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  PHP advisory file lock : flock

When we process a file in PHP, we may often need to acquire a lock so that other scripts cannot edit the same file at the same time. There is a flock() function in PHP which can help us lock the file we want to process. But there is one issue we should take care. Recently, ffb encountered one issue while he was trying to lock a file handle. The codes are below: $filename = "/tmp/lock.txt";      $fp = fopen($filename, "r+");   if (!$fp...

   flock(),advisory locking,PHP     2013-04-23 11:42:48

  <=> operator in MySQL

Have you ever seen "<=>" in a SQL query while using MySQL? Does it mean less and equals to and greater than? Actually if you consider it as the union of <= and =>, great, you are close to it. This is one form of equal operator in MySQL, it has the similar meaning to the = operator with some subtle difference. According to MySQL documentation, <=> is NULL-safe equal. This operator performs an equality comparison like the = operator, but returns 1 rather than NULL if both operand...

   MySQL,NULL safe,<=>     2014-03-24 06:23:22

  Check if query string variable exists ASP.NET C#/VB

One of the problems I encountered when I started programming ASP.NET websites was to do with the Request.QueryString function. The first projects I was worked on were built with VB.NET and I used the following code to check the existence of a query string variable:VB.NET Codeview plaincopy to clipboardprint?If Request.QueryString("[VARIABLE]") <> Nothing Then        'CODE HERE  End If  This code check...

   ASP.NET,Query string,Request,Empty,NULL,Check     2011-11-05 15:29:50

  Google+ is sick

Google says that Google+ now has over 170million registered users, but according a new research report of Fast Company about Google+,  Google+ is just a virtual ghost town.This research selected a sample of 40,000 random Google+ users. The result is :The average post on Google+ has less than one +1, less than one reply, and less than one re-shareRoughly 30% of users who make a public post never make a second oneEven after making five public posts, there is a 15% chance that a user will not ...

   Google+,Sick,Research     2012-05-16 05:41:35

  When to use STDERR instead of STDOUT

Every process is initialized with three open file descriptors, stdin, stdout, and stderr. stdin is an abstraction for accepting input (from the keyboard or from pipes) and stdout is an abstraction for giving output (to a file, to a pipe, to a console). That's a very simplified explanation but true nonetheless. Those three file descriptors are collectively called 'The Standard Streams'. Where does stderr come from? It's fairly straightforward to understand why stdin and stdout exist, however ...

   UNIX,STDERR,STDOUT,Difference     2012-01-14 12:07:43

  What is Hystrix and How does Hystrix work

Background In distributed systems, there is one effect where the unavailability of one service or some services will lead to the service unavailability of the whole system, this is called service avalanche effect. A common way to prevent service avalanche is do manual service fallback, in fact Hystrix also provides another option beside this. Definition of Service Avalanche Effect Service avalanche effect is a kind of effect where the service provider fails to provide service which causes t...

   AVALANCHE EFFECT,HYSTRIX,DISTRIBUTED SYSTEM     2019-02-04 06:00:38

  â€œExperience says it all”- Pentaho ETL Developers’ Comment on the Use of ETL Tools

Since months Pentaho ETL developers have been juggling with three distinct tools- Pentaho DI, SSIS, and PowerShell. Their experience has provided them new perspective on the cons and pros of every tool. In this post, they are sharing their experience with these tools and explain their significance. Before getting started, they first would like to explain ETL in brief and how the tools suits ETL landscape. ETL is Extract Transform Load. Informatica was the initial ETL tool introduced in the mid n...

   Pentaho BI ETL tools     2015-05-13 01:14:57

  How small should a function be?

"The well-designed functions are often relatively small, large function design is often a mess or there is a lot of room for optimization."Maybe you think there is no need to discuss the size of functions, because the nature of the function design is cohesive, its size is only its manifestations. But it is necessary to discuss about the size of function because the statement above .First let's understand the concept of minimum code processing unit : a basic operation (assignment, comparison, etc...

   Function size,Optimization     2012-12-18 13:58:07

  A Perl Regular Expression That Matches Prime Numbers

perl -lne '(1x$_) =~ /^1?$|^(11+?)\1+$/ || print "$_ is prime"' Can you figure out how it works? I give an explanation below, but try to figure it out yourself. Here is what happens when you run it: $ perl -lne '(1x$_) =~ /^1?$|^(11+?)\1+$/ || print "$_ is prime"' 1 2 2 is prime 3 3 is prime 4 5 5 is prime 6 7 7 is prime 8 9 10 11 11 is prime Here is how it works. First, the number is converted in its unary representation by (1x$_). For example, the number 5 gets converted into 1x5, which is ...

   Perl,Regex,Regular expression,Prime number,One line     2011-12-26 08:42:00

  What does a Bing driven Siri mean to Google?

On Tuesday, Apple announced that Bing would become the default search engine of the upcoming iOS 7. This is another Google service kicked out by Apple after Youtube and Google Maps.For Siri: if the default system of Siri can not answer your question, it will try to search the Internet. Currently, Siri connects to the Safari browser by default, and Safari's primary search engine is Google (Can change to Yahoo or Bing). But in iOS 7, Siri's default search engine will be replaced by Bing. Siri will...

   Siri,Bing,Google     2013-06-12 00:20:34

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