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  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

  HTML above flash (transparency + z-index)

We have faced this problem many of the times. When we want to display some message on top of all layers on a page or use some feature like jQuery light boxes. Normally the flash file continues to shine through the page. No matter what you do with layering the dom elements using z-index.See the layering flash content problem definition here.Before this, people used to dodge this issue with some fixes like hiding the flash area completely and then showing a static image of...

   HTML,Flash,Above,z-index,wmode,transpare     2011-05-01 15:46:34

  Crazy: 90 Percent of People Don't Know How to Use CTRL+F

This week, I talked with Dan Russell, a search anthropologist at Google, about the time he spends with random people studying how they search for stuff. One statistic blew my mind. 90 percent of people in their studies don't know how to use CTRL/Command + F to find a word in a document or web page! I probably use that trick 20 times per day and yet the vast majority of people don't use it at all."90 percent of the US Internet population does not know that. This is on a sample size of thousa...

   Ctrl-F,Shortcut,Common knowledge,Confusi     2011-09-02 11:16:48

  What are some lesser known but useful Unix commands?

A few that come to mind, some less known, some more: xargs or parallel: run things in parallel, with lots of options sed and awk: more well-known but still super useful for processing text files, and faster than Python or Ruby m4: simple macro processor screen: powerful terminal multiplexing and session persistence yes: print a string a lot cal: nice calendar env: run a command (useful in scripts) look: find English words (or lines in a file) beginning with a string cut and paste and join: data...

   Linux,Unix,Command,Less used     2011-12-27 09:27:49

  Why I Still Use Emacs

At school, I’m known as the Emacs guy; when people have questions about configuring Emacs or making it work a certain way, they often come and ask me. Sometimes, some people ask me why use Emacs at all? Isn’t it a really old editor and aren’t Eclipse or Visual Studio much better? I mean, they don’t have weird key bindings and have intellisense, that’s surely better for a programmer, right? I will attempt in this post to explain some of the reasons why I still c...

   Linux,Emacs,Editor,Advantage,IDE     2012-02-20 05:30:41

  Why, oh WHY, do those #?@! nutheads use vi?

Yes, even if you can't believe it, there are a lot fans of the 30-years-old vi editor (or its more recent, just-15-years-old, best clone & great improvement, vim). No, they are not dinosaurs who don't want to catch up with the times - the community of vi users just keeps growing: myself, I only got started 2 years ago (after over 10 years of being a professional programmer). Friends of mine are converting today. Heck, most vi users were not even born when...

   Linux,Vi,Vim,Advantage,History     2012-02-05 07:21:17

  PaaS vs. SaaS: The Differences And How To Pick The Right Option

Platform as a service (PaaS) and software as a service (SaaS) are two kinds of cloud computing products that enable businesses and their clients to deliver and use various services, respectively. Before diving into the differences between the two concepts, it’s important to take a step back and understand what a cloud service really is. Cloud computing primarily refers to large storage of data, programs, and operations that are accessible via the Internet and are not stored on a user&rsquo...

   CLOUD,PAAS,SAAS     2020-04-06 06:30:32

  Why does LinkedIn migrate to NodeJS from Ruby?

Node.js, the server-side JavaScript-based software platform used to build scalable network applications, has been all the rage among many developers for the past couple of years. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices. Because of these advantages, there are many websites are migrating to Node.js.One of them is LinkedIn. LinkedIn was initially built on Ruby...

   LinkedIn,NodeJS,Ruby     2014-03-21 23:39:25

  Native Audio with HTML5

Once upon a time, audio on the web lived primarily in the world of third-party browser plug-ins like Flash, QuickTime and Silverlight. This was not a bad world, but it had its issues.For one, most plug-ins require the user to install them, but not all users are willing (or able) to install them. Also, many players built with these plug-ins are inaccessible, making it difficult for folks who use assistive technologies to access the audio or alternative content.Then there are the front-end design ...

   Audio,HTML5,Built in,Audio tag,Video     2011-10-13 13:04:07

  Select top 3 values from each group in a table with SQL

Yesterday, my friend Liu Bing asked me a question about how to select top 3 values for each person in a database table using SQL. I think this question is interesting and it deserves some thoughts. Here I record down how to solve this issue. Assume we have a table which has two columns, one column contains the names of some people and the other column contains some values related to each person. One person can have more than one value. Each value has a numeric type. The question is we want to se...

   SQL,Correlated query,top 3     2013-05-23 03:21:25