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• SQL SERVER – Weekly Series – Memory Lane – #049

  - by Pinal Dave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Two Connections Related Global Variables Explained – @@CONNECTIONS and @@MAX_CONNECTIONS @@CONNECTIONS Returns the number of attempted connections, either successful or unsuccessful since SQL Server was last started. @@MAX_CONNECTIONS Returns the maximum number of simultaneous user connections allowed on an instance of SQL Server. The number returned is not necessarily the number currently configured. Query Editor – Microsoft SQL Server Management Studio This post may be very simple for most of the users of SQL Server 2005. Earlier this year, I have received one question many times – Where is Query Analyzer in SQL Server 2005? I wrote small post about it and pointed many users to that post – SQL SERVER – 2005 Query Analyzer – Microsoft SQL SERVER Management Studio. Recently I have been receiving similar question. OUTPUT Clause Example and Explanation with INSERT, UPDATE, DELETE SQL Server 2005 has a new OUTPUT clause, which is quite useful. OUTPUT clause has access to insert and deleted tables (virtual tables) just like triggers. OUTPUT clause can be used to return values to client clause. OUTPUT clause can be used with INSERT, UPDATE, or DELETE to identify the actual rows affected by these statements. OUTPUT clause can generate a table variable, a permanent table, or temporary table. Even though, @@Identity will still work with SQL Server 2005, however I find the OUTPUT clause very easy and powerful to use. Let us understand the OUTPUT clause using an example. Find Name of The SQL Server Instance Based on database server stored procedures has to run different logic. We came up with two different solutions. 1) When database schema is very much changed, we wrote completely new stored procedure and deprecated older version once it was not needed. 2) When logic depended on Server Name we used global variable @@SERVERNAME. It was very convenient while writing migrating script which depended on the server name for the same database. Explanation of TRY…CATCH and ERROR Handling With RAISEERROR Function One of the developers at my company thought that we can not use the RAISEERROR function in new feature of SQL Server 2005 TRY… CATCH. When asked for an explanation he suggested SQL SERVER – 2005 Explanation of TRY… CATCH and ERROR Handling article as excuse suggesting that I did not give example of RAISEERROR with TRY…CATCH. We all thought it was funny. Just to keep records straight, TRY… CATCH can sure use RAISEERROR function. Different Types of Cache Objects Serveral kinds of objects can be stored in the procedure cache: Compiled Plans: When the query optimizer finishes compiling a query plan, the principal output is compiled plan. Execution contexts: While executing a compiled plan, SQL Server has to keep track of information about the state of execution. Cursors: Cursors track the execution state of server-side cursors, including the cursor’s current location within a resultset. Algebrizer trees: The Algebrizer’s job is to produce an algebrizer tree, which represents the logic structure of a query. Open SSMS From Command Prompt – sqlwb.exe Example This article is written by request and suggestion of Sr. Web Developer at my organization. Due to the nature of this article most of the content is referred from Book On-Line. sqlwbcommand prompt utility which opens SQL Server Management Studio. Squib command does not run queries from the command prompt. sqlcmd utility runs queries from command prompt, read for more information. 2008 Puzzle – Solution – Computed Columns Datatype Explanation Just a day before I wrote article SQL SERVER – Puzzle – Computed Columns Datatype Explanation which was inspired by SQL Server MVP Jacob Sebastian. I suggest that before continuing this article read the original puzzle question SQL SERVER – Puzzle – Computed Columns Datatype Explanation.The question was if the computed column was of datatype TINYINT how to create a Computed Column of datatype INT? 2008 – Find If Index is Being Used in Database It is very often I get a query that how to find if any index is being used in the database or not. If any database has many indexes and not all indexes are used it can adversely affect performance. If the number of indices are higher it reduces the INSERT / UPDATE / DELETE operation but increase the SELECT operation. It is recommended to drop any unused indexes from table to improve the performance. 2009 Interesting Observation – Execution Plan and Results of Aggregate Concatenation Queries If you want to see what’s going on here, I think you need to shift your point of view from an implementation-centric view to an ANSI point of view. ANSI does not guarantee processing the order. Figure 2 is interesting, but it will be potentially misleading if you don’t understand the ANSI rule-set SQL Server operates under in most cases. Implementation thinking can certainly be useful at times when you really need that multi-million row query to finish before the backup fire off, but in this case, it’s counterproductive to understanding what is going on. SQL Server Management Studio and Client Statistics Client Statistics are very important. Many a times, people relate queries execution plan to query cost. This is not a good comparison. Both parameters are different, and they are not always related. It is possible that the query cost of any statement is less, but the amount of the data returned is considerably larger, which is causing any query to run slow. How do we know if any query is retrieving a large amount data or very little data? 2010 I encourage all of you to go through complete series and write your own on the subject. If you write an article and send it to me, I will publish it on this blog with due credit to you. If you write on your own blog, I will update this blog post pointing to your blog post. SQL SERVER – ORDER BY Does Not Work – Limitation of the View 1 SQL SERVER – Adding Column is Expensive by Joining Table Outside View – Limitation of the View 2 SQL SERVER – Index Created on View not Used Often – Limitation of the View 3 SQL SERVER – SELECT * and Adding Column Issue in View – Limitation of the View 4 SQL SERVER – COUNT(*) Not Allowed but COUNT_BIG(*) Allowed – Limitation of the View 5 SQL SERVER – UNION Not Allowed but OR Allowed in Index View – Limitation of the View 6 SQL SERVER – Cross Database Queries Not Allowed in Indexed View – Limitation of the View 7 SQL SERVER – Outer Join Not Allowed in Indexed Views – Limitation of the View 8 SQL SERVER – SELF JOIN Not Allowed in Indexed View – Limitation of the View 9 SQL SERVER – Keywords View Definition Must Not Contain for Indexed View – Limitation of the View 10 SQL SERVER – View Over the View Not Possible with Index View – Limitations of the View 11 SQL SERVER – Get Query Running in Session I was recently looking for syntax where I needed a query running in any particular session. I always remembered the syntax and ha d actually written it down before, but somehow it was not coming to mind quickly this time. I searched online and I ended up on my own article written last year SQL SERVER – Get Last Running Query Based on SPID. I felt that I am getting old because I forgot this really simple syntax. Find Total Number of Transaction on Interval In one of my recent Performance Tuning assignments I was asked how do someone know how many transactions are happening on a server during certain interval. I had a handy script for the same. Following script displays transactions happened on the server at the interval of one minute. You can change the WAITFOR DELAY to any other interval and it should work. 2011 Here are two DMV’s which are newly introduced in SQL Server 2012 and provides vital information about SQL Server. DMV – sys.dm_os_volume_stats – Information about operating system volume DMV – sys.dm_os_windows_info – Information about Operating System SQL Backup and FTP – A Quick and Handy Tool I have used this tool extensively since 2009 at numerous occasion and found it to be very impressive. What separates it from the crowd the most – it is it’s apparent simplicity and speed. When I install SQLBackupAndFTP and configure backups – all in 1 or 2 minutes, my clients are always impressed. Quick Note about JOIN – Common Questions and Simple Answers In this blog post we are going to talk about join and lots of things related to the JOIN. I recently started office hours to answer questions and issues of the community. I receive so many questions that are related to JOIN. I will share a few of the same over here. Most of them are basic, but note that the basics are of great importance. 2012 Importance of User Without Login Question: “In recent version of SQL Server we can create user without login. What is the use of it?” Great question indeed. Let me first attempt to answer this question but after reading my answer I need your help. I want you to help him as well with adding more value to it. Preserve Leading Zero While Coping to Excel from SSMS Earlier I wrote two articles about how to efficiently copy data from SSMS to Excel. Since I wrote that post there are plenty of interest generated on this subject. There are a few questions I keep on getting over this subject. One of the question is how to get the leading zero preserved while copying the data from SSMS to Excel. Well it is almost the same way as my earlier post SQL SERVER – Excel Losing Decimal Values When Value Pasted from SSMS ResultSet. The key here is in EXCEL and not in SQL Server. Solution – 2 T-SQL Puzzles – Display Star and Shortest Code to Display 1 Earlier on this blog we had asked two puzzles. The response from all of you is nothing but Amazing. I have received 350+ responses. Many are valid and many were indeed something I had not thought about it. I strongly suggest you read all the puzzles and their answers here - trust me if you start reading the comments you will not stop till you read every single comment. Seriously trust me on it. Personally I have learned a lot from it. Identify Most Resource Intensive Queries – SQL in Sixty Seconds #028 – Video http://www.youtube.com/watch?v=TvlYy-TGaaA Importance of User Without Login – T-SQL Demo Script Earlier I wrote a blog post about SQL SERVER – Importance of User Without Login and my friend and SQL Expert Vinod Kumar has written excellent follow up blog post about Contained Databases inside SQL Server 2012. Now lots of people asked me if I can also explain the same concept again so here is the small demonstration for it. Let me show you how login without user can help. Before we continue on this subject I strongly recommend that you read my earlier blog post here. In following demo I am going to demonstrate following situation. Login using the System Admin account Create a user without login Checking Access Impersonate the user without login Checking Access Revert Impersonation Give Permission to user without login Impersonate the user without login Checking Access Revert Impersonation Clean up Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• ODI - Creating a Repository in a 12c Pluggable Database

  - by David Allan

  To install ODI 11g into an Oracle 12c pluggable database, one way is to connect using a TNS string to the pluggable database service that is executing. For example when I installed my master repository, I used a JDBC URL such as; jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=mydbserver)(PORT=1522)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=PDBORA12.US.ORACLE.COM)))   I used the above approach rather than the host:port:sid which is a common mechanism many users use to quickly get up and going. Below you can see the repository creation wizard in action, I used the 11g release and simply installed the master and work repository into my pluggable database. Be wise with your repository IDs, I simply used the default, but you should be aware that these are key in larger deployments. The database in 12c has much more tighter control on users and resources, so just getting the user creating with sufficient resource on tablespaces etc in 12c was a little more work. Once you have the repositories up and running, then the fun starts using the 12c features. More to come.

