complex networks - Page 247

Is order of parameters for database Command object really important?

- by nawfal

I was debugging a database operation code and I found that proper UPDATE was never happening though the code never failed as such. This is the code: condb.Open(); OleDbCommand dbcom = new OleDbCommand("UPDATE Word SET word=?,sentence=?,mp3=? WHERE id=? AND exercise_id=?", condb); dbcom.Parameters.AddWithValue("id", wd.ID); dbcom.Parameters.AddWithValue("exercise_id", wd.ExID); dbcom.Parameters.AddWithValue("word", wd.Name); dbcom.Parameters.AddWithValue("sentence", wd.Sentence); dbcom.Parameters.AddWithValue("mp3", wd.Mp3); But after some tweaking this worked: condb.Open(); OleDbCommand dbcom = new OleDbCommand("UPDATE Word SET word=?,sentence=?,mp3=? WHERE id=? AND exercise_id=?", condb); dbcom.Parameters.AddWithValue("word", wd.Name); dbcom.Parameters.AddWithValue("sentence", wd.Sentence); dbcom.Parameters.AddWithValue("mp3", wd.Mp3); dbcom.Parameters.AddWithValue("id", wd.ID); dbcom.Parameters.AddWithValue("exercise_id", wd.ExID); Why is it so important that the parameters in WHERE clause has to be given the last in case of OleDb connection? Having worked with MySQL previously, I could (and usually do) write parameters of WHERE clause first because that's more logical to me. Is parameter order important when querying database in general? Some performance concern or something? Is there a specific order to be maintained in case of other databases like DB2, Sqlite etc? Update: I got rid of ? and included proper names with and without @. The order is really important. In both cases only when WHERE clause parameters was mentioned last, actual update happened. To make matter worse, in complex queries, its hard to know ourselves which order is Access expecting, and in all situations where order is changed, the query doesnt do its intended duty with no warning/error!!

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Is it a good or bad practice to call instance methods from a java constructor?

- by Steve

There are several different ways I can initialize complex objects (with injected dependencies and required set-up of injected members), are all seem reasonable, but have various advantages and disadvantages. I'll give a concrete example: final class MyClass { private final Dependency dependency; @Inject public MyClass(Dependency dependency) { this.dependency = dependency; dependency.addHandler(new Handler() { @Override void handle(int foo) { MyClass.this.doSomething(foo); } }); doSomething(0); } private void doSomething(int foo) { dependency.doSomethingElse(foo+1); } } As you can see, the constructor does 3 things, including calling an instance method. I've been told that calling instance methods from a constructor is unsafe because it circumvents the compiler's checks for uninitialized members. I.e. I could have called doSomething(0) before setting this.dependency, which would have compiled but not worked. What is the best way to refactor this? Make doSomething static and pass in the dependency explicitly? In my actual case I have three instance methods and three member fields that all depend on one another, so this seems like a lot of extra boilerplate to make all three of these static. Move the addHandler and doSomething into an @Inject public void init() method. While use with Guice will be transparent, it requires any manual construction to be sure to call init() or else the object won't be fully-functional if someone forgets. Also, this exposes more of the API, both of which seem like bad ideas. Wrap a nested class to keep the dependency to make sure it behaves properly without exposing additional API:class DependencyManager { private final Dependency dependency; public DependecyManager(Dependency dependency) { ... } public doSomething(int foo) { ... } } @Inject public MyClass(Dependency dependency) { DependencyManager manager = new DependencyManager(dependency); manager.doSomething(0); } This pulls instance methods out of all constructors, but generates an extra layer of classes, and when I already had inner and anonymous classes (e.g. that handler) it can become confusing - when I tried this I was told to move the DependencyManager to a separate file, which is also distasteful because it's now multiple files to do a single thing. So what is the preferred way to deal with this sort of situation?

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JPA - Can I create an Entity class, using an @DiscriminatorValue, that doesn't have its own table?

- by DaveyDaveDave

Hi - this is potentially a bit complex, so I'll do my best to describe my situation - it's also my first post here, so please forgive formatting mistakes, etc! I'm using JPA with joined inheritance and a database structure that looks like: ACTION --------- ACTION_ID ACTION_MAPPING_ID ACTION_TYPE DELIVERY_CHANNEL_ACTION -------------------------- ACTION_ID CHANNEL_ID OVERRIDE_ADDRESS_ACTION -------------------------- ACTION_ID (various fields specific to this action type) So, in plain English, I have multiple different types of action, all share an ACTION_MAPPING, which is referenced from the 'parent' ACTION table. DELIVERY_CHANNEL_ACTION and OVERRIDE_ADDRESS_ACTION both have extra, supplementary data of their own, and are mapped to ACTION with a FK. Real-world, I also have a 'suppress' action, but this doesn't have any supplementary data of its own, so it doesn't have a corresponding table - all it needs is an ACTION_MAPPING, which is stored in the ACTION table. Hopefully you're with me so far... I'm creating a new project from scratch, so am pretty flexible in what I can do, but obviously would like to get it right from the outset! My current implementation, which works, has three entities loosely defined as follows: @Entity @Table(name="ACTION") @Inheritance(strategy=InheritanceType.JOINED) @DiscriminatorValue("SUPPRESS") public class Action @Entity @Table(name="DELIVERY_CHANNEL_ACTION") @DiscriminatorValue("DELIVERY_CHANNEL") public class DeliveryChannelAction extends Action @Entity @Table(name="OVERRIDE_ADDRESS_ACTION") @DiscriminatorValue("OVERRIDE_ADDRESS") public class OverrideAddressAction extends Action That is - I have a concrete base class, Action, with a Joined inheritance strategy. DeliveryChannelAction and OverrideAddressAction both extend Action. What feels wrong here though, is that my Action class is the base class for these two actions, but also forms the concrete implementation for the suppress action. For the time being this works, but at some point more actions are likely to be added, and there's every chance that some of them will, like SUPPRESS, have no supplementary data, which will start to get difficult! So... what I would like to do, in the object model world, is to have Action be abstract, and create a SuppressAction class, which is empty apart from having a @DiscriminatorValue("SUPPRESS"). I've tried doing exactly what is described above, so, changing Action to: @Entity @Table(name="ACTION") @Inheritance(strategy=InheritanceType.JOINED) public abstract class Action and creating: @DiscriminatorValue("SUPPRESS") public class SuppressAction extends Action but no luck - it seems to work fine for DeliveryChannelAction and OverrideAddressAction, but when I try to create a SuppressAction and persist it, I get: java.lang.IllegalArgumentException: Object: com.mypackage.SuppressAction[actionId=null] is not a known entity type. at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.registerNewObjectForPersist(UnitOfWorkImpl.java:4147) at org.eclipse.persistence.internal.jpa.EntityManagerImpl.persist(EntityManagerImpl.java:368) at com.mypackage.test.util.EntityTestUtil.createSuppressAction(EntityTestUtil.java:672) at com.mypackage.entities.ActionTest.testCRUDAction(ActionTest.java:27) which I assume is down to the fact that SuppressAction isn't registered as an entity, but I don't know how I can do that, given that it doesn't have an associated table. Any pointers, either complete answers or hints for things to Google (I'm out of ideas!), most welcome :) EDIT: to correct my stacktrace.

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SQL Query takes about 10 - 20 minutes

- by masfenix

I have a select from (nothing to complex) Select * from VIEW This view has about 6000 records and about 40 columns. It comes from a Lotus Notes SQL database. So my ODBC drive is the LotusNotesSQL driver. The query takes about 30 seconds to execute. The company I worked for used EXCEL to run the query and write everything to the worksheet. Since I am assuming it writes everything cell by cell, it used to take up to 30 - 40 minutes to complete. I then used MS access. I made a replica local table on Access to store the data. My first try was INSERT INTO COLUMNS OF LOCAL TABLE FROM (SELECT * FROM VIEW) note that this is pseudocode. This ran successfully, but again took up to 20 - 30 minutes. Then I used VBA to loop through the data and insert it in manually (using an INSERT statement) for each seperate record. This took about 10 - 15 minutes. This has been my best case yet. What i need to do after: After i have the data, I need to filter through it by department. The thing is if I put a where clause in the SQL query (the time jumps from 30 seconds to execute the query, to about 10 minutes + the time to write to local table/excel). I dont know why. MAYBE because the columns are all text columns? If we change some of the columns to integer, would that make it faster in terms of the where clause? I am looking for suggestions on how to approach this. My boss has said we could employ some Java based solution. Will this help? I am not a java person but a c#, and maybe I'll convince them to use c# as well, but i am mainly looking for suggestions on how to cut down the time. I've already cut it down from 40 minutes to 10 minutes, but the want it under 2 minutes. Just to recap: Query takes about 30 seconds to exceute Query takes about 15 - 40 minutes to be used locally in excel/acess Need it under 2 minutes Could use java based solution You may suggest other solutions instead of java.

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Why does JAXB not create a member variable in its generated code when an XML schema base type and subtype have the same element declared in them?

- by belltower

I have a question regarding with regard to JAXB generated classes. As you can I see, I have a complex type, DG_PaymentIdentification1, declared in my schema. Its a restriction of PaymentIdentification1. DG_PaymentIdentification1 is also identical to PaymentIdentification1. I also have a type called DG_CreditTransferTransactionInformation10 which has a base type of CreditTransferTransactionInformation10 and is identical to it. I have included the relevant XML schema snippets below. <xs:complexType name="DG_PaymentIdentification1"> <xs:complexContent> <xs:restriction base="PaymentIdentification1"> <xs:sequence> <xs:element name="InstrId" type="DG_Max35Text_REF" minOccurs="0"/> <xs:element name="EndToEndId" type="DG_Max35Text_REF" id="DG-41"/> </xs:sequence> </xs:restriction> </xs:complexContent> </xs:complexType> <xs:complexType name="PaymentIdentification1"> <xs:sequence> <xs:element name="InstrId" type="Max35Text" minOccurs="0"/> <xs:element name="EndToEndId" type="Max35Text"/> </xs:sequence> </xs:complexType> <xs:complexType name="DG_CreditTransferTransactionInformation10"> <xs:complexContent> <xs:restriction base="CreditTransferTransactionInformation10"> <xs:sequence> <xs:element name="PmtId" type="DG_PaymentIdentification1"/> <xs:simpleType name="DG_Max35Text_REF"> <xs:restriction base="DG_NotEmpty35"> <xs:pattern value="[\-A-Za-z0-9\+/\?:\.,' ]*"/> </xs:restriction> </xs:simpleType> <xs:simpleType name="Max35Text"> <xs:restriction base="xs:string"> <xs:minLength value="1"/> <xs:maxLength value="35"/> </xs:restriction> </xs:simpleType> JAXB generates the following java class for DG_PaymentIdentification1: @XmlAccessorType(XmlAccessType.FIELD) @XmlType(name = "DG_CreditTransferTransactionInformDGion10") public class DGCreditTransferTransactionInformation10 extends CreditTransferTransactionInformation10 { } My question is why doesnt the DGCreditTransferTransactionInformation10 generated class have a variable of type DG_PaymentIdentification1 in the generated code? The base class CreditTransferTransactionInformation10 does have a type PaymentIdentification1 declared in it. Is there any way of ensuring that DGCreditTransferTransactionInformation10 will have a DG_PaymentIdentification1 in it?

