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Wednesday, January 19, 2011

System Columns in Postgresql

In postgresql ever table has several system columns that are implicitly defined by the system. Therefore, these names cannot be used as names of user-defined columns. 


oid

The object identifier (object ID) of a row. This column is only present if the table was created using WITH OIDS, or if the default_with_oids configuration variable was set at the time. This column is of type oid (same name as the column).

tableoid

The OID of the table containing this row. This column is particularly handy for queries that select from inheritance hierarchies, since without it, it's difficult to tell which individual table a row came from. The tableoid can be joined against the oid column of pg_class to obtain the table name.

xmin

The identity (transaction ID) of the inserting transaction for this row version. (A row version is an individual state of a row; each update of a row creates a new row version for the same logical row.)

cmin

The command identifier (starting at zero) within the inserting transaction.

xmax

The identity (transaction ID) of the deleting transaction, or zero for an undeleted row version. It is possible for this column to be nonzero in a visible row version. That usually indicates that the deleting transaction hasn't committed yet, or that an attempted deletion was rolled back.

cmax

The command identifier within the deleting transaction, or zero.

ctid

The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly, a row's ctid will change each time it is updated or moved by VACUUM FULL. Therefore ctid is useless as a long-term row identifier. The OID, or even better a user-defined serial number, should be used to identify logical rows.

Monday, January 10, 2011

9 rules of innovation from Google

1. Innovation, not instant perfection
"There are two different types of programmers. Some like to code for months or even years, and hope they will have built the perfect product. That's castle building. Companies work this way, too. Apple is great at it. If you get it right and you've built just the perfect thing, you get this worldwide 'Wow!' The problem is, if you get it wrong, you get a thud, a thud in which you've spent, like, five years and 100 people on something the market doesn't want."
"Others prefer to have something working at the end of the day, something to refine and improve the next day. That's what we do: our 'launch early and often' strategy. The hardest part about indoctrinating people into our culture is when engineers show me a prototype and I'm like, 'Great, let's go!' They'll say, 'Oh, no, it's not ready.
It's not up to Google standards. This doesn't look like a Google product yet.' They want to castle-build and do all these other features and make it all perfect."
"I tell them, 'The Googly thing is to launch it early on Google Labs and then iterate, learning what the market wants--and making it great.' The beauty of experimenting in this way is that you never get too far from what the market wants. The market pulls you back."

2. Ideas come from everywhere
"We have this great internal list where people post new ideas and everyone can go on and see them. It's like a voting pool where you can say how good or bad you think an idea is. Those comments lead to new ideas."

3. A license to pursue your dreams
"Since around 2000, we let engineers spend 20% of their time working on whatever they want, and we trust that they'll build interesting things. After September 11, one of our researchers, Krishna Bharat, would go to 10 or 15 news sites each day looking for information about the case. And he thought, Why don't I write a program to do this? So Krishna , who's an expert in artificial intelligence, used a Web crawler to cluster articles."
"He later emailed it around the company. My office mate and I got it, and we were like, 'This isn't just a cool little tool for Krishna . We could add more sources and build this into a great product.' That's how Google News came about. Krishna did not intend to build a product, but he accidentally gave us the idea for one."
"We let engineers spend 20% of their time working on whatever they want, and we trust that they'll build interesting things."

4. Morph projects don't kill them
"Eric [Schmidt, CEO] made this observation to me once, which I think is accurate: Any project that is good enough to make it to Labs probably has a kernel of something interesting in there so

5. Share as much information as you can
"People are blown away by the information you can get on MOMA, our intranet. Because there is so much information shared across the company, employees have insight into what's happening with the business and what's important."
"We also have people do things like Snippets. Every Monday, all the employees write an email that has five to seven bullet points on what you did the previous week. Being a search company, we take all the emails and make a giant Web page and index them."
"If you're wondering, 'Who's working on maps?' you can find out.. It allows us to share what we know across the whole company, and it reduces duplication."
Mew here, even if the market doesn't respond to it. It's our job to take the product and morph it into something that the market needs."

6. Users, users, users
"I used to call this 'Users, Not Money.' We believe that if we focus on the users, the money will come. In a truly virtual business, if you're successful, you'll be working at something that's so necessary people will pay for it in subscription form. Or you'll have so many users that advertisers will pay to sponsor the site."

7. Data is apolitical
"When I meet people who run design at other organizations, they're always like, 'Design is one of the most political areas of the company. This designer likes green and that one likes purple, and whose design gets picked? The one who buddies up to the boss.'
Some companies think of design as an art. We think of design as a science. It doesn't matter who is the favorite or how much you like this aesthetic versus that aesthetic. It all comes down to data. Run a 1% test [on 1% of the audience] and whichever design does best against the user-happiness metrics over a two-week period is the one we launch. We have a very academic environment where we're looking at data all the time.
We probably have somewhere between 50 and 100 experiments running on live traffic, everything from the default number of results to underlined links to how big an arrow should be. We're trying all those different things."