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• BPM 11g and Human Workflow Shadow Rows by Adam Desjardin

  - by JuergenKress

  During the OFM Forum last week, there were a few discussions around the relationship between the Human Workflow (WF_TASK*) tables in the SOA_INFRA schema and BPMN processes.  It is important to know how these are related because it can have a performance impact.  We have seen this performance issue several times when BPMN processes are used to model high volume system integrations without knowing all of the implications of using BPMN in this pattern. Most people assume that BPMN instances and their related data are stored in the CUBE_*, DLV_*, and AUDIT_* tables in the same way that BPEL instances are stored, with additional data in the BPM_* tables as well.  The group of tables that is not usually considered though is the WF* tables that are used for Human Workflow.  The WFTASK table is used by all BPMN processes in order to support features such as process level comments and attachments, whether those features are currently used in the process or not. For a standard human task that is created from a BPMN process, the following data is stored in the WFTASK table: One row per human task that is created The COMPONENTTYPE = "Workflow" TASKDEFINITIONID = Human Task ID (partition/CompositeName!Version/TaskName) ACCESSKEY = NULL Read the complete article here. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki

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• Metro: Dynamically Switching Templates with a WinJS ListView

  - by Stephen.Walther

  Imagine that you want to display a list of products using the WinJS ListView control. Imagine, furthermore, that you want to use different templates to display different products. In particular, when a product is on sale, you want to display the product using a special “On Sale” template. In this blog entry, I explain how you can switch templates dynamically when displaying items with a ListView control. In other words, you learn how to use more than one template when displaying items with a ListView control. Creating the Data Source Let’s start by creating the data source for the ListView. Nothing special here – our data source is a list of products. Two of the products, Oranges and Apples, are on sale. (function () { "use strict"; var products = new WinJS.Binding.List([ { name: "Milk", price: 2.44 }, { name: "Oranges", price: 1.99, onSale: true }, { name: "Wine", price: 8.55 }, { name: "Apples", price: 2.44, onSale: true }, { name: "Steak", price: 1.99 }, { name: "Eggs", price: 2.44 }, { name: "Mushrooms", price: 1.99 }, { name: "Yogurt", price: 2.44 }, { name: "Soup", price: 1.99 }, { name: "Cereal", price: 2.44 }, { name: "Pepsi", price: 1.99 } ]); WinJS.Namespace.define("ListViewDemos", { products: products }); })(); The file above is saved with the name products.js and referenced by the default.html page described below. Declaring the Templates and ListView Control Next, we need to declare the ListView control and the two Template controls which we will use to display template items. The markup below appears in the default.html file: <!-- Templates --> <div id="productItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="product"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> </div> <div id="productOnSaleTemplate" data-win-control="WinJS.Binding.Template"> <div class="product onSale"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> </div> <!-- ListView --> <div id="productsListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.products.dataSource, layout: { type: WinJS.UI.ListLayout } }"> </div> In the markup above, two Template controls are declared. The first template is used when rendering a normal product and the second template is used when rendering a product which is on sale. The second template, unlike the first template, includes the text “(On Sale!)”. The ListView control is bound to the data source which we created in the previous section. The ListView itemDataSource property is set to the value ListViewDemos.products.dataSource. Notice that we do not set the ListView itemTemplate property. We set this property in the default.js file. Switching Between Templates All of the magic happens in the default.js file. The default.js file contains the JavaScript code used to switch templates dynamically. Here’s the entire contents of the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll().then(function () { var productsListView = document.getElementById("productsListView"); productsListView.winControl.itemTemplate = itemTemplateFunction; });; } }; function itemTemplateFunction(itemPromise) { return itemPromise.then(function (item) { // Select either normal product template or on sale template var itemTemplate = document.getElementById("productItemTemplate"); if (item.data.onSale) { itemTemplate = document.getElementById("productOnSaleTemplate"); }; // Render selected template to DIV container var container = document.createElement("div"); itemTemplate.winControl.render(item.data, container); return container; }); } app.start(); })(); In the code above, a function is assigned to the ListView itemTemplate property with the following line of code: productsListView.winControl.itemTemplate = itemTemplateFunction;   The itemTemplateFunction returns a DOM element which is used for the template item. Depending on the value of the product onSale property, the DOM element is generated from either the productItemTemplate or the productOnSaleTemplate template. Using Binding Converters instead of Multiple Templates In the previous sections, I explained how you can use different templates to render normal products and on sale products. There is an alternative approach to displaying different markup for normal products and on sale products. Instead of creating two templates, you can create a single template which contains separate DIV elements for a normal product and an on sale product. The following default.html file contains a single item template and a ListView control bound to the template. <!-- Template --> <div id="productItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="product" data-win-bind="style.display: onSale ListViewDemos.displayNormalProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> <div class="product onSale" data-win-bind="style.display: onSale ListViewDemos.displayOnSaleProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> </div> <!-- ListView --> <div id="productsListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.products.dataSource, itemTemplate: select('#productItemTemplate'), layout: { type: WinJS.UI.ListLayout } }"> </div> The first DIV element is used to render a normal product: <div class="product" data-win-bind="style.display: onSale ListViewDemos.displayNormalProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> The second DIV element is used to render an “on sale” product: <div class="product onSale" data-win-bind="style.display: onSale ListViewDemos.displayOnSaleProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> Notice that both templates include a data-win-bind attribute. These data-win-bind attributes are used to show the “normal” template when a product is not on sale and show the “on sale” template when a product is on sale. These attributes set the Cascading Style Sheet display attribute to either “none” or “block”. The data-win-bind attributes take advantage of binding converters. The binding converters are defined in the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll(); } }; WinJS.Namespace.define("ListViewDemos", { displayNormalProduct: WinJS.Binding.converter(function (onSale) { return onSale ? "none" : "block"; }), displayOnSaleProduct: WinJS.Binding.converter(function (onSale) { return onSale ? "block" : "none"; }) }); app.start(); })(); The ListViewDemos.displayNormalProduct binding converter converts the value true or false to the value “none” or “block”. The ListViewDemos.displayOnSaleProduct binding converter does the opposite; it converts the value true or false to the value “block” or “none” (Sadly, you cannot simply place a NOT operator before the onSale property in the binding expression – you need to create both converters). The end result is that you can display different markup depending on the value of the product onSale property. Either the contents of the first or second DIV element are displayed: Summary In this blog entry, I’ve explored two approaches to displaying different markup in a ListView depending on the value of a data item property. The bulk of this blog entry was devoted to explaining how you can assign a function to the ListView itemTemplate property which returns different templates. We created both a productItemTemplate and productOnSaleTemplate and displayed both templates with the same ListView control. We also discussed how you can create a single template and display different markup by using binding converters. The binding converters are used to set a DIV element’s display property to either “none” or “block”. We created a binding converter which displays normal products and a binding converter which displays “on sale” products.

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• Output = MAXDOP 1

  - by Dave Ballantyne

  It is widely know that data modifications on table variables do not support parallelism, Peter Larsson has a good example of that here .  Whilst tracking down a performance issue,  I saw that using the OUTPUT clause also causes parallelism to not be used. By way of example,  first lets create two tables with a simple parent and child (one to one) relationship, and then populate them with 100,000 rows. Drop table ParentDrop table Childgocreate table Parent(id integer identity Primary Key,data1 char(255))Create Table Child(id integer Primary Key)goinsert into Parent(data1)Select top 1000000 NULL from sys.columns a cross join sys.columns b insert into ChildSelect id from Parentgo If we then execute update Parent set data1 =''from Parentjoin Child on Parent.Id = Child.Id where Parent.Id %100 =1 and Child.id %100 =1 We should see an execution plan using parallelism such as   However,  if the OUTPUT clause is now used update Parent set data1 =''output inserted.idfrom Parentjoin Child on Parent.Id = Child.Id where Parent.Id %100 =1 and Child.id %100 =1   The execution plan shows that Parallelism was not used Make of that what you will, but i thought that this was a pretty unexpected outcome. Update : Laurence Hoff has mailed me to note that when the OUTPUT results are captured to a temporary table using the INTO clause,  then parallelism is used.  Naturally if you use a table variable then there is still no parallelism  

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• Oracle Solaris 11 ZFS Lab for Openworld 2012

