Wide Column Store / Column Families

Hadoop / HBase: API: Java / any writer, Protocol: any write call, Query Method: MapReduce Java / any exec, Replication: HDFS Replication, Written in: Java, Concurrency: ?, Misc: Links: 3 Books [1, 2, 3]

Cassandra: API: many Thrift » languages, Protocol: ?, Query Method: MapReduce, Replicaton: , Written in: Java, Concurrency: eventually consistent , Misc: like "Big-Table on Amazon Dynamo alike",  initiated by Facebook, Slides » , Clients », Installation »

Hypertable:  API: Thrift (Java, PHP, Perl, Python, Ruby, etc.), Protocol: Thrift, Query Method: HQL, native Thrift API, Replication: HDFS Replication, Concurrency: MVCC, Consistency Model:  Fully consistent Misc:  High performance C++ implementation of Google's Bigtable.  Commercial support  »

Cloudera: Professional Software & Services based on Hadoop.

[SciDB: Array Data Model for Scientists, paper », poster », HiScaBlog »]
[OpenNeptune, Qbase, KDI]:

Document Store

CouchDB:  API: JSON, Protocol: REST, Query Method: MapReduceR of JavaScript Funcs, Replication: Master Master, Written in: Erlang, Concurrency: MVCC,  Misc: 
Links: 3 CouchDB books », Couch Lounge » (partitioning / clusering),  Dr. Dobbs »

MongoDB:  API: BSON, Protocol: lots of langs, Query Method: dynamic object-based language, Replication: Master Slave, Written in: C++,Concurrency: Update in Place. Misc: ... Links: Talk », Notes »

Terrastore: API: Java & http, Protocol: http, Language: Java, Querying: Range queries, Predicates, Replication: Partitioned with consistent hashing, Consistency: Per-record strict consistency, Misc: Based on Terracotta

ThruDB: (please help provide more facts!) Uses Apache Thrift to integrate multiple backend databases as BerkeleyDB, Disk, MySQL, S3.

OrientDB: Languages: Java, Schema: Has features of an Object-Database, DocumentDB, GraphDB or Key-Value DB, Written in: Java, Query Method: Native and SQL, Misc: really fast, lightweight, ACID with recovery.

RavenDB: .Net solution. Provides HTTP/JSON access. LINQ queries & Sharding supported. Misc: »

[CloudKit, Perservere, Jackrabbit »]

Key Value / Tuple Store

Amazon SimpleDB: Misc: not open source, Book »

Azure Table Storage:  Collections of free form entities (row key, partition key, timestamp). Blob and Queue Storage available, 3 times redundant. Accessible via REST or ATOM.

Riak: API: JSON, Protocol: REST, Query Method: MapReduce term matching , Scaling: Multiple Masters; Written in: Erlang, Concurrency: eventually consistent (stronger then MVCC via Vector Clocks), Misc: ... Links: talk »,

Chordless: API: Java & simple RPC to vals, Protocol: internal, Query Method: M/R inside value objects, Scaling: every node is master for its slice of namespace, Written in: Java, Concurrency: serializable transaction isolation, Links:

Redis :  API: Tons of languages, Written in: C, Concurrency: in memory and saves asynchronous disk after a defined time. Append only mode available. Different kinds of fsync policies. Replication: Master / Slave, Misc: also lists, sets, sorted sets, hashes. Cheat-Sheet: », good slides »

Scalaris: (please help provide more facts!) Written in: Erlang, Replication: Strong consistency over replicas, Concurrency: non blocking Paxos.

Tokyo Cabinet / Tyrant: Links: nice talk », slides », Misc: Kyoto Cabinet »

GT.M: API: M, C, Python, Perl, Protocol: native, inprocess C, Misc: Wrappers: M/DB for SimpleDB compatible HTTP », MDB:X for XML », PIP for mapping to tables for SQL », Features: Small footprint (17MB), Terabyte Scalability, Unicode support, Database encryption, Secure, ACID transactions (single node), eventual consistency (replication), License: AGPL v3 on x86 GNU/Linux, Links: Slides »,

MEMBASE: distributed K/V store. Apache 2.0 license. Article: »
NorthScale: based on Memcached

Keyspace:  API / Protocol: http (text, html, JSON), C, C++, Python, Java, Ruby, PHP,Perl. Concurrency: Paxos.

