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PostgreSQL (, ), also known as Postgres, is a free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance. It was originally named POSTGRES, referring to its origins as a successor to the Ingres database developed at the
University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant un ...
. In 1996, the project was renamed to PostgreSQL to reflect its support for SQL. After a review in 2007, the development team decided to keep the name PostgreSQL and the alias Postgres. PostgreSQL features transactions with
Atomicity, Consistency, Isolation, Durability In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a se ...
(ACID) properties, automatically updatable views, materialized views, triggers, foreign keys, and stored procedures. It is designed to handle a range of workloads, from single machines to data warehouses or Web services with many concurrent users. It is the default database for macOS Server and is also available for
Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for se ...
,
Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...
, FreeBSD, and OpenBSD.


History

PostgreSQL evolved from the Ingres project at the University of California, Berkeley. In 1982, the leader of the Ingres team, Michael Stonebraker, left Berkeley to make a proprietary version of Ingres. He returned to Berkeley in 1985, and began a post-Ingres project to address the problems with contemporary database systems that had become increasingly clear during the early 1980s. He won the
Turing Award The ACM A. M. Turing Award is an annual prize given by the Association for Computing Machinery (ACM) for contributions of lasting and major technical importance to computer science. It is generally recognized as the highest distinction in compu ...
in 2014 for these and other projects, and techniques pioneered in them. The new project, POSTGRES, aimed to add the fewest features needed to completely support
data type In computer science and computer programming, a data type (or simply type) is a set of possible values and a set of allowed operations on it. A data type tells the compiler or interpreter how the programmer intends to use the data. Most progra ...
s. These features included the ability to define types and to fully describe relationships something used widely, but maintained entirely by the user. In POSTGRES, the database understood relationships, and could retrieve information in related tables in a natural way using ''rules''. POSTGRES used many of the ideas of Ingres, but not its code. Starting in 1986, published papers described the basis of the system, and a prototype version was shown at the 1988 ACM SIGMOD Conference. The team released version 1 to a small number of users in June 1989, followed by version 2 with a re-written rules system in June 1990. Version 3, released in 1991, again re-wrote the rules system, and added support for multiple storage managers and an improved query engine. By 1993, the number of users began to overwhelm the project with requests for support and features. After releasing version 4.2 on June 30, 1994 primarily a cleanup the project ended. Berkeley released POSTGRES under an MIT License variant, which enabled other developers to use the code for any use. At the time, POSTGRES used an Ingres-influenced POSTQUEL query language interpreter, which could be interactively used with a
console application A console application is a computer program designed to be used via a text-only computer interface, such as a text terminal, the command-line interface of some operating systems ( Unix, DOS, etc.) or the text-based interface included with mo ...
named ''monitor''. In 1994, Berkeley graduate students Andrew Yu and Jolly Chen replaced the POSTQUEL query language interpreter with one for the SQL query language, creating Postgres95. The ''monitor'' console was also replaced by psql. Yu and Chen announced the first version (0.01) to beta testers on May 5, 1995. Version 1.0 of Postgres95 was announced on September 5, 1995, with a more liberal license that enabled the software to be freely modifiable. On July 8, 1996, Marc Fournier at Hub.org Networking Services provided the first non-university development server for the open-source development effort. With the participation of Bruce Momjian and Vadim B. Mikheev, work began to stabilize the code inherited from Berkeley. In 1996, the project was renamed to PostgreSQL to reflect its support for SQL. The online presence at the website PostgreSQL.org began on October 22, 1996. The first PostgreSQL release formed version 6.0 on January 29, 1997. Since then developers and volunteers around the world have maintained the software as The PostgreSQL Global Development Group. The project continues to make releases available under its free and open-source software PostgreSQL License. Code comes from contributions from proprietary vendors, support companies, and open-source programmers.


