SEARCH KEYWORD -- INDEX MERGE

  Sort an array with only one local variable

Array sorting algorithm question is frequently asked during technical interviews. There are lots of sort algorithms including bubble sort, selection sort, insertion sort, quick sort, merge sort etc. Usually interviewees will be asked to implement sort algorithms. But have you ever been asked to sort an array which you are allowed to define ONLY ONE local variable in your algorithm?  Bubble sort can be used to do this actually. Normally a bubble sort algorithm may need three local ...

   JAVASCRIPT,ALGORITHM,SORTING,BUBBLE SORT     2016-10-07 09:46:49

  How MySQL optmizes ORDER BY

In some situations, MySQL will just use an index to fulfill the requirement of an ORDER BY or GROUP BY statement without extra sorting. Although ORDER BY will not have the exact match with index, index can still be used as long as the portion that is not included in the index is included in the where clause. The following queries will all use index to process the ORDER BY or GROUP BY part: SELECT * FROM t1 ORDER BY key_part1,key_part2,... ;SELECT * FROM t1 WHERE key_part1=constant ORDER BY key_p...

   MySQL,index,ORDER BY,optimization     2012-11-13 11:01:05

  MySQL Index Merge Optimization Practices

In production environment databases, it is often seen that some SQL where conditions include: equal condition on a normal index + primary key range query + order by limit Although using a normal index would be more efficient, the system chooses to use index merge instead in some cases. This article explores such index merge situations. Index Merge Official Introduction   The Index Merge access method retrieves rows with multiple range scans and merges their results into one. Generall...

   INDEX MERGE,MYSQL,PRIMARY INDEX,SECONDARY INDEX     2024-09-10 04:52:26

  Frequently used Git commands

Git configuration git config --global user.name "robbin" git config --global user.email "fankai@gmail.com" git config --global color.ui true git config --global alias.co checkout git config --global alias.ci commit git config --global alias.st status git config --global alias.br branch git config --global core.editor "mate -w" # Configure Editor to use textmate git config -l #List all configurations User's git configuration file : ~/.gitconfig Frequently used Git commands Check、add...

   Git,Command     2013-03-11 19:41:06

  Mutli-inheritance bug between python 2.7 and 3.7

When we have run a py3.7 code under py2.x or a py2.x code under 3.x ,if a class do mutli-inheritance from 2 parent and the 2 parents also got inheritance from same parent, the different way to handle inheritance chain between python 2 and 3 will cause some running time bug: Assume we got this sample program inheritTest.py : # Purpose: Test mutli-inheritance different between python2 and 3 # Author: Yuancheng Liu # Created: 2019/05/16 class A: def getVal(self): print("cal...

   PYTHON,PYTHON 3,INHERITANCE     2019-05-16 08:33:52

  Read 10 new books from O'Reilly for free

Recently O'Reilly provided free access to some books. Some of them are even in early release status. Here we recommend 10 of them. 1、Mastering Perl 2、Git Pocket Guide 3、Vagrant: Up and Running 4、High Performance Browser Networking 5、802.11ac: A Survival Guide 6、Test-Driven Development with Python 7、Interactive Data Visualization for the Web 8、HTML5 Canvas 9、Programming JavaScript Applications 10、Agile Data Source : http://linu...

   O'Reilly,Free book,Early release     2013-07-03 07:56:20

  Simple tutorial on git cherry-pick

It is a common operation to move code from one branch to another branch in a multi-branch git repository. Normally there are two scenarios: Want to move all changes in one branch to another branch, now it's called git merge  Want to move only some change/changes from one branch to another branch, now it's called git cherry-pick Usage The purpose of git cherry-pick is to apply some change from one branch to another branch.  git cherry-pick [commitHash] The above command is to app...

   GIT,GIT CHERRY-PICK,TUTORIAL     2020-05-02 00:02:58

  Failed merge and acquisition cases in the Internet history

Bebo founder sold Bebo with 850 million US dollars in 2008, but later he bought it back with just 1 million US dollars. This news lets us think about those failed merge and acquisition cases in Internet history. Let's summarize some of them here. 1. Bebo Buyer : AOL Acquisition price : 650 million US dollars Sold price : 1 million US dollars Loss: 849 million US dollars In 2008, AOL was still belong to Time Warner. It made a decision to acquire the third largest social networking site Bebo, The...

   Merge and acquisition,Loss,MySpace     2013-07-03 08:37:13

  TIOBE : Objective-C overtakes C++

TIOBE recently released the programming community index for July. From the index,we can find that the biggest change is that Objective-C overtakes C++ as the 3rd most popular language among programmers. Because of the popularity of iPhone and iPad, Objective-C is used by more and more mobile developers who want to develop apps for Apple products. Also, many developers are willing to develop apps for Apple since they can gain more profit on Apple platform than on Android platform.C++ is mainly us...

   TIOBE,July,C++,Objective-C,overtake     2012-07-05 22:49:49

  JavaScript: Private variables

The first thing you often hear when talking about JavaScript is often “JavaScript doesn’t have visibility modifiers, hence it doesn’t support private variables”. This is only valid for 50%, because JavaScript indeed doesn’t have visibility modifiers (public, private, friend) but it has closures and function scopes. With these tools we can make variables private. Let’s take the following function: var names = ["Kenneth", "John", "Marc", "Robert"]; var lookup =...

   JavaScript,private variable,closure     2012-04-28 11:46:34

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