  - by user12626122

  Preface This is the content from the Oracle Openworld 2012 ZFS lab. It was well attended - the feedback was that it was a little short - thats probably because in writing it I bacame very time-concious after the ASM/ACFS on Solaris extravaganza I ran last year which was almost too long for mortal man to finish in the 1 hour session. Enjoy. Table of Contents Exercise Z.1: ZFS Pools Exercise Z.2: ZFS File Systems Exercise Z.3: ZFS Compression Exercise Z.4: ZFS Deduplication Exercise Z.5: ZFS Encryption Exercise Z.6: Solaris 11 Shadow Migration Introduction This set of exercises is designed to briefly demonstrate new features in Solaris 11 ZFS file system: Deduplication, Encryption and Shadow Migration. Also included is the creation of zpools and zfs file systems - the basic building blocks of the technology, and also Compression which is the compliment of Deduplication. The exercises are just introductions - you are referred to the ZFS Adminstration Manual for further information. From Solaris 11 onward the online manual pages consist of zpool(1M) and zfs(1M) with further feature-specific information in zfs_allow(1M), zfs_encrypt(1M) and zfs_share(1M). The lab is easily carried out in a VirtualBox running Solaris 11 with 6 virtual 3 Gb disks to play with. Exercise Z.1: ZFS Pools Task: You have several disks to use for your new file system. Create a new zpool and a file system within it. Lab: You will check the status of existing zpools, create your own pool and expand it. Your Solaris 11 installation already has a root ZFS pool. It contains the root file system. Check this: root@solaris:~# zpool list NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT rpool 15.9G 6.62G 9.25G 41% 1.00x ONLINE - root@solaris:~# zpool status pool: rpool state: ONLINE scan: none requested config: NAME STATE READ WRITE CKSUM rpool ONLINE 0 0 0 c3t0d0s0 ONLINE 0 0 0 errors: No known data errors Note the disk device the root pool is on - c3t0d0s0 Now you will create your own ZFS pool. First you will check what disks are available: root@solaris:~# echo | format Searching for disks...done AVAILABLE DISK SELECTIONS: 0. c3t0d0 <ATA-VBOX HARDDISK-1.0 cyl 2085 alt 2 hd 255 sec 63> /pci@0,0/pci8086,2829@d/disk@0,0 1. c3t2d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32> /pci@0,0/pci8086,2829@d/disk@2,0 2. c3t3d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32> /pci@0,0/pci8086,2829@d/disk@3,0 3. c3t4d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32> /pci@0,0/pci8086,2829@d/disk@4,0 4. c3t5d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32> /pci@0,0/pci8086,2829@d/disk@5,0 5. c3t6d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32> /pci@0,0/pci8086,2829@d/disk@6,0 6. c3t7d0 <ATA-VBOX HARDDISK-1.0 cyl 1534 alt 2 hd 128 sec 32> /pci@0,0/pci8086,2829@d/disk@7,0 Specify disk (enter its number): Specify disk (enter its number): The root disk is numbered 0. The others are free for use. Try creating a simple pool and observe the error message: root@solaris:~# zpool create mypool c3t2d0 c3t3d0 'mypool' successfully created, but with no redundancy; failure of one device will cause loss of the pool So destroy that pool and create a mirrored pool instead: root@solaris:~# zpool destroy mypool root@solaris:~# zpool create mypool mirror c3t2d0 c3t3d0 root@solaris:~# zpool status mypool pool: mypool state: ONLINE scan: none requested config: NAME STATE READ WRITE CKSUM mypool ONLINE 0 0 0 mirror-0 ONLINE 0 0 0 c3t2d0 ONLINE 0 0 0 c3t3d0 ONLINE 0 0 0 errors: No known data errors Back to topExercise Z.2: ZFS File Systems Task: You have to create file systems for later exercises. You can see that when a pool is created, a file system of the same name is created: root@solaris:~# zfs list NAME USED AVAIL REFER MOUNTPOINT mypool 86.5K 2.94G 31K /mypool Create your filesystems and mountpoints as follows: root@solaris:~# zfs create -o mountpoint=/data1 mypool/mydata1 The -o option sets the mount point and automatically creates the necessary directory. root@solaris:~# zfs list mypool/mydata1 NAME USED AVAIL REFER MOUNTPOINT mypool/mydata1 31K 2.94G 31K /data1 Back to top Exercise Z.3: ZFS Compression Task:Try out different forms of compression available in ZFS Lab:Create 2nd filesystem with compression, fill both file systems with the same data, observe results You can see from the zfs(1) manual page that there are several types of compression available to you, set with the property=value syntax: compression=on | off | lzjb | gzip | gzip-N | zle Controls the compression algorithm used for this dataset. The lzjb compression algorithm is optimized for performance while providing decent data compression. Setting compression to on uses the lzjb compression algorithm. The gzip compression algorithm uses the same compression as the gzip(1) command. You can specify the gzip level by using the value gzip-N where N is an integer from 1 (fastest) to 9 (best compression ratio). Currently, gzip is equivalent to gzip-6 (which is also the default for gzip(1)). Create a second filesystem with compression turned on. Note how you set and get your values separately: root@solaris:~# zfs create -o mountpoint=/data2 mypool/mydata2 root@solaris:~# zfs set compression=gzip-9 mypool/mydata2 root@solaris:~# zfs get compression mypool/mydata1 NAME PROPERTY VALUE SOURCE mypool/mydata1 compression off default root@solaris:~# zfs get compression mypool/mydata2 NAME PROPERTY VALUE SOURCE mypool/mydata2 compression gzip-9 local Now you can copy the contents of /usr/lib into both your normal and compressing filesystem and observe the results. Don't forget the dot or period (".") in the find(1) command below: root@solaris:~# cd /usr/lib root@solaris:/usr/lib# find . -print | cpio -pdv /data1 root@solaris:/usr/lib# find . -print | cpio -pdv /data2 The copy into the compressing file system takes longer - as it has to perform the compression but the results show the effect: root@solaris:/usr/lib# zfs list NAME USED AVAIL REFER MOUNTPOINT mypool 1.35G 1.59G 31K /mypool mypool/mydata1 1.01G 1.59G 1.01G /data1 mypool/mydata2 341M 1.59G 341M /data2 Note that the available space in the pool is shared amongst the file systems. This behavior can be modified using quotas and reservations which are not covered in this lab but are covered extensively in the ZFS Administrators Guide. Back to top Exercise Z.4: ZFS Deduplication The deduplication property is used to remove redundant data from a ZFS file system. With the property enabled duplicate data blocks are removed synchronously. The result is that only unique data is stored and common componenents are shared. Task:See how to implement deduplication and its effects Lab: You will create a ZFS file system with deduplication turned on and see if it reduces the amount of physical storage needed when we again fill it with a copy of /usr/lib. root@solaris:/usr/lib# zfs destroy mypool/mydata2 root@solaris:/usr/lib# zfs set dedup=on mypool/mydata1 root@solaris:/usr/lib# rm -rf /data1/* root@solaris:/usr/lib# mkdir /data1/2nd-copy root@solaris:/usr/lib# zfs list NAME USED AVAIL REFER MOUNTPOINT mypool 1.02M 2.94G 31K /mypool mypool/mydata1 43K 2.94G 43K /data1 root@solaris:/usr/lib# find . -print | cpio -pd /data1 2142768 blocks root@solaris:/usr/lib# zfs list NAME USED AVAIL REFER MOUNTPOINT mypool 1.02G 1.99G 31K /mypool mypool/mydata1 1.01G 1.99G 1.01G /data1 root@solaris:/usr/lib# find . -print | cpio -pd /data1/2nd-copy 2142768 blocks root@solaris:/usr/lib#zfs list NAME USED AVAIL REFER MOUNTPOINT mypool 1.99G 1.96G 31K /mypool mypool/mydata1 1.98G 1.96G 1.98G /data1 You could go on creating copies for quite a while...but you get the idea. Note that deduplication and compression can be combined: the compression acts on metadata. Deduplication works across file systems in a pool and there is a zpool-wide property dedupratio: root@solaris:/usr/lib# zpool get dedupratio mypool NAME PROPERTY VALUE SOURCE mypool dedupratio 4.30x - Deduplication can also be checked using "zpool list": root@solaris:/usr/lib# zpool list NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT mypool 2.98G 1001M 2.01G 32% 4.30x ONLINE - rpool 15.9G 6.66G 9.21G 41% 1.00x ONLINE - Before moving on to the next topic, destroy that dataset and free up some space: root@solaris:~# zfs destroy mypool/mydata1 Back to top Exercise Z.5: ZFS Encryption Task: Encrypt sensitive data. Lab: Explore basic ZFS encryption. This lab only covers the basics of ZFS Encryption. In particular it does not cover various aspects of key management. Please see the ZFS Adminastrion Manual and the zfs_encrypt(1M) manual page for more detail on this functionality. Back to top root@solaris:~# zfs create -o encryption=on mypool/data2 Enter passphrase for 'mypool/data2': ******** Enter again: ******** root@solaris:~# Creation of a descendent dataset shows that encryption is inherited from the parent: root@solaris:~# zfs create mypool/data2/data3 root@solaris:~# zfs get -r encryption,keysource,keystatus,checksum mypool/data2 NAME PROPERTY VALUE SOURCE mypool/data2 encryption on local mypool/data2 keysource passphrase,prompt local mypool/data2 keystatus available - mypool/data2 checksum sha256-mac local mypool/data2/data3 encryption on inherited from mypool/data2 mypool/data2/data3 keysource passphrase,prompt inherited from mypool/data2 mypool/data2/data3 keystatus available - mypool/data2/data3 checksum sha256-mac inherited from mypool/data2 You will find the online manual page zfs_encrypt(1M) contains examples. In particular, if time permits during this lab session you may wish to explore the changing of a key using "zfs key -c mypool/data2". Exercise Z.6: Shadow Migration Shadow Migration allows you to migrate data from an old file system to a new file system while simultaneously allowing access and modification to the new file system during the process. You can use Shadow Migration to migrate a local or remote UFS or ZFS file system to a local file system. Task: You wish to migrate data from one file system (UFS, ZFS, VxFS) to ZFS while mainaining access to it. Lab: Create the infrastructure for shadow migration and transfer one file system into another. First create the file system you want to migrate root@solaris:~# zpool create oldstuff c3t4d0 root@solaris:~# zfs create oldstuff/forgotten Then populate it with some files: root@solaris:~# cd /var/adm root@solaris:/var/adm# find . -print | cpio -pdv /oldstuff/forgotten You need the shadow-migration package installed: root@solaris:~# pkg install shadow-migration Packages to install: 1 Create boot environment: No Create backup boot environment: No Services to change: 1 DOWNLOAD PKGS FILES XFER (MB) Completed 1/1 14/14 0.2/0.2 PHASE ACTIONS Install Phase 39/39 PHASE ITEMS Package State Update Phase 1/1 Image State Update Phase 2/2 You then enable the shadowd service: root@solaris:~# svcadm enable shadowd root@solaris:~# svcs shadowd STATE STIME FMRI online 7:16:09 svc:/system/filesystem/shadowd:default Set the filesystem to be migrated to read-only root@solaris:~# zfs set readonly=on oldstuff/forgotten Create a new zfs file system with the shadow property set to the file system to be migrated: root@solaris:~# zfs create -o shadow=file:///oldstuff/forgotten mypool/remembered Use the shadowstat(1M) command to see the progress of the migration: root@solaris:~# shadowstat EST BYTES BYTES ELAPSED DATASET XFRD LEFT ERRORS TIME mypool/remembered 92.5M - - 00:00:59 mypool/remembered 99.1M 302M - 00:01:09 mypool/remembered 109M 260M - 00:01:19 mypool/remembered 133M 304M - 00:01:29 mypool/remembered 149M 339M - 00:01:39 mypool/remembered 156M 86.4M - 00:01:49 mypool/remembered 156M 8E 29 (completed) Note that if you had created /mypool/remembered as encrypted, this would be the preferred method of encrypting existing data. Similarly for compressing or deduplicating existing data. The procedure for migrating a file system over NFS is similar - see the ZFS Administration manual. That concludes this lab session.

