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• Erlang: How can I remove a node from other nodes' nodes()?

  - by sotbeosd

  I want to simulate the behavior of 'erl -sname example -hidden' but dynamically. How can I drop a node out of visibility in a cluster?

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• NoSQL Java API for MySQL Cluster: Questions & Answers

  - by Mat Keep

  The MySQL Cluster engineering team recently ran a live webinar, available now on-demand demonstrating the ClusterJ and ClusterJPA NoSQL APIs for MySQL Cluster, and how these can be used in building real-time, high scale Java-based services that require continuous availability. Attendees asked a number of great questions during the webinar, and I thought it would be useful to share those here, so others are also able to learn more about the Java NoSQL APIs. First, a little bit about why we developed these APIs and why they are interesting to Java developers. ClusterJ and Cluster JPA ClusterJ is a Java interface to MySQL Cluster that provides either a static or dynamic domain object model, similar to the data model used by JDO, JPA, and Hibernate. A simple API gives users extremely high performance for common operations: insert, delete, update, and query. ClusterJPA works with ClusterJ to extend functionality, including - Persistent classes - Relationships - Joins in queries - Lazy loading - Table and index creation from object model By eliminating data transformations via SQL, users get lower data access latency and higher throughput. In addition, Java developers have a more natural programming method to directly manage their data, with a complete, feature-rich solution for Object/Relational Mapping. As a result, the development of Java applications is simplified with faster development cycles resulting in accelerated time to market for new services. MySQL Cluster offers multiple NoSQL APIs alongside Java: - Memcached for a persistent, high performance, write-scalable Key/Value store, - HTTP/REST via an Apache module - C++ via the NDB API for the lowest absolute latency. Developers can use SQL as well as NoSQL APIs for access to the same data set via multiple query patterns – from simple Primary Key lookups or inserts to complex cross-shard JOINs using Adaptive Query Localization Marrying NoSQL and SQL access to an ACID-compliant database offers developers a number of benefits. MySQL Cluster’s distributed, shared-nothing architecture with auto-sharding and real time performance makes it a great fit for workloads requiring high volume OLTP. Users also get the added flexibility of being able to run real-time analytics across the same OLTP data set for real-time business insight. OK – hopefully you now have a better idea of why ClusterJ and JPA are available. Now, for the Q&A. Q & A Q. Why would I use Connector/J vs. ClusterJ? A. Partly it's a question of whether you prefer to work with SQL (Connector/J) or objects (ClusterJ). Performance of ClusterJ will be better as there is no need to pass through the MySQL Server. A ClusterJ operation can only act on a single table (e.g. no joins) - ClusterJPA extends that capability Q. Can I mix different APIs (ie ClusterJ, Connector/J) in our application for different query types? A. Yes. You can mix and match all of the API types, SQL, JDBC, ODBC, ClusterJ, Memcached, REST, C++. They all access the exact same data in the data nodes. Update through one API and new data is instantly visible to all of the others. Q. How many TCP connections would a SessionFactory instance create for a cluster of 8 data nodes? A. SessionFactory has a connection to the mgmd (management node) but otherwise is just a vehicle to create Sessions. Without using connection pooling, a SessionFactory will have one connection open with each data node. Using optional connection pooling allows multiple connections from the SessionFactory to increase throughput. Q. Can you give details of how Cluster J optimizes sharding to enhance performance of distributed query processing? A. Each data node in a cluster runs a Transaction Coordinator (TC), which begins and ends the transaction, but also serves as a resource to operate on the result rows. While an API node (such as a ClusterJ process) can send queries to any TC/data node, there are performance gains if the TC is where most of the result data is stored. ClusterJ computes the shard (partition) key to choose the data node where the row resides as the TC. Q. What happens if we perform two primary key lookups within the same transaction? Are they sent to the data node in one transaction? A. ClusterJ will send identical PK lookups to the same data node. Q. How is distributed query processing handled by MySQL Cluster ? A. If the data is split between data nodes then all of the information will be transparently combined and passed back to the application. The session will connect to a data node - typically by hashing the primary key - which then interacts with its neighboring nodes to collect the data needed to fulfil the query. Q. Can I use Foreign Keys with MySQL Cluster A. Support for Foreign Keys is included in the MySQL Cluster 7.3 Early Access release Summary The NoSQL Java APIs are packaged with MySQL Cluster, available for download here so feel free to take them for a spin today! Key Resources MySQL Cluster on-line demo  MySQL ClusterJ and JPA On-demand webinar  MySQL ClusterJ and JPA documentation MySQL ClusterJ and JPA whitepaper and tutorial

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• jstree will not fire onchange event

  - by vasion

  i have been really stuck on this. this is the code: js: var treeoptions={"data":{"type":"json","opts":{"url":"\/surveytags\/treejson"}}}; $('#treecontainer').tree(treeoptions); $("#treecontainer").tree({ callback : { ondblclk : function (node, tree) { alert(node.id); }, onmove : function (node,ref,type){ data= new Object(); data.node= new Object(); data.node.id = node.id; data.ref=new Object(); data.ref.id = ref.id; data.type = type; moveitem(data); }, onchange : function (){ alert('focused'); }, oncreate : function(node){ alert('create'); alert(node.data); } } }); this is the json: {"attributes":{"id":"1"},"data":{"title":"root"},"children":[{"attributes":{"id":"2"},"data":{"title":"blah"},"children":[{"attributes":{"id":"3"},"data":{"title":"tworows down"}},{"attributes":{"id":"4"},"data":{"title":"tooope"}}]}]} it loads. other events fire. BUT onchange will not...

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• treeview loses data when page is being refreshed in asp.net

  - by Greg

  Hi, I have a treeview and I written a code for his "treeNodePopulate" event: protected void ycActiveTree_TreeNodePopulate(object sender, TreeNodeEventArgs e) { if (Application["idList"] != null && e.Node.Depth == 0) { string[] words = ((String)Application["idList"]).Split(' '); // Yellow Card details TreeNode child = new TreeNode(""); // Go over all the yellow card details and populate the treeview for (int i = 1; i < words.Length; i++) { child.SelectAction = TreeNodeSelectAction.None; // Same yellow card if (words[i] != "*") { // End of details and start of point ip's if (words[i] == "$") { // Add the yellow card node TreeNode yellowCardNode = new TreeNode(child.Text); yellowCardNode.SelectAction = TreeNodeSelectAction.Expand; e.Node.ChildNodes.Add(yellowCardNode); child.Text = ""; } // yellow card details else { child.Text = child.Text + words[i] + " "; } } // End of yellow card else { child.PopulateOnDemand = false; child.SelectAction = TreeNodeSelectAction.None; // Populate the yellow card node e.Node.ChildNodes[e.Node.ChildNodes.Count - 1].ChildNodes.Add(child); TreeNode moveChild = new TreeNode("Move To Reviewed"); moveChild.PopulateOnDemand = false; moveChild.SelectAction = TreeNodeSelectAction.Select; e.Node.ChildNodes[e.Node.ChildNodes.Count - 1].ChildNodes.Add(moveChild); child = new TreeNode(""); } } Application["idList"] = null; } } I want the treenode to get the data from the Application variable and then nullify the Application variable so that the tree will take data from Applcation only if there is something in it (I put data into the application from another page and then redirect to this page) But when I refresh this page the data in the treenode isnt being saved. I mean after the refresh the Application is null so he isnt doing anything. The question is why is the data that I put in the treenode earlier isnt being saved? The "enableViewState" property is set to "true".. Thanks in advance, Greg

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• How to make xml in C#?