Multiversion concurrency control (MVCC)

PostgreSQL manages concurrency through
multiversion concurrency control Multiversion concurrency control (MCC or MVCC), is a concurrency control method commonly used by database management systems to provide concurrent access to the database and in programming languages to implement transactional memory. Description ...
(MVCC), which gives each transaction a "snapshot" of the database, allowing changes to be made without affecting other transactions. This largely eliminates the need for read locks, and ensures the database maintains ACID principles. PostgreSQL offers three levels of transaction isolation: Read Committed, Repeatable Read and Serializable. Because PostgreSQL is immune to dirty reads, requesting a Read Uncommitted transaction isolation level provides read committed instead. PostgreSQL supports full serializability via the serializable
snapshot isolation In databases, and transaction processing (transaction management), snapshot isolation is a guarantee that all reads made in a transaction will see a consistent snapshot of the database (in practice it reads the last committed values that existed ...
(SSI) method.


Storage and replication


Replication

PostgreSQL includes built-in binary replication based on shipping the changes ( write-ahead logs (WAL)) to replica nodes asynchronously, with the ability to run read-only queries against these replicated nodes. This allows splitting read traffic among multiple nodes efficiently. Earlier replication software that allowed similar read scaling normally relied on adding replication triggers to the master, increasing load. PostgreSQL includes built-in synchronous replication that ensures that, for each write transaction, the master waits until at least one replica node has written the data to its transaction log. Unlike other database systems, the durability of a transaction (whether it is asynchronous or synchronous) can be specified per-database, per-user, per-session or even per-transaction. This can be useful for workloads that do not require such guarantees, and may not be wanted for all data as it slows down performance due to the requirement of the confirmation of the transaction reaching the synchronous standby. Standby servers can be synchronous or asynchronous. Synchronous standby servers can be specified in the configuration which determines which servers are candidates for synchronous replication. The first in the list that is actively streaming will be used as the current synchronous server. When this fails, the system fails over to the next in line. Synchronous multi-master replication is not included in the PostgreSQL core. Postgres-XC which is based on PostgreSQL provides scalable synchronous multi-master replication. It is licensed under the same license as PostgreSQL. A related project is called Postgres-XL. Postgres-R is yet another fork. Bidirectional replication (BDR) is an asynchronous multi-master replication system for PostgreSQL. Tools such as repmgr make managing replication clusters easier. Several asynchronous trigger-based replication packages are available. These remain useful even after introduction of the expanded core abilities, for situations where binary replication of a full database cluster is inappropriate: *
Slony-I Slony-I is an asynchronous master-slave replication system for the PostgreSQL DBMS, providing support for cascading and failover. Asynchronous means that when a database transaction has been committed to the master server, it is not yet guaranteed ...
* Londiste, part of SkyTools (developed by
Skype Skype () is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for VoIP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, debi ...
) * Bucardo multi-master replication (developed by Backcountry.com) *
SymmetricDS SymmetricDS is open source software for database and file synchronization with Multi-master replication, filtered synchronization, and transformation capabilities. It is designed to scale for a large number of nodes, work across low-bandwidth con ...
multi-master, multi-tier replication


Indexes

PostgreSQL includes built-in support for regular B-tree and hash table indexes, and four index access methods: generalized search trees (
GiST In computing, GiST or Generalized Search Tree, is a data structure and API that can be used to build a variety of disk-based search trees. GiST is a generalization of the B+ tree, providing a concurrent and recoverable height-balanced search tree ...
), generalized inverted indexes (GIN), Space-Partitioned GiST (SP-GiST) and Block Range Indexes (BRIN). In addition, user-defined index methods can be created, although this is quite an involved process. Indexes in PostgreSQL also support the following features: * Expression indexes can be created with an index of the result of an expression or function, instead of simply the value of a column. * Partial indexes, which only index part of a table, can be created by adding a WHERE clause to the end of the CREATE INDEX statement. This allows a smaller index to be created. * The planner is able to use multiple indexes together to satisfy complex queries, using temporary in-memory bitmap index operations (useful for data warehouse applications for joining a large fact table to smaller dimension tables such as those arranged in a star schema). * ''k''-nearest neighbors (''k''-NN) indexing (also referred to KNN-GiST) provides efficient searching of "closest values" to that specified, useful to finding similar words, or close objects or locations with geospatial data. This is achieved without exhaustive matching of values. * Index-only scans often allow the system to fetch data from indexes without ever having to access the main table. * Block Range Indexes (BRIN).


