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  • Oracle 5th Annual Maintenance Summit - Orlando March 22-23, 2011

    - by stephen.slade(at)oracle.com
    It's not too late to register today or tomorrow for this exclusive 'Maintenance Professionals Only" event.  In 4 tracks, 27 customer and partner speakers will present case studies and success stories in these 'no-sell zone' sessions. The take-aways will be worth attending!This "2 in 1" event combines a Customer Showcase featuring Orlando Utilities Commission (OUC) and Maintenance Summit.  OUC - the local municipal utility providing residential, commercial, and industrial customers with clean, reliable, and affordable electric and water services - will open the event with their CIO as keynote speaker, and host tours of their fleet, facility, and power generation operations. Recognized as a green leader, OUC has been the most reliable power provider in Florida the past 9 years due, in large part, to the operational efficiencies of its plant and asset maintenance systems. This Summit will feature breakout session tracks for EBS, JD Edwards, PeopleSoft and Sustainability. Highlights include over 12 Oracle solution demo stations, over 25 interactive breakout sessions, pool-side networking reception with live band, partner exhibit pavilion and special appearance by Sean D. Tucker, Team Oracle Stunt-Pilot!  Dates:                   March 22-23, 2011 Location:             Orlando World Center Marriott, Orlando, Florida Evite:                     http://www.oracle.com/us/dm/h2fy11/65971-nafm10019768mpp191c003-oem-304204.html Highlights:          Keynotes, Oracle Expert Demo Stations, Interactive Breakout Sessions, Networking Reception, Partner Pavilion, Speakers Tracks:                 EBS, JDE, PSFT, Sustainability Tours:                  Orlando Utility Operations, Fleet and Facility Oracle Demo Stations:  Agile, AutoVue, Primavera, MOC/SSDM, Utilities, PIM, PDQ, UCM, On Demand, Business Accelerators, Facilities Work Management, EBS Enterprise Asset Management, PeopleSoft Maintenance Management, Technology, Hardware/Sun. Partner-Sponsors:   Viziya, Global PTM, MiPro, Asset Management Solutions, Venutureforth, Impac Services, EAM Master, LLC, Meridium

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  • Tests unitaires d'un DomainService WCF RIA : DomainServiceTestHost, un tutoriel de Kyle McClellan, traduit par Deepin Prayag

    Citation: Étant donné que WCF RIA Services emploie un « pipeline pattern » pour invoquer vos opérations DomainService, il n'est pas toujours évident de savoir comment les tester. Dans cette série d'articles nous allons voir un petit DomainService et comment le tester. Entre autres nous allons voir comment implémenter une IDomainServiceFactory personnalisée, comment implémenter le pattern Repository, et comment utiliser la DomainServiceTestHos...

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  • MySQL for Excel 1.1.3 has been released

    - by Javier Treviño
    The MySQL Windows Experience Team is proud to announce the release of MySQL for Excel version 1.1.3, the  latest addition to the MySQL Installer for Windows. MySQL for Excel is an application plug-in enabling data analysts to very easily access and manipulate MySQL data within Microsoft Excel. It enables you to directly work with a MySQL database from within Microsoft Excel so you can easily do tasks such as: Importing MySQL Data into Excel Exporting Excel data directly into MySQL to a new or existing table Editing MySQL data directly within Excel MySQL for Excel is installed using the MySQL Installer for Windows. The MySQL installer comes in 2 versions   Full (150 MB) which includes a complete set of MySQL products with their binaries included in the download Web (1.5 MB - a network install) which will just pull MySQL for Excel over the web and install it when run.   You can download MySQL Installer from our official Downloads page at http://dev.mysql.com/downloads/installer/. MySQL for Excel 1.1.3 introduces the following features:   Upon saving a Workbook containing Worksheets in Edit Mode, the user is asked if he wants to exit the Edit Mode on all Worksheets before their parent Workbook is saved so the Worksheets are saved unprotected, otherwise the Worksheets will remain protected and the users will be able to unprotect them later retrieving the passkeys from the application log after closing MySQL for Excel. Added background coloring to the column names header row of an Import Data operation to have the same look as the one in an Edit Data operation (i.e. gray-ish background). Connection passwords can be stored securely just like MySQL Workbench does and these secured passwords are shared with Workbench in the same way connections are. Changed the way the MySQL for Excel ribbon toggle button works, instead of just showing or hiding the add-in it actually opens and closes it. Added a connection test before any operation against the database (schema creation, data import, append, export or edition) so the operation dialog is not shown and a friendlier error message is shown.   Also this release contains the following bug fixes:   Added a check on every connection test for an expired password, if the password has been expired a dialog is now shown to the user to reset the password. Bug #17354118 - DON'T HANDLE EXPIRED PASSWORDS Added code to escape text values to be imported to an Excel worksheet that start with an equals sign so Excel does not treat those values as formulas that will fail evaluation. This is an option turned on by default that can be turned off by users if they wish to import values to be treated as Excel formulas. Bug #17354102 - ERROR IMPORTING TEXT VALUES TO EXCEL STARTING WITH AN EQUALS SIGN Added code to properly check the reason for a failing connection, if it's a failing password the user gets a dialog to retry the connection with a different password until the connection succeeds, a connection error not related to the password is thrown or the user cancels. If the failing connection is not related to a bad password an error message is shown to the users indicating the reason of the failure. Bug #16239007 - CONNECTIONS TO MYSQL SERVICES NOT RUNNING DISPLAY A WRONG PASSWORD ERROR MESSAGE Added global options dialog that can be accessed from the Schema Selection and DB Object Selection panels where the timeouts for the connection to the DB Server and for the query commands can be changed from their default values (15 seconds for the connection timeout and 30 seconds for the query timeout). MySQL Bug #68732, Bug #17191646 - QUERY TIMEOUT CANNOT BE ADJUSTED IN MYSQL FOR EXCEL Changed the Varchar(65,535) data type shown in the Export Data data type combo box to Text since the maximum row size is 65,535 bytes and any autodetected column data type with a length greater than 4,000 should be set to Text actually for the table to be created successfully. MySQL Bug #69779, Bug #17191633 - EXPORT FAILS FOR EXCEL FILES CONTAINING > 4000 CHARACTERS OF TEXT PER CELL Removed code that was replacing all spaces typed by the user in an overriden data type for a new column in an Export Data operation, also improved the data type detection code to flag as invalid data types with parenthesis but without any text inside or where the contents inside the parenthesis are not valid for the specific data type. Bug #17260260 - EXPORT DATA SET TYPE NOT WORKING WITH MEMBER VALUES CONTAINING SPACES Added support for the year data type with a length of 2 or 4 and a validation that valid values are integers between 1901-2155 (for 4-digit years) or between 0-99 (for 2-digit years). Bug #17259915 - EXPORT DATA YEAR DATA TYPE NOT RECOGNIZED IF DECLARED WITH A DISPLAY WIDTH) Fixed code for Export Data operations where users overrode the data type for columns typing Text in the data type combobox, which is a valid data type but was not recognized as such. Bug #17259490 - EXPORT DATA TEXT DATA TYPE NOT RECOGNIZED AS A VALID DATA TYPE Changed the location of the registry where the MySQL for Excel add-in is installed to HKEY_LOCAL_MACHINE instead of HKEY_CURRENT_USER so the add-in is accessible by all users and not only to the user that installed it. For this to work with Excel 2007 a hotfix may be required (see http://support.microsoft.com/kb/976477). MySQL Bug #68746, Bug #16675992 - EXCEL-ADD-IN IS ONLY INSTALLED FOR USER ACCOUNT THAT THE INSTALLATION RUNS UNDER Added support for Excel 2013 Single Document Interface, now that Excel 2013 creates 1 window per workbook also the Excel Add-In maintains an independent custom task pane in each window. MySQL Bug #68792, Bug #17272087 - MYSQL FOR EXCEL SIDEBAR DOES NOT APPEAR IN EXCEL 2013 (WITH WORKAROUND) Included the latest MySQL Utility with a code fix for the COM exception thrown when attempting to open Workbench in the Manage Connections window. Bug #17258966 - MYSQL WORKBENCH NOT OPENED BY CLICKING MANAGE CONNECTIONS HOTLABEL Fixed code for Append Data operations that was not applying a calculated automatic mapping correctly when the source and target tables had different number of columns, some columns with the same name but some of those lying on column indexes beyond the limit of the other source/target table. MySQL Bug #69220, Bug #17278349 - APPEND DOESN'T AUTOMATICALLY DETECT EXCEL COL HEADER WITH SAME NAME AS SQL FIELD Fixed some code for Edit Data operations that was escaping special characters twice (during edition in Excel and then upon sending the query to the MySQL server). MySQL Bug #68669, Bug #17271693 - A BACKSLASH IS INSERTED BEFORE AN APOSTROPHE EDITING TABLE WITH MYSQL FOR EXCEL Upgraded MySQL Utility with latest version that encapsulates dialog base classes and introduces more classes to handle Workbench connections, and removed these from the Excel project. Bug #16500331 - CAN'T DELETE CONNECTIONS CREATED WITHIN ADDIN You can access the MySQL for Excel documentation at http://dev.mysql.com/doc/refman/5.6/en/mysql-for-excel.html You can find our team’s blog at http://blogs.oracle.com/MySQLOnWindows. You can also post questions on our MySQL for Excel forum found at http://forums.mysql.com/. Enjoy and thanks for the support!