Berkeley DB: API: Many languages, Written in: C, Replication: Master / Slave, Concurrency: MVCC, License: Sleepycat, Berkeley DB Java Edition: API: Java, Written in: Java, Replication: Master / Slave, Concurrency: serializable transaction isolation, License: Sleepycat

MemcacheDB: API: Memcache protocol (get, set, add, replace, etc.), Written in: C, Data Model: Blob, Misc: Is Memcached writing to BerkleyDB.

HamsterDB:  (embedded solution) ACID Compliance, Lock Free Architecture (transactions fail on conflict rather than block), Transaction logging & fail recovery (redo logs), In Memory support – can be used as a non-persisted cache, B+ Trees – supported [Source: Tony Bain »]

Faircom C-Tree: API: C, C++, C#, Java, PHP, Perl, Written in: C,C++. Misc: Transaction logging. Client/server. Embedded. SQL wrapper (not core). Been around since 1979.

Mnesia: (ErlangDB »)

LightCloud:  (based on Tokyo Tyrant)

Pincaster: For geolocalized apps. Concurrency: in-memory with asynchronous disk writes. API: HTTP/JSON. Written in: C. License: BSD.

GenieDB: Immediate consistency sharded KV store with an eventually consistent AP store bringing eventual  consistency issues down to the theoretical minimum. It features efficient record coalescing. GenieDB speaks SQL and co-exists /  do intertable joins with SQL RDBMs.

[KaTree », TomP2P », Kumofs » ,NMDB, luxio, actord, keyspace, flare, schema-free, RAMCloud]

Amazon Dynamo: Misc: not open source (see KAI below)

Voldemort: Open-Source implementation of Amazons Dynamo Key-Value Store.

Dynomite: Open-Source implementation of Amazons Dynamo Key-Value Store. written in Erlang. With "data partitioning, versioning, and read repair, and user-provided storage engines provide persistence and query processing".

KAI: Open Source Amazon Dnamo implementation, Misc: slides ,

[SubRecord, Mo8onDb, Dovetaildb]

Graph Databases

Object Databases

db4o: API: Java, C#, .Net Langs, Protocol: language, Query Method: QBE (by Example), Soda, Native Queries, LINQ (.NET),  Replication: db4o2db4o & dRS to relationals, Written in: Java,  Cuncurrency: ACID serialized, Misc: embedded lib, Links: DZone Refcard #53 », Book », 

Versant: Languages/Protocol: Java, C#, C++, Python. Schema: language class model (easy changable). Modes: always consistent and eventually consistent  Replication: synchronous fault tolerant and peer to peer asynchronous. Concurrency:  optimistic and object based locks. Scaling: can add physical nodes on fly for scale out/in and migrate objects between nodes without impact to application code. Misc: MapReduce via parallel SQL like query across logical database groupings.

Objectivity: Languages: Java, C#, C++, Python, Smalltalk, SQL access through ODBC. Schema: native language class model, direct support for references, interoperable across all language bindings. 64 bit unique object ID (OID) supports multi exa-byte.  Platforms: 32 and 64 bit Windows, Linux, Mac OSX, *Unix. Modes: always consistent (ACID).  Concurrency: locks at cluster of objects (container) level. Scaling: unique distributed architecture, dynamic addition/removal of clients & servers, cloud environment ready. Replication: synchronous with quorum fault tolerant across peer to peer partitions.

[Gemstone, Progress ]

Perst: API: Java,Java ME,C#,Mono. Query method: OO via Perst collections, QBE, Native Queries, LINQ, native full-text search, JSQL Replication: Async+sync (master-slave) Written in: Java, C#.
Caching: Object cache (LRU, weak, strong), page pool, in-memory database Concurrency: Pessimistic+optimistic (MVCC) + async or sync (ACID) Index types: Many tree models + Time Series. Misc.: Embedded lib., encryption, automatic recovery, native full text search, on-line or off-line backup. 