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• Table Variables: an empirical approach.

  - by Phil Factor

  It isn’t entirely a pleasant experience to publish an article only to have it described on Twitter as ‘Horrible’, and to have it criticized on the MVP forum. When this happened to me in the aftermath of publishing my article on Temporary tables recently, I was taken aback, because these critics were experts whose views I respect. What was my crime? It was, I think, to suggest that, despite the obvious quirks, it was best to use Table Variables as a first choice, and to use local Temporary Tables if you hit problems due to these quirks, or if you were doing complex joins using a large number of rows. What are these quirks? Well, table variables have advantages if they are used sensibly, but this requires some awareness by the developer about the potential hazards and how to avoid them. You can be hit by a badly-performing join involving a table variable. Table Variables are a compromise, and this compromise doesn’t always work out well. Explicit indexes aren’t allowed on Table Variables, so one cannot use covering indexes or non-unique indexes. The query optimizer has to make assumptions about the data rather than using column distribution statistics when a table variable is involved in a join, because there aren’t any column-based distribution statistics on a table variable. It assumes a reasonably even distribution of data, and is likely to have little idea of the number of rows in the table variables that are involved in queries. However complex the heuristics that are used might be in determining the best way of executing a SQL query, and they most certainly are, the Query Optimizer is likely to fail occasionally with table variables, under certain circumstances, and produce a Query Execution Plan that is frightful. The experienced developer or DBA will be on the lookout for this sort of problem. In this blog, I’ll be expanding on some of the tests I used when writing my article to illustrate the quirks, and include a subsequent example supplied by Kevin Boles. A simplified example. We’ll start out by illustrating a simple example that shows some of these characteristics. We’ll create two tables filled with random numbers and then see how many matches we get between the two tables. We’ll forget indexes altogether for this example, and use heaps. We’ll try the same Join with two table variables, two table variables with OPTION (RECOMPILE) in the JOIN clause, and with two temporary tables. It is all a bit jerky because of the granularity of the timing that isn’t actually happening at the millisecond level (I used DATETIME). However, you’ll see that the table variable is outperforming the local temporary table up to 10,000 rows. Actually, even without a use of the OPTION (RECOMPILE) hint, it is doing well. What happens when your table size increases? The table variable is, from around 30,000 rows, locked into a very bad execution plan unless you use OPTION (RECOMPILE) to provide the Query Analyser with a decent estimation of the size of the table. However, if it has the OPTION (RECOMPILE), then it is smokin’. Well, up to 120,000 rows, at least. It is performing better than a Temporary table, and in a good linear fashion. What about mixed table joins, where you are joining a temporary table to a table variable? You’d probably expect that the query analyzer would throw up its hands and produce a bad execution plan as if it were a table variable. After all, it knows nothing about the statistics in one of the tables so how could it do any better? Well, it behaves as if it were doing a recompile. And an explicit recompile adds no value at all. (we just go up to 45000 rows since we know the bigger picture now)   Now, if you were new to this, you might be tempted to start drawing conclusions. Beware! We’re dealing with a very complex beast: the Query Optimizer. It can come up with surprises What if we change the query very slightly to insert the results into a Table Variable? We change nothing else and just measure the execution time of the statement as before. Suddenly, the table variable isn’t looking so much better, even taking into account the time involved in doing the table insert. OK, if you haven’t used OPTION (RECOMPILE) then you’re toast. Otherwise, there isn’t much in it between the Table variable and the temporary table. The table variable is faster up to 8000 rows and then not much in it up to 100,000 rows. Past the 8000 row mark, we’ve lost the advantage of the table variable’s speed. Any general rule you may be formulating has just gone for a walk. What we can conclude from this experiment is that if you join two table variables, and can’t use constraints, you’re going to need that Option (RECOMPILE) hint. Count Dracula and the Horror Join. These tables of integers provide a rather unreal example, so let’s try a rather different example, and get stuck into some implicit indexing, by using constraints. What unusual words are contained in the book ‘Dracula’ by Bram Stoker? Here we get a table of all the common words in the English language (60,387 of them) and put them in a table. We put them in a Table Variable with the word as a primary key, a Table Variable Heap and a Table Variable with a primary key. We then take all the distinct words used in the book ‘Dracula’ (7,558 of them). We then create a table variable and insert into it all those uncommon words that are in ‘Dracula’. i.e. all the words in Dracula that aren’t matched in the list of common words. To do this we use a left outer join, where the right-hand value is null. The results show a huge variation, between the sublime and the gorblimey. If both tables contain a Primary Key on the columns we join on, and both are Table Variables, it took 33 Ms. If one table contains a Primary Key, and the other is a heap, and both are Table Variables, it took 46 Ms. If both Table Variables use a unique constraint, then the query takes 36 Ms. If neither table contains a Primary Key and both are Table Variables, it took 116383 Ms. Yes, nearly two minutes!! If both tables contain a Primary Key, one is a Table Variables and the other is a temporary table, it took 113 Ms. If one table contains a Primary Key, and both are Temporary Tables, it took 56 Ms.If both tables are temporary tables and both have primary keys, it took 46 Ms. Here we see table variables which are joined on their primary key again enjoying a  slight performance advantage over temporary tables. Where both tables are table variables and both are heaps, the query suddenly takes nearly two minutes! So what if you have two heaps and you use option Recompile? If you take the rogue query and add the hint, then suddenly, the query drops its time down to 76 Ms. If you add unique indexes, then you've done even better, down to half that time. Here are the text execution plans.So where have we got to? Without drilling down into the minutiae of the execution plans we can begin to create a hypothesis. If you are using table variables, and your tables are relatively small, they are faster than temporary tables, but as the number of rows increases you need to do one of two things: either you need to have a primary key on the column you are using to join on, or else you need to use option (RECOMPILE) If you try to execute a query that is a join, and both tables are table variable heaps, you are asking for trouble, well- slow queries, unless you give the table hint once the number of rows has risen past a point (30,000 in our first example, but this varies considerably according to context). Kevin’s Skew In describing the table-size, I used the term ‘relatively small’. Kevin Boles produced an interesting case where a single-row table variable produces a very poor execution plan when joined to a very, very skewed table. In the original, pasted into my article as a comment, a column consisted of 100000 rows in which the key column was one number (1) . To this was added eight rows with sequential numbers up to 9. When this was joined to a single-tow Table Variable with a key of 2 it produced a bad plan. This problem is unlikely to occur in real usage, and the Query Optimiser team probably never set up a test for it. Actually, the skew can be slightly less extreme than Kevin made it. The following test showed that once the table had 54 sequential rows in the table, then it adopted exactly the same execution plan as for the temporary table and then all was well. Undeniably, real data does occasionally cause problems to the performance of joins in Table Variables due to the extreme skew of the distribution. We've all experienced Perfectly Poisonous Table Variables in real live data. As in Kevin’s example, indexes merely make matters worse, and the OPTION (RECOMPILE) trick does nothing to help. In this case, there is no option but to use a temporary table. However, one has to note that once the slight de-skew had taken place, then the plans were identical across a huge range. Conclusions Where you need to hold intermediate results as part of a process, Table Variables offer a good alternative to temporary tables when used wisely. They can perform faster than a temporary table when the number of rows is not great. For some processing with huge tables, they can perform well when only a clustered index is required, and when the nature of the processing makes an index seek very effective. Table Variables are scoped to the batch or procedure and are unlikely to hang about in the TempDB when they are no longer required. They require no explicit cleanup. Where the number of rows in the table is moderate, you can even use them in joins as ‘Heaps’, unindexed. Beware, however, since, as the number of rows increase, joins on Table Variable heaps can easily become saddled by very poor execution plans, and this must be cured either by adding constraints (UNIQUE or PRIMARY KEY) or by adding the OPTION (RECOMPILE) hint if this is impossible. Occasionally, the way that the data is distributed prevents the efficient use of Table Variables, and this will require using a temporary table instead. Tables Variables require some awareness by the developer about the potential hazards and how to avoid them. If you are not prepared to do any performance monitoring of your code or fine-tuning, and just want to pummel out stuff that ‘just runs’ without considering namby-pamby stuff such as indexes, then stick to Temporary tables. If you are likely to slosh about large numbers of rows in temporary tables without considering the niceties of processing just what is required and no more, then temporary tables provide a safer and less fragile means-to-an-end for you.