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  • Tomboy error while tring to sync with Ubuntu one; Can anyone help?

    - by Michael Chapman
    So I'm sure you've heard the song before, but after trying to sync my notes with Ubuntu One(on 10.10 AMD64) I get "Could not synchronize notes. Check the details below and try again." Of course the problem is that there are no details and trying again doesn't help. So I ran tomboy -debug and compared my error to any thing I could find about similar problems (such as the post here) but found nothing useful. Any way here's my first error, I got this using preferencessynchronizationUbuntu_one [ERROR 21:08:42.271] Synchronization failed with the following exception: String was not recognized as a valid DateTime. at System.DateTime.Parse (System.String s, IFormatProvider provider, DateTimeStyles styles) [0x00000] in <filename unknown>:0 at System.DateTime.Parse (System.String s, IFormatProvider provider) [0x00000] in <filename unknown>:0 at System.DateTime.Parse (System.String s) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.Api.NoteInfo.ParseJson (Hyena.Json.JsonObject jsonObj) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.Api.UserInfo.ParseJsonNoteArray (Hyena.Json.JsonArray jsonArray) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.Api.UserInfo.ParseJsonNotes (System.String jsonString, System.Nullable`1& latestSyncRevision) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.Api.UserInfo.GetNotes (Boolean includeContent, Int32 sinceRevision, System.Nullable`1& latestSyncRevision) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.WebSyncServer.GetNoteUpdatesSince (Int32 revision) [0x00000] in <filename unknown>:0 at Tomboy.Sync.SyncManager.SynchronizationThread () [0x00000] in <filename unknown>:0 The next thing I tried was using preferencessynchronizationtomboy_web with the default 'http://one.ubuntu.com/notes/' and got the same error plus one more. [ERROR 21:12:31.949] System.ObjectDisposedException: The object was used after being disposed. at System.Net.HttpListener.CheckDisposed () [0x00000] in <filename unknown>:0 at System.Net.HttpListener.EndGetContext (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.WebSyncPreferencesWidget.<OnAuthButtonClicked>m__1 (IAsyncResult localResult) [0x00000] in <filename unknown>:0 [ERROR 21:13:19.245] Synchronization failed with the following exception: String was not recognized as a valid DateTime. at System.DateTime.Parse (System.String s, IFormatProvider provider, DateTimeStyles styles) [0x00000] in <filename unknown>:0 at System.DateTime.Parse (System.String s, IFormatProvider provider) [0x00000] in <filename unknown>:0 at System.DateTime.Parse (System.String s) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.Api.NoteInfo.ParseJson (Hyena.Json.JsonObject jsonObj) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.Api.UserInfo.ParseJsonNoteArray (Hyena.Json.JsonArray jsonArray) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.Api.UserInfo.ParseJsonNotes (System.String jsonString, System.Nullable`1& latestSyncRevision) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.Api.UserInfo.GetNotes (Boolean includeContent, Int32 sinceRevision, System.Nullable`1& latestSyncRevision) [0x00000] in <filename unknown>:0 at Tomboy.WebSync.WebSyncServer.GetNoteUpdatesSince (Int32 revision) [0x00000] in <filename unknown>:0 at Tomboy.Sync.SyncManager.SynchronizationThread () [0x00000] in <filename unknown>:0 I Have also tried removing then re-adding My computer from my Ubuntu One account, but that did not help either. The only other Thing I have noticed is that under systempreferencesubuntu one services, "Notes" is not listed as a service. I don't know if this is normal or not. Thanks for any help and please let me know if anything is confusing.