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Hot to get rid of memory allocations/deallocations in swig wrappers?

- by Dmitriy Matveev

I want to use swig for generation of read-only wrappers for a complex object. The object which I want to wrap will always be existent while I will read it. And also I will only use my wrappers at the time that object is existent, thus I don't need any memory management from SWIG. For following swig interface: %module test %immutable; %inline %{ struct Foo { int a; }; struct Bar { int b; Foo f; }; %} I will have a wrappers which will have a lot of garbage in generated interfaces and do useless work which will reduce performance in my case. Generated java wrapper for Bar class will be like this: public class Bar { private long swigCPtr; protected boolean swigCMemOwn; protected Bar(long cPtr, boolean cMemoryOwn) { swigCMemOwn = cMemoryOwn; swigCPtr = cPtr; } protected static long getCPtr(Bar obj) { return (obj == null) ? 0 : obj.swigCPtr; } protected void finalize() { delete(); } public synchronized void delete() { if (swigCPtr != 0) { if (swigCMemOwn) { swigCMemOwn = false; testJNI.delete_Bar(swigCPtr); } swigCPtr = 0; } } public int getB() { return testJNI.Bar_b_get(swigCPtr, this); } public Foo getF() { return new Foo(testJNI.Bar_f_get(swigCPtr, this), true); } public Bar() { this(testJNI.new_Bar(), true); } } I don't need 'swigCMemOwn' field in my wrapper since it always will be false. All code related to this field will also be useless. There are also unnecessary logic in native code: SWIGEXPORT jlong JNICALL Java_some_testJNI_Bar_1f_1get(JNIEnv *jenv, jclass jcls, jlong jarg1, jobject jarg1_) { jlong jresult = 0 ; struct Bar *arg1 = (struct Bar *) 0 ; Foo result; (void)jenv; (void)jcls; (void)jarg1_; arg1 = *(struct Bar **)&jarg1; result = ((arg1)->f); { Foo * resultptr = (Foo *) malloc(sizeof(Foo)); memmove(resultptr, &result, sizeof(Foo)); *(Foo **)&jresult = resultptr; } return jresult; } I don't need these calls to malloc and memmove. I want to force swig to resolve both of these problems, but don't know how. Is it possible?

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Best way to have common class shared by both C++ and Ruby?

- by shuttle87

I am currently working on a project where a team of us are designing a game, all of us are proficient in ruby and some (but not all) of us are proficient in c++. Initially we made the backend in ruby but we ported it to c++ for more speed. The c++ port of the backend has exactly the same features and algorithms as the original ruby code. However we still have a bunch of code in ruby that does useful things but we want it to now get the data from the c++ classes. Our first thought was that we could save some of the data structures in something like XML or redis and call that, but some of the developers don't like that idea. We don't need anything particularly complex data structures to be passed between the different parts of the code, just tuples, strings and ints. Is there any way of integrating the ruby code so that it can call the c++ stuff natively? Will we need to embed code? Will we have to make a ruby extension? If so are there any good resources/tutorials you could suggest? For example say we have this code in the c++ backend: class The_game{ private: bool printinfo; //print the player diagnostic info at the beginning if true int numplayers; std::vector<Player*> players; string current_action; int action_is_on; // the index of the player in the players array that the action is now on //more code here public: Table(std::vector<Player *> in_players, std::vector<Statistics *> player_stats ,const int in_numplayers); ~Table(); void play_game(); History actions_history; }; class History{ private: int action_sequence_number; std::vector<Action*> hand_actions; public: void print_history(); void add_action(Action* the_action_to_be_added); int get_action_sequence_number(){ return action_sequence_number;} bool history_actions_are_equal(); int last_action_size(int street,int number_of_actions_ago); History(); ~History(); }; Is there any way to natively call something in the actions_history via The_game object in ruby? (The objects in the original ruby code all had the same names and functionality) By this I mean: class MyRubyClass def method1(arg1) puts arg1 self.f() # ... but still available puts cpp_method.the_current_game.actions_history.get_action_sequence_number() end # Constructor: def initialize(arg) puts "In constructor with arg #{arg}" #get the c++ object here and call it cpp_method end end Is this possible? Any advice or suggestions are appreciated.

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Inventory count in CakePHP

- by metrobalderas

We are developing an inventory tracking system. Basically we've got an order table in which orders are placed. When an order is payed, the status changes from 0 to 1. This table has multiple children in another table order_items. This is the main structure. CREATE TABLE order( id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, user_id INT UNSIGNED, status INT(1), total INT UNSIGNED ); CREATE TABLE order_items( id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, order_id INT UNSIGNED, article_id INT UNSIGNED, size enum('s', 'm', 'l', 'xl'), quantity INT UNSIGNED ); Now, we've got a stocks table with similar architecture for the acquisitions. This is the structure. CREATE TABLE stock( id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, article_id INT UNSIGNED ); CREATE TABLE stock_items( id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, stock_id INT UNSIGNED, size enum('s', 'm', 'l', 'xl'), quantity INT(2) ); The main difference is that stocks has no status field. What we are looking for is a way to sum each article size from stock_items, then sum each article size from order_items where Order.status = 1 and substract both these items to find our current inventory. This is the table we want to get from a single query: Size | Stocks | Sales | Available s | 10 | 3 | 7 m | 15 | 13 | 2 l | 7 | 4 | 3 Initially we thought abouth using complex find conditions, but perhaps that's the wrong approach. Also, since it's not a direct join, it turns out to be quite hard. This is the code we have to retrieve the stock's total for each item. function stocks_total($id){ $find = $this->StockItem->find('all', array( 'conditions' => array( 'StockItem.stock_id' => $this->find('list', array('conditions' => array('Stock.article_id' => $id))) ), 'fields' => array_merge( array( 'SUM(StockItem.cantidad) as total' ), array_keys($this->StockItem->_schema) ), 'group' => 'StockItem.size', 'order' => 'FIELD(StockItem.size, \'s\', \'m\' ,\'l\' ,\'xl\') ASC' )); return $find; } Thanks.

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Which MS technologies would be suited for a data intensive application?

- by steve.tse

I'm a junior VB.net developer with little application design knowledge. I've been reading a lot of material online regarding different design patterns, frameworks, and methodologies. It's become a bit confusing for me. Right now I'm trying to decide on what language would be best suited to convert an existing VB6 application (with SQL server backend.) I need to update the UI and add more user functionality and reporting capabilities. Initially I was thinking of using WPF and attempting the MVVM model for this big project. Reports would be generated from SSRS. A peer suggested using ASP.net and I don't have enough experience to determine what would be better. The senior programmers here are stuck on using VB6 and don't have any input on what to use. They are encouraging me to use the latest technologies. This application would be for ~20 users in a central location. Ideally I would stick to a Microsoft .net language. Current interface is similar to a datagrid table where the user would click in to see the detail of each record. They would need to have multiple records open at any given time. I look forward to all the advice I can get. EDIT 2010/04/22 2:47 PM EST What is your audience? Internal clients within an intranet How complex are the interactions you expect to implement? not very... displaying data from SQL server to UI. Allow user updates to said data. Typically just one user modifying a record. Do you require near real-time data updates? no How often do you expect to update the application after the first release? twice/year Do you expect a well-defined set of client platforms? Yes, windows xp environment, potentially upgrading to Win7. Currently in IE.6 moving to IE7 or 8 within a couple of months. Do users need access from anywhere? No, just from their PC.

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Spring OpenSessionInViewFilter with @Transactional annotation

- by Gautam

This is regarding Spring OpenSessionInViewFilter using with @Transactional annotation at service layer. i went through so many stack overflow post on this but still confused about whether i should use OpenSessionInViewFilter or not to avoid LazyInitializationException It would be great help if somebody help me find out answer to below queries. Is it bad practice to use OpenSessionInViewFilter in application having complex schema. using this filter can cause N+1 problem if we are using OpenSessionInViewFilter does it mean @Transactional not required? Below is my Spring config file <context:component-scan base-package="com.test"/> <context:annotation-config/> <bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource"> <property name="basename" value="resources/messages" /> <property name="defaultEncoding" value="UTF-8" /> </bean> <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" p:location="/WEB-INF/jdbc.properties" /> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" p:driverClassName="${jdbc.driverClassName}" p:url="${jdbc.databaseurl}" p:username="${jdbc.username}" p:password="${jdbc.password}" /> <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="configLocation"> <value>classpath:hibernate.cfg.xml</value> </property> <property name="configurationClass"> <value>org.hibernate.cfg.AnnotationConfiguration</value> </property> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">${jdbc.dialect}</prop> <prop key="hibernate.show_sql">true</prop>  </props> </property> </bean> <tx:annotation-driven /> <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager"> <property name="sessionFactory" ref="sessionFactory" /> </bean>

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Table row height in Internet Explorer

- by Fritz H

I have the following table: <table> <tr> <td style="height: 7px; width: 7px"> A1 </td> <td style="height: 7px"> B1 </td> <td style="height: 7px; width: 7px"> C1 </td> </tr> <tr> <td style="width: 7px"> A2 </td> <td> B2 </td> <td style="width: 7px"> C2 </td> </tr> <tr> <td style="height: 7px; width: 7px"> A3 </td> <td style="height: 7px"> B3 </td> <td style="height: 7px; width: 7px"> C3 </td> </tr> </table> The basic idea is that the first row must be 7 pixels high. The left- and rightmost cells (A1 and C1) must be 7px wide, and the middle cell (B1) must scale according to the width of the table. The same goes for the bottom row (A3, B3, C3). The middle row, however, needs to scale in height - in other words, it needs to be (tableheight - 14px). The left- and rightmost cells (A2, C2) need to be 7 pixels wide. An example: 7px x 7px |------|-------------------------|------| --- +------+-------------------------+------+ | | | | | | 7px | | | | | | | | | --- +------+-------------------------+------+ | | | | | | | | | | | | | | | | | | | | | y | | | | | | | | | | | | | | | | | | | | | | | | --- +------+-------------------------+------+ | | | | | | 7px | | | | | | | | | --- +------+-------------------------+------+ HOWEVER: In Internet Explorer, the widths work fine (columns A and C are 7px, column B scales dynamically) - but the heights don't. Rows 1, 2 and 3 turn out to be exactly 33% of the height of the table, no matter what I do. Unfortunately I have to use this table, so replacing it with a set of DIVs is not an option. I have the following DOCTYPE: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> I need to keep this, as some other elements on the page rely on some complex CSS-based layouts. Can anyone point me in the right direction to whip this into shape for IE? EDIT: Should have mentioned earlier - this table is resized on the fly using javascript.

