MapReduce - Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/MapReduce
MapReduce is a programming model and an associated implementation for processing and ... for a variety of applications by optimizing the execution engine once. ... disk-oriented mechanisms that incorporated full map and reduce capabilities. ... Run the user-provided Reduce() code – Reduce() is run exactly once for .
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NoSQL
From Wikipedia, the free encyclopedia
"Structured storage" redirects here. For the Microsoft technology also known as structured storage, see COM Structured Storage.
A NoSQL (originally referring to "non SQL" or "non relational")[1] database provides a mechanism for storage and retrieval of data which is modeled in means other than the tabular relations used in relational databases. Such databases have existed since the late 1960s, but did not obtain the "NoSQL" moniker until a surge of popularity in the early twenty-first century,[2] triggered by the needs of Web 2.0 companies such as Facebook, Google and Amazon.com.[3][4][5] NoSQL databases are increasingly used in big data and real-time web applications.[6] NoSQL systems are also sometimes called "Not only SQL" to emphasize that they may supportSQL-like query languages.[7][8]
Motivations for this approach include: simplicity of design, simpler "horizontal" scaling to clusters of machines (which is a problem for relational databases),[2] and finer control over availability. The data structures used by NoSQL databases (e.g. key-value, wide column, graph, or document) are different from those used by default in relational databases, making some operations faster in NoSQL. The particular suitability of a given NoSQL database depends on the problem it must solve. Sometimes the data structures used by NoSQL databases are also viewed as "more flexible" than relational database tables.[9]
Many NoSQL stores compromise consistency (in the sense of the CAP theorem) in favor of availability, partition tolerance, and speed. Barriers to the greater adoption of NoSQL stores include the use of low-level query languages (instead of SQL, for instance the lack of ability to perform ad-hoc JOINs across tables), lack of standardized interfaces, and huge previous investments in existing relational databases.[10] Most NoSQL stores lack true ACID transactions, although a few databases, such as MarkLogic, Aerospike, FairCom c-treeACE, Google Spanner (though technically a NewSQL database), Symas LMDB and OrientDB have made them central to their designs. (See ACID and JOIN Support.)
Instead, most NoSQL databases offer a concept of "eventual consistency" in which database changes are propagated to all nodes "eventually" (typically within milliseconds) so queries for data might not return updated data immediately or might result in reading data that is not accurate, a problem known as stale reads.[11]Additionally, some NoSQL systems may exhibit lost writes and other forms of data loss.[12] Fortunately, some NoSQL systems provide concepts such as write-ahead logging to avoid data loss.[13] For distributed transaction processing across multiple databases, data consistency is an even bigger challenge that is difficult for both NoSQL and relational databases. Even current relational databases "do not allow referential integrity constraints to span databases."[14] There are few systems that maintain both ACID transactions and X/Open XA standards for distributed transaction processing..
Agent and Multi-Agent Systems: Technologies and ...
https://books.google.com/books?isbn=3642016642
Anne Hakansson, Ronald Hartung - 2009 - Computers
It is also important to discuss about driving role execution highlighting the ... The second service provides the MR engine with values given to the parameters. ... to answer to a request, we consider that agents have a set of basic capabilities.Hive on Tez - Apache Hive - Apache Software Foundation
https://cwiki.apache.org/.../Hive+on+Tez
Jul 14, 2015 - Hive uses map-reduce as its execution engine. Any query will produce a graph of MR jobs potentially interspersed with some local/client-side ...
Apache Software Foundation
Hive on Spark - Apache Hive - Apache Software Foundation
https://cwiki.apache.org/.../Hive+on+Spark
Jan 12, 2015 - To use Spark as an execution engine in Hive, set the following: set hive.
Apache Software Foundation
A Cyclopædia of the Physical Sciences: Comprising ...
https://books.google.com/books?id=bxY5AAAAMAAJ
John Pringle Nichol - 1860 - Science
Now, Mr. s's enterprise was this, — he undertook to construct an engine capable ...Engine, to be a mere expression or possession of capability to execute all the ...A Cyclopædia of the Physical Sciences ... Maps, ...
https://books.google.com/books?id=xylbAAAAcAAJ
During the process of the construction of the Defermce Engine, Mr. Babbage's ...Engine, to be a mere expression or possession of capability to execute all the ...Interactive Query for Hadoop with Apache Hive on Apache Tez
hortonworks.com/.../supercharging-interactive-queries-hive...
By default, the Hive view runs with Tez as it's execution engine. That's because ... Select this property and then for it's value select, mr (short for MapReduce).
Hortonworks
Apache Hive on Apache Spark: Motivations and Design ...
blog.cloudera.com/.../apache-hive-on-apache-spark-motivations...
Jul 1, 2014 - Until recently, MapReduce was the only execution engine in the ... Furthermore, users will have access to a robust, non-MR execution engine that has .... shuffle capability, such as partitionBy , groupByKey , and sortByKey .
Cloudera
Big Data Reporting Services and Myth Busting | HCL ...
www.hcltech.com › ... › Big Data and Analytics
Sep 2, 2015 - Hive, the oldest SQL on Hadoop solution, is known to be slow as it relies on M/R for providing the execution engine capability. It connects to BI ...
HCL Technologies
The Semantic Web - ISWC 2003: Second International ...
https://books.google.com/books?isbn=3540397183
Katia Sycara, John Mylopoulos - 2003 - Computers
Semantic email: Adding lightweight data manipulation capabilities to the email habitat. In Sixth ... An adaptive query execution engine for data integration. In Proc. of SIGMOD, pages 299–310, 1999. J. Kahan and M.-R. Koivunen. Annotea: an ..
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