proxi [Proxy Interface]: Proxi Release 1.0.0.426: Proxi Release 1.0.0.426QuestTracker: QuestTracker 0.3: This release includes recurring quests! Now you can set a quest to uncomplete itself every X minutes, hours, or days! And the quests still retain t...Rensea Image Viewer: RIV 0.4.5: RIV Fix Version. You would need .NET Framework 4.0 to make it run RIVU Improved Version. With separated RIV up-loader, to upload images to Renjian...SCC Switch Provider: Provides a GUI to Switch Source Code Control Provi: Transferred from GotDotNet Workplace. Initial public Release. Downloaded ~922 times from original post.sTASKedit: sTASKedit v0.7a (Alpha): + Fixed: XOR text encoding + Fixed: adding timed rewards missing values + Fixed: occupations in clone()Synapse:Silverlight A Simple Silverlight Framework: Synapse Silverlight Alpha Release: Initial Road-map is being defined.ThoughtWorks Cruise Notification Interceptor: 1.0.0: Initial release.UDC indexes parser: UDC indexex parser Beta 2: Добавлена возможность работать с распределением определителей как если бы генератор был бы LALR(2) То что осталось: Если текстовое дополнение начи...Unscrambler: Release 1.0: Here's the first release of Unscrambler.WinXound: WinXound 3.3.0 Beta 2 for Mac OsX: New: Code Repository (for UDO and personal code) New: Format Code - Added the ability to format only the selected text of the code New: Explore...WPF Inspirational Quote Management System: Release 1.2.2: - Fixed issue some users were having when the application is minimised.Most Popular ProjectsRawrWBFS ManagerAJAX Control ToolkitSilverlight Toolkitpatterns & practices – Enterprise LibraryMicrosoft SQL Server Product Samples: DatabaseWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesPHPExcelMost Active Projectspatterns & practices – Enterprise LibraryRawrGMap.NET - Great Maps for Windows Forms & PresentationParticle Plot PivotBlogEngine.NETNB_Store - Free DotNetNuke Ecommerce Catalog ModuleFarseer Physics EngineIonics Isapi Rewrite FilterN2 CMSDotNetZip Library

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• Using transactions with LINQ-to-SQL

  - by Jalpesh P. Vadgama

  Today one of my colleague asked that how we can use transactions with the LINQ-to-SQL Classes when we use more then one entities updated at same time. It was a good question. Here is my answer for that.For ASP.NET 2.0  or higher version have a new class called TransactionScope which can be used to manage transaction with the LINQ. Let’s take a simple scenario we are having a shopping cart application in which we are storing details or particular order placed into the database using LINQ-to-SQL. There are two tables Order and OrderDetails which will have all the information related to order. Order will store particular information about orders while OrderDetails table will have product and quantity of product for particular order.We need to insert data in both tables as same time and if any errors comes then it should rollback the transaction. To use TransactionScope in above scenario first we have add a reference to System.Transactions like below. After adding the transaction we need to drag and drop the Order and Order Details tables into Linq-To-SQL Classes it will create entities for that. Below is the code for transaction scope to use mange transaction with Linq Context. MyContextDataContext objContext = new MyContextDataContext(); using (System.Transactions.TransactionScope tScope = new System.Transactions.TransactionScope(TransactionScopeOption.Required)) { objContext.Order.InsertOnSubmit(Order); objContext.OrderDetails.InsertOnSumbit(OrderDetails); objContext.SubmitChanges(); tScope.Complete(); } Here it will commit transaction only if using blocks will run successfully. Hope this will help you. Technorati Tags: Linq,Transaction,System.Transactions,ASP.NET

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• How do I configure postfix starttls

  - by Michael Temeschinko

  I need to install postfix on my webserver couse I need to use sendmail for my website. I only need to send mail not recieve or relay. send with starttls (port 587) via relay smtp.strato.de here is what happens Jul 15 00:02:38 negrita postfix/smtp[7120]: Host offered STARTTLS: [smtp.strato.de] Jul 15 00:02:38 negrita postfix/smtp[7120]: C717A181252: to=<[email protected]>, relay=smtp.strato.de[81.169.145.133]:587, delay=0.31, delays=0.09/0/0.16/0.04, dsn=5.7.0, status=bounced (host smtp.strato.de[81.169.145.133] said: 530 5.7.0 Bitte konfigurieren Sie ihr E-Mailprogramm fuer Authentifizierung am SMTP Server, wie auf www.strato.de/email-hilfe beschrieben. - Please configure your mail client for using SMTP Server Authentication (in reply to MAIL FROM command)) Jul 15 00:02:38 negrita postfix/cleanup[7118]: 29F5F181254: message-id=<20120714220238.29F5F181254@negrita> Jul 15 00:02:38 negrita postfix/qmgr[7102]: 29F5F181254: from=<>, size=2548, nrcpt=1 (queue active) Jul 15 00:02:38 negrita postfix/bounce[7121]: C717A181252: sender non-delivery notification: 29F5F181254 Jul 15 00:02:38 negrita postfix/qmgr[7102]: C717A181252: removed Jul 15 00:02:39 negrita postfix/local[7122]: 29F5F181254: to=<michael@negrita>, relay=local, delay=1.1, delays=0.04/0/0/1.1, dsn=2.0.0, status=sent (delivered to command: procmail -a "$EXTENSION") Jul 15 00:02:39 negrita postfix/qmgr[7102]: 29F5F181254: removed Jul 15 08:05:18 negrita postfix/master[1083]: daemon started -- version 2.9.1, configuration /etc/postfix Jul 15 08:05:29 negrita postfix/master[1083]: reload -- version 2.9.1, configuration /etc/postfix and my config michael@negrita:~$ postconf -n biff = no config_directory = /etc/postfix delay_warning_time = 4h home_mailbox = /home/michael/Maildir/ html_directory = /usr/share/doc/postfix/html inet_interfaces = localhost mailbox_command = procmail -a "$EXTENSION" mailbox_size_limit = 0 mydomain = example.com myhostname = negrita mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 notify_classes = resource, software, protocol readme_directory = /usr/share/doc/postfix recipient_delimiter = + relayhost = [smtp.strato.de]:587 smtp_sasl_password_maps = hash:/etc/postfix/sasl/passwd smtp_tls_enforce_peername = no smtp_tls_note_starttls_offer = yes smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) smtpd_sasl_auth_enable = yes smtpd_sasl_security_options = noanonymous smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtpd_use_tls = yes soft_bounce = yes the user and password is ok couse I can send mail with my thunderbird thanks in advance mike

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