  - by kacalapy

  i have not worked with XML in a while can someone post the syntax needed to build and save an xml node structure that resembles that of a tree structure that is created by a recursive function. basically i have a recursive function that saves data found an a page(url) and then follows each URL found on that page recursivley and does the same to it. to audit this i want an output as a xml file to disk so i can see how it is doing its recursion and parsing. the code i have is below. please add to it the needed xml calls needed to create a xml structure like the one i show below. (please include the full name space so i can see where the objects i need in .net are for this.) page1.htm has 2 links on it: <a href=page1_1.htm> <a href=page1_2.htm> page1_1.htm has 2 links on it <a href=page1_1_a.htm> (this then will have some links also) <a href=page1_1_b.htm> (this then will have no more links on it - dead end) the xml should do something like this: <node url=page1.htm> ...<node url=page1_1_a.htm> ...... <node url="xxx.htm"/> ...... <node url="yyy.htm".> ... </node> ...<node url=page1_1_b.htm /> </node>

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• How to Create Element in XSLT When Copying Using Templates

  - by John Dumont

  Hello, I'm trying to create an element in an XML where the basic content is copied and modified. My XML is something like <root> <node> <child>value</child> <child2>value2</child2> </node> <node2>bla</node2> </root> The number of children of node may change as well as the children of root. The XSLT should copy the whole content, modify some values and add some new. The copying and modifying is no problem: <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0"> <xsl:output method="xml" encoding="UTF-8"/> <xsl:template match="@*|node()"> <xsl:copy> <xsl:apply-templates select="@*|node()"/> </xsl:copy> </xsl:template> </xsl:stylesheet> (+ further templates for modifications). But how do I add a new element in this structure on some path, e.g. I want to add an element as the last element of the "node" node. The "node" element itself always exists.

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• A queue in C using structs and dynamic memory allocation (linked list)

  - by Martin Pugh

  I am tasked with making a queue data structure in C, as a linked list. Our lecturer gave us a large amount of code to implement a stack, but we have to adapt it to create a queue. The code our lecturer gave us ends up not compiling and segfaulting at the exact same point as the code I wrote for the queue. I'm very new to structs, malloc and C in general, so there could be something painfully obvious I've overlooked. Here is the code I am using: #include <stdio.h> #include <stdlib.h> struct node{ int data; //contains the actual data struct node *prev; //pointer to previous node (Closer to front) struct node *next; //pointer to next node (Closer to back) }; typedef struct node *Nodepointer; struct queue{ Nodepointer front; Nodepointer back; }; typedef struct queue *Queuepointer; main(){ Queuepointer myqueue; //create a queue called myqueue init(myqueue); //initialise the queue Nodepointer new = (Nodepointer)malloc(sizeof(struct node)); myqueue->front = new; } int init(Queuepointer q){ q = (Queuepointer)malloc(sizeof(struct queue)); q->front = NULL; q->back = NULL; } The idea is that the queue struct 'contains' the first and last nodes in a queue, and when a node is created, myqueue is updated. However, I cannot even get to that part (pop and push are written but omitted for brevity). The code is segfaulting at the line myqueue->front = new; with the following gdb output: Program received signal SIGSEGV, Segmentation fault. 0x08048401 in main () at queue.c:27 27 myqueue->front = new; Any idea what I'm doing wrong?

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• Drupal 6 node_view empty

  - by kristian nissen

  I'm trying to produce a page with a list of specific nodes but the node_view returns an empty string. This is my query: function events_upcoming() { $output = ''; $has_events = false; $res = pager_query(db_rewrite_sql("SELECT n.nid, n.created FROM {node} n WHERE n.type = 'events' AND n.status = 1 ORDER BY n.sticky DESC, n.created DESC"), variable_get('default_nodes_main', 10)); while ($n = db_fetch_object($res)) { $output .= node_view(node_load($n->nid), 1); $has_events = true; } if ($has_events) { $output .= theme('pager', NULL, variable_get('default_nodes_main', 10)); } return $output; } hook_menu (part of): 'events/upcoming' => array( 'title' => t('Upcoming Events'), 'page callback' => 'events_upcoming', 'access arguments' => array('access content'), 'type' => MENU_SUGGESTED_ITEM ), the implementation of hook_view: function events_view($node, $teaser = false, $page = false) { $node = node_prepare($node, $teaser); if ($page) { // TODO: Handle breadcrump } return $node; } now, if I add a var_dump($node) inside events_view the node is present and I can see the values I want, and if I add a var_dump inside while loop in events_upcoming I also get a node id from the query. the strange thing is, when I load localhost/events/upcoming I see the pager and nothing else. I have used the blog.module as a reference, but what am I missing here?

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• sorting names in a linked list

  - by sil3nt

  Hi there, I'm trying to sort names into alphabetical order inside a linked list but am getting a run time error. what have I done wrong here? #include <iostream> #include <string> using namespace std; struct node{ string name; node *next; }; node *A; void addnode(node *&listpointer,string newname){ node *temp; temp = new node; if (listpointer == NULL){ temp->name = newname; temp->next = listpointer; listpointer = temp; }else{ node *add; add = new node; while (true){ if(listpointer->name > newname){ add->name = newname; add->next = listpointer->next; break; } listpointer = listpointer->next; } } } int main(){ A = NULL; string name1 = "bob"; string name2 = "tod"; string name3 = "thomas"; string name4 = "kate"; string name5 = "alex"; string name6 = "jimmy"; addnode(A,name1); addnode(A,name2); addnode(A,name3); addnode(A,name4); addnode(A,name5); addnode(A,name6); while(true){ if(A == NULL){break;} cout<< "name is: " << A->name << endl; A = A->next; } return 0; }

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• Concurrency problem with arrays (Java)

  - by Johannes

  For an algorithm I'm working on I tried to develop a blacklisting mechanism that can blacklist arrays in a specific way: If "1, 2, 3" is blacklisted "1, 2, 3, 4, 5" is also considered blacklisted. I'm quite happy with the solution I've come up with so far. But there seem to be some serious problems when I access a blacklist from multiple threads. The method "contains" (see code below) sometimes returns true, even if an array is not blacklisted. This problem does not occur if I only use one thread, so it most likely is a concurrency problem. I've tried adding some synchronization, but it didn't change anything. I also tried some slightly different implementations using java.util.concurrent classes. Any ideas on how to fix this? public class Blacklist { private static final int ARRAY_GROWTH = 10; private final Node root = new Node(); private static class Node{ private volatile Node[] childNodes = new Node[ARRAY_GROWTH]; private volatile boolean blacklisted = false; public void blacklist(){ this.blacklisted = true; this.childNodes = null; } } public void add(final int[] array){ synchronized (root) { Node currentNode = this.root; for(final int edge : array){ if(currentNode.blacklisted) return; else if(currentNode.childNodes.length <= edge) { currentNode.childNodes = Arrays.copyOf(currentNode.childNodes, edge + ARRAY_GROWTH); } if(currentNode.childNodes[edge] == null) { currentNode.childNodes[edge] = new Node(); } currentNode = currentNode.childNodes[edge]; } currentNode.blacklist(); } } public boolean contains(final int[] array){ synchronized (root) { Node currentNode = this.root; for(final int edge : array){ if(currentNode.blacklisted) return true; else if(currentNode.childNodes.length <= edge || currentNode.childNodes[edge] == null) return false; currentNode = currentNode.childNodes[edge]; } return currentNode.blacklisted; } } }

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• OutOfMemoryError creating a tree recursively?