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  • Timestep schemes for physics simulations

    - by ktodisco
    The operations used for stepping a physics simulation are most commonly: Integrate velocity and position Collision detection and resolution Contact resolution (in advanced cases) A while ago I came across this paper from Stanford that proposed an alternative scheme, which is as follows: Collision detection and resolution Integrate velocity Contact resolution Integrate position It's intriguing because it allows for robust solutions to the stacking problem. So it got me wondering... What, if any, alternative schemes are available, either simple or complex? What are their benefits, drawbacks, and performance considerations?

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  • Transforming Government with ERP Solutions

    Liz La Rosa and Jerry Linden from Oracle's Public Sector Industry Strategy and Marketing team talk with Fred about the issues public sector managers face today and how governments can meet these challenges by using ERP systems to transform government operations.

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  • New Whitepaper: Oracle WebLogic Clustering

    - by ACShorten
    A new whitepaper is available that outlines the concepts and steps on implementing web application server clustering using the Oracle Utilities Application Framework and Oracle WebLogic Server. The whitepaper include the following: A short discussion on the concepts of clustering How to setup a cluster using Oracle WebLogic's utilities How to configure the Oracle Utilities Application Framework to take advantage of clustering How to deploy the Oracle Utilities Application based products in a clustered environment Common cluster operations The whitepaper is available from My Oracle Support at Doc Id: 1334558.1.

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  • Array Multiplication and Division

    - by Narfanator
    I came across a question that (eventually) landed me wondering about array arithmetic. I'm thinking specifically in Ruby, but I think the concepts are language independent. So, addition and subtraction are defined, in Ruby, as such: [1,6,8,3,6] + [5,6,7] == [1,6,8,3,6,5,6,7] # All the elements of the first, then all the elements of the second [1,6,8,3,6] - [5,6,7] == [1,8,3] # From the first, remove anything found in the second and array * scalar is defined: [1,2,3] * 2 == [1,2,3,1,2,3] But What, conceptually, should the following be? None of these are (as far as I can find) defined: Array x Array: [1,2,3] * [1,2,3] #=> ? Array / Scalar: [1,2,3,4,5] / 2 #=> ? Array / Scalar: [1,2,3,4,5] % 2 #=> ? Array / Array: [1,2,3,4,5] / [1,2] #=> ? Array / Array: [1,2,3,4,5] % [1,2] #=> ? I've found some mathematical descriptions of these operations for set theory, but I couldn't really follow them, and sets don't have duplicates (arrays do). Edit: Note, I do not mean vector (matrix) arithmetic, which is completely defined. Edit2: If this is the wrong stack exchange, tell me which is the right one and I'll move it. Edit 3: Add mod operators to the list. Edit 4: I figure array / scalar is derivable from array * scalar: a * b = c => a = b / c [1,2,3] * 3 = [1,2,3]+[1,2,3]+[1,2,3] = [1,2,3,1,2,3,1,2,3] => [1,2,3] = [1,2,3,1,2,3,1,2,3] / 3 Which, given that programmer's division ignore the remained and has modulus: [1,2,3,4,5] / 2 = [[1,2], [3,4]] [1,2,3,4,5] % 2 = [5] Except that these are pretty clearly non-reversible operations (not that modulus ever is), which is non-ideal. Edit: I asked a question over on Math that led me to Multisets. I think maybe extensible arrays are "multisets", but I'm not sure yet.

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  • Survey: Do you write custom SQL CLR procedures/functions/etc

    - by James Luetkehoelter
    I'm quite curious because despite the great capabilities of writing CLR-based stored procedures to off-load those nasty operations TSQL isn't that great at (like iteration, or complex math), I'm continuing to see a wealth of SQL 2008 databases with complex stored procedures and functions which would make great candidates. The in-house skill to create the CLR code exists as well, but there is flat out resistance to use it. In one scenario I was told "Oh, iteration isn't a problem because we've trained...(read more)

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  • Java collision detection and player movement: tips

    - by Loris
    I have read a short guide for game develompent (java, without external libraries). I'm facing with collision detection and player (and bullets) movements. Now i put the code. Most of it is taken from the guide (should i link this guide?). I'm just trying to expand and complete it. This is the class that take care of updates movements and firing mechanism (and collision detection): public class ArenaController { private Arena arena; /** selected cell for movement */ private float targetX, targetY; /** true if droid is moving */ private boolean moving = false; /** true if droid is shooting to enemy */ private boolean shooting = false; private DroidController droidController; public ArenaController(Arena arena) { this.arena = arena; this.droidController = new DroidController(arena); } public void update(float delta) { Droid droid = arena.getDroid(); //droid movements if (moving) { droidController.moveDroid(delta, targetX, targetY); //check if arrived if (droid.getX() == targetX && droid.getY() == targetY) moving = false; } //firing mechanism if(shooting) { //stop shot if there aren't bullets if(arena.getBullets().isEmpty()) { shooting = false; } for(int i = 0; i < arena.getBullets().size(); i++) { //current bullet Bullet bullet = arena.getBullets().get(i); System.out.println(bullet.getBounds()); //angle calculation double angle = Math.atan2(bullet.getEnemyY() - bullet.getY(), bullet.getEnemyX() - bullet.getX()); //increments x and y bullet.setX((float) (bullet.getX() + (Math.cos(angle) * bullet.getSpeed() * delta))); bullet.setY((float) (bullet.getY() + (Math.sin(angle) * bullet.getSpeed() * delta))); //collision with obstacles for(int j = 0; j < arena.getObstacles().size(); j++) { Obstacle obs = arena.getObstacles().get(j); if(bullet.getBounds().intersects(obs.getBounds())) { System.out.println("Collision detect!"); arena.removeBullet(bullet); } } //collisions with enemies for(int j = 0; j < arena.getEnemies().size(); j++) { Enemy ene = arena.getEnemies().get(j); if(bullet.getBounds().intersects(ene.getBounds())) { System.out.println("Collision detect!"); arena.removeBullet(bullet); } } } } } public boolean onClick(int x, int y) { //click on empty cell if(arena.getGrid()[(int)(y / Arena.TILE)][(int)(x / Arena.TILE)] == null) { //coordinates targetX = x / Arena.TILE; targetY = y / Arena.TILE; //enables movement moving = true; return true; } //click on enemy: fire if(arena.getGrid()[(int)(y / Arena.TILE)][(int)(x / Arena.TILE)] instanceof Enemy) { //coordinates float enemyX = x / Arena.TILE; float enemyY = y / Arena.TILE; //new bullet Bullet bullet = new Bullet(); //start coordinates bullet.setX(arena.getDroid().getX()); bullet.setY(arena.getDroid().getY()); //end coordinates (enemie) bullet.setEnemyX(enemyX); bullet.setEnemyY(enemyY); //adds bullet to arena arena.addBullet(bullet); //enables shooting shooting = true; return true; } return false; } As you can see for collision detection i'm trying to use Rectangle object. Droid example: import java.awt.geom.Rectangle2D; public class Droid { private float x; private float y; private float speed = 20f; private float rotation = 0f; private float damage = 2f; public static final int DIAMETER = 32; private Rectangle2D rectangle; public Droid() { rectangle = new Rectangle2D.Float(x, y, DIAMETER, DIAMETER); } public float getX() { return x; } public void setX(float x) { this.x = x; //rectangle update rectangle.setRect(x, y, DIAMETER, DIAMETER); } public float getY() { return y; } public void setY(float y) { this.y = y; //rectangle update rectangle.setRect(x, y, DIAMETER, DIAMETER); } public float getSpeed() { return speed; } public void setSpeed(float speed) { this.speed = speed; } public float getRotation() { return rotation; } public void setRotation(float rotation) { this.rotation = rotation; } public float getDamage() { return damage; } public void setDamage(float damage) { this.damage = damage; } public Rectangle2D getRectangle() { return rectangle; } } For now, if i start the application and i try to shot to an enemy, is immediately detected a collision and the bullet is removed! Can you help me with this? If the bullet hit an enemy or an obstacle in his way, it must disappear. Ps: i know that the movements of the bullets should be managed in another class. This code is temporary. update I realized what happens, but not why. With those for loops (which checks collisions) the movements of the bullets are instantaneous instead of gradual. In addition to this, if i add the collision detection to the Droid, the method intersects returns true ALWAYS while the droid is moving! public void moveDroid(float delta, float x, float y) { Droid droid = arena.getDroid(); int bearing = 1; if (droid.getX() > x) { bearing = -1; } if (droid.getX() != x) { droid.setX(droid.getX() + bearing * droid.getSpeed() * delta); //obstacles collision detection for(Obstacle obs : arena.getObstacles()) { if(obs.getRectangle().intersects(droid.getRectangle())) { System.out.println("Collision detected"); //ALWAYS HERE } } //controlla se è arrivato if ((droid.getX() < x && bearing == -1) || (droid.getX() > x && bearing == 1)) droid.setX(x); } bearing = 1; if (droid.getY() > y) { bearing = -1; } if (droid.getY() != y) { droid.setY(droid.getY() + bearing * droid.getSpeed() * delta); if ((droid.getY() < y && bearing == -1) || (droid.getY() > y && bearing == 1)) droid.setY(y); } }