Schemas

In PostgreSQL, a
schema The word schema comes from the Greek word ('), which means ''shape'', or more generally, ''plan''. The plural is ('). In English, both ''schemas'' and ''schemata'' are used as plural forms. Schema may refer to: Science and technology * SCHEMA ...
holds all objects, except for roles and tablespaces. Schemas effectively act like namespaces, allowing objects of the same name to co-exist in the same database. By default, newly created databases have a schema called ''public'', but any further schemas can be added, and the public schema isn't mandatory. A setting determines the order in which PostgreSQL checks schemas for unqualified objects (those without a prefixed schema). By default, it is set to ( refers to the currently connected database user). This default can be set on a database or role level, but as it is a session parameter, it can be freely changed (even multiple times) during a client session, affecting that session only. Non-existent schemas listed in search_path are silently skipped during objects lookup. New objects are created in whichever valid schema (one that presently exists) appears first in the search_path.


Data types

A wide variety of native
data type In computer science and computer programming, a data type (or simply type) is a set of possible values and a set of allowed operations on it. A data type tells the compiler or interpreter how the programmer intends to use the data. Most progra ...
s are supported, including: * Boolean * Arbitrary-precision numerics * Character (text, varchar, char) * Binary * Date/time (timestamp/time with/without time zone, date, interval) * Money * Enum * Bit strings * Text search type * Composite * HStore, an extension enabled key-value store within PostgreSQL * Arrays ( variable-length and can be of any data type, including text and composite types) up to 1 GB in total storage size * Geometric primitives * IPv4 and
IPv6 Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. I ...
addresses *
Classless Inter-Domain Routing Classless Inter-Domain Routing (CIDR ) is a method for allocating IP addresses and for IP routing. The Internet Engineering Task Force introduced CIDR in 1993 to replace the previous classful network addressing architecture on the Internet. I ...
(CIDR) blocks and
MAC address A media access control address (MAC address) is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. This use is common in most IEEE 802 networking te ...
es *
XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ...
supporting XPath queries * Universally unique identifier (UUID) * JavaScript Object Notation ( JSON), and a faster binary JSONB (not the same as BSON) In addition, users can create their own data types which can usually be made fully indexable via PostgreSQL's indexing infrastructures GiST, GIN, SP-GiST. Examples of these include the
geographic information system A geographic information system (GIS) is a type of database containing geographic data (that is, descriptions of phenomena for which location is relevant), combined with software tools for managing, analyzing, and visualizing those data. In a ...
(GIS) data types from the PostGIS project for PostgreSQL. There is also a data type called a ''domain'', which is the same as any other data type but with optional constraints defined by the creator of that domain. This means any data entered into a column using the domain will have to conform to whichever constraints were defined as part of the domain. A data type that represents a range of data can be used which are called range types. These can be discrete ranges (e.g. all integer values 1 to 10) or continuous ranges (e.g., any time between and ). The built-in range types available include ranges of integers, big integers, decimal numbers, time stamps (with and without time zone) and dates. Custom range types can be created to make new types of ranges available, such as IP address ranges using the inet type as a base, or float ranges using the float data type as a base. Range types support inclusive and exclusive range boundaries using the / and / characters respectively. (e.g., represents all integers starting from and including 4 up to but not including 9.) Range types are also compatible with existing operators used to check for overlap, containment, right of etc.


