is excellent, single node can handle more than 100,000 reads and writes per second;3. Low cost: This is the common feature of most distributed databases, because it is mainly open source software, there is no expensive license cost;But his flaws, the NoSQL database still has a lot of shortcomings, the common main has the following these several:1. Does not provide support for SQL: If the industry standard such as SQL is not supported, the user will h
Label:The CAP theory is the basis of a NoSQL database that represents consistency (strong consistency), availability (availability), Partition tolerance (partition fault tolerance), and the data system can only meet two of these features.C: The system is still in a consistent state after performing an operation. In a distributed system, when the update operation succeeds, all users are able to read the late
The cap principle, also known as the cap theorem, refers to consistency (consistency), availability (availability), Partition tolerance (partition fault tolerance) in a distributed system, which cannot be combined.The CAP principle is the cornerstone of a NoSQL database. Consistency (consistency). Availability (availab
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Line cap style sheet:
CAP introduction and use [Video]. cap introduction videoPreface
Many may have a better understanding of the CAP project, including her working principles and applicable scenarios. Therefore, the blogger has prepared a live broadcast to explain it to you, this video is a live video.
I didn't plan to launch this livestream, so I was not prepared for it. So some e
Tags: family basic BSP Cap art condition create default linear About five or six years ago, for the first time, it was a nosql that was already hot topic. But at that time the use of mysql,nosql for me is still new things, and not really use, just unknown. But the impression is such a picture (later Google to the picture from here): This picture is about the
From: orders
HAT-TRICK). In a distributed data system
CAP THEOREM)But this is not his hat. The CAP principle has three elements:
CONSISTENCY)
AVAILABILITY)
PARTITION TOLERANCE)The CAP principle refers to the three elements.
Up to two points can be implemented simultaneously,
It's impossible to take both of them into consideration.. Therefore, you must make a trad
Tags: style god model introduces put traditional conditional value versionAbout five or six years ago, for the first time, it was a nosql that was already hot topic. But at that time the use of mysql,nosql for me is still new things, and not really use, just unknown. But the impression is such a picture (later Google to the picture from here):This picture is about the relationship between the database (incl
About five or six years ago, for the first time, it was a nosql that was already hot topic. But at that time the use of mysql,nosql for me is still new things, and not really use, just unknown. But the impression is such a picture (later Google to the picture from here):650) this.width=650; "Src=" http://images2015.cnblogs.com/blog/1089769/201705/ 1089769-20170518084908150-1684749942.png "style=" margin:0px
(impossibility result).Engineering implications of CAPAfter the CAP theory was proposed 7 or 8 years later, the NoSQL circle used the CAP theory as a basis for countering the traditional relational database, stating that it was correct to relax the requirements of data consistency (consistency) [6], and then aroused a wide range of discussions about
Http://nathanmarz.com/blog/how-to-beat-the-cap-theorem.html
Http://kb.cnblogs.com/page/124567/
The CAP theorem indicates that a database cannot satisfy consistency, availability, and partition fault tolerance at the same time ).
However, partition fault tolerance cannot be sacrificed. Therefore, we can only make trade-offs on consistency and availability. How to handle such trade-offs is the core focus of
Do a year's freshman year project, for relational database structure or some understand, sometimes still feel that the two-dimensional table is not very comfortable. After reading an article, there is a preliminary understanding of NoSQL (Https://keen.io/blog/53958349217/analytics-for-hackers-how-to-think-about-event-data). This article is written very well, indeed written out in the actual situation of the "NoSQL
owning the CA, CP, and AP separately.
CA without P: if p is not required (partitions are not allowed), C (strong consistency) and a (availability) are guaranteed. But in fact partitions are not what you want to do, but always exist, the CA system is basically a stand-alone system, such as stand-alone database. 2PC is a concrete means to achieve strong consistency.
CP without a: If you do not require a (available), the equivalent of each request to a strong consistency between the Server, and P
strong consistency (C), achieving higher availability (A) and partition tolerance (P) is the core idea of most NoSQL databases on the market by abandoning consistency.In Amazon's well-known distributed database Dynamo, it is a similar approach: "3 copies, 2 successful after the return of success, the remaining 1 copies of the subsequent synchronization", we call this mode "final consistency"Typical representatives in this area are:
Dynamo (K
mainly emphasizes basic availability. If you need high availability, that is, pure high performance, you must sacrifice consistency or fault tolerance, the base solution has the potential to explore performance.Now the nosql movement enriches the base idea and can customize special solutions according to specific situations, such as ignoring consistency and achieving high availability. nosql should have th
want our system is highly available, then, how to sacrifice a certain consistency to ensure availability?Iv. ClusterAs you can see, the above approach combines the first two methods. In the same analysis, different data synchronization strategies are used, and the system cap is guaranteed to be different. However, the general database system will provide an optional configuration, we choose different characteristics according to different scenarios.I
evolved based on the CAP theory. The core idea is that even if it cannot reach strong consistency ), however, eventual consistency can be achieved through appropriate methods based on application characteristics. Base is short for the three phrases basically available, soft state, and eventually consistent. It is an extension of C A in CAP. Meaning of base:
(1) basically available: Basic available;
(2)
NoSQL data model (4) Summary of nosql aggregation, NoSQLBackground in the first three articles, we have introduced three databases that belong to the aggregation model in NoSQL: Key-value type, document type, and column family type. The following analyzes the common points and differences of the three aggregate data models to better understand their respective ch
Key-Value Store databaseTemporary: as memcached. The temporary key-value database stores the data in memory, which in two cases results in the loss of data, the first is the power outage, but the data content exceeds the memory size. The benefits of this treatment are very fast.Permanent type: such as Tokyo Tyrant, flare and RomaThe two are both types: Redis. Redis first data in memory, and then meet certain conditions (the default is 15 minutes more than 1 times, 5 minutes more than 10, 11 minu
, waiting for the other one to update. Many NOSQL systems work, one node updates itself locally and a background process synchronizes all other nodes accordingly ... The only problem is so you'll lose consistency of some time. For eg., a customer's call reaches your wife first and before the clerk have a chance to update your notebook, the custome R ' calls back and it reaches. Then he won ' t get a consistent reply. But the said, this is not at all a
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