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  • Oracle Database 12 c New Partition Maintenance Features by Gwen Lazenby

    - by hamsun
    One of my favourite new features in Oracle Database 12c is the ability to perform partition maintenance operations on multiple partitions. This means we can now add, drop, truncate and merge multiple partitions in one operation, and can split a single partition into more than two partitions also in just one command. This would certainly have made my life slightly easier had it been available when I administered a data warehouse at Oracle 9i. To demonstrate this new functionality and syntax, I am going to create two tables, ORDERS and ORDERS_ITEMS which have a parent-child relationship. ORDERS is to be partitioned using range partitioning on the ORDER_DATE column, and ORDER_ITEMS is going to partitioned using reference partitioning and its foreign key relationship with the ORDERS table. This form of partitioning was a new feature in 11g and means that any partition maintenance operations performed on the ORDERS table will also take place on the ORDER_ITEMS table as well. First create the ORDERS table - SQL CREATE TABLE orders ( order_id NUMBER(12), order_date TIMESTAMP, order_mode VARCHAR2(8), customer_id NUMBER(6), order_status NUMBER(2), order_total NUMBER(8,2), sales_rep_id NUMBER(6), promotion_id NUMBER(6), CONSTRAINT orders_pk PRIMARY KEY(order_id) ) PARTITION BY RANGE(order_date) (PARTITION Q1_2007 VALUES LESS THAN (TO_DATE('01-APR-2007','DD-MON-YYYY')), PARTITION Q2_2007 VALUES LESS THAN (TO_DATE('01-JUL-2007','DD-MON-YYYY')), PARTITION Q3_2007 VALUES LESS THAN (TO_DATE('01-OCT-2007','DD-MON-YYYY')), PARTITION Q4_2007 VALUES LESS THAN (TO_DATE('01-JAN-2008','DD-MON-YYYY')) ); Table created. Now the ORDER_ITEMS table SQL CREATE TABLE order_items ( order_id NUMBER(12) NOT NULL, line_item_id NUMBER(3) NOT NULL, product_id NUMBER(6) NOT NULL, unit_price NUMBER(8,2), quantity NUMBER(8), CONSTRAINT order_items_fk FOREIGN KEY(order_id) REFERENCES orders(order_id) on delete cascade) PARTITION BY REFERENCE(order_items_fk) tablespace example; Table created. Now look at DBA_TAB_PARTITIONS to get details of what partitions we have in the two tables – SQL select table_name,partition_name, partition_position position, high_value from dba_tab_partitions where table_owner='SH' and table_name like 'ORDER_%' order by partition_position, table_name; TABLE_NAME PARTITION_NAME POSITION HIGH_VALUE -------------- --------------- -------- ------------------------- ORDERS Q1_2007 1 TIMESTAMP' 2007-04-01 00:00:00' ORDER_ITEMS Q1_2007 1 ORDERS Q2_2007 2 TIMESTAMP' 2007-07-01 00:00:00' ORDER_ITEMS Q2_2007 2 ORDERS Q3_2007 3 TIMESTAMP' 2007-10-01 00:00:00' ORDER_ITEMS Q3_2007 3 ORDERS Q4_2007 4 TIMESTAMP' 2008-01-01 00:00:00' ORDER_ITEMS Q4_2007 4 Just as an aside it is also now possible in 12c to use interval partitioning on reference partitioned tables. In 11g it was not possible to combine these two new partitioning features. For our first example of the new 12cfunctionality, let us add all the partitions necessary for 2008 to the tables using one command. Notice that the partition specification part of the add command is identical in format to the partition specification part of the create command as shown above - SQL alter table orders add PARTITION Q1_2008 VALUES LESS THAN (TO_DATE('01-APR-2008','DD-MON-YYYY')), PARTITION Q2_2008 VALUES LESS THAN (TO_DATE('01-JUL-2008','DD-MON-YYYY')), PARTITION Q3_2008 VALUES LESS THAN (TO_DATE('01-OCT-2008','DD-MON-YYYY')), PARTITION Q4_2008 VALUES LESS THAN (TO_DATE('01-JAN-2009','DD-MON-YYYY')); Table altered. Now look at DBA_TAB_PARTITIONS and we can see that the 4 new partitions have been added to both tables – SQL select table_name,partition_name, partition_position position, high_value from dba_tab_partitions where table_owner='SH' and table_name like 'ORDER_%' order by partition_position, table_name; TABLE_NAME PARTITION_NAME POSITION HIGH_VALUE -------------- --------------- -------- ------------------------- ORDERS Q1_2007 1 TIMESTAMP' 2007-04-01 00:00:00' ORDER_ITEMS Q1_2007 1 ORDERS Q2_2007 2 TIMESTAMP' 2007-07-01 00:00:00' ORDER_ITEMS Q2_2007 2 ORDERS Q3_2007 3 TIMESTAMP' 2007-10-01 00:00:00' ORDER_ITEMS Q3_2007 3 ORDERS Q4_2007 4 TIMESTAMP' 2008-01-01 00:00:00' ORDER_ITEMS Q4_2007 4 ORDERS Q1_2008 5 TIMESTAMP' 2008-04-01 00:00:00' ORDER_ITEMS Q1_2008 5 ORDERS Q2_2008 6 TIMESTAMP' 2008-07-01 00:00:00' ORDER_ITEM Q2_2008 6 ORDERS Q3_2008 7 TIMESTAMP' 2008-10-01 00:00:00' ORDER_ITEMS Q3_2008 7 ORDERS Q4_2008 8 TIMESTAMP' 2009-01-01 00:00:00' ORDER_ITEMS Q4_2008 8 Next, we can drop or truncate multiple partitions by giving a comma separated list in the alter table command. Note the use of the plural ‘partitions’ in the command as opposed to the