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• Metro: Dynamically Switching Templates with a WinJS ListView

  - by Stephen.Walther

  Imagine that you want to display a list of products using the WinJS ListView control. Imagine, furthermore, that you want to use different templates to display different products. In particular, when a product is on sale, you want to display the product using a special “On Sale” template. In this blog entry, I explain how you can switch templates dynamically when displaying items with a ListView control. In other words, you learn how to use more than one template when displaying items with a ListView control. Creating the Data Source Let’s start by creating the data source for the ListView. Nothing special here – our data source is a list of products. Two of the products, Oranges and Apples, are on sale. (function () { "use strict"; var products = new WinJS.Binding.List([ { name: "Milk", price: 2.44 }, { name: "Oranges", price: 1.99, onSale: true }, { name: "Wine", price: 8.55 }, { name: "Apples", price: 2.44, onSale: true }, { name: "Steak", price: 1.99 }, { name: "Eggs", price: 2.44 }, { name: "Mushrooms", price: 1.99 }, { name: "Yogurt", price: 2.44 }, { name: "Soup", price: 1.99 }, { name: "Cereal", price: 2.44 }, { name: "Pepsi", price: 1.99 } ]); WinJS.Namespace.define("ListViewDemos", { products: products }); })(); The file above is saved with the name products.js and referenced by the default.html page described below. Declaring the Templates and ListView Control Next, we need to declare the ListView control and the two Template controls which we will use to display template items. The markup below appears in the default.html file: <!-- Templates --> <div id="productItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="product"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> </div> <div id="productOnSaleTemplate" data-win-control="WinJS.Binding.Template"> <div class="product onSale"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> </div> <!-- ListView --> <div id="productsListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.products.dataSource, layout: { type: WinJS.UI.ListLayout } }"> </div> In the markup above, two Template controls are declared. The first template is used when rendering a normal product and the second template is used when rendering a product which is on sale. The second template, unlike the first template, includes the text “(On Sale!)”. The ListView control is bound to the data source which we created in the previous section. The ListView itemDataSource property is set to the value ListViewDemos.products.dataSource. Notice that we do not set the ListView itemTemplate property. We set this property in the default.js file. Switching Between Templates All of the magic happens in the default.js file. The default.js file contains the JavaScript code used to switch templates dynamically. Here’s the entire contents of the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll().then(function () { var productsListView = document.getElementById("productsListView"); productsListView.winControl.itemTemplate = itemTemplateFunction; });; } }; function itemTemplateFunction(itemPromise) { return itemPromise.then(function (item) { // Select either normal product template or on sale template var itemTemplate = document.getElementById("productItemTemplate"); if (item.data.onSale) { itemTemplate = document.getElementById("productOnSaleTemplate"); }; // Render selected template to DIV container var container = document.createElement("div"); itemTemplate.winControl.render(item.data, container); return container; }); } app.start(); })(); In the code above, a function is assigned to the ListView itemTemplate property with the following line of code: productsListView.winControl.itemTemplate = itemTemplateFunction;   The itemTemplateFunction returns a DOM element which is used for the template item. Depending on the value of the product onSale property, the DOM element is generated from either the productItemTemplate or the productOnSaleTemplate template. Using Binding Converters instead of Multiple Templates In the previous sections, I explained how you can use different templates to render normal products and on sale products. There is an alternative approach to displaying different markup for normal products and on sale products. Instead of creating two templates, you can create a single template which contains separate DIV elements for a normal product and an on sale product. The following default.html file contains a single item template and a ListView control bound to the template. <!-- Template --> <div id="productItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="product" data-win-bind="style.display: onSale ListViewDemos.displayNormalProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> <div class="product onSale" data-win-bind="style.display: onSale ListViewDemos.displayOnSaleProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> </div> <!-- ListView --> <div id="productsListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.products.dataSource, itemTemplate: select('#productItemTemplate'), layout: { type: WinJS.UI.ListLayout } }"> </div> The first DIV element is used to render a normal product: <div class="product" data-win-bind="style.display: onSale ListViewDemos.displayNormalProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> The second DIV element is used to render an “on sale” product: <div class="product onSale" data-win-bind="style.display: onSale ListViewDemos.displayOnSaleProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> Notice that both templates include a data-win-bind attribute. These data-win-bind attributes are used to show the “normal” template when a product is not on sale and show the “on sale” template when a product is on sale. These attributes set the Cascading Style Sheet display attribute to either “none” or “block”. The data-win-bind attributes take advantage of binding converters. The binding converters are defined in the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll(); } }; WinJS.Namespace.define("ListViewDemos", { displayNormalProduct: WinJS.Binding.converter(function (onSale) { return onSale ? "none" : "block"; }), displayOnSaleProduct: WinJS.Binding.converter(function (onSale) { return onSale ? "block" : "none"; }) }); app.start(); })(); The ListViewDemos.displayNormalProduct binding converter converts the value true or false to the value “none” or “block”. The ListViewDemos.displayOnSaleProduct binding converter does the opposite; it converts the value true or false to the value “block” or “none” (Sadly, you cannot simply place a NOT operator before the onSale property in the binding expression – you need to create both converters). The end result is that you can display different markup depending on the value of the product onSale property. Either the contents of the first or second DIV element are displayed: Summary In this blog entry, I’ve explored two approaches to displaying different markup in a ListView depending on the value of a data item property. The bulk of this blog entry was devoted to explaining how you can assign a function to the ListView itemTemplate property which returns different templates. We created both a productItemTemplate and productOnSaleTemplate and displayed both templates with the same ListView control. We also discussed how you can create a single template and display different markup by using binding converters. The binding converters are used to set a DIV element’s display property to either “none” or “block”. We created a binding converter which displays normal products and a binding converter which displays “on sale” products.

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• Getting Started with TypeScript – Classes, Static Types and Interfaces

  - by dwahlin

  I had the opportunity to speak on different JavaScript topics at DevConnections in Las Vegas this fall and heard a lot of interesting comments about JavaScript as I talked with people. The most frequent comment I heard from people was, “I guess it’s time to start learning JavaScript”. Yep – if you don’t already know JavaScript then it’s time to learn it. As HTML5 becomes more and more popular the amount of JavaScript code written will definitely increase. After all, many of the HTML5 features available in browsers have little to do with “tags” and more to do with JavaScript (web workers, web sockets, canvas, local storage, etc.). As the amount of JavaScript code being used in applications increases, it’s more important than ever to structure the code in a way that’s maintainable and easy to debug. While JavaScript patterns can certainly be used (check out my previous posts on the subject or my course on Pluralsight.com), several alternatives have come onto the scene such as CoffeeScript, Dart and TypeScript. In this post I’ll describe some of the features TypeScript offers and the benefits that they can potentially offer enterprise-scale JavaScript applications. It’s important to note that while TypeScript has several great features, it’s definitely not for everyone or every project especially given how new it is. The goal of this post isn’t to convince you to use TypeScript instead of standard JavaScript….I’m a big fan of JavaScript. Instead, I’ll present several TypeScript features and let you make the decision as to whether TypeScript is a good fit for your applications. TypeScript Overview Here’s the official definition of TypeScript from the http://typescriptlang.org site: “TypeScript is a language for application-scale JavaScript development. TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. Any browser. Any host. Any OS. Open Source.” TypeScript was created by Anders Hejlsberg (the creator of the C# language) and his team at Microsoft. To sum it up, TypeScript is a new language that can be compiled to JavaScript much like alternatives such as CoffeeScript or Dart. It isn’t a stand-alone language that’s completely separate from JavaScript’s roots though. It’s a superset of JavaScript which means that standard JavaScript code can be placed in a TypeScript file (a file with a .ts extension) and used directly. That’s a very important point/feature of the language since it means you can use existing code and frameworks with TypeScript without having to do major code conversions to make it all work. Once a TypeScript file is saved it can be compiled to JavaScript using TypeScript’s tsc.exe compiler tool or by using a variety of editors/tools. TypeScript offers several key features. First, it provides built-in type support meaning that you define variables and function parameters as being “string”, “number”, “bool”, and more to avoid incorrect types being assigned to variables or passed to functions. Second, TypeScript provides a way to write modular code by directly supporting class and module definitions and it even provides support for custom interfaces that can be used to drive consistency. Finally, TypeScript integrates with several different tools such as Visual Studio, Sublime Text, Emacs, and Vi to provide syntax highlighting, code help, build support, and more depending on the editor. Find out more about editor support at http://www.typescriptlang.org/#Download. TypeScript can also be used with existing JavaScript frameworks such as Node.js, jQuery, and others and even catch type issues and provide enhanced code help. Special “declaration” files that have a d.ts extension are available for Node.js, jQuery, and other libraries out-of-the-box. Visit http://typescript.codeplex.com/SourceControl/changeset/view/fe3bc0bfce1f#samples%2fjquery%2fjquery.d.ts for an example of a jQuery TypeScript declaration file that can be used with tools such as Visual Studio 2012 to provide additional code help and ensure that a string isn’t passed to a parameter that expects a number. Although declaration files certainly aren’t required, TypeScript’s support for declaration files makes it easier to catch issues upfront while working with existing libraries such as jQuery. In the future I expect TypeScript declaration files will be released for different HTML5 APIs such as canvas, local storage, and others as well as some of the more popular JavaScript libraries and frameworks. Getting Started with TypeScript To get started learning TypeScript visit the TypeScript Playground available at http://www.typescriptlang.org. Using the playground editor you can experiment with TypeScript code, get code help as you type, and see the JavaScript that TypeScript generates once it’s compiled. Here’s an example of the TypeScript playground in action:   One of the first things that may stand out to you about the code shown above is that classes can be defined in TypeScript. This makes it easy to group related variables and functions into a container which helps tremendously with re-use and maintainability especially in enterprise-scale JavaScript applications. While you can certainly simulate classes using JavaScript patterns (note that ECMAScript 6 will support classes directly), TypeScript makes it quite easy especially if you come from an object-oriented programming background. An example of the Greeter class shown in the TypeScript Playground is shown next: class Greeter { greeting: string; constructor (message: string) { this.greeting = message; } greet() { return "Hello, " + this.greeting; } } Looking through the code you’ll notice that static types can be defined on variables and parameters such as greeting: string, that constructors can be defined, and that functions can be defined such as greet(). The ability to define static types is a key feature of TypeScript (and where its name comes from) that can help identify bugs upfront before even running the code. Many types are supported including primitive types like string, number, bool, undefined, and null as well as object literals and more complex types such as HTMLInputElement (for an <input> tag). Custom types can be defined as well. The JavaScript output by compiling the TypeScript Greeter class (using an editor like Visual Studio, Sublime Text, or the tsc.exe compiler) is shown next: var Greeter = (function () { function Greeter(message) { this.greeting = message; } Greeter.prototype.greet = function () { return "Hello, " + this.greeting; }; return Greeter; })(); Notice that the code is using JavaScript prototyping and closures to simulate a Greeter class in JavaScript. The body of the code is wrapped with a self-invoking function to take the variables and functions out of the global JavaScript scope. This is important feature that helps avoid naming collisions between variables and functions. In cases where you’d like to wrap a class in a naming container (similar to a namespace in C# or a package in Java) you can use TypeScript’s module keyword. The following code shows an example of wrapping an AcmeCorp module around the Greeter class. In order to create a new instance of Greeter the module name must now be used. This can help avoid naming collisions that may occur with the Greeter class.   module AcmeCorp { export class Greeter { greeting: string; constructor (message: string) { this.greeting = message; } greet() { return "Hello, " + this.greeting; } } } var greeter = new AcmeCorp.Greeter("world"); In addition to being able to define custom classes and modules in TypeScript, you can also take advantage of inheritance by using TypeScript’s extends keyword. The following code shows an example of using inheritance to define two report objects:   class Report { name: string; constructor (name: string) { this.name = name; } print() { alert("Report: " + this.name); } } class FinanceReport extends Report { constructor (name: string) { super(name); } print() { alert("Finance Report: " + this.name); } getLineItems() { alert("5 line items"); } } var report = new FinanceReport("Month's Sales"); report.print(); report.getLineItems();   In this example a base Report class is defined that has a variable (name), a constructor that accepts a name parameter of type string, and a function named print(). The FinanceReport class inherits from Report by using TypeScript’s extends keyword. As a result, it automatically has access to the print() function in the base class. In this example the FinanceReport overrides the base class’s print() method and adds its own. The FinanceReport class also forwards the name value it receives in the constructor to the base class using the super() call. TypeScript also supports the creation of custom interfaces when you need to provide consistency across a set of objects. The following code shows an example of an interface named Thing (from the TypeScript samples) and a class named Plane that implements the interface to drive consistency across the app. Notice that the Plane class includes intersect and normal as a result of implementing the interface.   interface Thing { intersect: (ray: Ray) => Intersection; normal: (pos: Vector) => Vector; surface: Surface; } class Plane implements Thing { normal: (pos: Vector) =>Vector; intersect: (ray: Ray) =>Intersection; constructor (norm: Vector, offset: number, public surface: Surface) { this.normal = function (pos: Vector) { return norm; } this.intersect = function (ray: Ray): Intersection { var denom = Vector.dot(norm, ray.dir); if (denom > 0) { return null; } else { var dist = (Vector.dot(norm, ray.start) + offset) / (-denom); return { thing: this, ray: ray, dist: dist }; } } } }   At first glance it doesn’t appear that the surface member is implemented in Plane but it’s actually included automatically due to the public surface: Surface parameter in the constructor. Adding public varName: Type to a constructor automatically adds a typed variable into the class without having to explicitly write the code as with normal and intersect. TypeScript has additional language features but defining static types and creating classes, modules, and interfaces are some of the key features it offers. So is TypeScript right for you and your applications? That’s a not a question that I or anyone else can answer for you. You’ll need to give it a spin to see what you think. In future posts I’ll discuss additional details about TypeScript and how it can be used with enterprise-scale JavaScript applications. In the meantime, I’m in the process of working with John Papa on a new Typescript course for Pluralsight that we hope to have out in December of 2012.