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Please Describe Your Struggles with Minimizing Use of Global Variables

- by MetaHyperBolic

Most of the programs I write are relatively flowchartable processes, with a defined start and hoped-for end. The problems themselves can be complex but do not readily lean towards central use of objects and event-driven programming. Often, I am simply churning through great varied batches of text data to produce different text data. Only occasionally do I need to create a class: As an example, to track warnings, errors, and debugging message, I created a class (Problems) with one instantiation (myErr), which I believe to be an example of the Singleton design pattern. As a further factor, my colleagues are more old school (procedural) than I and are unacquainted with object-oriented programming, so I am loath to create things they could not puzzle through. And yet I hear, again and again, how even the Singleton design pattern is really an anti-pattern and ought to be avoided because Global Variables Are Bad. Minor functions need few arguments passed to them and have no need to know of configuration (unchanging) or program state (changing) -- I agree. However, the functions in the middle of the chain, which primarily control program flow, have a need for a large number of configuration variables and some program state variables. I believe passing a dozen or more arguments along to a function is a "solution," but hardly an attractive one. I could, of course, cram variables into a single hash/dict/associative array, but that seems like cheating. For instance, connecting to the Active Directory to make a new account, I need such configuration variables as an administrative username, password, a target OU, some default groups, a domain, etc. I would have to pass those arguments down through a variety of functions which would not even use them, merely shuffle them off down through a chain which would eventually lead to the function that actually needs them. I would at least declare the configuration variables to be constant, to protect them, but my language of choice these days (Python) provides no simple manner to do this, though recipes do exist as workarounds. Numerous Stack Overflow questions have hit on the why? of the badness and the requisite shunning, but do not often mention tips on living with this quasi-religious restriction. How have you resolved, or at least made peace with, the issue of global variables and program state? Where have you made compromises? What have your tricks been, aside from shoving around flocks of arguments to functions?

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How to find an specific key/value (property list)

- by Bob Rivers

Hi, I'm learning cocoa/objective-c. Right now I'm dealing with key/value coding. After reading Aaron's book and other sources, I thought that I was able to left the simple examples and try a complex one... I'm trying read iTunes property list (iTunes Music Library.xml). I would like to retrieve the tracks held by an specific playlist. Probably everybody knows it, but bellow I put a piece of the xml: <plist version="1.0"> <dict> <key>Major Version</key><integer>1</integer> ... <key>Playlists</key> <array> <dict> <key>Name</key><string>Library</string> ... <key>Playlist Items</key> <array> <dict> <key>Track ID</key><integer>10281</integer> </dict> ... </array> </dict> <dict> ... </dict> </array> </dict> </plist> As you can see, the playlists are stored as dictionaries inside an array, and the key that identifies it is inside it, not as a <key> preceding it. The problem is that I'm not able to figure out how to search for a key that is inside another one. With the following code I can find the the array in which the playlists are stored, but how to find an specific <dict>? NSDictionary *rootDict = [[NSDictionary alloc] initWithContentsOfFile:file]; NSArray *playlists = [rootDict objectForKey:@"Playlists"]; Here at Stackoverflow I found this post, but I'm not sure if iterate over the array and test it is a good idea. I'm quite sure that I could use valueForKeyPath, but I'm unable to figure out how to do it. Any help is welcome. TIA, Bob

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Are there any CMS editors out there which users can populate locked down HTML templates with content

- by Deep

Hi there, We work in email marketing, creating HTML/TEXT emails for clients. In essence we design HTML email templates for our clients. Clients then post us content (via a form) to populate these templates before we send them out. Right now we do this manually, basically cutting and pasting the content from their submitted form into the relevant parts of the template, which is time consuming and particularly mind-numbing. What we're looking for (and have so far been unable to find) is a simple system which will allow us to capture this client content in a sort of WYSIWYG HTML format. Basically they populate a locked down version of the template, entering text where necessary, before submitting to us. This is our most basic requirement, and a friend of mine kindly demo'd a proof of concept here: http://advantageone.co.uk/mbe/ Note: If you click on a text area in the body of the template, an editor pop ups. Now what we are looking for a CMS editor out there which can be easily adapted to do the above and the following for our end clients? User login View previously submitted campaigns that they have created and edit these Create new - selecting from template (assigned to their user/client id), perhaps being able to add new rows to the template. And have these HTML templates locked down so they can only edit what they're allowed too (like in the demo above), and perhaps make some areas required. Perhaps have a simple workflow or approval built in Allow us to lock submitted campaigns after a point so they can't be further edited, and as administrators view all campaigns from all users Be so incredibly simple, with any extraneous functionality switched off Essentially an extremley simple stripped down CMS, but we use the outputted HTML for sending out as an email, rather than publishing onto the web. Now to the actual dilemma: we're looking for something really simple, and the above sounds like a CMS. But we haven't been able to find anything that already does, or can be easily adapted to do this. Everything is either too complex, or simple and inflexible. We're sure there must be something off the shelf available, rather than us coding something ourselves. But we've kind of got stuck. Does anyone know of a system, or could recommend a system that can do the above out of the box, or with a few days tweaking? Forgive me if this is a little disjointed, if I'm being incredibly dopey and there is something out there please let me know! Kind regards, Dp.

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When i add a bitmap to an array list the last element is duplicated in previous indexes

- by saxofone2

I'm trying to implement a personal way of undo/redo in a finger paint-like app. I have in synthesis three objects: the Main class (named ScorePadActivity), the relative Main Layout (with buttons, menus, etc, as well as a View object where I create my drawings), and a third object named ArrayList where i'm writing the undo/redo code. The problem is, when I press the undo button nothing happens, but if I draw anything again "one-time" and press undo, the screen is updated. If I draw many times, to see any changes happen on screen I have to press the undo button the same number of times I have drawn. Seems like (as in title) when I add a bitmap to the array list the last element is duplicated in previous indexes, and for some strange reason, everytime I press the Undo Button, the system is ok for one time, but starts to duplicate until the next undo. The index increase is verified with a series of System.out.println inserted in code. Now when I draw something on screen, the array list is updated with the code inserted after the invocation of touchup(); method in motionEvent touch_up(); } this.arrayClass.incrementArray(mBitmap); mPath.rewind(); invalidate(); and in ArrayList activity; public void incrementArray(Bitmap mBitmap) { this._mBitmap=mBitmap; _size=undoArray.size(); undoArray.add(_size, _mBitmap); } (All Logs removed for clear reading) The undo button in ScorePadActivity calls the undo method in View activity: Button undobtn= (Button)findViewById(R.id.undo); undobtn.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { mView.undo(); } }); in View activity: public void undo() { this.mBitmap= arrayClass.undo(); mCanvas = new Canvas(mBitmap); mPath.rewind(); invalidate(); } that calls the relative undo method in ArrayList activity: public Bitmap undo() { // TODO Auto-generated method stub _size=undoArray.size(); if (_size>1) { undoArray.remove(_size-1); _size=undoArray.size(); _mBitmap = ((Bitmap) undoArray.get(_size-1)).copy(Bitmap.Config.ARGB_8888,true); } return _mBitmap; } return mBitmap and invalidate: Due to my bad English I have made a scheme to make the problem more clear: I have tried with HashMap, with a simple array, I have tried to change mPath.rewind(); with reset();, new Path(); etc but nothing. Why? Sorry for the complex answer, i want give you a great thanks in advance. Best regards

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PHP-OOP extending two classes?

- by user1292810

I am very beginner to OOP and now I am trying to write some PHP class to connect with FTP server. class ftpConnect { private $server; private $user; private $password; private $connection_id; private $connection_correct = false; public function __construct($server, $user = "anonymous", $password = "[email protected]") { $this->server = $server; $this->user = $user; $this->password = $password; $this->connection_id = ftp_connect($this->server); $this->connection_correct = ftp_login($this->connection_id, $this->user, $this->password); if ( (!$this->connection_id) || (!$this->connection_correct) ){ echo "Error! Couldn't connect to $this->server"; var_dump($this->connection_id); var_dump($this->connection_correct); return false; } else { echo "Successfully connected to $this->server, user: $this->user"; $this->connection_correct = true; return true; } } } I reckon that body of the class is insignificant at the moment. Main issue is that I have some problems with understanding OOP idea. I wanted to add sending emails every time, when the code is run. I have downloaded PHPMailer Class and extended my class with it: class ftpConnect extends PHPMailer {...} I have added some variables and methods and everything works as expected to that point. I thought: why not to add storing everything in database. Everytime user runs above code, proper information should be stored in database. I could edit my ftpConnect class and add database connecting to the constructor, and some other methods to updating tables. But database connecting and all that stuff could be used by other classes in the future, so it definitely should be implemented in seperate class. But my "main" ftpConnect class already extends one class and could not extend not a single one more. I have no idea how can I resolve this problem. Maybe my ftpConnect class is to complex and I should somehow divide it into couple smaller classes? Any help is much appreciated.