singular ‘partition’ prior to 12c– SQL alter table orders drop partitions Q3_2008,Q2_2008,Q1_2008; Table altered. Now look at DBA_TAB_PARTITIONS and we can see that the 3 partitions have been dropped in both the two tables – TABLE_NAME PARTITION_NAME POSITION HIGH_VALUE -------------- --------------- -------- ------------------------- ORDERS Q1_2007 1 TIMESTAMP' 2007-04-01 00:00:00' ORDER_ITEMS Q1_2007 1 ORDERS Q2_2007 2 TIMESTAMP' 2007-07-01 00:00:00' ORDER_ITEMS Q2_2007 2 ORDERS Q3_2007 3 TIMESTAMP' 2007-10-01 00:00:00' ORDER_ITEMS Q3_2007 3 ORDERS Q4_2007 4 TIMESTAMP' 2008-01-01 00:00:00' ORDER_ITEMS Q4_2007 4 ORDERS Q4_2008 5 TIMESTAMP' 2009-01-01 00:00:00' ORDER_ITEMS Q4_2008 5 Now let us merge all the 2007 partitions together to form one single partition – SQL alter table orders merge partitions Q1_2005, Q2_2005, Q3_2005, Q4_2005 into partition Y_2007; Table altered. TABLE_NAME PARTITION_NAME POSITION HIGH_VALUE -------------- --------------- -------- ------------------------- ORDERS Y_2007 1 TIMESTAMP' 2008-01-01 00:00:00' ORDER_ITEMS Y_2007 1 ORDERS Q4_2008 2 TIMESTAMP' 2009-01-01 00:00:00' ORDER_ITEMS Q4_2008 2 Splitting partitions is a slightly more involved. In the case of range partitioning one of the new partitions must have no high value defined, and in list partitioning one of the new partitions must have no list of values defined. I call these partitions the ‘everything else’ partitions, and will contain any rows contained in the original partition that are not contained in the any of the other new partitions. For example, let us split the Y_2007 partition back into 4 quarterly partitions – SQL alter table orders split partition Y_2007 into (PARTITION Q1_2007 VALUES LESS THAN (TO_DATE('01-APR-2007','DD-MON-YYYY')), PARTITION Q2_2007 VALUES LESS THAN (TO_DATE('01-JUL-2007','DD-MON-YYYY')), PARTITION Q3_2007 VALUES LESS THAN (TO_DATE('01-OCT-2007','DD-MON-YYYY')), PARTITION Q4_2007); Now look at DBA_TAB_PARTITIONS to get details of the new partitions – TABLE_NAME PARTITION_NAME POSITION HIGH_VALUE -------------- --------------- -------- ------------------------- ORDERS Q1_2007 1 TIMESTAMP' 2007-04-01 00:00:00' ORDER_ITEMS Q1_2007 1 ORDERS Q2_2007 2 TIMESTAMP' 2007-07-01 00:00:00' ORDER_ITEMS Q2_2007 2 ORDERS Q3_2007 3 TIMESTAMP' 2007-10-01 00:00:00' ORDER_ITEMS Q3_2007 3 ORDERS Q4_2007 4 TIMESTAMP' 2008-01-01 00:00:00' ORDER_ITEMS Q4_2007 4 ORDERS Q4_2008 5 TIMESTAMP' 2009-01-01 00:00:00' ORDER_ITEMS Q4_2008 5 Partition Q4_2007 has a high value equal to the high value of the original Y_2007 partition, and so has inherited its upper boundary from the partition that was split. As for a list partitioning example let look at the following another table, SALES_PAR_LIST, which has 2 partitions, Americas and Europe and a partitioning key of country_name. SQL select table_name,partition_name, high_value from dba_tab_partitions where table_owner='SH' and table_name = 'SALES_PAR_LIST'; TABLE_NAME PARTITION_NAME HIGH_VALUE -------------- --------------- ----------------------------- SALES_PAR_LIST AMERICAS 'Argentina', 'Canada', 'Peru', 'USA', 'Honduras', 'Brazil', 'Nicaragua' SALES_PAR_LIST EUROPE 'France', 'Spain', 'Ireland', 'Germany', 'Belgium', 'Portugal', 'Denmark' Now split the Americas partition into 3 partitions – SQL alter table sales_par_list split partition americas into (partition south_america values ('Argentina','Peru','Brazil'), partition north_america values('Canada','USA'), partition central_america); Table altered. Note that no list of values was given for the ‘Central America’ partition. However it should have inherited any values in the original ‘Americas’ partition that were not assigned to either the ‘North America’ or ‘South America’ partitions. We can confirm this by looking at the DBA_TAB_PARTITIONS view. SQL select table_name,partition_name, high_value from dba_tab_partitions where table_owner='SH' and table_name = 'SALES_PAR_LIST'; TABLE_NAME PARTITION_NAME HIGH_VALUE --------------- --------------- -------------------------------- SALES_PAR_LIST SOUTH_AMERICA 'Argentina', 'Peru', 'Brazil' SALES_PAR_LIST NORTH_AMERICA 'Canada', 'USA' SALES_PAR_LIST CENTRAL_AMERICA 'Honduras', 'Nicaragua' SALES_PAR_LIST EUROPE 'France', 'Spain', 'Ireland', 'Germany', 'Belgium', 'Portugal', 'Denmark' In conclusion, I hope that DBA’s whose work involves maintaining partitions will find the operations a bit more straight forward to carry out once they have upgraded to Oracle Database 12c. Gwen Lazenby is a Principal Training Consultant at Oracle. She is part of Oracle University's Core Technology delivery team based in the UK, teaching Database Administration and Linux courses. Her specialist topics include using Oracle Partitioning and Parallelism in Data Warehouse environments, as well as Oracle Spatial and RMAN.

