Embed Size (px)
DESCRIPTION
Citation preview
NoSQL研究⽣生 鍾聖彥
指導⽼老師 李永⼭山教授
NoSQL 意指不僅僅是 SQL
Introduction
• NoSQL⼀一詞最早出現於1998年，是Carlo Strozzi開發的⼀一個輕量、開放原始碼、不提供SQL功能的關係資料庫
• 2009年來⾃自Rackspace的Eric Evans再次提出了NoSQL的概念，這時的NoSQL主要指⾮非關係型、分布式、不提供ACID的資料庫設計模式。（為聚會取名⼦子>>>NoSQL）
• NoSQL資料庫通常都是基於21世紀早期網站需求⽽而設計
• 聚焦在叢集上的巨量資料
NoSQL是⼀一個不⼩小⼼心被創⽴立的名詞
NoSQL資料庫的共通特性•不使⽤用關聯式模型
•在叢集上可以良好執⾏行
•開放原始碼
•爲21世紀的網站所建⽴立
•無綱要的
•不使⽤用SQL作為查詢語⾔言
為什麼要⽤用 NoSQL？(1/2) • 管理⼤大規模資料：NoSQL 資料庫能輕易處理⼤大量的讀寫週期、眾多⽤用⼾戶，以及數以 petabytes 計的資料。
(petabytes =250 bytes; 1024 terabytes, or a million gigabytes.)
• 不需要資料庫綱要 (Schema)：當涉及到綱要建構時，它們提供了相當廣泛的選擇空間，能輕易地和物件相對應。
• 開發者親和性：NoSQL 資料庫對各主要程式語⾔言提供了簡單的 API，因此再也⽤用不著複雜的 ORM 框架。如果特定程式語⾔言沒有 API 可⽤用時，還是可以透過簡單的 Restful API，使⽤用 XML 以及 JSON 格式經由 HTTP 存取資料。
• 可⽤用性： 多數分散式 NoSQL 資料庫都提供簡易的資料複製，單⼀一節點的毀損較不會影響資料的可⽤用性。
• 延展性：NoSQL 資料庫不需要專⽤用的⾼高效能伺服器。輕易地運⾏行在⼀一般硬體組成的叢集上。
• 低延遲
為什麼要⽤用 NoSQL？(2/2)
Do not fully support relational features no join operations (except within partitions), no referential integrity constraints across partitions.
How did we get?
• Explosion of social media sites (Google,Facebook, Twitter) with large data needs
• Rise of cloud-based solutions such as Amazon S3 (simple storage solution)
• Open-source community
Who influences？
Dynamo and BigTable
• Three major papers were the seeds of the NoSQL movement:
BigTable (Google)
Dynamo (Amazon)
• CAP Theorem
CAP Theorem• ⼜又被稱作 布魯爾定理（Brewer's theorem）
• Brewer’s CAP “Theorem”: for any system sharing data it is impossible to guarantee simultaneously all of these three properties：
• Consistency: all nodes see the same data at the same time
• Availability: a guarantee that every request receives a response about whether it was successful or failed
• Partition tolerance: the system continues to operate despite arbitrary message loss or failure of part of the system
CAP Theorem!
• Very large systems will partition at some point： It is necessary to decide between C and A !• Traditional DBMS prefer C over A and P !• Most Web applications choose A (except in specific
applications such as order processing)
NoSQL database
NoSQL 資料模型(1/2)• Key-value Stores:⼀一般只包含⼀一系列的全域鍵值對，每個值各伴隨有獨特的鍵
• Document stores：模型的著名實作包括 MongoDB、CouchDB、RavenDB
• Column-oriented：Google 針對內部使⽤用的 BigTable 分散式儲存系統，發表研究論⽂文之後，以列為導向的資料庫知名的其他實作包括 Hadoop Hbase、Apache Cassandra、HyperTable
• 圖形 (Graph)：適合⽤用來記錄任何擁有複雜關係的資料，如社群網路、產品偏好或是任何規則等。ex: Twitter ⽤用以實現⽤用⼾戶追蹤 (follow) 圖形的 FlockDB.