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Are python list comprehensions always a good programming practice?

- by dln385

To make the question clear, I'll use a specific example. I have a list of college courses, and each course has a few fields (all of which are strings). The user gives me a string of search terms, and I return a list of courses that match all of the search terms. This can be done in a single list comprehension or a few nested for loops. Here's the implementation. First, the Course class: class Course: def __init__(self, date, title, instructor, ID, description, instructorDescription, *args): self.date = date self.title = title self.instructor = instructor self.ID = ID self.description = description self.instructorDescription = instructorDescription self.misc = args Every field is a string, except misc, which is a list of strings. Here's the search as a single list comprehension. courses is the list of courses, and query is the string of search terms, for example "history project". def searchCourses(courses, query): terms = query.lower().strip().split() return tuple(course for course in courses if all( term in course.date.lower() or term in course.title.lower() or term in course.instructor.lower() or term in course.ID.lower() or term in course.description.lower() or term in course.instructorDescription.lower() or any(term in item.lower() for item in course.misc) for term in terms)) You'll notice that a complex list comprehension is difficult to read. I implemented the same logic as nested for loops, and created this alternative: def searchCourses2(courses, query): terms = query.lower().strip().split() results = [] for course in courses: for term in terms: if (term in course.date.lower() or term in course.title.lower() or term in course.instructor.lower() or term in course.ID.lower() or term in course.description.lower() or term in course.instructorDescription.lower()): break for item in course.misc: if term in item.lower(): break else: continue break else: continue results.append(course) return tuple(results) That logic can be hard to follow too. I have verified that both methods return the correct results. Both methods are nearly equivalent in speed, except in some cases. I ran some tests with timeit, and found that the former is three times faster when the user searches for multiple uncommon terms, while the latter is three times faster when the user searches for multiple common terms. Still, this is not a big enough difference to make me worry. So my question is this: which is better? Are list comprehensions always the way to go, or should complicated statements be handled with nested for loops? Or is there a better solution altogether?

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Custom InputIterator for Boost graph (BGL)

- by Shadow

Hi, I have a graph with custom properties to the vertices and edges. I now want to create a copy of this graph, but I don't want the vertices to be as complex as in the original. By this I mean that it would suffice that the vertices have the same indices (vertex_index_t) as they do in the original graph. Instead of doing the copying by hand I wanted to use the copy-functionality of boost::adjacency_list (s. http://www.boost.org/doc/libs/1_37_0/libs/graph/doc/adjacency_list.html): template <class EdgeIterator> adjacency_list(EdgeIterator first, EdgeIterator last, vertices_size_type n, edges_size_type m = 0, const GraphProperty& p = GraphProperty()) The description there says: The EdgeIterator must be a model of InputIterator. The value type of the EdgeIterator must be a std::pair, where the type in the pair is an integer type. The integers will correspond to vertices, and they must all fall in the range of [0, n). Unfortunately I have to admit that I don't quite get it how to define an EdgeIterator that is a model of InputIterator. Here's what I've succeded so far: template< class EdgeIterator, class Edge > class MyEdgeIterator// : public input_iterator< std::pair<int, int> > { public: MyEdgeIterator() {}; MyEdgeIterator(EdgeIterator& rhs) : actual_edge_it_(rhs) {}; MyEdgeIterator(const MyEdgeIterator& to_copy) {}; bool operator==(const MyEdgeIterator& to_compare) { return actual_edge_it_ == to_compare.actual_edge_it_; } bool operator!=(const MyEdgeIterator& to_compare) { return !(*this == to_compare); } Edge operator*() const { return *actual_edge_it_; } const MyEdgeIterator* operator->() const; MyEdgeIterator& operator ++() { ++actual_edge_it_; return *this; } MyEdgeIterator operator ++(int) { MyEdgeIterator<EdgeIterator, Edge> tmp = *this; ++*this; return tmp; } private: EdgeIterator& actual_edge_it_; } However, this doesn't work as it is supposed to and I ran out of clues. So, how do I define the appropriate InputIterator?

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Passing a panel widget to a function

- by user2939801

I have written a quite complex script which calls a server handler to refresh elements in a grid at the press of a button. For code re-use and consistent behaviour, I am wanting to call that server handler directly during the initial painting of the grid. When the server handler gets called by clicking on the button, all expected widgets are available and can be queried with e.parameter.widget etc. When I call the function directly and pass it the panel variable, the value of e is just 'AbsolutePanel'. Is there some way I can emulate the addCallbackElement way of passing the entire panel and all widgets it contains to the function? Or a way of automatically firing a server handler on script start? Please forgive any syntax errors below, I have pruned 500 lines of code down to the pertinent bits! Thanks Tony function doGet() { var app = UiApp.createApplication(); var mainPanel = app.createAbsolutePanel(); var monthsAbbr = ['Jan.', 'Feb.', 'Mar.', 'Apr.', 'May.', 'Jun.', 'Jul.', 'Aug.', 'Sep.', 'Oct.', 'Nov.', 'Dec.']; var Dates = Array(); var period = 5; var dateHidden = Array(); var dayOfMonth = new Date(((period * 28) + 15887) * 86400000); var dateString = ''; var dayOfWeek = 0; for (var i=0; i<84; i++) { dateString = dayOfMonth.getDate() + ' ' + monthsAbbr[dayOfMonth.getMonth()] + ' ' + (dayOfMonth.getFullYear() - 2000); Dates [i] = dateString; dateHidden[i] = app.createHidden('dates'+i, dateString).setId('dates'+i); mainPanel.add(dateHidden[i]); dayOfMonth = new Date(dayOfMonth.getTime() + 86400000); } var buttonReset = app.createButton('Reset').setId('buttonReset'); var handlerChange = app.createServerHandler('myHandlerChange'); handlerChange.addCallbackElement(mainPanel); mainPanel.add(buttonReset.addChangeHandler(handlerChange)); app.add(mainPanel); myHandlerChange(mainPanel); return app; } function myHandlerChange(e) { var app = UiApp.getActiveApplication(); Logger.log('Here are the widgets passed into the function: ' + Utilities.jsonStringify(e)); return app; }

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C# 4: The Curious ConcurrentDictionary

- by James Michael Hare

In my previous post (here) I did a comparison of the new ConcurrentQueue versus the old standard of a System.Collections.Generic Queue with simple locking. The results were exactly what I would have hoped, that the ConcurrentQueue was faster with multi-threading for most all situations. In addition, concurrent collections have the added benefit that you can enumerate them even if they're being modified. So I set out to see what the improvements would be for the ConcurrentDictionary, would it have the same performance benefits as the ConcurrentQueue did? Well, after running some tests and multiple tweaks and tunes, I have good and bad news. But first, let's look at the tests. Obviously there's many things we can do with a dictionary. One of the most notable uses, of course, in a multi-threaded environment is for a small, local in-memory cache. So I set about to do a very simple simulation of a cache where I would create a test class that I'll just call an Accessor. This accessor will attempt to look up a key in the dictionary, and if the key exists, it stops (i.e. a cache "hit"). However, if the lookup fails, it will then try to add the key and value to the dictionary (i.e. a cache "miss"). So here's the Accessor that will run the tests: 1: internal class Accessor 2: { 3: public int Hits { get; set; } 4: public int Misses { get; set; } 5: public Func<int, string> GetDelegate { get; set; } 6: public Action<int, string> AddDelegate { get; set; } 7: public int Iterations { get; set; } 8: public int MaxRange { get; set; } 9: public int Seed { get; set; } 10: 11: public void Access() 12: { 13: var randomGenerator = new Random(Seed); 14: 15: for (int i=0; i<Iterations; i++) 16: { 17: // give a wide spread so will have some duplicates and some unique 18: var target = randomGenerator.Next(1, MaxRange); 19: 20: // attempt to grab the item from the cache 21: var result = GetDelegate(target); 22: 23: // if the item doesn't exist, add it 24: if(result == null) 25: { 26: AddDelegate(target, target.ToString()); 27: Misses++; 28: } 29: else 30: { 31: Hits++; 32: } 33: } 34: } 35: } Note that so I could test different implementations, I defined a GetDelegate and AddDelegate that will call the appropriate dictionary methods to add or retrieve items in the cache using various techniques. So let's examine the three techniques I decided to test: Dictionary with mutex - Just your standard generic Dictionary with a simple lock construct on an internal object. Dictionary with ReaderWriterLockSlim - Same Dictionary, but now using a lock designed to let multiple readers access simultaneously and then locked when a writer needs access. ConcurrentDictionary - The new ConcurrentDictionary from System.Collections.Concurrent that is supposed to be optimized to allow multiple threads to access safely. So the approach to each of these is also fairly straight-forward. Let's look at the GetDelegate and AddDelegate implementations for the Dictionary with mutex lock: 1: var addDelegate = (key,val) => 2: { 3: lock (_mutex) 4: { 5: _dictionary[key] = val; 6: } 7: }; 8: var getDelegate = (key) => 9: { 10: lock (_mutex) 11: { 12: string val; 13: return _dictionary.TryGetValue(key, out val) ? val : null; 14: } 15: }; Nothing new or fancy here, just your basic lock on a private object and then query/insert into the Dictionary. Now, for the Dictionary with ReadWriteLockSlim it's a little more complex: 1: var addDelegate = (key,val) => 2: { 3: _readerWriterLock.EnterWriteLock(); 4: _dictionary[key] = val; 5: _readerWriterLock.ExitWriteLock(); 6: }; 7: var getDelegate = (key) => 8: { 9: string val; 10: _readerWriterLock.EnterReadLock(); 11: if(!_dictionary.TryGetValue(key, out val)) 12: { 13: val = null; 14: } 15: _readerWriterLock.ExitReadLock(); 16: return val; 17: }; And finally, the ConcurrentDictionary, which since it does all it's own concurrency control, is remarkably elegant and simple: 1: var addDelegate = (key,val) => 2: { 3: _concurrentDictionary[key] = val; 4: }; 5: var getDelegate = (key) => 6: { 7: string s; 8: return _concurrentDictionary.TryGetValue(key, out s) ? s : null; 9: }; Then, I set up a test harness that would simply ask the user for the number of concurrent Accessors to attempt to Access the cache (as specified in Accessor.Access() above) and then let them fly and see how long it took them all to complete. Each of these tests was run with 10,000,000 cache accesses divided among the available Accessor instances. All times are in milliseconds. 1: Dictionary with Mutex Locking 2: --------------------------------------------------- 3: Accessors Mostly Misses Mostly Hits 4: 1 7916 3285 5: 10 8293 3481 6: 100 8799 3532 7: 1000 8815 3584 8: 9: 10: Dictionary with ReaderWriterLockSlim Locking 11: --------------------------------------------------- 12: Accessors Mostly Misses Mostly Hits 13: 1 8445 3624 14: 10 11002 4119 15: 100 11076 3992 16: 1000 14794 4861 17: 18: 19: Concurrent Dictionary 20: --------------------------------------------------- 21: Accessors Mostly Misses Mostly Hits 22: 1 17443 3726 23: 10 14181 1897 24: 100 15141 1994 25: 1000 17209 2128 The first test I did across the board is the Mostly Misses category. The mostly misses (more adds because data requested was not in the dictionary) shows an interesting trend. In both cases the Dictionary with the simple mutex lock is much faster, and the ConcurrentDictionary is the slowest solution. But this got me thinking, and a little research seemed to confirm it, maybe the ConcurrentDictionary is more optimized to concurrent "gets" than "adds". So since the ratio of misses to hits were 2 to 1, I decided to reverse that and see the results. So I tweaked the data so that the number of keys were much smaller than the number of iterations to give me about a 2 to 1 ration of hits to misses (twice as likely to already find the item in the cache than to need to add it). And yes, indeed here we see that the ConcurrentDictionary is indeed faster than the standard Dictionary here. I have a strong feeling that as the ration of hits-to-misses gets higher and higher these number gets even better as well. This makes sense since the ConcurrentDictionary is read-optimized. Also note that I tried the tests with capacity and concurrency hints on the ConcurrentDictionary but saw very little improvement, I think this is largely because on the 10,000,000 hit test it quickly ramped up to the correct capacity and concurrency and thus the impact was limited to the first few milliseconds of the run. So what does this tell us? Well, as in all things, ConcurrentDictionary is not a panacea. It won't solve all your woes and it shouldn't be the only Dictionary you ever use. So when should we use each? Use System.Collections.Generic.Dictionary when: You need a single-threaded Dictionary (no locking needed). You need a multi-threaded Dictionary that is loaded only once at creation and never modified (no locking needed). You need a multi-threaded Dictionary to store items where writes are far more prevalent than reads (locking needed). And use System.Collections.Concurrent.ConcurrentDictionary when: You need a multi-threaded Dictionary where the writes are far more prevalent than reads. You need to be able to iterate over the collection without locking it even if its being modified. Both Dictionaries have their strong suits, I have a feeling this is just one where you need to know from design what you hope to use it for and make your decision based on that criteria.