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  • More Great Improvements to the Windows Azure Management Portal

    - by ScottGu
    Over the last 3 weeks we’ve released a number of enhancements to the new Windows Azure Management Portal.  These new capabilities include: Localization Support for 6 languages Operation Log Support Support for SQL Database Metrics Virtual Machine Enhancements (quick create Windows + Linux VMs) Web Site Enhancements (support for creating sites in all regions, private github repo deployment) Cloud Service Improvements (deploy from storage account, configuration support of dedicated cache) Media Service Enhancements (upload, encode, publish, stream all from within the portal) Virtual Networking Usability Enhancements Custom CNAME support with Storage Accounts All of these improvements are now live in production and available to start using immediately.  Below are more details on them: Localization Support The Windows Azure Portal now supports 6 languages – English, German, Spanish, French, Italian and Japanese. You can easily switch between languages by clicking on the Avatar bar on the top right corner of the Portal: Selecting a different language will automatically refresh the UI within the portal in the selected language: Operation Log Support The Windows Azure Portal now supports the ability for administrators to review the “operation logs” of the services they manage – making it easy to see exactly what management operations were performed on them.  You can query for these by selecting the “Settings” tab within the Portal and then choosing the “Operation Logs” tab within it.  This displays a filter UI that enables you to query for operations by date and time: As of the most recent release we now show logs for all operations performed on Cloud Services and Storage Accounts.  You can click on any operation in the list and click the “Details” button in the command bar to retrieve detailed status about it.  This now makes it possible to retrieve details about every management operation performed. In future updates you’ll see us extend the operation log capability to apply to all Windows Azure Services – which will enable great post-mortem and audit support. Support for SQL Database Metrics You can now monitor the number of successful connections, failed connections and deadlocks in your SQL databases using the new “Dashboard” view provided on each SQL Database resource: Additionally, if the database is added as a “linked resource” to a Web Site or Cloud Service, monitoring metrics for the linked SQL database are shown along with the Web Site or Cloud Service metrics in the dashboard. This helps with viewing and managing aggregated information across both resources in your application. Enhancements to Virtual Machines The most recent Windows Azure Portal release brings with it some nice usability improvements to Virtual Machines: Integrated Quick Create experience for Windows and Linux VMs Creating a new Windows or Linux VM is now easy using the new “Quick Create” experience in the Portal: In addition to Windows VM templates you can also now select Linux image templates in the quick create UI: This makes it incredibly easy to create a new Virtual Machine in only a few seconds. Enhancements to Web Sites Prior to this past month’s release, users were forced to choose a single geographical region when creating their first site.  After that, subsequent sites could only be created in that same region.  This restriction has now been removed, and you can now create sites in any region at any time and have up to 10 free sites in each supported region: One of the new regions we’ve recently opened up is the “East Asia” region.  This allows you to now deploy sites to North America, Europe and Asia simultaneously.  Private GitHub Repository Support This past week we also enabled Git based continuous deployment support for Web Sites from private GitHub and BitBucket repositories (previous to this you could only enable this with public repositories).  Enhancements to Cloud Services Experience The most recent Windows Azure Portal release brings with it some nice usability improvements to Cloud Services: Deploy a Cloud Service from a Windows Azure Storage Account The Windows Azure Portal now supports deploying an application package and configuration file stored in a blob container in Windows Azure Storage. The ability to upload an application package from storage is available when you custom create, or upload to, or update a cloud service deployment. To upload an application package and configuration, create a Cloud Service, then select the file upload dialog, and choose to upload from a Windows Azure Storage Account: To upload an application package from storage, click the “FROM STORAGE” button and select the application package and configuration file to use from the new blob storage explorer in the portal. Configure Windows Azure Caching in a caching enabled cloud service If you have deployed the new dedicated cache within a cloud service role, you can also now configure the cache settings in the portal by navigating to the configuration tab of for your Cloud Service deployment. The configuration experience is similar to the one in Visual Studio when you create a cloud service and add a caching role.  The portal now allows you to add or remove named caches and change the settings for the named caches – all from within the Portal and without needing to redeploy your application. Enhancements to Media Services You can now upload, encode, publish, and play your video content directly from within the Windows Azure Portal.  This makes it incredibly easy to get started with Windows Azure Media Services and perform common tasks without having to write any code. Simply navigate to your media service and then click on the “Content” tab.  All of the media content within your media service account will be listed here: Clicking the “upload” button within the portal now allows you to upload a media file directly from your computer: This will cause the video file you chose from your local file-system to be uploaded into Windows Azure.  Once uploaded, you can select the file within the content tab of the Portal and click the “Encode” button to transcode it into different streaming formats: The portal includes a number of pre-set encoding formats that you can easily convert media content into: Once you select an encoding and click the ok button, Windows Azure Media Services will kick off an encoding job that will happen in the cloud (no need for you to stand-up or configure a custom encoding server).  When it’s finished, you can select the video in the “Content” tab and then click PUBLISH in the command bar to setup an origin streaming end-point to it: Once the media file is published you can point apps against the public URL and play the content using Windows Azure Media Services – no need to setup or run your own streaming server.  You can also now select the file and click the “Play” button in the command bar to play it using the streaming endpoint directly within the Portal: This makes it incredibly easy to try out and use Windows Azure Media Services and test out an end-to-end workflow without having to write any code.  Once you test things out you can of course automate it using script or code – providing you with an incredibly powerful Cloud Media platform that you can use. Enhancements to Virtual Network Experience Over the last few months, we have received feedback on the complexity of the Virtual Network creation experience. With these most recent Portal updates, we have added a Quick Create experience that makes the creation experience very simple. All that an administrator now needs to do is to provide a VNET name, choose an address space and the size of the VNET address space. They no longer need to understand the intricacies of the CIDR format or walk through a 4-page wizard or create a VNET / subnet. This makes creating virtual networks really simple: The portal also now has a “Register DNS Server” task that makes it easy to register DNS servers and associate them with a virtual network. Enhancements to Storage Experience The portal now lets you register custom domain names for your Windows Azure Storage Accounts.  To enable this, select a storage resource and then go to the CONFIGURE tab for a storage account, and then click MANAGE DOMAIN on the command bar: Clicking “Manage Domain” will bring up a dialog that allows you to register any CNAME you want: Summary The above features are all now live in production and available to use immediately.  If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using them today.  Visit the Windows Azure Developer Center to learn more about how to build apps with it. One of the other cool features that is now live within the portal is our new Windows Azure Store – which makes it incredibly easy to try and purchase developer services from a variety of partners.  It is an incredibly awesome new capability – and something I’ll be doing a dedicated post about shortly. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • SQL SERVER – BI Quiz Hint – Performance Tuning Cubes – Hints