8. Creativity loves constraints
"This is one of my favorites. People think of creativity as this sort of unbridled thing, but engineers thrive on constraints. They love to think their way out of that little box: 'We know you said it was impossible, but we're going to do this, this, and that to get us there.'"

9. You're brilliant? We're hiring
"When I was a grad student at Stanford, I saw that phrase on a flyer for another company in the basement of the computer-science building. It made me stop dead in my tracks and laugh out loud."
"A couple of months later, I'm working at Google, and the engineers were asked to write job ads for engineers. We had a contest. I put, 'You're brilliant? We're hiring. Come work at Google,' and got eight times the click rate that anyone else got.
"Google now has a thousand times as many people as when I started, which is just staggering to me. What's remarkable, though, is what hasn't changed--the types of people who work here and the types of things that they like to work on. It's almost identical to the first 20 or so of us at Google."
"There is this amazing element to the culture of wanting to work on big problems that matter, wanting to do great things for the world, believing that we can build a successful business without compromising our standards and values.."
"If I'm an entrepreneur and I want to start a Web site, I need a billing system. Oh, there's Google Checkout. I need a mapping function. Oh, there's Google Maps. Okay, I need to monetize. There's Google AdSense, right? I need a user name and password-authentication system. There's Google Accounts."
"This is just way easier than going out and trying to create all of that from scratch. That's how we're going to stay innovative. We're going to continue to attract entrepreneurs who say, 'I found an idea, and I can go to Google and have a demo in a month and be launched in six.'"

Thursday, January 6, 2011

Scheduled Jobs in Windows (Cron jobs)


Open Schedule Tasks 

Click the add Task in the folder 




In the Scheduled task wizard Click "Next"



Select the desired program you want to run in a periodic time, Here in this example I am trying to run a php file daily at 4:31 PM using Google chrome browser

















Give a name to task and select the frequency

Set the date an time (This dialog will vary according to the selection on the previous screen I have selected daily )


After adding the program we have to include the file to run at the end of the Run command as below In this example I have used cron.php file in my root directory , We can modify settings here also



  













Done :)

KDE Timeline (2010)

