Apache Cassandra
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Apache Cassandra is a free and open-source database management system designed to handle large volumes of data across multiple commodity servers. The system prioritizes availability and scalability over consistency, making it particularly suited for systems with high write throughput requirements due to its LSM tree indexing storage layer. As a wide-column database, Cassandra supports flexible schemas and efficiently handles data models with numerous sparse columns. The system is optimized for applications with well-defined data access patterns that can be incorporated into the schema design. Cassandra supports computer clusters which may span multiple data centers, featuring asynchronous and masterless replication. It enables low-latency operations for all clients and incorporates Amazon's Dynamo distributed storage and replication techniques, combined with Google's Bigtable data storage engine model.
Apache Cassandra is a free and open-source database management system designed to handle large volumes of data across multiple commodity servers. The system prioritizes availability and scalability over consistency, making it particularly suited for systems with high write throughput requirements due to its LSM tree indexing storage layer. As a wide-column database, Cassandra supports flexible schemas and efficiently handles data models with numerous sparse columns. The system is optimized for applications with well-defined data access patterns that can be incorporated into the schema design. Cassandra supports computer clusters which may span multiple data centers, featuring asynchronous and masterless replication. It enables low-latency operations for all clients and incorporates Amazon's Dynamo distributed storage and replication techniques, combined with Google's Bigtable data storage engine model. The key space in Cassandra is a namespace that defines data replication across nodes. Therefore, replication is defined at the key space level. Below is an example of key space creation, including a column family in CQL 3.0: CREATE KEYSPACE MyKeySpace WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 3 }; USE MyKeySpace; CREATE COLUMNFAMILY MyColumns (id text, lastName text, firstName text, PRIMARY KEY(id)); INSERT INTO MyColumns (id, lastName, firstName) VALUES ('1', 'Doe', 'John'); SELECT * FROM MyColumns; Which gives: id | lastName | firstName ----+----------+---------- 1 | Doe | John (1 rows)
Management and monitoring
Cassandra is a Java-based system that can be managed and monitored via Java Management Extensions (JMX). The JMX-compliant Nodetool utility, for instance, can be used to manage a Cassandra cluster. Nodetool also offers a number of commands to return Cassandra metrics pertaining to disk usage, latency, compaction, garbage collection, and more. Since the release of Cassandra 2.0.2 in 2013, measures of several metrics are produced via the Dropwizard metrics framework, and may be queried via JMX using tools such as JConsole or passed to external monitoring systems via Dropwizard-compatible reporter plugins.
Bibliography
External links
From the OSCON 2009 talk on RDBMS vs. Dynamo, Bigtable, and Cassandra.
Text derived from https://en.wikipedia.org/w/index.php?oldid=1344024191 under CC BY-SA 4.0; modifications have been made.