    - by pinaldave
    I earlier wrote about SQL BI Quiz over here and here. The details of the quiz is here: Working with huge data is very common when it is about Data Warehousing. It is necessary to create Cubes on the data to make it meaningful and consumable. There are cases when retrieving the data from cube takes lots of the time. Let us assume that your cube is returning you data very quickly. Suddenly on one day it is returning the data very slowly. What are the three things will you to diagnose this. After diagnose what you will do to resolve performance issue. Participate in my question over here I required BI Expert Jason Thomas to help with few hints to blog readers. He is one of the leading SSAS expert and writes a complicated subject in simple words. If queries were executing properly before but now take a long time to return the data, it means that there has been a change in the environment in which it is running. Some possible changes are listed below:-  1) Data factors:- Compare the data size then and now. Increase in data can result in different execution times. Poorly written queries as well as poor design will not start showing issues till the data grows. How to find it out? (Ans : SQL Server profiler and Perfmon Counters can be used for identifying the issues and performance  tuning the MDX queries)  2) Internal Factors:- Is some slow MDX query / multiple mdx queries running at the same time, which was not running when you had tested it before? Is there any locking happening due to proactive caching or processing operations? Are the measure group caches being cleared by processing operations? (Ans : Again, profiler and perfmon counters will help in finding it out. Load testing can be done using AS Performance Workbench (http://asperfwb.codeplex.com/) by running multiple queries at once)  3) External factors:- Is some other application competing for the same resources?  HINT : Read “Identifying and Resolving MDX Query Performance Bottlenecks in SQL Server 2005 Analysis Services” (http://sqlcat.com/whitepapers/archive/2007/12/16/identifying-and-resolving-mdx-query-performance-bottlenecks-in-sql-server-2005-analysis-services.aspx) Well, these are great tips. Now win big prizes by participate in my question over here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • What are the basic features of an email module in a common web application?

    - by Coral Doe
    When developing an email module, what are the features to have in mind, besides actual email sending? I am talking about an email module that notifies users of events and periodically sends reports. The only other feature I have in mind is maintaining grey/black lists for users that do illegal operations in the system or any other things that may lead to email/domain/IP banning. Is there an etiquette for developing email modules? Are there some references of requirements for such modules?

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  • Precompiling LINQ Queries

    Did you know that by precompiling LINQ queries you might actually be degrading your app’s performance if you’re not careful? Julie Lerman explains how to ensure you’re not re-precompiling queries each time and losing the expected performance benefits across post-backs, short-lived service operations and other code where critical instances are going out of scope.

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  • Design Anti-Patterns - C# - Do you call this a God object?

    - by Reddy S R
    I am writing Portfolio module for my web site and it has 3 components. Gallery Category, Gallery, & Gallery Images. I am doing all the request handling, (creating, reading, updating, other), for the above 3 components in 1 class, Portfolio. DB handling jobs for Portfolio module is done in another file. My question is, even just for request handling purpose, can you do all the operations in 1 class? -Reddy

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  • Announcing: Improvements to the Windows Azure Portal