  - by Alexander Khaos Greenstein

  root = new TreeNode(N); constructTree(N, root); private void constructTree(int N, TreeNode node) { if (N > 0) { node.setLeft(new TreeNode(N-1)); constructTree(N-1, node.getLeft()); } if (N > 1) { node.setMiddle(new TreeNode(N-2)); constructTree(N-2, node.getMiddle()); } if (N > 2) { node.setRight(new TreeNode(N-3)); constructTree(N-3, node.getRight()); } Assume N is the root number, and the three will create a left middle right node of N-1, N-2, N-3. EX: 5 / | \ 4 3 2 /|\ 3 2 1 etc. My GameNode class has the following variables: private int number; private GameNode left, middle, right; Whenever I construct a tree with an integer greater than 28, I get a OutOfMemoryError. Is my recursive method just incredibly inefficient or is this natural? Thanks!

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• Mysql Cluster not working on Ubuntu

  - by user53864

  I am unable to setup MySQL Cluster on ubuntu servers. As a starting point I started from the link but I am not successful and the tar ball version I download is 6.3.45. As I wanted to test the mysql cluster, the Data node and SQL node are same but sql never appeared as connected in management node console and it looks like below. [ndbd(NDB)] 2 node(s) id=2 @192.168.1.107 (Version: version number, Nodegroup: 0, Master) id=3 @192.168.1.108 (Version: version number, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=1 @192.168.1.105 (Version: version number) [mysqld(API)] 2 node(s) id=4 (not connected, accepting connect from 192.168.1.107) id=5 (not connected, accepting connect from 192.168.1.108) On all the 3 machines mysql-server & client(apt-get install mysql-server mysql-client) were already installed and I completely stopped and also removed them at the system start up. Now the mysqld is from extracted cluster tar ball(/usr/local/mysql/support-files/mysql.server). As for testing, I created a test database on both the data nodes but the tables are also not syncing on other node. I checked many links, configurations are remained similar in all the links but somewhere it's going wrong. Anymore extra package is required?, Could anyone help me here..?. I am trying this for past 3 days... Thank you!

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• vagrant and puppet security for ssl certificates

  - by Sirex

  I'm pretty new to vagrant, would someone who knows more about it (and puppet) be able to explain how vagrant deals with the ssl certs needed when making vagrant testing machines that are processing the same node definition as the real production machines ? I run puppet in master / client mode, and I wish to spin up a vagrant version of my puppet production nodes, primarily to test new puppet code against. If my production machine is, say, sql.domain.com I spin up a vagrant machine of, say, sql.vagrant.domain.com. In the vagrant file I then use the puppet_server provisioner, and give a puppet.puppet_node entry of “sql.domain.com” to it gets the same puppet node definition. On the puppet server I use a regex of something like /*.sql.domain.com/ on that node entry so that both the vagrant machine and the real one get that node entry on the puppet server. Finally, I enable auto-signing for *.vagrant.domain.com in puppet's autosign.conf, so the vagrant machine gets signed. So far, so good... However: If one machine on my network gets rooted, say, unimportant.domain.com, what's to stop the attacker changing the hostname on that machine to sql.vagrant.domain.com, deleting the old puppet ssl cert off of it and then re-run puppet with a given node name of sql.domain.com ? The new ssl cert would be autosigned by puppet, match the node name regex, and then this hacked node would get all the juicy information intended for the sql machine ?! One solution I can think of is to avoid autosigning, and put the known puppet ssl cert for the real production machine into the vagrant shared directory, and then have a vagrant ssh job move it into place. The downside of this is I end up with all my ssl certs for each production machine sitting in one git repo (my vagrant repo) and thereby on each developer's machine – which may or may not be an issue, but it dosen't sound like the right way of doing this. tl;dr: How do other people deal with vagrant & puppet ssl certificates for development or testing clones of production machines ?

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• Cannot browse remote networks even with WINS configured

  - by paradroid

  As the NetBIOS protocol acts on Layer 2 and so is not routable, In order to enable network browsing of remote networks, WINS has been installed and configured on two domain controllers, both of which are on different networks. The WINS servers seem to be replicating with eachother, and each has 127.0.0.1 set as the Primary WINS Server in each of their LAN interface properties, with nothing entered for Secondary WINS Server. The DC which holds the PDC Emulator FSMO role has the Computer Browser service running and set to Auto start, and it has the WINS/NBT node type network setting at 0x8 (H-node - Hybrid node). Remote network browsing does not work. Is the WINS/NBT node type correct for this scenario? The reason why I think it may not be the right one is because I set the DHCP Server's 046 WINS/NBT node type option to 0x8 as well, after which the DHCP clients started to disappear from the Network folders. When that option is not set, does it default to B-node (Broadcast node)? Or could it be a problem with the WINS servers setup?

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• SOA Suite Integration: Part 3: Loading files

  - by Anthony Shorten

  One of the most common scenarios in SOA Integration is the loading of a file into the product from an external source. In Oracle SOA Suite there is a File Adapter that can process many file types into your BPEL process. For this example I will use the File Adapter to load a file of user and emails to update the user object within the Oracle Utilities Application Framework. Remember you can repeat this process with other objects and other file types. Again I am illustrating the ease of integration. The first thing is to create an empty BPEL process that will hold our flow. In Oracle JDeveloper this can be achieved by specifying the Define Service Later template (as other templates have predefined inputs and outputs and in this case we want to specify those). So I will create simpleFileLoad process to house our process. You will start with an empty canvas so you need to first specify the load part of the process using the File Adapter. Select the File Adapter from the Component Palette under BPEL Services and drag and drop it to the left side Partner Links (left is input). You name the Service. In this case I chose LoadFile. Press Next. We will define the interface as part of the wizard so select Define from operation and schema (specified later). Press Next. We are going to choose Read File to denote that we will read the file and specify the default Operation Name as Read. Press Next. The next step is to tell the Adapter the location of the files, how to process them and what to do with them after they have been processed. I am using hardcoded locations in this example but you can have logical locations as well. Press Next. I am now going to tell the adapter how to recognize the files I want to load. In my case I am using CSV files and more importantly I am tell the adapter to run the process for each record in the file it encounters. Press Next. Now, I tell the adapter how often I want to poll for the files. I have taken the defaults. Press Next. At this stage I have no explanation of the format of the input. So I am going to invoke the Native Format Wizard which will guide me through the process of creating the file input format. Clicking the purple cog icon will start the wizard. After an introduction screen (not shown), you specify the format of the input file. The File Adapter supports multiple format types. For this example, I will use Delimited as I am going to load a CSV file. Press Next. The best way for the wizard to work is with a sample. I have a sample file and the wizard will ask how much of the file to use as a template. I will use the defaults. Note: If you are using a language that has other languages other than US-ASCII, it is at this point you specify the character set to use.  Press Next. The sample contains multiple instances of a single record type. The wizard supports complex types as well. We will use the appropriate setting for our file. Press Next. You have to specify the file element and the record element. This will be used by the input wizard to translate the CSV data into an XML structure (this will make sense later). I am using LoadUsers as my file delimiter (root element) and User Record as my record root element. Press Next. As the file is CSV the delimiter is "," so I will also specify that the End Of Line (EOL) indicator indicates the end of a record. Press Next. Up until this point your have not given the columns their names. In my case my sample includes the column names in the first record. This is not always the case but you can specify the names and formats of columns in this dialog (not shown). Press Next. The wizard now generates the schema for the input file. You can specify a name for the schema. I have used userupdate.xsd. We want to verify the schema so press Test. You can test the schema by specifying an input sample. and pressing the green play button. You will see the delimiters you specified earlier for the file and the records. Press Ok to continue. A confirmation screen will be displayed showing you the location of the schema in your project. Press Finish to return to the File Adapter configuration. You will now see the schema and elements prepopulated from the wizard. Press Next. The File Adapter configuration is now complete. Press Finish. Now you need to receive the input from the LoadFile component so we need to place a Receive node in the BPEL process by drag and dropping the Receive component from the Component Palette under BPEL Constructs onto the BPEL process. We link the receive process with the LoadFile component by dragging the left most connect node of the Receive node to the LoadFile component. Once the link is established you need to name the Receive node appropriately and as in the post of the last part of this series you need to generate input variables for the BPEL process to hold the input records in. You need to now add the product Web Service. The process is the same as described in the post of the last part of this series. You drop the Web Service BPEL Service onto the right side of the process and fill in the details of the WSDL URL . You also have to add an Invoke node to call the service and generate the input and outputs variables for the call in the Invoke node. Now, to get the inputs from File to the service. You have to use a Transform (you can use an Assign action but a Transform action is more flexible). You drag and drop the Transform component from the Component Palette under Oracle Extensions and place it between the Receive and Invoke nodes. We name the Transform Node, Mapper File and associate the source of the mapping the schema from the Receive node and the output will be the input variable from the Invoke node. We now build the transform. We first map the user and email attributes by drag and drop the elements from the left to the right. The reason we needed to use the transform is that we will be telling the AS-User service that we want to issue an update action. Remember when we registered the service we actually used Read as the default. If we do not otherwise inform the service to use the Update action it will use the Read action instead (which is not desired). To specify the update action you need to click on the transactionType node on the right and select Set Text to set the action. You need to specify the transactionType of UPD (for update). The mapping is now complete. The final BPEL process is ready for deployment. You then deploy the BPEL process to the server and to test the service by simply dropping a file, in the same pattern/name as you specified, in the directory you specified in the File Adapter. You will see each record as a separate instance entry in the Fusion Middleware Control console. You can now load files into the product. You can repeat this process for each type of file to process. While this was a simple example it illustrates the method of loading data can be achieved using SOA Suite in conjunction with our products.