  Timeline

  • KDE was founded in October 1996. Its announcement is dated 14th October 1996.
  • August 15, 1997: KDE-ONE in Arnsberg, Germany, 15 participants
  • December 1997: KDE e.V.i.G. was founded to shield core members from legal and financial liabilities
  • April 8, 1998: The KDE Free Qt Foundation was announced
  • Beta 1 Oct 20, 1997 - Beta 2 Nov 23, 1997 - Beta3 February 1, 1998 - Beta4 April 19, 1998
  • 1.0 was released on July 12, 1998
  • 1.1 was released on February 6th, 1999
  • 1.1.1 was released on May 5th, 1999
  • 1.1.2 was released on Sep 13th, 1999
  • KDE-Two meeting in Erlangen, Oct 7-10 1999
  • 1.89 was released on Dec 15th, 1999
  • 1.90 (KDE2 beta1) May 12th, 2000 - 1.91 (KDE2 beta2) June 14th, 2000 - 1.92 (KDE2 beta3) July 31st, 2000
  • KDE-Three Beta meeting in Trysil (Norway), July 9-19 2000
  • 1.93 (KDE2 beta4) was released on August 23th, 2000
  • Qt goes GPL September 04th, 2000
    More information on the The Qt Issue
  • 1.94 (KDE2 beta5) was released on September 15th, 2000
  • 2.0 Release Candidate was released on October 10th, 2000
  • 2.0 was released on October 23th, 2000
  • 2.0.1 was released on December 5th, 2000
  • 2.1 Beta 1 was released on December 16th, 2000
  • 2.1 Beta 2 was released on January 31st, 2001
  • 2.1 was released on February 26th, 2001
  • 2.1.1 was released on March 27th, 2001
  • 2.1.2 was released on April 30th, 2001
  • 2.2 Beta1 was released on July 4th, 2001
  • 2.2 was released on August 15th, 2001
  • 2.2.1 was released on September 19th, 2001
  • 2.2.2 was released on November 21st, 2001
  • 3.0 was released on April 3rd, 2002
  • 3.0.1 was released on May 22th, 2002
  • 3.0.2 was released on July 2nd, 2002
  • 3.1 Alpha1 was released on July 11th, 2002
  • 3.0.3 was released on August 19th, 2002
  • 3.1 Beta1 was released on August 21st, 2002
  • 3.1 Beta2 was released on October 2nd, 2002
  • 3.0.4 was released on October 9th, 2002
  • 3.0.5 was released on November 18th, 2002
  • 3.0.5a was released on December 21st, 2002
  • 3.1 was released on January 28th, 2003
  • 3.1.1 was released on March 20th, 2003
  • 3.1.2 was released on May 19th, 2003
  • 3.1.3 was released on July 29th, 2003
  • 3.2 Alpha 1 was released on September 10th, 2003
  • 3.1.4 was released on September 16th, 2003
  • 3.1.5 was released on January 14th, 2004
  • 3.2 was released on February 3rd, 2004
  • 3.2.1 was released on March 9th, 2004
  • 3.2.2 was released on April 19th, 2004
  • 3.2.3 was released on June 9th, 2004
  • 3.3 was released on August 19th, 2004
  • 3.3.1 was released on October 12th, 2004
  • 3.3.2 was released on December 8th, 2004
  • 3.4 was released on March 16th, 2005
  • 3.4.1 was released on May 31st, 2005
  • 3.4.2 was released on July 28th, 2005
  • 3.4.3 was released on October 13th, 2005
  • 3.5 was released on November 29th, 2005
  • 3.5.1 was released on January 31st, 2006
  • 3.5.2 was released on March 28th, 2006
  • 3.5.3 was released on May 31st, 2006
  • 3.5.4 was released on August 2nd, 2006
  • 3.5.5 was released on October 11th, 2006
  • 3.5.6 was released on January 25th, 2007
  • 4.0 Alpha 1 was released on May 11th, 2007
  • 3.5.7 was released on May 22nd, 2007
  • 4.0 Alpha 2 was released on July 4th, 2007
  • 4.0 Beta 1 was released on August 2nd, 2007
  • 4.0 Beta 2 was released on September 6th, 2007
  • 3.5.8 was released on October 16th, 2007
  • 4.0 Beta 3 was released on October 18th, 2007
  • 4.0 Beta 4 was released on October 30th, 2007
  • 4.0 Development Platform Release Candidate 1 was released on October 30th, 2007
  • 4.0 RC 1 was released on November 20th, 2007
  • 4.0 RC 2 was released on December 11th, 2007
  • 4.0 was released on January 11th, 2008
  • 4.0.1 was released on February 5th, 2008
  • 3.5.9 was released on February 19th, 2008
  • 4.0.2 was released on March 5th, 2008
  • 4.0.3 was released on April 2nd, 2008
  • 4.1 Alpha1 was released on April 29th, 2008
  • 4.0.4 was released on May 7th, 2008
  • 4.1 Beta 1 was released on May 27th, 2008
  • 4.0.5 was released on June 4th, 2008
  • 4.1 Beta 2 was released on June 24th, 2008
  • 4.1 RC1 was released on July 15th, 2008
  • 4.1 was released on July 29th, 2008
  • 3.5.10 was released on August 26th, 2008
  • 4.1.1 was released on September 3rd, 2008
  • 4.1.2 was released on October 3rd, 2008
  • 4.1.3 was released on November 5th, 2008
  • 4.2 Beta 1 was released on November 26th, 2008
  • 4.2 Beta 2 was released on December 18th, 2008
  • 4.1.4 was released on January 13th, 2009
  • 4.2 RC was released on January 13th, 2009
  • 4.2.0 was released on January 27th, 2009
  • 4.2.1 was released on March 4th, 2009
  • 4.2.2 was released on April 2nd, 2009
  • 4.2.3 was released on May 6th, 2009
  • 4.3 Beta 1 was released on May 13th, 2009
  • 4.2.4 was released on June 3rd, 2009
  • 4.3 Beta 2 was released on June 10th, 2009
  • 4.3 RC1 was released on July 1st, 2009
  • 4.3 RC2 was released on July 9th, 2009
  • 4.3 RC3 was released on July 22nd, 2009
  • 4.3.0 was released on August 4th, 2009
  • 4.3.1 was released on September 1st, 2009
  • 4.3.2 was released on October 6th, 2009
  • 4.3.3 was released on November 3rd, 2009
  • Rebranding of KDE on November 24th, 2009
    (KDE is no longer software created by people, but people who create software.)
  • 4.3.4 was released on December 1st, 2009
  • 4.4 Beta 1 was released on December 4th, 2009
  • 4.4 Beta 2 was released on December 21st, 2009
  • 4.4 RC 1 was released on January 8th, 2010
  • 4.4 RC 2 was released on January 25th, 2010
  • 4.3.5 was released on January 26th, 2010
  • 4.4 RC 3 was released on February 1st, 2010
  • 9th February 2010 - KDE SC 4.4.0 Released 
  • 2nd March 2010 - KDE SC 4.4.1 Released 
  • 30th March 2010 - KDE SC 4.4.2 Released 
  • 5th May 2010 - KDE SC 4.4.3 Released 
  • 31st August 2010 - KDE SC 4.5.1 Released 
  • 9th June 2010 - KDE SC 4.5 Beta2 Released