as hash

Redis is a memory-based database with all the data stored in memory. So how to optimize storage and reduce memory footprint is a very important topic. Thin key names and key values are the most intuitive way to reduce memory footprint, such as

The basic idea of the Sub-Library table The basic idea of sharding is to divide a database into several parts and put it on a different database (server) to alleviate the performance problem of a single database. Not too strictly speaking, for a

The debugger statement does not start the debugger. However, if the debugger is already running, this statement will actually produce a breakpoint. For example, if you use the Firefox debug extension Firebug, you must first enable Firebug for the

The most notable feature of linux® is flexibility and extensibility, such as its virtual file system exchanger (VFS). You can create file systems on a variety of devices, including traditional disks, USB flash drives, memory, and other storage

Let's talk a little bit. Top k algorithm, the specific contents are as follows Application Scenario: The search engine logs all the search strings used by the user for each retrieval using a log file, with a length of 1-255 bytes per query

I remember just beginning to learn Java, one encounter multithreading situation is synchronized, relative to us at that time synchronized is so magical and powerful, at that time we give it a name "sync", Also become our solution to multithreading

There are a lot of plug-ins in the eclipse environment that can help us with the static analysis of the code, which can help us find bugs in the code as early as possible. Here are a few common plug-ins: 1. PMD We can install the PMD plug-in for

2.PHP Getting Started The online tutorials on the PHP site have been great. There are also links to some other tutorials. This section of this article will give you a bit of familiarity with PHP. I can not do without any omission, my purpose is to

A flexible string. Because of the flexibility of the expression, we can use the "mapping" method to bring up a string or function. $a = ' B '; $b = ' 123 '; echo $ $a; This can output 123. But the better habit is the echo ${$a}, which is clearer. $c

A basic table new two tables: Table1 and table2 Table 1 (id,uid,name), the UID is a set of foreign keys, the foreign key does not have to set the automatic self increase and unsigned place do not draw √. ID as the primary key, set to self increase.

Lightweight locks The JDK1.6 appeared. It is not a substitute for a heavyweight lock, which is meant to reduce the performance consumption of traditional heavyweight locks using operating system mutexes without multiple threading competition.

Digital signature is only the sender of information can be produced by others can not forge a string of numbers, this string is also the sender of information to send information authenticity of a valid proof. The combination of asymmetric key

Concept: Sequencefile is a text storage file consisting of a binary serialized Key/value byte stream, which can be used during the input/output format of the map/reduce process. During the map/reduce process, the temporary output of map processing

"Definition": 1. Hash function: Establish a deterministic correspondence between the stored location of the record and its keyword ƒ, which corresponds to a unique storage location in each keyword and structure, which is called the ƒ (hash function

2016-07-16 Hotspot Virtual Machine Object Issue 1: How to resolve both object A and object B to allocate memory using the original pointer when allocating memory space. There are two ways to solve this problem: 1) synchronous processing of the

In the previous series, we introduced sequential lookups based on unordered lists, binary lookups based on ordered arrays, balanced lookup trees, and red and black trees, with their time complexity in the mean and worst cases: It can be seen that

Turn from: 51333169Let's start the tutorial with a simple example that explains why we need a database index. Let's say we have a database table Employee, and this table has three fields (columns), Employee_Name, Employee_age, and employee_address,

What is load balancing Load balancing, the English name is load Balance, refers to the multiple servers in a symmetric way to form a collection of servers, each server has an equivalent status, can be provided separately from external services

A. Question and answer: 1. A simple description of how to install a Apache open source version of Hadoop, only described, no need to list the full steps, to list the steps better. 1) Install the JDK and configure environment variables (/etc/profile)

Storage EngineWhat is a storage engine?The library built in MySQL is a folder, and the built table is a file. There are different types of files, the tables in the database have different types, the table type is different, it will correspond to the