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• PHP parsing XML file with and without namespaces

  - by Mike

  I need to get a XML File into a Database. Thats not the problem. Cant read it, parse it and create some Objects to map to the DB. Problem is, that sometimes the XML File can contain namespaces and sometimes not. Furtermore sometimes there is no namespace defined at all. So what i first got was something like this: <?xml version="1.0" encoding="UTF-8"?> <struct xmlns:b="http://www.w3schools.com/test/"> <objects> <object> <node_1>value1</node_1> <node_2>value2</node_2> <node_3 iso_land="AFG"/> <coords lat="12.00" long="13.00"/> </object> </objects> </struct> And the parsing: $t = $xml->xpath('/objects/object'); foreach($nodes AS $node) { if($t[0]->$node) { $obj->$node = (string) $t[0]->$node; } } Thats fine as long as there are no namespaces. Here comes the XML File with namespaces: <?xml version="1.0" encoding="UTF-8"?> <b:struct xmlns:b="http://www.w3schools.com/test/"> <b:objects> <b:object> <b:node_1>value1</b:node_1> <b:node_2>value2</b:node_2> <b:node_3 iso_land="AFG"/> <b:coords lat="12.00" long="13.00"/> </b:object> </b:objects> </b:struct> I now came up with something like this: $xml = simplexml_load_file("test.xml"); $namespaces = $xml->getNamespaces(TRUE); $ns = count($namespaces) ? 'a:' : ''; $xml->registerXPathNamespace("a", "http://www.w3schools.com/test/"); $nodes = array('node_1', 'node_2'); $obj = new stdClass(); foreach($nodes AS $node) { $t = $xml->xpath('/'.$ns.'objects/'.$ns.'object/'.$ns.$node); if($t[0]) { $obj->$node = (string) $t[0]; } } $t = $xml->xpath('/'.$ns.'objects/'.$ns.'object/'.$ns.'node_3'); if($t[0]) { $obj->iso_land = (string) $t[0]->attributes()->iso_land; } $t = $xml->xpath('/'.$ns.'objects/'.$ns.'object/'.$ns.'coords'); if($t[0]) { $obj->lat = (string) $t[0]->attributes()->lat; $obj->long = (string) $t[0]->attributes()->long; } That works with namespaces and without. But i feel that there must be a better way. Before that i could do something like this: $t = $xml->xpath('/'.$ns.'objects/'.$ns.'object'); foreach($nodes AS $node) { if($t[0]->$node) { $obj->$node = (string) $t[0]->$node; } } But that just wont work with namespaces.

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• How to remove a model object from an EMF model and its GEF Editor via Adapter

  - by s.d

  This question is principally a follow-up to my question about EMF listening mechanisms. So, I have a third-party EMF model (uneditable) which is based on a generic graph model. The structure is as follows: Project | ItemGraph | Item | Document | DocumentGraph / | \ Tokens Nodes Relations(Edges) I have a GEF editor which works on the DocumentGraph (i.e., not the root object, perhaps this is a problem?): getGraphicalViewer().setContents(documentGraph). THe editor has the following edit part structure: DocumentGraphEP / \ Primary Connection LayerEP LayerEP / \ | TokenEP NodeEP RelationEP PrimaryLayerEP and ConnectionLayerEP both have simple Strings as model, which are not represented in the EMF (domain) model. They are simply used to add a primary (i.e., node) layer, and a connection layer (with ShortestPathConnectionRouter) to the editor. Problem: I am trying to get myself into the workings of EMF adapters, and have tried to make use of the available tutorials, mainly the EMF-GEF Eclipse tutorial, vainolo's blog, and vogella's tutorial. I thought I'd start with an easy thing, so tried to remove a node from the graph and see if I get it to work. Which I didn't, and I don't see where the problem is. I can select a node, and have the generic delete Action in my toolbar, but when I click it, nothing happens. Here is the respective source code for the different responsible parts. Please be so kind to point me to any errors (of thinking, coding errors, whathaveyou) you can find. NodeEditPart public class NodeEditPart extends AbstractGraphicalEditPart implements Adapter { protected IFigure createFigure() { return new NodeFigure(); } protected void createEditPolicies() { .... installEditPolicy(EditPolicy.COMPONENT_ROLE, new NodeComponentEditPolicy()); } protected void refreshVisuals() { NodeFigure figure = (NodeFigure) getFigure(); SNode model = (SNode) getModel(); PrimaryLayerEditPart parent = (PrimaryLayerEditPart) getParent(); // Set text figure.getLabel().setText(model.getSName()); .... } public void activate() { if (isActive()) return; // start listening for changes in the model ((Notifier)getModel()).eAdapters().add(this); super.activate(); } public void deactivate() { if (!isActive()) return; // stop listening for changes in the model ((Notifier)getModel()).eAdapters().remove(this); super.deactivate(); } private Notifier getSDocumentGraph() { return ((SNode)getModel()).getSDocumentGraph(); } @Override public void notifyChanged(Notification notification) { int type = notification.getEventType(); switch( type ) { case Notification.ADD: case Notification.ADD_MANY: case Notification.REMOVE: case Notification.REMOVE_MANY: refreshChildren(); break; case Notification.SET: refreshVisuals(); break; } } @Override public Notifier getTarget() { return target; } @Override public void setTarget(Notifier newTarget) { this.target = newTarget; } @Override public boolean isAdapterForType(Object type) { return type.equals(getModel().getClass()); } } NodeComponentEditPolicy public class NodeComponentEditPolicy extends ComponentEditPolicy { public NodeComponentEditPolicy() { super(); } protected Command createDeleteCommand(GroupRequest deleteRequest) { DeleteNodeCommand cmd = new DeleteNodeCommand(); cmd.setSNode((SNode) getHost().getModel()); return cmd; } } DeleteNodeCommand public class DeleteNodeCommand extends Command { private SNode node; private SDocumentGraph graph; @Override public void execute() { node.setSDocumentGraph(null); } @Override public void undo() { node.setSDocumentGraph(graph); } public void setSNode(SNode node) { this.node = node; this.graph = node.getSDocumentGraph(); } } All seems to work fine: When a node is selected in the editor, the delete symbol is activated in the toolbar, but when it is clicked, nothing happens in the editor. I'd be very thankful for any pointers :).