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Complete Guide to Symbolic Links (symlinks) on Windows or Linux

- by Matthew Guay

Want to easily access folders and files from different folders without maintaining duplicate copies? Here’s how you can use Symbolic Links to link anything in Windows 7, Vista, XP, and Ubuntu. So What Are Symbolic Links Anyway? Symbolic links, otherwise known as symlinks, are basically advanced shortcuts. You can create symbolic links to individual files or folders, and then these will appear like they are stored in the folder with the symbolic link even though the symbolic link only points to their real location. There are two types of symbolic links: hard and soft. Soft symbolic links work essentially the same as a standard shortcut. When you open a soft link, you will be redirected to the folder where the files are stored. However, a hard link makes it appear as though the file or folder actually exists at the location of the symbolic link, and your applications won’t know any different. Thus, hard links are of the most interest in this article. Why should I use Symbolic Links? There are many things we use symbolic links for, so here’s some of the top uses we can think of: Sync any folder with Dropbox – say, sync your Pidgin Profile Across Computers Move the settings folder for any program from its original location Store your Music/Pictures/Videos on a second hard drive, but make them show up in your standard Music/Pictures/Videos folders so they’ll be detected my your media programs (Windows 7 Libraries can also be good for this) Keep important files accessible from multiple locations And more! If you want to move files to a different drive or folder and then symbolically link them, follow these steps: Close any programs that may be accessing that file or folder Move the file or folder to the new desired location Follow the correct instructions below for your operating system to create the symbolic link. Caution: Make sure to never create a symbolic link inside of a symbolic link. For instance, don’t create a symbolic link to a file that’s contained in a symbolic linked folder. This can create a loop, which can cause millions of problems you don’t want to deal with. Seriously. Create Symlinks in Any Edition of Windows in Explorer Creating symlinks is usually difficult, but thanks to the free Link Shell Extension, you can create symbolic links in all modern version of Windows pain-free. You need to download both Visual Studio 2005 redistributable, which contains the necessary prerequisites, and Link Shell Extension itself (links below). Download the correct version (32 bit or 64 bit) for your computer. Run and install the Visual Studio 2005 Redistributable installer first. Then install the Link Shell Extension on your computer. Your taskbar will temporally disappear during the install, but will quickly come back. Now you’re ready to start creating symbolic links. Browse to the folder or file you want to create a symbolic link from. Right-click the folder or file and select Pick Link Source. To create your symlink, right-click in the folder you wish to save the symbolic link, select “Drop as…”, and then choose the type of link you want. You can choose from several different options here; we chose the Hardlink Clone. This will create a hard link to the file or folder we selected. The Symbolic link option creates a soft link, while the smart copy will fully copy a folder containing symbolic links without breaking them. These options can be useful as well. Here’s our hard-linked folder on our desktop. Notice that the folder looks like its contents are stored in Desktop\Downloads, when they are actually stored in C:\Users\Matthew\Desktop\Downloads. Also, when links are created with the Link Shell Extension, they have a red arrow on them so you can still differentiate them. And, this works the same way in XP as well. Symlinks via Command Prompt Or, for geeks who prefer working via command line, here’s how you can create symlinks in Command Prompt in Windows 7/Vista and XP. In Windows 7/Vista In Windows Vista and 7, we’ll use the mklink command to create symbolic links. To use it, we have to open an administrator Command Prompt. Enter “command” in your start menu search, right-click on Command Prompt, and select “Run as administrator”. To create a symbolic link, we need to enter the following in command prompt: mklink /prefix link_path file/folder_path First, choose the correct prefix. Mklink can create several types of links, including the following: /D – creates a soft symbolic link, which is similar to a standard folder or file shortcut in Windows. This is the default option, and mklink will use it if you do not enter a prefix. /H – creates a hard link to a file /J – creates a hard link to a directory or folder So, once you’ve chosen the correct prefix, you need to enter the path you want for the symbolic link, and the path to the original file or folder. For example, if I wanted a folder in my Dropbox folder to appear like it was also stored in my desktop, I would enter the following: mklink /J C:\Users\Matthew\Desktop\Dropbox C:\Users\Matthew\Documents\Dropbox Note that the first path was to the symbolic folder I wanted to create, while the second path was to the real folder. Here, in this command prompt screenshot, you can see that I created a symbolic link of my Music folder to my desktop. And here’s how it looks in Explorer. Note that all of my music is “really” stored in C:\Users\Matthew\Music, but here it looks like it is stored in C:\Users\Matthew\Desktop\Music. If your path has any spaces in it, you need to place quotes around it. Note also that the link can have a different name than the file it links to. For example, here I’m going to create a symbolic link to a document on my desktop: mklink /H “C:\Users\Matthew\Desktop\ebook.pdf” “C:\Users\Matthew\Downloads\Before You Call Tech Support.pdf” Don’t forget the syntax: mklink /prefix link_path Target_file/folder_path In Windows XP Windows XP doesn’t include built-in command prompt support for symbolic links, but we can use the free Junction tool instead. Download Junction (link below), and unzip the folder. Now open Command Prompt (click Start, select All Programs, then Accessories, and select Command Prompt), and enter cd followed by the path of the folder where you saved Junction. Junction only creates hard symbolic links, since you can use shortcuts for soft ones. To create a hard symlink, we need to enter the following in command prompt: junction –s link_path file/folder_path As with mklink in Windows 7 or Vista, if your file/folder path has spaces in it make sure to put quotes around your paths. Also, as usual, your symlink can have a different name that the file/folder it points to. Here, we’re going to create a symbolic link to our My Music folder on the desktop. We entered: junction -s “C:\Documents and Settings\Administrator\Desktop\Music” “C:\Documents and Settings\Administrator\My Documents\My Music” And here’s the contents of our symlink. Note that the path looks like these files are stored in a Music folder directly on the Desktop, when they are actually stored in My Documents\My Music. Once again, this works with both folders and individual files. Please Note: Junction would work the same in Windows 7 or Vista, but since they include a built-in symbolic link tool we found it better to use it on those versions of Windows. Symlinks in Ubuntu Unix-based operating systems have supported symbolic links since their inception, so it is straightforward to create symbolic links in Linux distros such as Ubuntu. There’s no graphical way to create them like the Link Shell Extension for Windows, so we’ll just do it in Terminal. Open terminal (open the Applications menu, select Accessories, and then click Terminal), and enter the following: ln –s file/folder_path link_path Note that this is opposite of the Windows commands; you put the source for the link first, and then the path second. For example, let’s create a symbolic link of our Pictures folder in our Desktop. To do this, we entered: ln -s /home/maguay/Pictures /home/maguay/Desktop Once again, here is the contents of our symlink folder. The pictures look as if they’re stored directly in a Pictures folder on the Desktop, but they are actually stored in maguay\Pictures. Delete Symlinks Removing symbolic links is very simple – just delete the link! Most of the command line utilities offer a way to delete a symbolic link via command prompt, but you don’t need to go to the trouble. Conclusion Symbolic links can be very handy, and we use them constantly to help us stay organized and keep our hard drives from overflowing. Let us know how you use symbolic links on your computers! Download Link Shell Extension for Windows 7, Vista, and XP Download Junction for XP Similar Articles Productive Geek Tips Using Symlinks in Windows VistaHow To Figure Out Your PC’s Host Name From the Command PromptInstall IceWM on Ubuntu LinuxAdd Color Coding to Windows 7 Media Center Program GuideSync Your Pidgin Profile Across Multiple PCs with Dropbox TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Gadfly is a cool Twitter/Silverlight app Enable DreamScene in Windows 7 Microsoft’s “How Do I ?” Videos Home Networks – How do they look like & the problems they cause Check Your IMAP Mail Offline In Thunderbird Follow Finder Finds You Twitter Users To Follow