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• Which algorithms/data structures should I "recognize" and know by name?

  - by Earlz

  I'd like to consider myself a fairly experienced programmer. I've been programming for over 5 years now. My weak point though is terminology. I'm self-taught, so while I know how to program, I don't know some of the more formal aspects of computer science. So, what are practical algorithms/data structures that I could recognize and know by name? Note, I'm not asking for a book recommendation about implementing algorithms. I don't care about implementing them, I just want to be able to recognize when an algorithm/data structure would be a good solution to a problem. I'm asking more for a list of algorithms/data structures that I should "recognize". For instance, I know the solution to a problem like this: You manage a set of lockers labeled 0-999. People come to you to rent the locker and then come back to return the locker key. How would you build a piece of software to manage knowing which lockers are free and which are in used? The solution, would be a queue or stack. What I'm looking for are things like "in what situation should a B-Tree be used -- What search algorithm should be used here" etc. And maybe a quick introduction of how the more complex(but commonly used) data structures/algorithms work. I tried looking at Wikipedia's list of data structures and algorithms but I think that's a bit overkill. So I'm looking more for what are the essential things I should recognize?

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• Using XML as data storage

  - by Kian Mayne

  I was thinking about the XML format and the following quote: “XML is not a database. It was never meant to be a database. It is never going to be a database. Relational databases are proven technology with more than 20 years of implementation experience. They are solid, stable, useful products. They are not going away. XML is a very useful technology for moving data between different databases or between databases and other programs. However, it is not itself a database. Don't use it like one.“ -Effective XML: 50 Specific Ways to Improve Your XML by Elliotte Rusty Harold (page 230, Part 4, Item 41, 2nd paragraph) This seems to really stress that XML should not be used for data storage and should only be used for program to program interoperability. Personally, I disagree and .NET's app.config file that's used to store a program's settings is an example of data storage in an XML file. However for databases rather than configurations etc XML should not be used. To develop my point, I will use two examples: A) Data about customers with fields that are all on one level i.e. there are a number of fields all relating to one customer with no children B) Data about configuration of an application where nested fields and properties make a lot of sense So my question is, Is this still a valid statement and is it now acceptable to store data using XML? EDIT: I've sent an email to the author of that quote to ask for his input/extra context.

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• Highly SEO optimised forum posts

  - by Tom Gullen

  Given the following forum post: Basics of how internals of Construct work I've used GameMaker in the past. And I know some C++ and have used a few 3d engines with it. I have also looked at Unity, though I didn't get too much into it. So I know my way around programming etc... My question is, how does construct work internally? I know it allows python scripting, which itself is "technically" interpreted, though python is pretty fast as far as being interpreted goes. But what about the rest? Is the executable that gets cre... The forum software will take the first 150 chars of the first post as the page meta description, and the title will be the thread title. All ok. So in Google it will appear as: Basics of how internals of Construct work I've used GameMaker in the past. And I know some C++ and have used a few 3d engines with it. I have also looked at Unity, though I didn't get too much... http://www.domain.com/forum/basics-of-how-internals-of-construct-work.html Now the problem is (not so much with this thread, but other ones) is the first 150 chars don't always create the best meta description. Is it worth my time to cherry pick threads and manually set their description/title tags so they read like: Internal workings of Construct 2 Events aren't converted to any other language. The runtime is a standalone compiled EXE application, which is optimised and actually very fast. Your events... http://www.domain.com/forum/basics-of-how-internals-of-construct-work.html The H1 on the page is still the original title, but we have overridden the title and description to look more friendly on search results. Is this advantageous forgetting the obvious time cost?

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• C#: Handling Notifications: inheritance, events, or delegates?