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• Overloading stream insertion without violating information hiding?

  - by Chris

  I'm using yaml-cpp for a project. I want to overload the << and >> operators for some classes, but I'm having an issue grappling with how to "properly" do this. Take the Note class, for example. It's fairly boring: class Note { public: // constructors Note( void ); ~Note( void ); // public accessor methods void number( const unsigned long& number ) { _number = number; } unsigned long number( void ) const { return _number; } void author( const unsigned long& author ) { _author = author; } unsigned long author( void ) const { return _author; } void subject( const std::string& subject ) { _subject = subject; } std::string subject( void ) const { return _subject; } void body( const std::string& body ) { _body = body; } std::string body( void ) const { return _body; } private: unsigned long _number; unsigned long _author; std::string _subject; std::string _body; }; The << operator is easy sauce. In the .h: YAML::Emitter& operator << ( YAML::Emitter& out, const Note& v ); And in the .cpp: YAML::Emitter& operator << ( YAML::Emitter& out, const Note& v ) { out << v.number() << v.author() << v.subject() << v.body(); return out; } No sweat. Then I go to declare the >> operator. In the .h: void operator >> ( const YAML::Node& node, Note& note ); But in the .cpp I get: void operator >> ( const YAML::Node& node, Note& note ) { node[0] >> ? node[1] >> ? node[2] >> ? node[3] >> ? return; } If I write things like node[0] >> v._number; then I would need to change the CV-qualifier to make all of the Note fields public (which defeats everything I was taught (by professors, books, and experience))) about data hiding. I feel like doing node[0] >> temp0; v.number( temp0 ); all over the place is not only tedious, error-prone, and ugly, but rather wasteful (what with the extra copies). Then I got wise: I attempted to move these two operators into the Note class itself, and declare them as friends, but the compiler (GCC 4.4) didn't like that: src/note.h:44: error: ‘YAML::Emitter& Note::operator<<(YAML::Emitter&, const Note&)’ must take exactly one argument src/note.h:45: error: ‘void Note::operator(const YAML::Node&, Note&)’ must take exactly one argument Question: How do I "properly" overload the >> operator for a class Without violating the information hiding principle? Without excessive copying?

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• Make interchangeable class types via pointer casting only, without having to allocate any new objects?

  - by HostileFork

  UPDATE: I do appreciate "don't want that, want this instead" suggestions. They are useful, especially when provided in context of the motivating scenario. Still...regardless of goodness/badness, I've become curious to find a hard-and-fast "yes that can be done legally in C++11" vs "no it is not possible to do something like that". I want to "alias" an object pointer as another type, for the sole purpose of adding some helper methods. The alias cannot add data members to the underlying class (in fact, the more I can prevent that from happening the better!) All aliases are equally applicable to any object of this type...it's just helpful if the type system can hint which alias is likely the most appropriate. There should be no information about any specific alias that is ever encoded in the underlying object. Hence, I feel like you should be able to "cheat" the type system and just let it be an annotation...checked at compile time, but ultimately irrelevant to the runtime casting. Something along these lines: Node<AccessorFoo>* fooPtr = Node<AccessorFoo>::createViaFactory(); Node<AccessorBar>* barPtr = reinterpret_cast< Node<AccessorBar>* >(fooPtr); Under the hood, the factory method is actually making a NodeBase class, and then using a similar reinterpret_cast to return it as a Node<AccessorFoo>*. The easy way to avoid this is to make these lightweight classes that wrap nodes and are passed around by value. Thus you don't need casting, just Accessor classes that take the node handle to wrap in their constructor: AccessorFoo foo (NodeBase::createViaFactory()); AccessorBar bar (foo.getNode()); But if I don't have to pay for all that, I don't want to. That would involve--for instance--making a special accessor type for each sort of wrapped pointer (AccessorFooShared, AccessorFooUnique, AccessorFooWeak, etc.) Having these typed pointers being aliased for one single pointer-based object identity is preferable, and provides a nice orthogonality. So back to that original question: Node<AccessorFoo>* fooPtr = Node<AccessorFoo>::createViaFactory(); Node<AccessorBar>* barPtr = reinterpret_cast< Node<AccessorBar>* >(fooPtr); Seems like there would be some way to do this that might be ugly but not "break the rules". According to ISO14882:2011(e) 5.2.10-7: An object pointer can be explicitly converted to an object pointer of a different type.70 When a prvalue v of type "pointer to T1" is converted to the type "pointer to cv T2", the result is static_cast(static_cast(v)) if both T1 and T2 are standard-layout types (3.9) and the alignment requirements of T2 are no stricter than those of T1, or if either type is void. Converting a prvalue of type "pointer to T1" to the type "pointer to T2" (where T1 and T2 are object types and where the alignment requirements of T2 are no stricter than those of T1) and back to its original type yields the original pointer value. The result of any other such pointer conversion is unspecified. Drilling into the definition of a "standard-layout class", we find: has no non-static data members of type non-standard-layout-class (or array of such types) or reference, and has no virtual functions (10.3) and no virtual base classes (10.1), and has the same access control (clause 11) for all non-static data members, and has no non-standard-layout base classes, and either has no non-static data member in the most-derived class and at most one base class with non-static data members, or has no base classes with non-static data members, and has no base classes of the same type as the first non-static data member. Sounds like working with something like this would tie my hands a bit with no virtual methods in the accessors or the node. Yet C++11 apparently has std::is_standard_layout to keep things checked. Can this be done safely? Appears to work in gcc-4.7, but I'd like to be sure I'm not invoking undefined behavior.

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• Clusterware 11gR2 &ndash; Setting up an Active/Passive failover configuration