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Basics of Join Predicate Pushdown in Oracle

- by Maria Colgan

Happy New Year to all of our readers! We hope you all had a great holiday season. We start the new year by continuing our series on Optimizer transformations. This time it is the turn of Predicate Pushdown. I would like to thank Rafi Ahmed for the content of this blog.Normally, a view cannot be joined with an index-based nested loop (i.e., index access) join, since a view, in contrast with a base table, does not have an index defined on it. A view can only be joined with other tables using three methods: hash, nested loop, and sort-merge joins. Introduction The join predicate pushdown (JPPD) transformation allows a view to be joined with index-based nested-loop join method, which may provide a more optimal alternative. In the join predicate pushdown transformation, the view remains a separate query block, but it contains the join predicate, which is pushed down from its containing query block into the view. The view thus becomes correlated and must be evaluated for each row of the outer query block. These pushed-down join predicates, once inside the view, open up new index access paths on the base tables inside the view; this allows the view to be joined with index-based nested-loop join method, thereby enabling the optimizer to select an efficient execution plan. The join predicate pushdown transformation is not always optimal. The join predicate pushed-down view becomes correlated and it must be evaluated for each outer row; if there is a large number of outer rows, the cost of evaluating the view multiple times may make the nested-loop join suboptimal, and therefore joining the view with hash or sort-merge join method may be more efficient. The decision whether to push down join predicates into a view is determined by evaluating the costs of the outer query with and without the join predicate pushdown transformation under Oracle's cost-based query transformation framework. The join predicate pushdown transformation applies to both non-mergeable views and mergeable views and to pre-defined and inline views as well as to views generated internally by the optimizer during various transformations. The following shows the types of views on which join predicate pushdown is currently supported. UNION ALL/UNION view Outer-joined view Anti-joined view Semi-joined view DISTINCT view GROUP-BY view Examples Consider query A, which has an outer-joined view V. The view cannot be merged, as it contains two tables, and the join between these two tables must be performed before the join between the view and the outer table T4. A: SELECT T4.unique1, V.unique3 FROM T_4K T4, (SELECT T10.unique3, T10.hundred, T10.ten FROM T_5K T5, T_10K T10 WHERE T5.unique3 = T10.unique3) VWHERE T4.unique3 = V.hundred(+) AND T4.ten = V.ten(+) AND T4.thousand = 5; The following shows the non-default plan for query A generated by disabling join predicate pushdown. When query A undergoes join predicate pushdown, it yields query B. Note that query B is expressed in a non-standard SQL and shows an internal representation of the query. B: SELECT T4.unique1, V.unique3 FROM T_4K T4, (SELECT T10.unique3, T10.hundred, T10.ten FROM T_5K T5, T_10K T10 WHERE T5.unique3 = T10.unique3 AND T4.unique3 = V.hundred(+) AND T4.ten = V.ten(+)) V WHERE T4.thousand = 5; The execution plan for query B is shown below. In the execution plan BX, note the keyword 'VIEW PUSHED PREDICATE' indicates that the view has undergone the join predicate pushdown transformation. The join predicates (shown here in red) have been moved into the view V; these join predicates open up index access paths thereby enabling index-based nested-loop join of the view. With join predicate pushdown, the cost of query A has come down from 62 to 32. As mentioned earlier, the join predicate pushdown transformation is cost-based, and a join predicate pushed-down plan is selected only when it reduces the overall cost. Consider another example of a query C, which contains a view with the UNION ALL set operator.C: SELECT R.unique1, V.unique3 FROM T_5K R, (SELECT T1.unique3, T2.unique1+T1.unique1 FROM T_5K T1, T_10K T2 WHERE T1.unique1 = T2.unique1 UNION ALL SELECT T1.unique3, T2.unique2 FROM G_4K T1, T_10K T2 WHERE T1.unique1 = T2.unique1) V WHERE R.unique3 = V.unique3 and R.thousand < 1; The execution plan of query C is shown below. In the above, 'VIEW UNION ALL PUSHED PREDICATE' indicates that the UNION ALL view has undergone the join predicate pushdown transformation. As can be seen, here the join predicate has been replicated and pushed inside every branch of the UNION ALL view. The join predicates (shown here in red) open up index access paths thereby enabling index-based nested loop join of the view. Consider query D as an example of join predicate pushdown into a distinct view. We have the following cardinalities of the tables involved in query D: Sales (1,016,271), Customers (50,000), and Costs (787,766). D: SELECT C.cust_last_name, C.cust_city FROM customers C, (SELECT DISTINCT S.cust_id FROM sales S, costs CT WHERE S.prod_id = CT.prod_id and CT.unit_price > 70) V WHERE C.cust_state_province = 'CA' and C.cust_id = V.cust_id; The execution plan of query D is shown below. As shown in XD, when query D undergoes join predicate pushdown transformation, the expensive DISTINCT operator is removed and the join is converted into a semi-join; this is possible, since all the SELECT list items of the view participate in an equi-join with the outer tables. Under similar conditions, when a group-by view undergoes join predicate pushdown transformation, the expensive group-by operator can also be removed. With the join predicate pushdown transformation, the elapsed time of query D came down from 63 seconds to 5 seconds. Since distinct and group-by views are mergeable views, the cost-based transformation framework also compares the cost of merging the view with that of join predicate pushdown in selecting the most optimal execution plan. Summary We have tried to illustrate the basic ideas behind join predicate pushdown on different types of views by showing example queries that are quite simple. Oracle can handle far more complex queries and other types of views not shown here in the examples. Again many thanks to Rafi Ahmed for the content of this blog post.

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Top Tweets SOA Partner Community – March 2012

- by JuergenKress

Send your tweets @soacommunity #soacommunity and follow us at http://twitter.com/soacommunity SOA Community ?SOA Community Newsletter February 2012 wp.me/p10C8u-o0 Marc ?Reading through the #OFM 11.1.1.6 , patchset 5 documentation. What is the best way to upgrade your whole dev…prd street. SOA Community Thanks for the successful and super interesting #sbidays ! Wonderful discussions around the Integration, case management and security tracks Torsten Winterberg Schon den neuen Opitz Technology-Blog gebookmarked? The Cattle Crew bit.ly/yLPwBD wird ab sofort regelmäßig Erkenntnisse posten. OTNArchBeat ? Unit Testing Asynchronous BPEL Processes Using soapUI | @DanielAmadei bit.ly/x9NsS9 Rolando Carrasco ?Video de Human Task en BPM 11g. Por @edwardo040. bit.ly/wki9CA cc @OracleBPM @OracleSOA @soacommunity View video Marcel Mertin SOA Security Hands-On by Dirk Krafzig and Mamoon Yunus at #sbidays is also great! SOA Community Workshop day #sbidays #BPMN2.0 by Volker Stiehl from #SAP great training – now I can model & execute in #bpmsuite #soacommunity Simone Geib ?Just updated our advanced #soasuite #otn page with a number of very interesting @orclateamsoa blog posts: bit.ly/advancedsoasui… OTNArchBeat ? Start Small, Grow Fast: SOA Best Practices article by @biemond, @rluttikhuizen, @demed bit.ly/yem9Zv Steffen Miller ? Nice new features in SOA Suite Business Rules #PS5 Testing rules with scenarios and output validation bit.ly/zj64Q3 @SOACOMMUNITY OTNArchBeat ? Reply SOA Blackbelt training by David Shaffer, April 30th–May 4th 2012 bit.ly/xGdC24 OTNArchBeat ? What have BPM, big data, social tools, and business models got in common? | Andy Mulholland bit.ly/xUkOGf SOA Community ? Live hacking at #sbidays – cheaper shopping, bias cracking, payment systems, secure your SOA! pic.twitter.com/y7YaIdug SOA Community Future #BPM & #ACM solutions can make use of ontology’s, based on #sqarql #sbidays pic.twitter.com/xLb1Z5zs Simone Geib ? @soacommunity: SOA Blackbelt training by David Shaffer, April 30th–May 4th 2012 wp.me/p10C8u-nX Biemond Changing your ADF Connections in Enterprise Manager with PS5: With Patch Set 5 of Fusion Middleware you can fina… bit.ly/zF7Rb1 Marc ? HUGE (!) CPU and Heap improvement on Oracle Fusion Middleware tinyurl.com/762drzp @wlscommunity @soacommunity #OSB #SOA #WLS SOA Community ?Networking @ SOA & BPM Partner Community blogs.oracle.com/soacommunity/e… #soacommunity #otn #opn #oracle SOA Community ?Published the SOA Partner Community newsletter February edition – READ it. Not yet a member? oracle.com/goto/emea/soa #soacommunity #otn #opn AMIS, Oracle & Java Blog by Lucas Jellema: "Book Review: Do More with SOA Integration: Best of Packt (december 2011, various authors)" bit.ly/wq633E Jon petter hjulstad @SOASimone Excellent summary! Lots of new features! Simone Geib ?Do you want to know what’s new in #soasuite #PS5? Go to bit.ly/xBX06f and let me know what you think SOA Community ? Unit Testing Asynchronous BPEL Processes Using soapUI oracle.com/technetwork/ar… #soacommunity #soa #otn #oracle #bpel Retweeted by SOA Community View media Retweeted by SOA Community Eric Elzinga ? Oracle Fusion Middleware Partner Community Forum Malage, The Overview, bit.ly/AA9BKd #ofmforum SOA&Cloud Symposium ? The February issue of the Service Technology Magazine is now published. servicetechmag.com SOA Community ? Oracle SOA Suite 11g Database Growth Management – must read! oracle.com/technetwork/da… #soacommunity #soa #purging demed ? Have you exposed internal processes to mobile devices using #oraclesoa? Interested in an article? DM me! #osb #rest #multichannel #mobile orclateamsoa ? A-Team SOA Blog: Enhanced version of Thread Dump Analyzer (TDA A-Team) ow.ly/1hpk7l SOA Community Reply BPM Suite #PS5 (11.1.1.6) available for download soacommunity.wordpress.com/2012/02/22/soa… Send us your feedback! #soacommunity #bpmsuite #opn SOA Community ? SOA Suite #PS5 (11.1.1.6) available for download soacommunity.wordpress.com/2012/02/22/soa… Send us your feedback! #soacommunity #soasuite SOA Community BPM Suite #PS5 1(1.1.1.6) available for download. List of new BPM features blogs.oracle.com/soacommunity/e… #soacommunity #bpm #bpmsuite #opn OracleBlogs BPM in Utilties Industry ow.ly/1hC3fp Retweeted by SOA Community OTNArchBeat ? Demystifying Oracle Enterprise Gateway | Naresh Persaud bit.ly/xtDNe2 OTNArchBeat ? Architect’s Guide to Big Data; Test BPEL Processes Using SoapUI; Development Debate bit.ly/xbDYSo Frank Nimphius ? Finished my book review of "Do More with SOA Integration: Best of Packt ". Here are my review comments: bit.ly/x2k9OZ Lucas Jellema ? That is my one stop-and-go download center for #PS5 : edelivery.oracle.com/EPD/Download/g… Lucas Jellema ? Interesting piece of documentation: Fusion Applications Extensibility Guide – docs.oracle.com/cd/E15586_01/f… source for design time @ run time inspira Lucas Jellema ? Strongly improved support for testing Business Rules at Design Time in #PS5 see docs.oracle.com/cd/E23943_01/u… Lucas Jellema ? SOA Suite 11gR1 PS5: new BPEL Component testing – docs.oracle.com/cd/E23943_01/d… Lucas Jellema ? PS5 available for CEP (Complex Event Processing) – a personal favorite of mine : oracle.com/technetwork/mi… Lucas Jellema ?What’s New in Fusion Developer’s Guide 11gR1 PS5: docs.oracle.com/cd/E23943_01/w… Lucas Jellema ? BPMN Correlation (FMW 11gR1 PS5): docs.oracle.com/cd/E23943_01/d… Lucas Jellema ? Modifying running BPM Process instances (FMW 11gR1 PS5): docs.oracle.com/cd/E23943_01/d… Lucas Jellema ? SOA Suite 11gR1 PS5 – new aggregation pattern: docs.oracle.com/cd/E23943_01/d… routing multiple messages to same instance Melvin van der Kuijl ? Automating Testing of SOA Composite Applications in PS5. docs.oracle.com/cd/E23943_01/d… Cato Aune ? SOA suite PS5 Enterprise Deployment Guide is available in ePub docs.oracle.com/cd/E23943_01/c… . Much better than pdf on Galaxy Note SOA Community ?JDeveloper 11.1.1.6 is available for download bit.ly/wGYrwE #soacommunity SOA Community ? Your first experience #PS5 – let us know @soacommunity – send us your tweets and blog posts! #soacommunity Jon petter hjulstad ? WLS 10.3.6 New features, ex better logging of jdbc use: docs.oracle.com/cd/E23943_01/w… Heidi Buelow ? Get it now! RT @soacommunity: BPM Suite PS5 11.1.1.6 available for download bit.ly/AgagT5 #bpm #soacommunity Jon petter hjulstad ?SOA Suite PS5 EDG contains OSB! docs.oracle.com/cd/E23943_01/c… Jon petter hjulstad ? Testing Oracle Rules from JDeveloper is easier in PS5: docs.oracle.com/cd/E23943_01/u… Biemond® ? What’s New in Oracle Service Bus 11.1.1.6.0 oracle.com/technetwork/mi… Jon petter hjulstad ? Adminguide New and Changed Features for PS5, ex GridLink data sources: docs.oracle.com/cd/E23943_01/c… Retweeted by SOA Community Andreas Koop ? Unbelievable! #OFM Doc Lib growth from 11gPS4->11gPS5 by 1.2G! View media SOA Community ?ODI PS5 is available oracle.com/technetwork/mi… #odi #soacommunity 22 Feb View media SOA Community Service Bus 11g Development Cookbook soacommunity.wordpress.com/2012/02/20/ser… #osb #soacommunity #ace #opn View media For regular information on Oracle SOA Suite become a member in the SOA Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) Blog Twitter LinkedIn Mix Forum Technorati Tags: soacommunity,twitter,Oracle,SOA Community,Jürgen Kress,OPN,SOA,BPM