User-defined objects

New types of almost all objects inside the database can be created, including: * Casts * Conversions * Data types * Data domains * Functions, including aggregate functions and window functions * Indexes including custom indexes for custom types * Operators (existing ones can be overloaded) * Procedural languages


Inheritance

Tables can be set to inherit their characteristics from a ''parent'' table. Data in child tables will appear to exist in the parent tables, unless data is selected from the parent table using the ONLY keyword, i.e. . Adding a column in the parent table will cause that column to appear in the child table. Inheritance can be used to implement table partitioning, using either triggers or rules to direct inserts to the parent table into the proper child tables. This feature is not fully supported. In particular, table constraints are not currently inheritable. All check constraints and not-null constraints on a parent table are automatically inherited by its children. Other types of constraints (unique, primary key, and foreign key constraints) are not inherited. Inheritance provides a way to map the features of generalization hierarchies depicted in entity relationship diagrams (ERDs) directly into the PostgreSQL database.


Other storage features

* Referential integrity constraints including foreign key constraints, column constraints, and row checks * Binary and textual large-object storage * Tablespaces * Per-column collation * Online backup * Point-in-time recovery, implemented using write-ahead logging * In-place upgrades with pg_upgrade for less downtime


Control and connectivity


Foreign data wrappers

PostgreSQL can link to other systems to retrieve data via foreign data wrappers (FDWs). These can take the form of any data source, such as a file system, another relational database management system (RDBMS), or a web service. This means that regular database queries can use these data sources like regular tables, and even join multiple data-sources together.


Interfaces

For connecting to applications, PostgreSQL includes the built-in interfaces libpq (the official C application interface) and ECPG (an embedded C system). Third-party libraries for connecting to PostgreSQL are available for many
programming language A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming ...
s, including C++,
Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...
, Julia, Python,
Node.js Node.js is an open-source server environment. Node.js is cross-platform and runs on Windows, Linux, Unix, and macOS. Node.js is a back-end JavaScript runtime environment. Node.js runs on the V8 JavaScript Engine and executes JavaScript cod ...
, Go, and
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.


Procedural languages

Procedural languages allow developers to extend the database with custom
subroutine In computer programming, a function or subroutine is a sequence of program instructions that performs a specific task, packaged as a unit. This unit can then be used in programs wherever that particular task should be performed. Functions may ...
s (functions), often called '' stored procedures''. These functions can be used to build database triggers (functions invoked on modification of certain data) and custom data types and aggregate functions. Procedural languages can also be invoked without defining a function, using a DO command at SQL level. Languages are divided into two groups: Procedures written in ''safe'' languages are sandboxed and can be safely created and used by any user. Procedures written in ''unsafe'' languages can only be created by
superuser In computing, the superuser is a special user account used for system administration. Depending on the operating system (OS), the actual name of this account might be root, administrator, admin or supervisor. In some cases, the actual name of t ...
s, because they allow bypassing a database's security restrictions, but can also access sources external to the database. Some languages like Perl provide both safe and unsafe versions. PostgreSQL has built-in support for three procedural languages: * Plain SQL (safe). Simpler SQL functions can get expanded inline into the calling (SQL) query, which saves function call overhead and allows the query optimizer to "see inside" the function. * Procedural Language/PostgreSQL ( PL/pgSQL) (safe), which resembles Oracle's Procedural Language for SQL ( PL/SQL) procedural language and SQL/Persistent Stored Modules ( SQL/PSM). * C (unsafe), which allows loading one or more custom shared library into the database. Functions written in C offer the best performance, but bugs in code can crash and potentially corrupt the database. Most built-in functions are written in C. In addition, PostgreSQL allows procedural languages to be loaded into the database through extensions. Three language extensions are included with PostgreSQL to support
Perl Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offic ...
, Tcl, and Python. For Python, the current is used, and the discontinued is no longer supported as of PostgreSQL 15. Both were supported previously, defaulting to , while old and new versions couldn't be used in the same session. External projects provide support for many other languages, including PL/
Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...
,
JavaScript JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of websites use JavaScript on the client side for webpage behavior, of ...
(PL/V8), PL/ Julia PL/ R, PL/
Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called ...
, and others.