  - by Gilles Haro

  Oracle is providing a large range of interesting solutions to ensure High Availability of the database. Dataguard, RAC or even both configurations (as recommended by Oracle for a Maximum Available Architecture - MAA) are the most frequently found and used solutions. But, when it comes to protecting a system with an Active/Passive architecture with failover capabilities, people often thinks to other expensive third party cluster systems. Oracle Clusterware technology, which comes along at no extra-cost with Oracle Database or Oracle Unbreakable Linux, is - in the knowing of most people - often linked to Oracle RAC and therefore, is seldom used to implement failover solutions. Oracle Clusterware 11gR2  (a part of Oracle 11gR2 Grid Infrastructure)  provides a comprehensive framework to setup automatic failover configurations. It is actually possible to make "failover-able'", and then to protect, almost any kind of application (from the simple xclock to the most complex Application Server). Quoting Oracle: “Oracle Clusterware is a portable cluster software that allows clustering of single servers so that they cooperate as a single system. Oracle Clusterware also provides the required infrastructure for Oracle Real Application Clusters (RAC). In addition Oracle Clusterware enables the protection of any Oracle application or any other kind of application within a cluster.” In the next couple of lines, I will try to present the different steps to achieve this goal : Have a fully operational 11gR2 database protected by automatic failover capabilities. I assume you are fluent in installing Oracle Database 11gR2, Oracle Grid Infrastructure 11gR2 on a Linux system and that ASM is not a problem for you (as I am using it as a shared storage). If not, please have a look at Oracle Documentation. As often, I made my tests using an Oracle VirtualBox environment. The scripts are tested and functional on my system. Unfortunately, there can always be a typo or a mistake. This blog entry does not replace a course around the Clusterware Framework. I just hope it will let you see how powerful it is and that it will give you the whilst to go further with it...  Note : This entry has been revised (rev.2) following comments from Philip Newlan. Prerequisite 2 Linux boxes (OELCluster01 and OELCluster02) at the same OS level. I used OEL 5 Update 5 with an Enterprise Kernel. Shared Storage (SAN). On my VirtualBox system, I used Openfiler to simulate the SAN Oracle 11gR2 Database (11.2.0.1) Oracle 11gR2 Grid Infrastructure (11.2.0.1)   Step 1 - Install the software Using asmlib, create 3 ASM disks (ASM_CRS, ASM_DTA and ASM_FRA) Install Grid Infrastructure for a cluster (OELCluster01 and OELCluster02 are the 2 nodes of the cluster) Use ASM_CRS to store Voting Disk and OCR. Use SCAN. Install Oracle Database Standalone binaries on both nodes. Use asmca to check/mount the disk groups on 2 nodes Use dbca to create and configure a database on the primary node Let's name it DB11G. Copy the pfile, password file to the second node. Create adump directoty on the second node.   Step 2 - Setup the resource to be protected After its creation with dbca, the database is automatically protected by the Oracle Restart technology available with Grid Infrastructure. Consequently, it restarts automatically (if possible) after a crash (ex: kill -9 smon). A database resource has been created for that in the Cluster Registry. We can observe this with the command : crsctl status resource that shows and ora.dba11g.db entry. Let's save the definition of this resource, for future use : mkdir -p /crs/11.2.0/HA_scripts chown oracle:oinstall /crs/11.2.0/HA_scripts crsctl status resource ora.db11g.db -p > /crs/11.2.0/HA_scripts/myResource.txt Although very interesting, Oracle Restart is not cluster aware and cannot restart the database on any other node of the cluster. So, let's remove it from the OCR definitions, we don't need it ! srvctl stop database -d DB11G srvctl remove database -d DB11G Instead of it, we need to create a new resource of a more general type : cluster_resource. Here are the steps to achieve this : Create an action script :  /crs/11.2.0/HA_scripts/my_ActivePassive_Cluster.sh #!/bin/bash export ORACLE_HOME=/oracle/product/11.2.0/dbhome_1 export ORACLE_SID=DB11G case $1 in 'start')   $ORACLE_HOME/bin/sqlplus /nolog <<EOF   connect / as sysdba   startup EOF   RET=0   ;; 'stop')   $ORACLE_HOME/bin/sqlplus /nolog <<EOF   connect / as sysdba   shutdown immediate EOF   RET=0   ;; 'clean')   $ORACLE_HOME/bin/sqlplus /nolog <<EOF   connect / as sysdba   shutdown abort    ##for i in `ps -ef | grep -i $ORACLE_SID | awk '{print $2}' ` ;do kill -9 $i; done EOF   RET=0   ;; 'check')    ok=`ps -ef | grep smon | grep $ORACLE_SID | wc -l`    if [ $ok = 0 ]; then      RET=1    else      RET=0    fi    ;; '*')      RET=0   ;; esac if [ $RET -eq 0 ]; then    exit 0 else    exit 1 fi   This script must provide, at least, methods to start, stop, clean and check the database. It is self-explaining and contains nothing special. Just be aware that it must be runnable (+x), it runs as Oracle user (because of the ACL property - see later) and needs to know about the environment. Also make sure it exists on every node of the cluster. Moreover, as of 11.2, the clean method is mandatory. It must provide the “last gasp clean up”, for example, a shutdown abort or a kill –9 of all the remaining processes. chmod +x /crs/11.2.0/HA_scripts/my_ActivePassive_Cluster.sh scp  /crs/11.2.0/HA_scripts/my_ActivePassive_Cluster.sh   oracle@OELCluster02:/crs/11.2.0/HA_scripts Create a new resource file, based on the information we got from previous  myResource.txt . Name it myNewResource.txt. myResource.txt  is shown below. As we can see, it defines an ora.database.type resource, named ora.db11g.db. A lot of properties are related to this type of resource and do not need to be used for a cluster_resource. NAME=ora.db11g.db TYPE=ora.database.type ACL=owner:oracle:rwx,pgrp:oinstall:rwx,other::r-- ACTION_FAILURE_TEMPLATE= ACTION_SCRIPT= ACTIVE_PLACEMENT=1 AGENT_FILENAME=%CRS_HOME%/bin/oraagent%CRS_EXE_SUFFIX% AUTO_START=restore CARDINALITY=1 CHECK_INTERVAL=1 CHECK_TIMEOUT=600 CLUSTER_DATABASE=false DB_UNIQUE_NAME=DB11G DEFAULT_TEMPLATE=PROPERTY(RESOURCE_CLASS=database) PROPERTY(DB_UNIQUE_NAME= CONCAT(PARSE(%NAME%, ., 2), %USR_ORA_DOMAIN%, .)) ELEMENT(INSTANCE_NAME= %GEN_USR_ORA_INST_NAME%) DEGREE=1 DESCRIPTION=Oracle Database resource ENABLED=1 FAILOVER_DELAY=0 FAILURE_INTERVAL=60 FAILURE_THRESHOLD=1 GEN_AUDIT_FILE_DEST=/oracle/admin/DB11G/adump GEN_USR_ORA_INST_NAME= GEN_USR_ORA_INST_NAME@SERVERNAME(oelcluster01)=DB11G HOSTING_MEMBERS= INSTANCE_FAILOVER=0 LOAD=1 LOGGING_LEVEL=1 MANAGEMENT_POLICY=AUTOMATIC NLS_LANG= NOT_RESTARTING_TEMPLATE= OFFLINE_CHECK_INTERVAL=0 ORACLE_HOME=/oracle/product/11.2.0/dbhome_1 PLACEMENT=restricted PROFILE_CHANGE_TEMPLATE= RESTART_ATTEMPTS=2 ROLE=PRIMARY SCRIPT_TIMEOUT=60 SERVER_POOLS=ora.DB11G SPFILE=+DTA/DB11G/spfileDB11G.ora START_DEPENDENCIES=hard(ora.DTA.dg,ora.FRA.dg) weak(type:ora.listener.type,uniform:ora.ons,uniform:ora.eons) pullup(ora.DTA.dg,ora.FRA.dg) START_TIMEOUT=600 STATE_CHANGE_TEMPLATE= STOP_DEPENDENCIES=hard(intermediate:ora.asm,shutdown:ora.DTA.dg,shutdown:ora.FRA.dg) STOP_TIMEOUT=600 UPTIME_THRESHOLD=1h USR_ORA_DB_NAME=DB11G USR_ORA_DOMAIN=haroland USR_ORA_ENV= USR_ORA_FLAGS= USR_ORA_INST_NAME=DB11G USR_ORA_OPEN_MODE=open USR_ORA_OPI=false USR_ORA_STOP_MODE=immediate VERSION=11.2.0.1.0 I removed database type related entries from myResource.txt and modified some other to produce the following myNewResource.txt. Notice the NAME property that should not have the ora. prefix Notice the TYPE property that is not ora.database.type but cluster_resource. Notice the definition of ACTION_SCRIPT. Notice the HOSTING_MEMBERS that enumerates the members of the cluster (as returned by the olsnodes command). NAME=DB11G.db TYPE=cluster_resource DESCRIPTION=Oracle Database resource ACL=owner:oracle:rwx,pgrp:oinstall:rwx,other::r-- ACTION_SCRIPT=/crs/11.2.0/HA_scripts/my_ActivePassive_Cluster.sh PLACEMENT=restricted ACTIVE_PLACEMENT=0 AUTO_START=restore CARDINALITY=1 CHECK_INTERVAL=10 DEGREE=1 ENABLED=1 HOSTING_MEMBERS=oelcluster01 oelcluster02 LOGGING_LEVEL=1 RESTART_ATTEMPTS=1 START_DEPENDENCIES=hard(ora.DTA.dg,ora.FRA.dg) weak(type:ora.listener.type,uniform:ora.ons,uniform:ora.eons) pullup(ora.DTA.dg,ora.FRA.dg) START_TIMEOUT=600 STOP_DEPENDENCIES=hard(intermediate:ora.asm,shutdown:ora.DTA.dg,shutdown:ora.FRA.dg) STOP_TIMEOUT=600 UPTIME_THRESHOLD=1h Register the resource. Take care of the resource type. It needs to be a cluster_resource and not a ora.database.type resource (Oracle recommendation) .   crsctl add resource DB11G.db  -type cluster_resource -file /crs/11.2.0/HA_scripts/myNewResource.txt Step 3 - Start the resource crsctl start resource DB11G.db This command launches the ACTION_SCRIPT with a start and a check parameter on the primary node of the cluster. Step 4 - Test this We will test the setup using 2 methods. crsctl relocate resource DB11G.db This command calls the ACTION_SCRIPT  (on the two nodes)  to stop the database on the active node and start it on the other node. Once done, we can revert back to the original node, but, this time we can use a more "MS$ like" method :Turn off the server on which the database is running. After short delay, you should observe that the database is relocated on node 1. Conclusion Once the software installed and the standalone database created (which is a rather common and usual task), the steps to reach the objective are quite easy : Create an executable action script on every node of the cluster. Create a resource file. Create/Register the resource with OCR using the resource file. Start the resource. This solution is a very interesting alternative to licensable third party solutions. References Clusterware 11gR2 documentation Oracle Clusterware Resource Reference Clusterware for Unbreakable Linux Using Oracle Clusterware to Protect A Single Instance Oracle Database 11gR1 (to have an idea of complexity) Oracle Clusterware on OTN   Gilles Haro Technical Expert - Core Technology, Oracle Consulting   