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Adding DTrace Probes to PHP Extensions

- by cj

The powerful DTrace tracing facility has some PHP-specific probes that can be enabled with --enable-dtrace. DTrace for Linux is being created by Oracle and is currently in tech preview. Currently it doesn't support userspace tracing so, in the meantime, Systemtap can be used to monitor the probes implemented in PHP. This was recently outlined in David Soria Parra's post Probing PHP with Systemtap on Linux. My post shows how DTrace probes can be added to PHP extensions and traced on Linux. I was using Oracle Linux 6.3. Not all Linux kernels are built with Systemtap, since this can impact stability. Check whether your running kernel (or others installed) have Systemtap enabled, and reboot with such a kernel: # grep CONFIG_UTRACE /boot/config-`uname -r` # grep CONFIG_UTRACE /boot/config-* When you install Systemtap itself, the package systemtap-sdt-devel is needed since it provides the sdt.h header file: # yum install systemtap-sdt-devel You can now install and build PHP as shown in David's article. Basically the build is with: $ cd ~/php-src $ ./configure --disable-all --enable-dtrace $ make (For me, running 'make' a second time failed with an error. The workaround is to do 'git checkout Zend/zend_dtrace.d' and then rerun 'make'. See PHP Bug 63704) David's article shows how to trace the probes already implemented in PHP. You can also use Systemtap to trace things like userspace PHP function calls. For example, create test.php: <?php $c = oci_connect('hr', 'welcome', 'localhost/orcl'); $s = oci_parse($c, "select dbms_xmlgen.getxml('select * from dual') xml from dual"); $r = oci_execute($s); $row = oci_fetch_array($s, OCI_NUM); $x = $row[0]->load(); $row[0]->free(); echo $x; ?> The normal output of this file is the XML form of Oracle's DUAL table: $ ./sapi/cli/php ~/test.php <?xml version="1.0"?> <ROWSET> <ROW> <DUMMY>X</DUMMY> </ROW> </ROWSET> To trace the PHP function calls, create the tracing file functrace.stp: probe process("sapi/cli/php").function("zif_*") { printf("Started function %s\n", probefunc()); } probe process("sapi/cli/php").function("zif_*").return { printf("Ended function %s\n", probefunc()); } This makes use of the way PHP userspace functions (not builtins) like oci_connect() map to C functions with a "zif_" prefix. Login as root, and run System tap on the PHP script: # cd ~cjones/php-src # stap -c 'sapi/cli/php ~cjones/test.php' ~cjones/functrace.stp Started function zif_oci_connect Ended function zif_oci_connect Started function zif_oci_parse Ended function zif_oci_parse Started function zif_oci_execute Ended function zif_oci_execute Started function zif_oci_fetch_array Ended function zif_oci_fetch_array Started function zif_oci_lob_load <?xml version="1.0"?> <ROWSET> <ROW> <DUMMY>X</DUMMY> </ROW> </ROWSET> Ended function zif_oci_lob_load Started function zif_oci_free_descriptor Ended function zif_oci_free_descriptor Each call and return is logged. The Systemtap scripting language allows complex scripts to be built. There are many examples on the web. To augment this generic capability and the PHP probes in PHP, other extensions can have probes too. Below are the steps I used to add probes to OCI8: I created a provider file ext/oci8/oci8_dtrace.d, enabling three probes. The first one will accept a parameter that runtime tracing can later display: provider php { probe oci8__connect(char *username); probe oci8__nls_start(); probe oci8__nls_done(); }; I updated ext/oci8/config.m4 with the PHP_INIT_DTRACE macro. The patch is at the end of config.m4. The macro takes the provider prototype file, a name of the header file that 'dtrace' will generate, and a list of sources files with probes. When --enable-dtrace is used during PHP configuration, then the outer $PHP_DTRACE check is true and my new probes will be enabled. I've chosen to define an OCI8 specific macro, HAVE_OCI8_DTRACE, which can be used in the OCI8 source code: diff --git a/ext/oci8/config.m4 b/ext/oci8/config.m4 index 34ae76c..f3e583d 100644 --- a/ext/oci8/config.m4 +++ b/ext/oci8/config.m4 @@ -341,4 +341,17 @@ if test "$PHP_OCI8" != "no"; then PHP_SUBST_OLD(OCI8_ORACLE_VERSION) fi + + if test "$PHP_DTRACE" = "yes"; then + AC_CHECK_HEADERS([sys/sdt.h], [ + PHP_INIT_DTRACE([ext/oci8/oci8_dtrace.d], + [ext/oci8/oci8_dtrace_gen.h],[ext/oci8/oci8.c]) + AC_DEFINE(HAVE_OCI8_DTRACE,1, + [Whether to enable DTrace support for OCI8 ]) + ], [ + AC_MSG_ERROR( + [Cannot find sys/sdt.h which is required for DTrace support]) + ]) + fi + fi In ext/oci8/oci8.c, I added the probes at, for this example, semi-arbitrary places: diff --git a/ext/oci8/oci8.c b/ext/oci8/oci8.c index e2241cf..ffa0168 100644 --- a/ext/oci8/oci8.c +++ b/ext/oci8/oci8.c @@ -1811,6 +1811,12 @@ php_oci_connection *php_oci_do_connect_ex(char *username, int username_len, char } } +#ifdef HAVE_OCI8_DTRACE + if (DTRACE_OCI8_CONNECT_ENABLED()) { + DTRACE_OCI8_CONNECT(username); + } +#endif + /* Initialize global handles if they weren't initialized before */ if (OCI_G(env) == NULL) { php_oci_init_global_handles(TSRMLS_C); @@ -1870,11 +1876,22 @@ php_oci_connection *php_oci_do_connect_ex(char *username, int username_len, char size_t rsize = 0; sword result; +#ifdef HAVE_OCI8_DTRACE + if (DTRACE_OCI8_NLS_START_ENABLED()) { + DTRACE_OCI8_NLS_START(); + } +#endif PHP_OCI_CALL_RETURN(result, OCINlsEnvironmentVariableGet, (&charsetid_nls_lang, 0, OCI_NLS_CHARSET_ID, 0, &rsize)); if (result != OCI_SUCCESS) { charsetid_nls_lang = 0; } smart_str_append_unsigned_ex(&hashed_details, charsetid_nls_lang, 0); + +#ifdef HAVE_OCI8_DTRACE + if (DTRACE_OCI8_NLS_DONE_ENABLED()) { + DTRACE_OCI8_NLS_DONE(); + } +#endif } timestamp = time(NULL); The oci_connect(), oci_pconnect() and oci_new_connect() calls all use php_oci_do_connect_ex() internally. The first probe simply records that the PHP application made a connection call. I already showed a way to do this without needing a probe, but adding a specific probe lets me record the username. The other two probes can be used to time how long the globalization initialization takes. The relationships between the oci8_dtrace.d names like oci8__connect, the probe guards like DTRACE_OCI8_CONNECT_ENABLED() and probe names like DTRACE_OCI8_CONNECT() are obvious after seeing the pattern of all three probes. I included the new header that will be automatically created by the dtrace tool when PHP is built. I did this in ext/oci8/php_oci8_int.h: diff --git a/ext/oci8/php_oci8_int.h b/ext/oci8/php_oci8_int.h index b0d6516..c81fc5a 100644 --- a/ext/oci8/php_oci8_int.h +++ b/ext/oci8/php_oci8_int.h @@ -44,6 +44,10 @@ # endif # endif /* osf alpha */ +#ifdef HAVE_OCI8_DTRACE +#include "oci8_dtrace_gen.h" +#endif + #if defined(min) #undef min #endif Now PHP can be rebuilt: $ cd ~/php-src $ rm configure && ./buildconf --force $ ./configure --disable-all --enable-dtrace \ --with-oci8=instantclient,/home/cjones/instantclient $ make If 'make' fails, do the 'git checkout Zend/zend_dtrace.d' trick I mentioned. The new probes can be seen by logging in as root and running: # stap -l 'process.provider("php").mark("oci8*")' -c 'sapi/cli/php -i' process("sapi/cli/php").provider("php").mark("oci8__connect") process("sapi/cli/php").provider("php").mark("oci8__nls_done") process("sapi/cli/php").provider("php").mark("oci8__nls_start") To test them out, create a new trace file, oci.stp: global numconnects; global start; global numcharlookups = 0; global tottime = 0; probe process.provider("php").mark("oci8-connect") { printf("Connected as %s\n", user_string($arg1)); numconnects += 1; } probe process.provider("php").mark("oci8-nls_start") { start = gettimeofday_us(); numcharlookups++; } probe process.provider("php").mark("oci8-nls_done") { tottime += gettimeofday_us() - start; } probe end { printf("Connects: %d, Charset lookups: %ld\n", numconnects, numcharlookups); printf("Total NLS charset initalization time: %ld usecs/connect\n", (numcharlookups 0 ? tottime/numcharlookups : 0)); } This calculates the average time that the NLS character set lookup takes. It also prints out the username of each connection, as an example of using parameters. Login as root and run Systemtap over the PHP script: # cd ~cjones/php-src # stap -c 'sapi/cli/php ~cjones/test.php' ~cjones/oci.stp Connected as cj <?xml version="1.0"?> <ROWSET> <ROW> <DUMMY>X</DUMMY> </ROW> </ROWSET> Connects: 1, Charset lookups: 1 Total NLS charset initalization time: 164 usecs/connect This shows the time penalty of making OCI8 look up the default character set. This time would be zero if a character set had been passed as the fourth argument to oci_connect() in test.php.