Triggers

Triggers are events triggered by the action of SQL data manipulation language (DML) statements. For example, an
INSERT Insert may refer to: *Insert (advertising) *Insert (composites) *Insert (effects processing) *Insert (filmmaking) *Insert key on a computer keyboard, used to switch between insert mode and overtype mode *Insert (molecular biology) *Insert (SQL) *Fi ...
statement might activate a trigger that checks if the values of the statement are valid. Most triggers are only activated by either INSERT or UPDATE statements. Triggers are fully supported and can be attached to tables. Triggers can be per-column and conditional, in that UPDATE triggers can target specific columns of a table, and triggers can be told to execute under a set of conditions as specified in the trigger's WHERE clause. Triggers can be attached to views by using the INSTEAD OF condition. Multiple triggers are fired in alphabetical order. In addition to calling functions written in the native PL/pgSQL, triggers can also invoke functions written in other languages like PL/Python or PL/Perl.


Asynchronous notifications

PostgreSQL provides an asynchronous messaging system that is accessed through the NOTIFY, LISTEN and UNLISTEN commands. A session can issue a NOTIFY command, along with the user-specified channel and an optional payload, to mark a particular event occurring. Other sessions are able to detect these events by issuing a LISTEN command, which can listen to a particular channel. This functionality can be used for a wide variety of purposes, such as letting other sessions know when a table has updated or for separate applications to detect when a particular action has been performed. Such a system prevents the need for continuous polling by applications to see if anything has yet changed, and reducing unnecessary overhead. Notifications are fully transactional, in that messages are not sent until the transaction they were sent from is committed. This eliminates the problem of messages being sent for an action being performed which is then rolled back. Many connectors for PostgreSQL provide support for this notification system (including libpq, JDBC, Npgsql, psycopg and node.js) so it can be used by external applications. PostgreSQL can act as an effective, persistent "pub/sub" server or job server by combining LISTEN with FOR UPDATE SKIP LOCKED.


Rules

Rules allow the "query tree" of an incoming query to be rewritten. "Query Re-Write Rules" are attached to a table/class and "Re-Write" the incoming DML (select, insert, update, and/or delete) into one or more queries that either replace the original DML statement or execute in addition to it. Query Re-Write occurs after DML statement parsing, but before query planning.


Other querying features

* Transactions * Full-text search * Views ** Materialized views ** Updateable views ** Recursive views * Inner, outer (full, left and right), and cross joins * Sub- selects ** Correlated sub-queries * Regular expressions * common table expressions and writable common table expressions * Encrypted connections via Transport Layer Security (TLS); current versions do not use vulnerable SSL, even with that configuration option * Domains *
Savepoint A savepoint is a way of implementing subtransactions (also known as nested transactions) within a relational database management system by indicating a point within a transaction that can be " rolled back to" without affecting any work done in ...
s * Two-phase commit * The Oversized-Attribute Storage Technique (TOAST) is used to transparently store large table attributes (such as big MIME attachments or XML messages) in a separate area, with automatic compression. * Embedded SQL is implemented using preprocessor. SQL code is first written embedded into C code. Then code is run through ECPG preprocessor, which replaces SQL with calls to code library. Then code can be compiled using a C compiler. Embedding works also with C++ but it does not recognize all C++ constructs.


Concurrency model

PostgreSQL server is process-based (not threaded), and uses one operating system process per database session. Multiple sessions are automatically spread across all available CPUs by the operating system. Many types of queries can also be parallelized across multiple background worker processes, taking advantage of multiple CPUs or cores. Client applications can use threads and create multiple database connections from each thread.