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• Clusterware 11gR2 &ndash; Setting up an Active/Passive failover configuration

  - by Gilles Haro

  Oracle provides many interesting ways to ensure High Availability. Dataguard configurations, RAC configurations or even both (as recommended for a Maximum Available Architecture - MAA) are the most frequently found. But when it comes to protecting a system with an Active/Passive architecture with failover capabilities, one often thinks to expensive third party cluster systems. Oracle Clusterware technology, which comes free with Oracle Database, is – in the knowing of most people - often linked to Oracle RAC and therefore, is rarely used to implement failover solutions. 11gR2 Clusterware – which is part of Oracle Grid Infrastructure - provides a comprehensive framework to setup automatic failover configurations. It is actually possible to make “failover-able'” and, therefore to protect, almost every kind of application (from xclock to the more complex Application Server) In the next couple of lines, I will try to present the different steps to achieve this goal : Have a fully operational 11gR2 database protected by automatic failover capabilities. I assume you are fluent in installing Oracle Database 11gR2, Oracle Grid Infrastructure 11gR2 on a Linux system and that ASM is not a problem for you (as I am using it as a shared storage). If not, please have a look at Oracle Documentation. As often, I made my tests using an Oracle VirtualBox environment. The scripts are tested and functional. Unfortunately, there can always be a typo or a mistake. This blog entry is not a course around the Clusterware Framework. I just hope it will let you see how powerful it is and that it will give you the whilst to go further with it…   Prerequisite 2 Linux boxes (OELCluster01 and OELCluster02) at the same OS level. I used OEL 5 Update 5 with Enterprise Kernel. Shared Storage (SAN). On my VirtualBox system, I used Openfiler to simulate the SAN Oracle 11gR2 Database (11.2.0.1) Oracle 11gR2 Grid Infrastructure (11.2.0.1)   Step 1 – Install the software Using asmlib, create 3 ASM disks (ASM_CRS, ASM_DTA and ASM_FRA) Install Grid Infrastructure for a cluster (OELCluster01 and OELCluster02 are the 2 nodes of the cluster) Use ASM_CRS to store Voting Disk and OCR. Use SCAN. Install Oracle Database Standalone binaries on both nodes. Use asmca to check/mount the disk groups on 2 nodes Use dbca to create and configure a database on the primary node Let’s name it DB11G. Copy the pfile, password file to the second node. Create adump directoty on the second node.   Step 2 - Setup the resource to be protected After its creation with dbca, the database is automatically protected by the Oracle Restart technology available with Grid Infrastructure. Consequently, it restarts automatically (if possible) after a crash (ex: kill –9 smon). A database resource has been created for that in the Cluster Registry. We can observe this with the command : crsctl status resource that shows and ora.dba11g.db entry. Let’s save the definition of this resource, for future use : mkdir –p /crs/11.2.0/HA_scripts chown oracle:oinstall /crs/11.2.0/HA_scripts crsctl status resource ora.db11g.db -p > /crs/11.2.0/HA_scripts/myResource.txt Although very interesting, Oracle Restart is not cluster aware and cannot restart the database on any other node of the cluster. So, let’s remove it from the OCR definitions, we don’t need it ! srvctl stop database -d DB11G srvctl remove database -d DB11G Instead of it, we need to create a new resource of a more general type : cluster_resource. Here are the steps to achieve this : Create an action script :  /crs/11.2.0/HA_scripts/my_ActivePassive_Cluster.sh #!/bin/bash export ORACLE_HOME=/oracle/product/11.2.0/dbhome_1 export ORACLE_SID=DB11G case $1 in 'start')   $ORACLE_HOME/bin/sqlplus /nolog <<EOF   connect / as sysdba   startup EOF   RET=0   ;; 'stop')   $ORACLE_HOME/bin/sqlplus /nolog <<EOF   connect / as sysdba   shutdown immediate EOF   RET=0   ;; 'check')    ok=`ps -ef | grep smon | grep $ORACLE_SID | wc -l`    if [ $ok = 0 ]; then      RET=1    else      RET=0    fi    ;; '*')      RET=0   ;; esac if [ $RET -eq 0 ]; then    exit 0 else    exit 1 fi   This script must provide, at least, methods to start, stop and check the database. It is self-explaining and contains nothing special. Just be aware that it is run as Oracle user (because of the ACL property – see later) and needs to know about the environment. It also needs to be present on every node of the cluster. chmod +x /crs/11.2.0/HA_scripts/my_ActivePassive_Cluster.sh scp  /crs/11.2.0/HA_scripts/my_ActivePassive_Cluster.sh   oracle@OELCluster02:/crs/11.2.0/HA_scripts Create a new resource file, based on the information we got from previous  myResource.txt . Name it myNewResource.txt. myResource.txt  is shown below. As we can see, it defines an ora.database.type resource, named ora.db11g.db. A lot of properties are related to this type of resource and do not need to be used for a cluster_resource. NAME=ora.db11g.db TYPE=ora.database.type ACL=owner:oracle:rwx,pgrp:oinstall:rwx,other::r-- ACTION_FAILURE_TEMPLATE= ACTION_SCRIPT= ACTIVE_PLACEMENT=1 AGENT_FILENAME=%CRS_HOME%/bin/oraagent%CRS_EXE_SUFFIX% AUTO_START=restore CARDINALITY=1 CHECK_INTERVAL=1 CHECK_TIMEOUT=600 CLUSTER_DATABASE=false DB_UNIQUE_NAME=DB11G DEFAULT_TEMPLATE=PROPERTY(RESOURCE_CLASS=database) PROPERTY(DB_UNIQUE_NAME= CONCAT(PARSE(%NAME%, ., 2), %USR_ORA_DOMAIN%, .)) ELEMENT(INSTANCE_NAME= %GEN_USR_ORA_INST_NAME%) DEGREE=1 DESCRIPTION=Oracle Database resource ENABLED=1 FAILOVER_DELAY=0 FAILURE_INTERVAL=60 FAILURE_THRESHOLD=1 GEN_AUDIT_FILE_DEST=/oracle/admin/DB11G/adump GEN_USR_ORA_INST_NAME= GEN_USR_ORA_INST_NAME@SERVERNAME(oelcluster01)=DB11G HOSTING_MEMBERS= INSTANCE_FAILOVER=0 LOAD=1 LOGGING_LEVEL=1 MANAGEMENT_POLICY=AUTOMATIC NLS_LANG= NOT_RESTARTING_TEMPLATE= OFFLINE_CHECK_INTERVAL=0 ORACLE_HOME=/oracle/product/11.2.0/dbhome_1 PLACEMENT=restricted PROFILE_CHANGE_TEMPLATE= RESTART_ATTEMPTS=2 ROLE=PRIMARY SCRIPT_TIMEOUT=60 SERVER_POOLS=ora.DB11G SPFILE=+DTA/DB11G/spfileDB11G.ora