DBMS > Cassandra vs. Datomic vs. Firebase Realtime Database vs. Kdb vs. Microsoft Azure Data Explorer

System Properties Comparison Cassandra vs. Datomic vs. Firebase Realtime Database vs. Kdb vs. Microsoft Azure Data Explorer

Editorial information provided by DB-Engines

Name

Description

Wide-column store based on ideas of BigTable and DynamoDB

Optimized for write access

Datomic builds on immutable values, supports point-in-time queries and uses 3rd party systems for durability

Cloud-hosted realtime document store. iOS, Android, and JavaScript clients share one Realtime Database instance and automatically receive updates with the newest data.

High performance Time Series DBMS

Fully managed big data interactive analytics platform

Primary database model

Wide column store

Relational DBMS

Document store

Time Series DBMS
Vector DBMS

Relational DBMS

column oriented

Secondary database models

Vector DBMS

starting with release V5

Relational DBMS

Document store

If a column is of type dynamic docs.microsoft.com/en-us/azure/kusto/query/scalar-data-types/dynamic then it's possible to add arbitrary JSON documents in this cell
Event Store

this is the general usage pattern at Microsoft. Billing, Logs, Telemetry events are stored in ADX and the state of an individual entity is defined by the arg_max(timestamps)
Spatial DBMS
Search engine

support for complex search expressions docs.microsoft.com/en-us/azure/kusto/query/parseoperator FTS, Geospatial docs.microsoft.com/en-us/azure/kusto/query/geo-point-to-geohash-function distributed search -> ADX acts as a distributed search engine
Time Series DBMS

see docs.microsoft.com/en-us/azure/data-explorer/time-series-analysis

DB-Engines Ranking measures the popularity of database management systems
Trend Chart

Score	98.83
Rank	#12	Overall
	#1	Wide column stores

Score	1.66
Rank	#144	Overall
	#66	Relational DBMS

Score	13.64
Rank	#39	Overall
	#6	Document stores

Score	7.71
Rank	#49	Overall
	#2	Time Series DBMS
	#1	Vector DBMS

Score	3.80
Rank	#81	Overall
	#43	Relational DBMS

Website

cassandra.apache.org

www.datomic.com

firebase.google.com/products/realtime-database

kx.com

azure.microsoft.com/services/data-explorer

Technical documentation

cassandra.apache.org/doc/latest

docs.datomic.com

firebase.google.com/docs/database

code.kx.com

docs.microsoft.com/en-us/azure/data-explorer

Developer

Apache Software Foundation

Apache top level project, originally developped by Facebook

Cognitect

Google

acquired by Google 2014

Kx Systems, a division of First Derivatives plc

Microsoft

Initial release

2008

2012

2000

kdb was released 2000, kdb+ in 2003

2019

Current release

4.1.3, July 2023

1.0.6735, June 2023

3.6, May 2018

cloud service with continuous releases

License

Commercial or Open Source

Open Source

Apache version 2

commercial

limited edition free

commercial

free 32-bit version

commercial

Cloud-based only

Only available as a cloud service

yes

DBaaS offerings (sponsored links)

Database as a Service

Providers of DBaaS offerings, please contact us to be listed.

Astra DB: Multi-cloud DBaaS built on Apache Cassandra.

Implementation language

Java

Java, Clojure

Server operating systems

BSD
Linux
OS X
Windows

All OS with a Java VM

hosted

Linux
OS X
Solaris
Windows

hosted

Data scheme

schema-free

yes

schema-free

yes

Fixed schema with schema-less datatypes (dynamic)

Typing

predefined data types such as float or date

yes

bool, datetime, dynamic, guid, int, long, real, string, timespan, double: docs.microsoft.com/en-us/azure/kusto/query/scalar-data-types

XML support

Some form of processing data in XML format, e.g. support for XML data structures, and/or support for XPath, XQuery or XSLT.