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MvcExtensions – Bootstrapping

- by kazimanzurrashid

When you create a new ASP.NET MVC application you will find that the global.asax contains the following lines: namespace MvcApplication1 { // Note: For instructions on enabling IIS6 or IIS7 classic mode, // visit http://go.microsoft.com/?LinkId=9394801 public class MvcApplication : System.Web.HttpApplication { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL with parameters new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults ); } protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes); } } } As the application grows, there are quite a lot of plumbing code gets into the global.asax which quickly becomes a design smell. Lets take a quick look at the code of one of the open source project that I recently visited: public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute("Default","{controller}/{action}/{id}", new { controller = "Home", action = "Index", id = "" }); } protected override void OnApplicationStarted() { Error += OnError; EndRequest += OnEndRequest; var settings = new SparkSettings() .AddNamespace("System") .AddNamespace("System.Collections.Generic") .AddNamespace("System.Web.Mvc") .AddNamespace("System.Web.Mvc.Html") .AddNamespace("MvcContrib.FluentHtml") .AddNamespace("********") .AddNamespace("********.Web") .SetPageBaseType("ApplicationViewPage") .SetAutomaticEncoding(true); #if DEBUG settings.SetDebug(true); #endif var viewFactory = new SparkViewFactory(settings); ViewEngines.Engines.Add(viewFactory); #if !DEBUG PrecompileViews(viewFactory); #endif RegisterAllControllersIn("********.Web"); log4net.Config.XmlConfigurator.Configure(); RegisterRoutes(RouteTable.Routes); Factory.Load(new Components.WebDependencies()); ModelBinders.Binders.DefaultBinder = new Binders.GenericBinderResolver(Factory.TryGet<IModelBinder>); ValidatorConfiguration.Initialize("********"); HtmlValidationExtensions.Initialize(ValidatorConfiguration.Rules); } private void OnEndRequest(object sender, System.EventArgs e) { if (((HttpApplication)sender).Context.Handler is MvcHandler) { CreateKernel().Get<ISessionSource>().Close(); } } private void OnError(object sender, System.EventArgs e) { CreateKernel().Get<ISessionSource>().Close(); } protected override IKernel CreateKernel() { return Factory.Kernel; } private static void PrecompileViews(SparkViewFactory viewFactory) { var batch = new SparkBatchDescriptor(); batch.For<HomeController>().For<ManageController>(); viewFactory.Precompile(batch); } As you can see there are quite a few of things going on in the above code, Registering the ViewEngine, Compiling the Views, Registering the Routes/Controllers/Model Binders, Settings up Logger, Validations and as you can imagine the more it becomes complex the more things will get added in the application start. One of the goal of the MVCExtensions is to reduce the above design smell. Instead of writing all the plumbing code in the application start, it contains BootstrapperTask to register individual services. Out of the box, it contains BootstrapperTask to register Controllers, Controller Factory, Action Invoker, Action Filters, Model Binders, Model Metadata/Validation Providers, ValueProvideraFactory, ViewEngines etc and it is intelligent enough to automatically detect the above types and register into the ASP.NET MVC Framework. Other than the built-in tasks you can create your own custom task which will be automatically executed when the application starts. When the BootstrapperTasks are in action you will find the global.asax pretty much clean like the following: public class MvcApplication : UnityMvcApplication { public void ErrorLog_Filtering(object sender, ExceptionFilterEventArgs e) { Check.Argument.IsNotNull(e, "e"); HttpException exception = e.Exception.GetBaseException() as HttpException; if ((exception != null) && (exception.GetHttpCode() == (int)HttpStatusCode.NotFound)) { e.Dismiss(); } } } The above code is taken from my another open source project Shrinkr, as you can see the global.asax is longer cluttered with any plumbing code. One special thing you have noticed that it is inherited from the UnityMvcApplication rather than regular HttpApplication. There are separate version of this class for each IoC Container like NinjectMvcApplication, StructureMapMvcApplication etc. Other than executing the built-in tasks, the Shrinkr also has few custom tasks which gets executed when the application starts. For example, when the application starts, we want to ensure that the default users (which is specified in the web.config) are created. The following is the custom task that is used to create those default users: public class CreateDefaultUsers : BootstrapperTask { protected override TaskContinuation ExecuteCore(IServiceLocator serviceLocator) { IUserRepository userRepository = serviceLocator.GetInstance<IUserRepository>(); IUnitOfWork unitOfWork = serviceLocator.GetInstance<IUnitOfWork>(); IEnumerable<User> users = serviceLocator.GetInstance<Settings>().DefaultUsers; bool shouldCommit = false; foreach (User user in users) { if (userRepository.GetByName(user.Name) == null) { user.AllowApiAccess(ApiSetting.InfiniteLimit); userRepository.Add(user); shouldCommit = true; } } if (shouldCommit) { unitOfWork.Commit(); } return TaskContinuation.Continue; } } There are several other Tasks in the Shrinkr that we are also using which you will find in that project. To create a custom bootstrapping task you have create a new class which either implements the IBootstrapperTask interface or inherits from the abstract BootstrapperTask class, I would recommend to start with the BootstrapperTask as it already has the required code that you have to write in case if you choose the IBootstrapperTask interface. As you can see in the above code we are overriding the ExecuteCore to create the default users, the MVCExtensions is responsible for populating the ServiceLocator prior calling this method and in this method we are using the service locator to get the dependencies that are required to create the users (I will cover the custom dependencies registration in the next post). Once the users are created, we are returning a special enum, TaskContinuation as the return value, the TaskContinuation can have three values Continue (default), Skip and Break. The reason behind of having this enum is, in some special cases you might want to skip the next task in the chain or break the complete chain depending upon the currently running task, in those cases you will use the other two values instead of the Continue. The last thing I want to cover in the bootstrapping task is the Order. By default all the built-in tasks as well as newly created task order is set to the DefaultOrder(a static property), in some special cases you might want to execute it before/after all the other tasks, in those cases you will assign the Order in the Task constructor. For Example, in Shrinkr, we want to run few background services when the all the tasks are executed, so we assigned the order as DefaultOrder + 1. Here is the code of that Task: public class ConfigureBackgroundServices : BootstrapperTask { private IEnumerable<IBackgroundService> backgroundServices; public ConfigureBackgroundServices() { Order = DefaultOrder + 1; } protected override TaskContinuation ExecuteCore(IServiceLocator serviceLocator) { backgroundServices = serviceLocator.GetAllInstances<IBackgroundService>().ToList(); backgroundServices.Each(service => service.Start()); return TaskContinuation.Continue; } protected override void DisposeCore() { backgroundServices.Each(service => service.Stop()); } } That’s it for today, in the next post I will cover the custom service registration, so stay tuned.

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