Security

PostgreSQL manages its internal security on a per- role basis. A role is generally regarded to be a user (a role that can log in), or a group (a role of which other roles are members). Permissions can be granted or revoked on any object down to the column level, and can also allow/prevent the creation of new objects at the database, schema or table levels. PostgreSQL's SECURITY LABEL feature (extension to SQL standards), allows for additional security; with a bundled loadable module that supports label-based mandatory access control (MAC) based on
Security-Enhanced Linux Security-Enhanced Linux (SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, including mandatory access controls (MAC). SELinux is a set of kernel modifications and user-space ...
(SELinux) security policy. PostgreSQL natively supports a broad number of external authentication mechanisms, including: * Password: either SCRAM-SHA-256, MD5 or plain-text * Generic Security Services Application Program Interface (GSSAPI) *
Security Support Provider Interface Security Support Provider Interface (SSPI) is a component of Windows API that performs security-related operations such as authentication. SSPI functions as a common interface to several Security Support Providers (SSPs): A Security Support Provid ...
(SSPI) * Kerberos * ident (maps O/S user-name as provided by an ident server to database user-name) * Peer (maps local user name to database user name) *
Lightweight Directory Access Protocol The Lightweight Directory Access Protocol (LDAP ) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an Internet Protocol (IP) network. Directory servi ...
(LDAP) **
Active Directory Active Directory (AD) is a directory service developed by Microsoft for Windows domain networks. It is included in most Windows Server operating systems as a set of processes and services. Initially, Active Directory was used only for centralize ...
(AD) *
RADIUS In classical geometry, a radius (plural, : radii) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', ...
* Certificate * Pluggable authentication module (PAM) The GSSAPI, SSPI, Kerberos, peer, ident and certificate methods can also use a specified "map" file that lists which users matched by that authentication system are allowed to connect as a specific database user. These methods are specified in the cluster's host-based authentication configuration file (pg_hba.conf), which determines what connections are allowed. This allows control over which user can connect to which database, where they can connect from (IP address, IP address range, domain socket), which authentication system will be enforced, and whether the connection must use Transport Layer Security (TLS).


Standards compliance

PostgreSQL claims high, but not complete, conformance with the latest SQL standard (for version 13 "in September 2020, PostgreSQL conforms to at least 170 of the 179 mandatory features for SQL:2016 Core conformance", and no other databases fully conformed to it). One exception is the handling of unquoted identifiers like table or column names. In PostgreSQL they are folded, internally, to lower case characters whereas the standard says that unquoted identifiers should be folded to upper case. Thus, should be equivalent to not according to the standard. Other shortcomings concern the absence of temporal tables allowing automatic logging of row versions during transactions with the possibility of browsing in time (FOR SYSTEM TIME predicate).


Benchmarks and performance

Many informal performance studies of PostgreSQL have been done. Performance improvements aimed at improving scalability began heavily with version 8.1. Simple benchmarks between version 8.0 and version 8.4 showed that the latter was more than 10 times faster on read-only workloads and at least 7.5 times faster on both read and write workloads. The first industry-standard and peer-validated benchmark was completed in June 2007, using the Sun Java System Application Server (proprietary version of GlassFish) 9.0 Platform Edition, UltraSPARC T1-based Sun Fire server and PostgreSQL 8.2. This result of 778.14 SPECjAppServer2004 JOPS@Standard compares favourably with the 874 JOPS@Standard with Oracle 10 on an Itanium-based HP-UX system. In August 2007, Sun submitted an improved benchmark score of 813.73 SPECjAppServer2004 JOPS@Standard. With the system under test at a reduced price, the price/performance improved from $84.98/JOPS to $70.57/JOPS. The default configuration of PostgreSQL uses only a small amount of dedicated memory for performance-critical purposes such as caching database blocks and sorting. This limitation is primarily because older operating systems required kernel changes to allow allocating large blocks of shared memory. PostgreSQL.org provides advice on basic recommended performance practice in a wiki. In April 2012, Robert Haas of EnterpriseDB demonstrated PostgreSQL 9.2's linear CPU scalability using a server with 64 cores. Matloob Khushi performed benchmarking between PostgreSQL 9.0 and MySQL 5.6.15 for their ability to process genomic data. In his performance analysis he found that PostgreSQL extracts overlapping genomic regions eight times faster than MySQL using two datasets of 80,000 each forming random human DNA regions. Insertion and data uploads in PostgreSQL were also better, although general searching ability of both databases was almost equivalent.