!
• Hierarchical :These databases store data in the form of hierarchical relevance, that is, tree or parent-child relationship.
ex:階層式資料庫著名的實作包括 Microsoft 的 Windows Registry 與 IBM 的 IMS 資料庫
• Triple stores:Triple stores save data in the form of subject-predicate-object with the predicate being the linking factor between subject and object.
NoSQL 資料模型(2/2)
Support Semantic Web and RDF Storage
Complexity
Key-value StoresExtremely simple interface Data model: (key, value) pairs Operations: Insert(key,value), Fetch(key), Update(key), Delete(key) Implementa2on: efficiency, scalability, fault-‐tolerance • Records distributed to nodes based on key • Replication • Single-record transactions, “eventual consistency” • Riak – Based on Amazon’s Dynamo.Example systems Google BigTable, Amazon Dynamo, Cassandra, Voldemort, HBase, …
Key-value Stores
!• Riak – Based on Amazon’s Dynamo.
Suitable or Not suitable
合適的使⽤用狀況 不適合使⽤用狀況
儲存網路通訊對話資訊 取得不同資料間的關係
使⽤用者喜好設定 多個鍵值操作
購物⾞車資料 ⽤用資料來查詢
Document storesLike Key-Value Stores except value is document
Data model: (key, document) pairs Document: JSON, XML, other semistructured formats Basic operations: Insert(key,document), Fetch(key), Update(key), Delete(key) Also Fetch based on document contents.
Example systems CouchDB, MongoDB, SimpleDB, …
Document stores
Suitable or Not suitable
合適的使⽤用狀況 不適合使⽤用狀況
事件歷史記錄 包含多種複雜交易
內容管理系統、部落格 在不同叢集結構上查詢
網路分析、即時資料分析
Column-orientedBased on JSON format: a data model which supports lists, maps, dates, Boolean with nesting Really: indexed semistructured documents !
Example: Mongo { Name:"Jaroslav",
Address:"Malostranske nám. 25, 118 00 Praha 1“ Grandchildren: [Claire: "7", Barbara: "6", "Magda: "3", "Kirsten: "1", "Otis: "3", Richard: "1"] }
Column-oriented
Column-oriented
Id username email Department
1 John [email protected] Sales
2 Mary [email protected] Marketing
3 Yoda [email protected] IT
Id
1
2
3
Username
John
Mary
Yoda
Department
Sales
Marketing
IT
Row oriented
Column oriented
Suitable or Not suitable
合適的使⽤用狀況 不適合使⽤用狀況
事件歷史記錄 讀取或寫⼊入ACID交易系統
內容管理系統、部落格平台 開發初期階段
限期使⽤用(廣告推播) 查詢變更(COST)
Graph stores
• Data model: nodes and edges • Nodes may have properties (including ID) • Edges may have labels or roles
• Interfaces and query languages vary • Example systems: Neo4j, FlockDB, Pregel, … • RDF “triple stores” can map to graph databases
Graph stores
Graph stores
Suitable or Not suitable
合適的使⽤用狀況 不適合使⽤用狀況
社群網路發佈 更新全部或實體⼦子集
轉發、傳遞基於位置的服務
Recommendation
Conclusion and DiscussNoSQL database cover only a part of data-intensive cloud applications (mainly Web applications). !
Problems with cloud computing: • SaaS applications require enterprise-level functionality,
including ACID transactions, security, and other features associated with commercial RDBMS technology, i.e.
!• NoSQL should not be the only option in the cloud. !!!
Conclusion and Discuss!
!
Hybrid solutions: Voldemort with MySQL as one of storage backend
deal with NoSQL data as semistructured data integrating RDBMS and NoSQL via SQL/XML
!
Reference
http://www.ithome.com.tw/itadm/article.php?c=63360&s=5
http://www.openfoundry.org/index.php?option=com_content&task=view&id=9040&Itemid=4;isletter=1
http://www.julianbrowne.com/article/viewer/brewers-cap-theorem
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.20.1495
Book:搞懂NoSQL的15堂課（Pramod J. Sadalage、Martin Fowler）
End
