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  Do You Make These 5 Database Design Mistakes?

Look, everyone makes mistakes. It’s true. But not all of us have the chance to make mistakes that end up costing millions of dollars in hardware and production support costs. Any one of the following five mistakes listed below will add additional costs to your company. It’s guaranteed. The costs could be hardware related (extra disk space, network bandwidth), which tend to add up quickly. The costs are also support related (bad performance, database re-design, report cre...

   Database design,Mistake,Advice,Data type,Compatibility     2012-01-03 11:25:13

  WireGuard VPN: Setup WG_VPN client App on Android phone and connect to local WG_VPN server on VM

We will show the detail steps about how to setup the WireGuard VPN client on an Android phone/pad and configure the VPN client to connect a WG_VPN server in local network. The setup process contents three main steps: Install WireGuard and create a key-pair in WireGuard client. Add the Android client peer information in the WireGuard server’s config file. Config the Android WireGuard client to connect to the server. The test environment network configuration:  Step 1. Install Wire...

   WIREGUARD,VPN,TUTORIAL     2020-10-24 08:46:42

  How does MySQL handle DROP TABLE

A few days ago, when executing DROP TABLE in MySQL, all processes including DDL and DML were hung until DROP TABLE was completed. I am confused about this phenomenon. I have reviewed the source codes of MySQL to check how MySQL internally handle DROP TABLE. When user trigger DROP TABLE command: ########################MySQL SERVER drop table######################## /* Sql_table.cc  delete (drop) tables. */bool mysql_rm_table( )   /*   Execute the drop of a normal or temporary...

   MySQL,DROP TABLE     2012-09-24 11:34:05

  CASSANDRA data model

Cassandra is an open source distributed database, it combines dynamic key/value and column oriented feature of Bigtable. Features of Cassandra are: Flexible schema, no need to design schema first, it's very convenient to add or delete strings Support range search on keys High usability, extensible. The single node error will not affect the cluster. We can think Cassandra's data model as a 4 or 5 dimensional Hash. COLUMN Columns is the smallest data unit in Cassandra, it is a 3 dimensional data...

   Cassandra,database,sort     2013-06-08 22:07:40

  XMLHttpRequest Level 2 user guide

XMLHttpRequest is a web browser interface, it makes it possible for JavaScript doing HTTP(s) communication. Microsoft's IE5 first introduced XMLHttpRequest, because it's so useful that many other browsers also adopted this. AJAX came to the front since. However, this interface is not standardized, implementation among different browsers is different, with the emerging of HTML5, W3C is considering to standardize this interface. In February 2008, they proposed a XMLHttpRequest Level 2 draft. This ...

   XMLHttpRequest, progress, upload, binary data     2012-09-19 11:51:50

  9 useful jQuery code snippets

jQuery is one of the most popular JS library among front end developers because of its functionality and usability. Here we share with you some useful jQuery code snippets which can be used in our daily front end development. 1. Smoothly return to page top $(document).ready(function() { $("a.topLink").click(function() { $("html, body").animate({ scrollTop: $($(this).attr("href")).offset().top + "px" }, { duration: 500, easing: "swing" ...

   jQuery,Code snippet     2013-07-13 00:11:10

  Difference between keystore and truststore

Security has become a vital concern in most of the online transactions nowadays. Lots of the world's most popular websites have adopted security protocols to transfer data, especially sensitive data. These security protocols including SSL/TLS which are using the private/public key exchange mechanism to establish secure connections.  The private/public key cryptography is a really important invention and it allows data to be transferred securely and solves the big problem of transferrin...

   KEYSTORE,TRUSTSTORE,SECURITY,SSL     2017-03-04 07:52:47

  Mastering Async/Await in JavaScript: A Comprehensive Guide with Examples

As a veteran JavaScript developer, I have seen the evolution of JavaScript's asynchronous programming landscape. From callbacks to promises and now async/await, JavaScript has come a long way in making it easier to handle asynchronous operations in a clean and readable manner. In this article, we will delve into the world of async/await and explore why it has become a popular choice for handling asynchronous operations in JavaScript. We will cover the basics of async/await, its syntax, and how i...

   JAVASCRIPT,COMPARISON,PROMISE,ASYNC AWAIT     2023-02-12 07:26:15

  Why are column oriented databases so much faster than row oriented databases?

I have been playing around with Hybrid Word Aligned Bitmaps for a few weeks now, and they turn out to be a rather remarkable data structure.  I believe that they are utilized extensively in modern column oriented databases such as Vertica and MonetDB. Essentially HWABs are a data structure that allows you to represent a sparse bitmap (series of 0's and 1's) really efficiently in memory.  The key trick here is the use of run length encoding to compress the bitmap into fe...

   Database,Column oriented,Speed analysis,Vertica     2012-01-29 04:27:05

  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

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