START_DEPENDENCIES=hard(ora.DTA.dg,ora.FRA.dg) weak(type:ora.listener.type,uniform:ora.ons,uniform:ora.eons) pullup(ora.DTA.dg,ora.FRA.dg) START_TIMEOUT=600 STATE_CHANGE_TEMPLATE= STOP_DEPENDENCIES=hard(intermediate:ora.asm,shutdown:ora.DTA.dg,shutdown:ora.FRA.dg) STOP_TIMEOUT=600 UPTIME_THRESHOLD=1h USR_ORA_DB_NAME=DB11G USR_ORA_DOMAIN=haroland USR_ORA_ENV= USR_ORA_FLAGS= USR_ORA_INST_NAME=DB11G USR_ORA_OPEN_MODE=open USR_ORA_OPI=false USR_ORA_STOP_MODE=immediate VERSION=11.2.0.1.0 I removed database type related entries from myResource.txt and modified some other to produce the following myNewResource.txt. Notice the NAME property that should not have the ora. prefix Notice the TYPE property that is not ora.database.type but cluster_resource. Notice the definition of ACTION_SCRIPT. Notice the HOSTING_MEMBERS that enumerates the members of the cluster (as returned by the olsnodes command). NAME=DB11G.db TYPE=cluster_resource DESCRIPTION=Oracle Database resource ACL=owner:oracle:rwx,pgrp:oinstall:rwx,other::r-- ACTION_SCRIPT=/crs/11.2.0/HA_scripts/my_ActivePassive_Cluster.sh PLACEMENT=restricted ACTIVE_PLACEMENT=0 AUTO_START=restore CARDINALITY=1 CHECK_INTERVAL=10 DEGREE=1 ENABLED=1 HOSTING_MEMBERS=oelcluster01 oelcluster02 LOGGING_LEVEL=1 RESTART_ATTEMPTS=1 START_DEPENDENCIES=hard(ora.DTA.dg,ora.FRA.dg) weak(type:ora.listener.type,uniform:ora.ons,uniform:ora.eons) pullup(ora.DTA.dg,ora.FRA.dg) START_TIMEOUT=600 STOP_DEPENDENCIES=hard(intermediate:ora.asm,shutdown:ora.DTA.dg,shutdown:ora.FRA.dg) STOP_TIMEOUT=600 UPTIME_THRESHOLD=1h Register the resource. Take care of the resource type. It needs to be a cluster_resource and not a ora.database.type resource (Oracle recommendation) .   crsctl add resource DB11G.db  -type cluster_resource -file /crs/11.2.0/HA_scripts/myNewResource.txt Step 3 - Start the resource crsctl start resource DB11G.db This command launches the ACTION_SCRIPT with a start and a check parameter on the primary node of the cluster. Step 4 - Test this We will test the setup using 2 methods. crsctl relocate resource DB11G.db This command calls the ACTION_SCRIPT  (on the two nodes)  to stop the database on the active node and start it on the other node. Once done, we can revert back to the original node, but, this time we can use a more “MS$ like” method :Turn off the server on which the database is running. After short delay, you should observe that the database is relocated on node 1. Conclusion Once the software installed and the standalone database created (which is a rather common and usual task), the steps to reach the objective are quite easy : Create an executable action script on every node of the cluster. Create a resource file. Create/Register the resource with OCR using the resource file. Start the resource. This solution is a very interesting alternative to licensable third party solutions.   References Clusterware 11gR2 documentation Oracle Clusterware Resource Reference   Gilles Haro Technical Expert - Core Technology, Oracle Consulting   

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• Graph Theory: How to compute closeness centrality for each node in a set of data?

  - by Jordan

  I'd like to learn how to apply network theory to my own cache of relational data. I'm trying to build a demo of a new way of browsing a music library, using network theory, that I think would make for a very intuitive and useful way of finding the right song at any given time. I have all the data (artists as nodes, similarity from 0 to 1 between each artist and those it is related to) and I can already program, but I don't know how to actually calculate the centrality of a node from that. I've spent a while trying to email different professors at my school but no one seems to know where I can learn this. I hope someone's done something similar. Thanks in advance you guys! ~Jordan

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• Make MySQL database replication always use the most free node?

  - by Chad Johnson

  We started using Multi-Master Replication Manager for MySQL, and I am wondering whether it is possible to to treat this setup like multi-symmetric processing: a process pops off the process queue, and the node (in this case a server) that is most free is selected for the job. It seems that what happens is, the service switches to a slave ONLY when it mysqld crashes or goes away. Is there a way to make database replication for MySQL act in more of a distributed manner? Maybe there is other software besides MMM that can do this? Is there a way to switch the reader role to another server whene mysqld slows down (rather than just when it fails)?

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• Optional Fields in Infopath; Getting the xml node with VBA

  - by Sunscreen

  Hi all, I use vb to get data through my form. I have some optional fileds in my form and I have this problem with the following code: MsgBox(myXPathNavigator.SelectSingleNode("/my:Status/my:Questions/my:Questions1", _ Me.NamespaceManager).IsNode.ToString) When the optional filed 'Questions1' is inserted to the form I get the value 'true' by the IsNode function. If the field it is not inserted I have an exception, stating that the reference is not correct (and it is indeed true). Is there a way to verify about a node, whether it is present or not in my form? Thanks in advance, Sun

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• Multilingual in Drupal: Can't have a node and it's translations as frontpage. How to?

  - by takpar

  hi, i built a page in Persian. set it's path to front set drupal frontpage to /front everything is O.K. in mysite.com/fa i translate the page to en problem arises. now the path of Persian page changes to default node/33. now in language's frontpage drupal says Can't find the page. i tried to set path front to the translated english page. but it did not helped. i alse tried to assign path fa/front to my Persian page. nothing helped. translating brakes path in other nodes. how can i have these pages /front and /fa/front translated of each other as the same time?

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