yes

Secondary indexes

restricted

only equality queries, not always the best performing solution

yes

table attribute 'grouped'

all fields are automatically indexed

SQL

Support of SQL

SQL-like SELECT, DML and DDL statements (CQL)

SQL-like query language (q)

Kusto Query Language (KQL), SQL subset

APIs and other access methods

Proprietary protocol

CQL (Cassandra Query Language, an SQL-like language)
Thrift

RESTful HTTP API

Android
iOS
JavaScript API
RESTful HTTP API

HTTP API
JDBC
Jupyter
Kafka
ODBC
WebSocket

Microsoft SQL Server communication protocol (MS-TDS)
RESTful HTTP API

Supported programming languages

C#
C++
Clojure
Erlang
Go
Haskell
Java
JavaScript

Node.js
Perl
PHP
Python
Ruby
Scala

Clojure
Java

Java
JavaScript
Objective-C

C
C#
C++
Go
J
Java
JavaScript
Lua
MatLab
Perl
PHP
Python
R
Scala

.Net
Go
Java
JavaScript (Node.js)
PowerShell
Python
R

Server-side scripts

Stored procedures

yes

Transaction Functions

limited functionality with using 'rules'

user defined functions

Yes, possible languages: KQL, Python, R

Triggers

yes

By using transaction functions

Callbacks are triggered when data changes

yes

with views

yes

see docs.microsoft.com/en-us/azure/kusto/management/updatepolicy

Partitioning methods

Methods for storing different data on different nodes

Sharding

no "single point of failure"

none

But extensive use of caching in the application peers

horizontal partitioning

Sharding

Implicit feature of the cloud service

Replication methods

Methods for redundantly storing data on multiple nodes

selectable replication factor

Representation of geographical distribution of servers is possible

none

But extensive use of caching in the application peers

Source-replica replication

yes

Implicit feature of the cloud service. Replication either local, cross-facility or geo-redundant.

MapReduce

Offers an API for user-defined Map/Reduce methods

yes

similar paradigm used for internal processing

Spark connector (open source): github.com/Azure/azure-kusto-spark

Consistency concepts

Methods to ensure consistency in a distributed system

Eventual Consistency
Immediate Consistency

can be individually decided for each write operation

Immediate Consistency

Eventual Consistency

if the client is offline
Immediate Consistency

if the client is online

Immediate Consistency

Eventual Consistency
Immediate Consistency

Foreign keys

Referential integrity

yes

Transaction concepts

Support to ensure data integrity after non-atomic manipulations of data

Atomicity and isolation are supported for single operations

ACID

yes

Concurrency

Support for concurrent manipulation of data

yes

Durability

Support for making data persistent

yes

using external storage systems (e.g. Cassandra, DynamoDB, PostgreSQL, Couchbase and others)

yes

In-memory capabilities

Is there an option to define some or all structures to be held in-memory only.

yes

recommended only for testing and development

yes

User concepts

Access control

Access rights for users can be defined per object

yes, based on authentication and database rules

rights management via user accounts

Azure Active Directory Authentication

More information provided by the system vendor

Specific characteristics

Apache Cassandra is the leading NoSQL, distributed database management system, well...
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Integrated columnar database & programming system for streaming, real time and historical...
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Competitive advantages

No single point of failure ensures 100% availability . Operational simplicity for...
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provides seamless scalability; runs on industry standard server platforms; is top-ranked...
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Typical application scenarios

Internet of Things (IOT), fraud detection applications, recommendation engines, product...
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tick database streaming sensor data massive intelligence applications oil and gas...
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Key customers

Apple, Netflix, Uber, ING,, Intuit,Fidelity, NY Times, Outbrain, BazaarVoice, Best...
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Goldman Sachs Morgan Stanley Merrill Lynch J.P. Morgan Deutsche Bank IEX Securities...
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Market metrics

Cassandra is used by 40% of the Fortune 100.
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kdb+ performance and reliability proven by our customers in critical infrastructure...
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Licensing and pricing models

Apache licenseÂ Pricing for commercial distributions provided by DataStax and available...
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upon request
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