  - by James Michael Hare

  Often times as developers we have to design a class where we get notification when certain things happen. In older object-oriented code this would often be implemented by overriding methods -- with events, delegates, and interfaces, however, we have far more elegant options. So, when should you use each of these methods and what are their strengths and weaknesses? Now, for the purposes of this article when I say notification, I'm just talking about ways for a class to let a user know that something has occurred. This can be through any programmatic means such as inheritance, events, delegates, etc. So let's build some context. I'm sitting here thinking about a provider neutral messaging layer for the place I work, and I got to the point where I needed to design the message subscriber which will receive messages from the message bus. Basically, what we want is to be able to create a message listener and have it be called whenever a new message arrives. Now, back before the flood we would have done this via inheritance and an abstract class: 1:  2: // using inheritance - omitting argument null checks and halt logic 3: public abstract class MessageListener 4: { 5: private ISubscriber _subscriber; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber) 11: { 12: _subscriber = subscriber; 13: _messageThread = new Thread(MessageLoop); 14: _messageThread.Start(); 15: } 16:  17: // user will override this to process their messages 18: protected abstract void OnMessageReceived(Message msg); 19:  20: // handle the looping in the thread 21: private void MessageLoop() 22: { 23: while(!_isHalted) 24: { 25: // as long as processing, wait 1 second for message 26: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 27: if(msg != null) 28: { 29: OnMessageReceived(msg); 30: } 31: } 32: } 33: ... 34: } It seems so odd to write this kind of code now. Does it feel odd to you? Maybe it's just because I've gotten so used to delegation that I really don't like the feel of this. To me it is akin to saying that if I want to drive my car I need to derive a new instance of it just to put myself in the driver's seat. And yet, unquestionably, five years ago I would have probably written the code as you see above. To me, inheritance is a flawed approach for notifications due to several reasons: Inheritance is one of the HIGHEST forms of coupling. You can't seal the listener class because it depends on sub-classing to work. Because C# does not allow multiple-inheritance, I've spent my one inheritance implementing this class. Every time you need to listen to a bus, you have to derive a class which leads to lots of trivial sub-classes. The act of consuming a message should be a separate responsibility than the act of listening for a message (SRP). Inheritance is such a strong statement (this IS-A that) that it should only be used in building type hierarchies and not for overriding use-specific behaviors and notifications. Chances are, if a class needs to be inherited to be used, it most likely is not designed as well as it could be in today's modern programming languages. So lets look at the other tools available to us for getting notified instead. Here's a few other choices to consider. Have the listener expose a MessageReceived event. Have the listener accept a new IMessageHandler interface instance. Have the listener accept an Action<Message> delegate. Really, all of these are different forms of delegation. Now, .NET events are a bit heavier than the other types of delegates in terms of run-time execution, but they are a great way to allow others using your class to subscribe to your events: 1: // using event - ommiting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private bool _isHalted = false; 6: private Thread _messageThread; 7:  8: // assign the subscriber and start the messaging loop 9: public MessageListener(ISubscriber subscriber) 10: { 11: _subscriber = subscriber; 12: _messageThread = new Thread(MessageLoop); 13: _messageThread.Start(); 14: } 15:  16: // user will override this to process their messages 17: public event Action<Message> MessageReceived; 18:  19: // handle the looping in the thread 20: private void MessageLoop() 21: { 22: while(!_isHalted) 23: { 24: // as long as processing, wait 1 second for message 25: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 26: if(msg != null && MessageReceived != null) 27: { 28: MessageReceived(msg); 29: } 30: } 31: } 32: } Note, now we can seal the class to avoid changes and the user just needs to provide a message handling method: 1: theListener.MessageReceived += CustomReceiveMethod; However, personally I don't think events hold up as well in this case because events are largely optional. To me, what is the point of a listener if you create one with no event listeners? So in my mind, use events when handling the notification is optional. So how about the delegation via interface? I personally like this method quite a bit. Basically what it does is similar to inheritance method mentioned first, but better because it makes it easy to split the part of the class that doesn't change (the base listener behavior) from the part that does change (the user-specified action after receiving a message). So assuming we had an interface like: 1: public interface IMessageHandler 2: { 3: void OnMessageReceived(Message receivedMessage); 4: } Our listener would look like this: 1: // using delegation via interface - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private IMessageHandler _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler.OnMessageReceived(msg); 28: } 29: } 30: } 31: } And they would call it by creating a class that implements IMessageHandler and pass that instance into the constructor of the listener. I like that this alleviates the issues of inheritance and essentially forces you to provide a handler (as opposed to events) on construction. Well, this is good, but personally I think we could go one step further. While I like this better than events or inheritance, it still forces you to implement a specific method name. What if that name collides? Furthermore if you have lots of these you end up either with large classes inheriting multiple interfaces to implement one method, or lots of small classes. Also, if you had one class that wanted to manage messages from two different subscribers differently, it wouldn't be able to because the interface can't be overloaded. This brings me to using delegates directly. In general, every time I think about creating an interface for something, and if that interface contains only one method, I start thinking a delegate is a better approach. Now, that said delegates don't accomplish everything an interface can. Obviously having the interface allows you to refer to the classes that implement the interface which can be very handy. In this case, though, really all you want is a method to handle the messages. So let's look at a method delegate: 1: // using delegation via delegate - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler(msg); 28: } 29: } 30: } 31: } Here the MessageListener now takes an Action<Message>.  For those of you unfamiliar with the pre-defined delegate types in .NET, that is a method with the signature: void SomeMethodName(Message). The great thing about delegates is it gives you a lot of power. You could create an anonymous delegate, a lambda, or specify any other method as long as it satisfies the Action<Message> signature. This way, you don't need to define an arbitrary helper class or name the method a specific thing. Incidentally, we could combine both the interface and delegate approach to allow maximum flexibility. Doing this, the user could either pass in a delegate, or specify a delegate interface: 1: // using delegation - give users choice of interface or delegate 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // passes the interface method as a delegate using method group 19: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 20: : this(subscriber, handler.OnMessageReceived) 21: { 22: } 23:  24: // handle the looping in the thread 25: private void MessageLoop() 26: { 27: while(!_isHalted) 28: { 29: // as long as processing, wait 1 second for message 30: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 31: if(msg != null) 32: { 33: _handler(msg); 34: } 35: } 36: } 37: } } This is the method I tend to prefer because it allows the user of the class to choose which method works best for them. You may be curious about the actual performance of these different methods. 1: Enter iterations: 2: 1000000 3:  4: Inheritance took 4 ms. 5: Events took 7 ms. 6: Interface delegation took 4 ms. 7: Lambda delegate took 5 ms. Before you get too caught up in the numbers, however, keep in mind that this is performance over over 1,000,000 iterations. Since they are all < 10 ms which boils down to fractions of a micro-second per iteration so really any of them are a fine choice performance wise. As such, I think the choice of what to do really boils down to what you're trying to do. Here's my guidelines: Inheritance should be used only when defining a collection of related types with implementation specific behaviors, it should not be used as a hook for users to add their own functionality. Events should be used when subscription is optional or multi-cast is desired. Interface delegation should be used when you wish to refer to implementing classes by the interface type or if the type requires several methods to be implemented. Delegate method delegation should be used when you only need to provide one method and do not need to refer to implementers by the interface name.

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• Java stored procedures in Oracle, a good idea?

  - by Scott A

  I'm considering using a Java stored procedure as a very small shim to allow UDP communication from a PL/SQL package. Oracle does not provide a UTL_UDP to match its UTL_TCP. There is a 3rd party XUTL_UDP that uses Java, but it's closed source (meaning I can't see how it's implemented, not that I don't want to use closed source). An important distinction between PL/SQL and Java stored procedures with regards to networking: PL/SQL sockets are closed when dbms_session.reset_package is called, but Java sockets are not. So if you want to keep a socket open to avoid the tear-down/reconnect costs, you can't do it in sessions that are using reset_package (like mod_plsql or mod_owa HTTP requests). I haven't used Java stored procedures in a production capacity in Oracle before. This is a very large, heavily-used database, and this particular shim would be heavily used as well (it serves as a UDP bridge between a PL/SQL RFC 5424 syslog client and the local rsyslog daemon). Am I opening myself up for woe and horror, or are Java stored procedures stable and robust enough for usage in 10g? I'm wondering about issues with the embedded JVM, the jit, garbage collection, or other things that might impact a heavily used database.

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• Controlling what data populates STAR

  - by user10747017

  Beginning with the Primavera Reporting Database 2.2\P6 Analytics 1.2 release, the first release that supported the P6 Extended Schema, a new ability was added to filter which projects could be included during an ETL run. In previous releases, all projects were included in an ETL run. Additionally, all projects with the option to enable publication are included in the ETL run by default.Because the reporting needs for P6 Extended Schema are different from those of STAR, you can define a filter that will limit the data that is included in the STAR schema. For example, your STAR schema can be filter to only include all projects in a specific Portfolio, or all projects with a project code assignment of 'For Analytics.'  Any criteria that can be defined in a Where clause and added to a view can be used to filter the projects included in the STAR schema. I highly suggest this approach when dealing with large databases. Unnecessary projects could cause the Extract portion of the ETL process to take longer. A table in STAR called etl_projectlist is the key for what projects are targeted during the ETL process. To setup the filter, perform the following steps:1. Connect to your Primavera P6 Project Management Database as Pxrptuser (extended schema owner) and create a new view:create or replace view star_project_viewasselect PROJECTOBJECTID objectidfrom projectportfolio pp, projectprojectportfolio pppwhere pp.objectid = ppp.PROJECTPORTFOLIOOBJECTIDand pp.name = 'STAR Projects'--The main field that MUST be selected in the view is the projectobjectid. Selecting any other field besides the projectobjectid will cause the view to be invalid and will not work. Any Where clause can be used, but projectobjectid is the key.2. In your STAR installation directory go the \res folder and edit the staretl.properties file.  Here you will define the view to be used.  Add the following line or update if exists:star.project.filter.ds1=star_project_view3. When running the  staretl.cmd or staretl.sh process the database link to Pxrtpuser will be accessed and this view will be used to populate the etl_projectlist table  with the appropriate projectobjectids as defined in the view created in step 1 above.

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• Swap drive not operating correctly

  - by Blue Ice

  At first, I started seeing the warning signs. The halting pages. The molasses speed of the windows closing. The pictures not rendering. Then, I took action. Recently I added a swap drive to my computer. For a while, everything was good. Unicorns frolicked among the new bits and bytes resplendent on the shiny metal platter known as my swap drive. Today, I opened Chromium, and got on the 7th tab (start.csail.mit.edu) "He's dead, Jim!". This used to happen before I added my swap drive, but now I thought that it wouldn't happen because I added more memory. I fear for the safety of the unicorns. Please help me make my swap drive work again. As a side note, here is the result of cat /proc/swaps: Filename Type Size Used Priority /dev/sda5 partition 39075836 213896 -1 Result of free: total used free shared buffers cached Mem: 507472 330792 176680 0 6208 71252 -/+ buffers/cache: 253332 254140 Result of df -h: Filesystem Size Used Avail Use% Mounted on /dev/sdb1 147G 8.9G 130G 7% / none 4.0K 0 4.0K 0% /sys/fs/cgroup udev 240M 12K 240M 1% /dev tmpfs 50M 824K 49M 2% /run none 5.0M 0 5.0M 0% /run/lock none 248M 208K 248M 1% /run/shm none 100M 20K 100M 1% /run/user

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• Ubuntu 12.04 VPN default route issue when using the UI

  - by Pieter Pabst

  When setting up a VPN connection using the UI (System settings = Network) the VPN connection is used as the default route after connecting to it. How can I avoid this? That is without assigning manual addresses. I want the connection to use DHCP. It should use the eth* interfaces for my default route, like they are used before making the connection. The VPN route should only be used when connecting to addresses in the ppp0 adapters range. If possible using the UI only, not that I'm not used to editing config files... But the point of using Ubuntu for me was the "it just works" concept (which is true for 99% of the time, keep up the good work). I tried setting the "Method" combobox in the "Configure..." dialogue to "Automatic (VPN) addresses only". That doesn't make a difference. (Another thing I noticed; the UI shows my connection as a "Wireless connection" in the list control on the left. Don't know why... it has the right icon, but that's probably something for the bug tracker)

