scenariosEvent recordsContent Management System and blog platformWebsite analysis and real-time analysisE-commerce applications(A flexible mode is required to establish a data model at a low cost)
Unsuitable scenariosComplex queries that contain multiple operationsQuery continuously changing aggregate structures
Column Family database
ProductHBaseAmazon SimpleDBCassdndraHypertableBigTable (google)
Applicable scenariosEvent records(Save
Recently, an explosive news came out in the database field. Some experts have proposed open-source NoSQL projects. Simply put, they want to overturn the original Relational Database
Recently, an explosive news came out in the database field. Some experts have proposed open-source NoSQL projects. Simply put, they want to overturn the original Relational Database
Recently, an explosive news came out in t
pattern, and often avoids the use of SQL join operations, generally have the characteristics of horizontal scalability.
NoSQL history?
1, the word NoSQL first appeared in 1998, is a lightweight, open source, and does not provide SQL function database for Carlo Strozzi development.In 2, 2009, Last.fm's Johan Oskarsson launched a discussion on distributed open source databases, and Eric Evans from Rackspac
NoSQL series: Redis (1)
Redis environment preparation rredis function library rredis basic Use Cases
Each chapter is divided into "text description" and "code section" to ensure consistency between the text description and the code.
Chapter 1 prepare the Redis Environment
Text description:
First, prepare the environment. Here I chose the 64-bit server version of Linux Ubuntu operating system 12.04. You can
Tags: style blog http using OS dataContent directory:
Why use a NoSQL database?
Key-Value Database
Document Database
Column Family Database
Graph database
Attached Mind Map
Reference
NoSQL Series: Choosing the right database why use a NoSQL database?
Impedance imbalanceRel
0. IntroductionNoSQL (NoSQL = not-only sql), meaning "not just SQL," refers to a non-relational database, because NoSQL is more than just a database. Like MySQL and Oracle in relational databases, NoSQL also has memcached, MongoDB, and Redis.NoSQL Database Storage principle is very simple (the typical data type is k-v), there is no complex chain of relationships,
is treated as an key empty string, so an operation that does not exist key BITCOUNT results in0eg> Set name 123OK> Get name"123"> Bitcount nameTen> Bitcount nameTen> Bitcount Count0> Set Test 1OK> Get Test"1"> Bitcount Test3> Set name 0OK> Get Naem(nil)> Get name"0"> Bitcount name2> Set name 3OK> Get name"3"> Bitcount name4(one): GetRange key Start endGets the specified substring of the valu corresponding to the keyeg:> Set name JilindaxueOK> GetRange Name 1 4"Ilin"(+1): incr key increment that
1 time series and stochastic processes
Random variable sequence Y t:t=0,±1,±2,±3,... is called a stochastic process and is used as a model for observing time series. 2 mean, variance and covariance
For the random process Y t:t=0,±1,±2,±3,..., the mean function is defined as follows:Μt =e (Y t), t=0,±1,±2,...That is, μt
From:http://www.cnblogs.com/kemaswill/archive/2013/04/01/2993583.htmlIn the time series, we need to predict the following trend based on the current data of the time series, and the three exponential smoothing (Triple/three Order exponential smoothing,holt-winters) algorithm can predict the
Tags: Layer III ase HTTPS article Zabbix storage thinking dataWThinking about the time series database-csdn.net http://www.csdn.net/article/2015-07-13/2825192Store and process timeseries data ("Time series Databases" chapter III) 1190000002797644 selection criteria for time
First of all, from the point of view of time can be a series of basically divided into 3 categories:
1. Pure random sequence (white noise sequence), this time can stop the analysis, because it is like predicting the next coin which side is as irregular as possible.
2. Stationary non-white noise sequences , whose mean and variance are constants, for such sequences
This learning note is from the "Time series analysis-based on R" written by teacher Wang
After the preprocessing of a time series, it is shown that the model has the value of extracting information, then the next model is established to make the prediction. Here are three important models for fitting
DDoS attacks are essentially time-series data, and the data characteristics of t+1 moments are strongly correlated with T-moments, so it is necessary to use HMM or CRF for detection! --and a sentence of the word segmentation algorithm CRF no difference!Note: Traditional DDoS detection is directly based on the IP data sent traffic to identify, through the hardware firewall. Big data scenarios are done for sl
Project questions:When a new user logs on to the mailbox of OWA, it's always time to set the time zone, if it's a test, it doesn't matter.If it is production, you have thousands of people of the enterprise, this certainly is not possible.Workaround:The following workaround is provided by a student that I have not cared about because I do not care about the enterprise it, but this is useful for each student,
interval of those parameters), and the randomness of the individual associated with the specific point of the prediction.For example, a study found that the prediction interval was calculated to include real results 95% of the time only between 71% and 87% of the time to get it (thanks to Hyndman again on his blog easy to get the results). There are many reasons, but the main reason is that uncertainty in
fully dynamic applications through the Web. These applications usually need to be as fast as possible to provide near-real-time components. In this 5-part new series, we will learn how to use reverse Ajax (reverse Ajax) technology to develop event-driven Web applications.
In this first article, we need to understand reverse Ajax, polling, streaming, Comet, and long polling ). Learn how to implement differe
value. The default value for the date-time Data Type field column can be set to this "1900-01-01" base date. SQL Server provides a datetime date-time data type that internally uses two 4-byte integers to store the data value. The first 4 bytes stores the number of days before or after the base date (that is, January 1, 1900). The base date is the system reference date. Another 4-byte storage day, expresse
Linux2.6 kernel process scheduling series -- scheduler_tick () function 2. Update the time slice of the real-time process,
RT
/*** Decrease the time slice counter of the current process and check whether the time slice has been used up. * The operations executed by functions
[Best Practices Series] PHP date, time and time zone Processing API and component processing date and time need to consider a lot of things, such as the date format, time zone, leap year and days of different months, self-processing is too error-prone. we should use the Date
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