Platforms

PostgreSQL is available for the following operating systems:
Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...
(all recent distributions), 64-bit x86 installers available and tested for
macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and la ...
(OS X) version 10.6 and newer
Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for se ...
(with installers available and tested for 64-bit
Windows Server 2019 Windows Server 2019 is the ninth version of the Windows Server operating system by Microsoft, as part of the Windows NT family of operating systems. It is the second version of the server operating system based on the Windows 10 platform, ...
and 2016; some older PostgreSQL versions are tested back to Windows 2008 R2, while for PostgreSQL version 10 and older a 32-bit installer is available and tested down to 32-bit Windows 2008 R1; compilable by e.g.
Visual Studio Visual Studio is an integrated development environment (IDE) from Microsoft. It is used to develop computer programs including web site, websites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development platfor ...
, version 2013 up to the most recent 2019 version) FreeBSD, OpenBSD, NetBSD,
AIX Aix or AIX may refer to: Computing * AIX, a line of IBM computer operating systems *An Alternate Index, for a Virtual Storage Access Method Key Sequenced Data Set * Athens Internet Exchange, a European Internet exchange point Places Belgiu ...
, HP-UX, Solaris, and UnixWare; and not officially tested:
DragonFly BSD DragonFly BSD is a free and open-source Unix-like operating system forked from FreeBSD 4.8. Matthew Dillon, an Amiga developer in the late 1980s and early 1990s and FreeBSD developer between 1994 and 2003, began working on DragonFly BSD ...
, BSD/OS,
IRIX IRIX ( ) is a discontinued operating system developed by Silicon Graphics (SGI) to run on the company's proprietary MIPS workstations and servers. It is based on UNIX System V with BSD extensions. In IRIX, SGI originated the XFS file system a ...
,
OpenIndiana OpenIndiana is a free and open-source Illumos#Current_distributions, illumos distribution Unix-derived UNIX_System_V, System V SVR4 operating system, started as OpenSolaris continuation project. fork (software development), Forked from OpenSolar ...
, OpenSolaris,
OpenServer Xinuos OpenServer, previously SCO UNIX and SCO Open Desktop (SCO ODT), is a closed source computer operating system developed by Santa Cruz Operation (SCO), later acquired by SCO Group, and now owned by Xinuos. Early versions of OpenServer wer ...
, and Tru64 UNIX . Most other Unix-like systems could also work; most modern do support. PostgreSQL works on any of the following
instruction set architecture In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ...
s: x86 and x86-64 on
Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was release to manufacturing, released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct upgrade to its predecessors, Wind ...
(or later) and other operating systems; these are supported on other than Windows: IA-64 Itanium (external support for HP-UX), PowerPC, PowerPC 64,
S/390 The IBM System/390 is a discontinued mainframe product family implementing the ESA/390, the fifth generation of the System/360 instruction set architecture. The first computers to use the ESA/390 were the Enterprise System/9000 (ES/9000 ...
, S/390x,
SPARC SPARC (Scalable Processor Architecture) is a reduced instruction set computer (RISC) instruction set architecture originally developed by Sun Microsystems. Its design was strongly influenced by the experimental Berkeley RISC system develope ...
, SPARC 64, ARMv8-A (
64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size. A ...
) and older ARM ( 32-bit, including older such as
ARMv6 ARM (stylised in lowercase as arm, formerly an acronym for Advanced RISC Machines and originally Acorn RISC Machine) is a family of reduced instruction set computer (RISC) instruction set architectures for computer processors, configured ...
in Raspberry Pi), MIPS, MIPSel, and PA-RISC. It was also known to work on some other platforms (while not been tested on for years, i.e. for latest versions).