    - by ScottGu
    Earlier today we released a number of enhancements to the new Windows Azure Management Portal.  These new capabilities include: Service Bus Management and Monitoring Support for Managing Co-administrators Import/Export support for SQL Databases Virtual Machine Experience Enhancements Improved Cloud Service Status Notifications Media Services Monitoring Support Storage Container Creation and Access Control Support All of these improvements are now live in production and available to start using immediately.  Below are more details on them: Service Bus Management and Monitoring The new Windows Azure Management Portal now supports Service Bus management and monitoring. Service Bus provides rich messaging infrastructure that can sit between applications (or between cloud and on-premise environments) and allow them to communicate in a loosely coupled way for improved scale and resiliency. With the new Service Bus experience, you can now create and manage Service Bus Namespaces, Queues, Topics, Relays and Subscriptions. You can also get rich monitoring for Service Bus Queues, Topics and Subscriptions. To create a Service Bus namespace, you can now select the “Service Bus” tab in the Windows Azure portal and then simply select the CREATE command: Doing so will bring up a new “Create a Namespace” dialog that allows you to name and create a new Service Bus Namespace: Once created, you can obtain security credentials associated with the Namespace via the ACCESS KEY command. This gives you the ability to obtain the connection string associated with the service namespace. You can copy and paste these values into any application that requires these credentials: It is also now easy to create Service Bus Queues and Topics via the NEW experience in the portal drawer.  Simply click the NEW command and navigate to the “App Services” category to create a new Service Bus entity: Once you provision a new Queue or Topic it can be managed in the portal.  Clicking on a namespace will display all queues and topics within it: Clicking on an item in the list will allow you to drill down into a dashboard view that allows you to monitor the activity and traffic within it, as well as perform operations on it. For example, below is a view of an “orders” queue – note how we now surface both the incoming and outgoing message flow rate, as well as the total queue length and queue size: To monitor pub/sub subscriptions you can use the ADD METRICS command within a topic and select a specific subscription to monitor. Support for Managing Co-Administrators You can now add co-administrators for your Windows Azure subscription using the new Windows Azure Portal. This allows you to share management of your Windows Azure services with other users. Subscription co-administrators share the same administrative rights and permissions that service administrator have - except a co-administrator cannot change or view billing details about the account, nor remove the service administrator from a subscription. In the SETTINGS section, click on the ADMINISTRATORS tab, and select the ADD button to add a co-administrator to your subscription: To add a co-administrator, you specify the email address for a Microsoft account (formerly Windows Live ID) or an organizational account, and choose the subscription you want to add them to: You can later update the subscriptions that the co-administrator has access to by clicking on the EDIT button, and then select or deselect the subscriptions to which they belong. Import/Export Support for SQL Databases The Windows Azure administration portal now supports importing and exporting SQL Databases to/from Blob Storage.  Databases can be imported/exported to blob storage using the same BACPAC file format that is supported with SQL Server 2012.  Among other benefits, this makes it easy to copy and migrate databases between on-premise and cloud environments. SQL Databases now have an EXPORT command in the bottom drawer that when pressed will prompt you to save your database to a Windows Azure storage container: The UI allows you to choose an existing storage account or create a new one, as well as the name of the BACPAC file to persist in blob storage: You can also now import and create a new SQL Database by using the NEW command.  This will prompt you to select the storage container and file to import the database from: The Windows Azure Portal enables you to monitor the progress of import and export operations. If you choose to log out of the portal, you can come back later and check on the status of all of the operations in the new history tab of the SQL Database server – this shows your entire import and export history and the status (success/fail) of each: Enhancements to the Virtual Machine Experience One of the common pain-points we have heard from customers using the preview of our new Virtual Machine support has been the inability to delete the associated VHDs when a VM instance (or VM drive) gets deleted. Prior to today’s release the VHDs would continue to be in your storage account and accumulate storage charges. You can now navigate to the Disks tab within the Virtual Machine extension, select a VM disk to delete, and click the DELETE DISK command: When you click the DELETE DISK button you have the option to delete the disk + associated .VHD file (completely clearing it from storage).  Alternatively you can delete the disk but still retain a .VHD copy of it in storage. Improved Cloud Service Status Notifications The Windows Azure portal now exposes more information of the health status of role instances.  If any of the instances are in a non-running state, the status at the top of the dashboard will summarize the status (and update automatically as the role health changes): Clicking the instance hyperlink within this status summary view will navigate you to a detailed role instance view, and allow you to get more detailed health status of each of the instances.  The portal has been updated to provide more specific status information within this detailed view – giving you better visibility into the health of your app: Monitoring Support for Media Services Windows Azure Media Services allows you to create media processing jobs (for example: encoding media files) in your Windows Azure Media Services account. In the Windows Azure Portal, you can now monitor the number of encoding jobs that are queued up for processing as well as active, failed and queued tasks for encoding jobs. On your media services account dashboard, you can visualize the monitoring data for last 6 hours, 24 hours or 7 days. Storage Container Creation and Access Control Support You can now create Windows Azure Storage storage containers from within the Windows Azure Portal.  After selecting a storage account, you can navigate to the CONTAINERS tab and click the ADD CONTAINER command: This will display a dialog that lets you name the new container and control access to it: You can also update the access setting as well as container metadata of existing containers by selecting one and then using the new EDIT CONTAINER command: This will then bring up the edit container dialog that allows you to change and save its settings: In addition to creating and editing containers, you can click on them within the portal to drill-in and view blobs within them.  Summary The above features are all now live in production and available to use immediately.  If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using them today.  Visit the Windows Azure Developer Center to learn more about how to build apps with it. We’ll have even more new features and enhancements coming later this month – including support for the recent Windows Server 2012 and .NET 4.5 releases (we will enable new web and worker role images with Windows Server 2012 and .NET 4.5, and support .NET 4.5 with Websites).  Keep an eye out on my blog for details as these new features become available. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • Why Solid-State Drives Slow Down As You Fill Them Up

    - by Chris Hoffman
    The benchmarks are clear: Solid-state drives slow down as you fill them up. Fill your solid-state drive to near-capacity and its write performance will decrease dramatically. The reason why lies in the way SSDs and NAND Flash storage work. Filling the drive to capacity is one of the things you should never do with a solid-state drive. A nearly full solid-state drive will have much slower write operations, slowing down your computer.    

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  • Google I/O 2012 - Managing Google Compute Engine Virtual Machines Through Google App Engine

    Google I/O 2012 - Managing Google Compute Engine Virtual Machines Through Google App Engine Alon Levi, Adam Eijdenberg Google Compute Engine provides highly efficient and scalable virtual machines for large scale data processing operations. Integration with Google App Engine provides an orchestration framework to manage large virtual machine clusters used for data processing. This session will talk demonstrate integration and discuss future use cases of the two technologies. For all I/O 2012 sessions, go to developers.google.com From: GoogleDevelopers Views: 0 0 ratings Time: 51:06 More in Science & Technology

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  • Internal Mutation of Persistent Data Structures

    - by Greg Ros
    To clarify, when I mean use the terms persistent and immutable on a data structure, I mean that: The state of the data structure remains unchanged for its lifetime. It always holds the same data, and the same operations always produce the same results. The data structure allows Add, Remove, and similar methods that return new objects of its kind, modified as instructed, that may or may not share some of the data of the original object. However, while a data structure may seem to the user as persistent, it may do other things under the hood. To be sure, all data structures are, internally, at least somewhere, based on mutable storage. If I were to base a persistent vector on an array, and copy it whenever Add is invoked, it would still be persistent, as long as I modify only locally created arrays. However, sometimes, you can greatly increase performance by mutating a data structure under the hood. In more, say, insidious, dangerous, and destructive ways. Ways that might leave the abstraction untouched, not letting the user know anything has changed about the data structure, but being critical in the implementation level. For example, let's say that we have a class called ArrayVector implemented using an array. Whenever you invoke Add, you get a ArrayVector build on top of a newly allocated array that has an additional item. A sequence of such updates will involve n array copies and allocations. Here is an illustration: However, let's say we implement a lazy mechanism that stores all sorts of updates -- such as Add, Set, and others in a queue. In this case, each update requires constant time (adding an item to a queue), and no array allocation is involved. When a user tries to get an item in the array, all the queued modifications are applied under the hood, requiring a single array allocation and copy (since we know exactly what data the final array will hold, and how big it will be). Future get operations will be performed on an empty cache, so they will take a single operation. But in order to implement this, we need to 'switch' or mutate the internal array to the new one, and empty the cache -- a very dangerous action. However, considering that in many circumstances (most updates are going to occur in sequence, after all), this can save a lot of time and memory, it might be worth it -- you will need to ensure exclusive access to the internal state, of course. This isn't a question about the efficacy of such a data structure. It's a more general question. Is it ever acceptable to mutate the internal state of a supposedly persistent or immutable object in destructive and dangerous ways? Does performance justify it? Would you still be able to call it immutable? Oh, and could you implement this sort of laziness without mutating the data structure in the specified fashion?

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