ZODB: API:  Python, Protocol:  Internal, ZEO, Query Method: Direct object access, zope.catalog, gocept.objectquery, Replication: ZEO, ZEORAID, RelStorage Written in:  Python, C Concurrency:  MVCC, License: Zope Public License (OSI approved) Misc:Used in production since 1998

NEO:  API: Python - ZODB "Storage" interface,  Protocol: native,  Query Method: transactional key-value,  Replication: native,  Written in: Python,  Concurrency: MVCC at ZODB level,  License: GPL "v2 or later",  Misc: Load balancing, fault tolerant, hot-extensible.

StupidDB », KiokuDB » (Perl solution),

Grid Database Solutions

GigaSpaces: Popular SpaceBased Grid Solution:

Hazelcast: P2P Data Grid Solution on java.util.*, On a 100 Noce EC2 Cluster »

Joafip:

GridGain, Infinispan, Coherence, eXtremeScale

XML Databases

Mark Logic Server:  (commercial system) API: Java, .NET Protocols: HTTP, REST Query Method: XQuery, XSLT Written in: C++ (code closed, API open) Concurrency: Share-nothing cluster architecture Misc: Petabyte-scalable XML server. Cloudable. Combines application server, transactional persistent storage (XML, text, and binary), and a full-text search engine. Developer Network »

EMC Documentum xDB:   (commercial system) API: Java, XQuery, Protocol: WebDAV, web services, Query method: XQuery, XPath, XPointer, Replication: lazy primary copy replication (master/replicas), Written in: Java, Concurrency: concurrent reads, writes with lock; transaction isolation, Misc: Fully transactional persistent DOM; versioning; multiple index types; metadata and non-XML data support; unlimited horizontal scaling. Developer Network »

Tamino:

eXist: API: XQuery, XML:DB API, DOM, SAX, Protocols: HTTP/REST, WebDAV, SOAP, XML-RPC, Atom, Query Method: XQuery, Written in: Java (open source), Concurrency: Concurrent reads, lock on write; Misc: Entire web applications can be written in XQuery, using XSLT, XHTML, CSS, and Javascript (for AJAX functionality). (1.4) adds a new full text search index based on Apache Lucene, a lightweight URL rewriting and MVC framework, and support for XProc.

Sedna: Misc: ACID transactions, security, indices, hot backup. Flexible XML processing facilities include W3C XQuery implementation, tight integration of XQuery with full-text search facilities and a node-level update language.

Xindice:

Qizx:  Open Source version, written in Java, http server.

Berkeley DB XML: API: Many languages, Written in: C++, Query Method: XQuery, Replication: Master / Slave, Concurrency: MVCC, License: Sleepycat

Multivalue Databases

U2 (UniVerse, UniData): MultiValue Databases, Data Structure: MultiValued, Supports nested entities, Virtual Metadata, API: BASIC, InterCall, Socket, .NET and Java API's, IDE: Native, Record Oriented, Scalability: automatic table space allocation, Protocol: Client Server, SOA,  Terminal Line, X-OFF/X-ON, Written in: C, Query Method: Native mvQuery, (Retrieve/UniQuery) and SQL, Replication: yes, Hot standby, Concurrency: Record and File Locking (Fine and Coarse Granularity)

OpenInsight: API:  Basic+, .Net, COM, Socket, ODBC, Protocol: TCP/IP, Named Pipes, Telnet, VT100. HTTP/S Query Method: RList, SQL & XPath Written in: Native 4GL, C, C++, Basic+, .Net, Java  Replication: Hot Standby Concurrency: table &/or row locking, optionally transaction based & commit & rollback Data structure: Relational &/or MultiValue, supports nested entities Scalability: rows and tables size dynamically

other NoSQL related databases

IBM Lotus/Domino: Type: Document Store, API: Java, HTTP, IIOP, C API, REST Web Services, DXL, Languages: Java, JavaScript, LotusScript, C, @Formulas, Protocol: HTTP, NRPC, Replication: Master/Master, Written in: C
Concurrency: Eventually Consistent, Scaling: Replication Clusters

eXtremeDB: Type: In-Memory Database; Written in: C; API: C/C++, SQL, JNI; Replication: Async+sync (master-slave), Scalability: 64-bit and MVCC

ISIS Family: (semistructured databases) »

Prevayler: Java RAM Data structure journalling.

Yserial: Python wrapper over sqlite3

unresolved and uncategorized