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• Displaying Exceptions Thrown or Caught in Managed Beans

  - by Frank Nimphius

  Just came a cross a sample written by Steve Muench, which somewhere deep in its implementation details uses the following code to route exceptions to the ADF binding layer to be handled by the ADF model error handler (which can be customized by overriding the DCErrorHandlerImpl class and configuring the custom class in DataBindings.cpx file) To route an exception to the ADFm error handler, Steve used the following code ((DCBindingContainer)BindingContext.getCurrent().getCurrentBindingsEntry()).reportException(ex); The same code however can be used in managed beans as well to enforce consistent error handling in ADF. As an example, lets assume a managed bean method hits an exception. To simulate this, let's use the following code: public void onToolBarButtonAction(ActionEvent actionEvent) {    throw new JboException("Just to tease you !!!!!");        } The exception shows at runtime as displayed in the following image: Assuming a try-catch block is used to intercept the exception caused by a managed bean action, you can route the error message display to the ADF model error handler. Again, let's simulate the code that would need to go into a try-catch block public void onToolBarButtonAction(ActionEvent actionEvent) {    JboException ex = new JboException("Just to tease you !!!!!");  BindingContext bctx = BindingContext.getCurrent();    ((DCBindingContainer)bctx.getCurrentBindingsEntry()).reportException(ex); } The error now displays as shown in the image below As you can see, the error is now handled by the ADFm Error handler, which - as mentioned before - could be a custom error handler. Using the ADF model error handling for displaying exceptions thrown in managed beans require the current ADF Faces page to have an associated PageDef file (which is the case if the page or view contains ADF bound components). Note that to invoke methods exposed on the business service it is recommended to always work through the binding layer (method binding) so that in case of an error the ADF model error handler is automatically used.

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• GPL - what is distribution?

  - by Martin Beckett

  An interesting point came up on another thread about alleged misappropriation of a GPL project. In this case the enterprise software was used by some large companies who essentially took the code, changed the name, removed the GPL notices and used the result. The point was - if the company did this and only used the software internally then there isn't any distribution and that's perfectly legal under GPL. Modifications by their own employees for internal use would also be allowed. So At what point does it become a distribution? Presumably if they brought in outside contractors under 'work for hire' their modifications would also be internal and so not a distribution. If they hired an external software outfit to do modifications and those changes were only used internally by the company - would those changes be distributed? Does the GPL apply to the client or to the external developers? If the company then give the result to another department, another business unit, another company? What if the other company is a wholly owned subsidiary? ps. yes I know the answer is ask a lawyer. But all the discussion I have seen over GPL2/GPL3 distribution has been about webservices - not about internal use.

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• Ubuntu 10.04 LTS Server - fresh install - failed apt-get update

  - by user87227

  Good day and greetings to all, I just did a fresh installation of Ubuntu 10.04 LTS server without any issues. However, the apt-get update or aptitude update is giving the following errors: a. bzip2:(stdin) is not bzip2 file.ign for all lines plus the following errors : etched 3,582B in 0s (74.1kB/s) Reading package lists... W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used.GPG error: //security.ubuntu.com lucid-security Release: The following signatures were invalid: NODATA 1 NODATA 2 W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used.GPG error: //in.archive.ubuntu.com lucid Release: The following signatures were invalid: NODATA 1 NODATA 2 W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used.GPG error: in.archive.ubuntu.com lucid-updates Release: The following signatures were invalid: NODATA 1 NODATA 2 W: Failed to fetch security.ubuntu.com/ubuntu/dists/lucid-security/Release W: Failed to fetch in.archive.ubuntu.com/ubuntu/dists/lucid/Release W: Failed to fetch in.archive.ubuntu.com/ubuntu/dists/lucid-updates/Release W: Some index files failed to download, they have been ignored, or old ones used instead. Please guide in resolving this error. TIA Regards Venu

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• Language Niches and Niche Libraries

  - by Roman A. Taycher

  "Everyone Knows" ... ... that c is widely used for low level programs in large part because operating system/device apis are usually in c. ... that Java is widely used for enterprise applications in large part because of enterprise libraries and ide support. ... that ruby is widely used for webapps thanks in large part because of rails and its library ecosytem But lets go into to details what are the specific niches and subniches. Especially with respect to libraries. Where might you embed lua for application scripting versus python. Where would you use Java vs C#. Which languages do different scientists use? Also which languages have libraries for these subniches? Things like bioperl/scipy/Incanter. Please no flamewars about how nice each language or environment is. This is where they used. Also no complaints about marketing/PHBs. (Manually migrated) I asked this question again after it was closed on stackoverflow.com

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• DualLayout OpenSourceFood demo site installation instructions

  - by svdoever

  We released DualLayout which enables advanced web design with the power of SharePoint. DualLayout and a demo site can be downloaded from the DualLayout product page. This blogpost contains detailed instructions on installing the demo site. The demo site is based on the site http://opensourcefood.com. The demo site requires internet access because it still links to pages and resources of the real site. Execute the following steps to install the demo site: Copy the OpenSourceFoodDemo.zip file to your SharePoint Server 2010 Make sure that the zip file in “unblocked”, otherwise files are assumed from other computer (right-click on zip file, press “Unblock” button if available) Unzip the OpenSourceFoodDemo.zip to a folder of your choice (c:\OpenSourceFoodDemo) Open the SharePoint  Start->Microsoft SharePoint 2010 Products->SharePoint 2010 Management Shell Change directory to the unzip folder (cd c:\OpenSourceFoodDemo) Start install script: .\InstallDemoSite.ps1 Answer the questions, default values in most cases ok. A little guidance: Question: Give credentials for the account that will be used for the application pool Answer: use for example same account as used for the application pool of your SharePoint site (lookup in IIS Manager) Question: Give credentials for the account that will be used for the application pool Answer: Use same account you are currently logged in with The demo site is made available through a backup and restore. The SharePoint Server 2010 installation must be patched to a level equal or higher to the update level on the SharePoint Server used to create the backup. If you get errors with respect to restore check http://technet.microsoft.com/en-us/sharepoint/ff800847.aspx for downloading the latest cumulative update.

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• Code base migration - old versioning system to modern

  - by JohnP

  Our current code base is contained in a versioning system that is old and outdated (Visual Sourcesafe 5.0, mid 1990's), and contains a mix of packages that are no longer used, ones that are being used but no longer updated, and newer code. It is also a mix of 4 languages, and includes libraries for some of our systems (Such as Dialogic, Sun Tzu {clipper}) implementations. This breaks down into the following categories: Legacy code - No longer used (Systems that have been retired or replaced, etc) Legacy code - In current use (No intentions for upgrades or minor bug fixes, only major fixes if needed) Current code - In current use, and will be used for future versions/development Support libraries - For both legacy and current code (Some of the legacy libraries are no longer available as well) We would like to migrate this to a newer versioning system as we will be adding more developers, and expanding the reach to include remote programmers. When migrating, how do you structure it? Do you just perform a dump of all the data and then import it into the new system, or do you segregate according to type before you bring it into the new system? Do you set up a separate area for libraries, or keep them with the relevant packages? Do you separate by language, system, both? A general outline and methodology is fine, it doesn't need to be broken down to individual program level.

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• How to adjust the appearance of the Unity in 12.10?

  - by piedro

  Now I updated to 12.10 and would like to adjust the desktop, well unity, appearance. I know there is the theme setting, but I cannot adjust the symbol theme or windows decoration with the systemsettings. I used to use the tool "unsettings" but it doesn't work with 12.10 anymore. Ubuntu Tweak used to be an option but at this point many features are broken and a lot of settings seem to mess up my system or they don't change anything at all (I understand that there has been a design settings change - gsettings, dconf, something ...) myunity has some options to change stuff but I couldn't find it for 12.10 ... not to forget "gnome-tweak-tool" which seems to work for most settings but not for all, e.g. it doesn't change the mouse cursor and the windows decorations do not show some decorations I'd like to use and I am also afraid of messing things up because it is supposed to be used in gnomeshell ... actually as I found out right now it really messes things up: fonts get inverted, suddenly high contrast accessibility setings are used in some windows, nautilus has white fonts on white background and even the login manager is a mess now ... So: How can I adjust the theme, symbol, decorations, fonts for the normal user and for the desktop and for the applications including the applications started as sudo user? I should mention that I upgraded from 12.04 and that some applications like synaptic completely ignore any settings ... sadly it is a mess, there was a time when gnome theming was really well done and very adjustable, I wonder what happened ... Just now I read that further development of Ubuntu Tweak has been stopped. The developer announced that he won't go any further with the software and the online services ... That is sad and destroys my hope for easy appearance editing just by waiting ... has been such a nice tool for 12.04 ... r.i.p.

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• Multitouch screen not detected on Asus Taichi 21DH71

  - by geekfreak

  I just bought this Ultrabook "Asus Taichi 21 DH71". This has Intel 3rd generation i7 processor and 4gb ram with 256 gb SSD. The main feature is that it is a hybrid machine. Naming it has dual screens. When the lid is closed it can be used as a tablet and when lid open it can be used as a notebook. This machine can also be used with the two screens on at the same time. I used ubuntu many years ago and loved it. But I never tried any linux later. My questions are Does the new version of Ubuntu support the Multitouch interface? Will it work specifically on this machine? Will Ubuntu support gestures on multi touchpad? Update 2/22/2013 I did try the latest 64bit Ubuntu(12.10) from live usb and noticed that it couldn't detect the tablet screen. Everything else worked seamlessly. Do you guys think the tablet screen would be detected if I make a complete installation on to the notebook? Please help guys..

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