Database administration

Open source front-ends and tools for administering PostgreSQL include: ; psql: The primary front-end for PostgreSQL is the command-line program, which can be used to enter SQL queries directly, or execute them from a file. In addition, psql provides a number of meta-commands and various shell-like features to facilitate writing scripts and automating a wide variety of tasks; for example tab completion of object names and SQL syntax. ; pgAdmin: The pgAdmin package is a free and open-source
graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, ins ...
(GUI) administration tool for PostgreSQL, which is supported on many computer platforms. The program is available in more than a dozen languages. The first prototype, named pgManager, was written for PostgreSQL 6.3.2 from 1998, and rewritten and released as pgAdmin under the GNU General Public License (GPL) in later months. The second incarnation (named pgAdmin II) was a complete rewrite, first released on January 16, 2002. The third version, pgAdmin III, was originally released under the Artistic License and then released under the same license as PostgreSQL. Unlike prior versions that were written in Visual Basic, pgAdmin III is written in C++, using the wxWidgets framework allowing it to run on most common operating systems. The query tool includes a scripting language called pgScript for supporting admin and development tasks. In December 2014, Dave Page, the pgAdmin project founder and primary developer, announced that with the shift towards web-based models, work has begun on pgAdmin 4 with the aim to facilitate cloud deployments. In 2016, pgAdmin 4 was released. pgAdmin 4 backend was written in Python, using Flask and
Qt framework Qt (pronounced "cute") is cross-platform software for creating graphical user interfaces as well as cross-platform applications that run on various software and hardware platforms such as Linux, Windows, macOS, Android or embedded systems wi ...
. ; phpPgAdmin: phpPgAdmin is a web-based administration tool for PostgreSQL written in PHP and based on the popular
phpMyAdmin phpMyAdmin is a free and open source administration tool for MySQL and MariaDB. As a portable web application written primarily in PHP, it has become one of the most popular MySQL administration tools, especially for web hosting services. His ...
interface originally written for
MySQL MySQL () is an open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, and "SQL", the acronym for Structured Query Language. A relational database ...
administration. ; PostgreSQL Studio: PostgreSQL Studio allows users to perform essential PostgreSQL database development tasks from a web-based console. PostgreSQL Studio allows users to work with cloud databases without the need to open firewalls. ; TeamPostgreSQL: AJAX/JavaScript-driven web interface for PostgreSQL. Allows browsing, maintaining and creating data and database objects via a web browser. The interface offers tabbed SQL editor with autocompletion, row editing widgets, click-through foreign key navigation between rows and tables, ''favorites'' management for commonly used scripts, among other features. Supports SSH for both the web interface and the database connections. Installers are available for Windows, Macintosh, and Linux, and a simple cross-platform archive that runs from a script. ; LibreOffice, OpenOffice.org: LibreOffice and OpenOffice.org Base can be used as a front-end for PostgreSQL. ; pgBadger: The pgBadger PostgreSQL log analyzer generates detailed reports from a PostgreSQL log file. ; pgDevOps: pgDevOps is a suite of web tools to install & manage multiple PostgreSQL versions, extensions, and community components, develop SQL queries, monitor running databases and find performance problems. ; Adminer:
Adminer Adminer (formerly known as phpMinAdmin) is a tool for managing content in databases. It natively supports MySQL, MariaDB, PostgreSQL, SQLite, MS SQL, Oracle, Elasticsearch and MongoDB. Adminer is distributed under Apache license (or GPL v ...
is a simple web-based administration tool for PostgreSQL and others, written in PHP. ; pgBackRest: pgBackRest is a backup and restore tool for PostgreSQL that provides support for full, differential, and incremental backups. ; pgaudit: pgaudit is a PostgreSQL extension that provides detailed session and/or object audit logging via the standard logging facility provided by PostgreSQL. ; wal-e: Wal-e is a backup and restore tool for PostgreSQL that provides support for physical (WAL based) backups, written in Python A number of companies offer proprietary tools for PostgreSQL. They often consist of a universal core that is adapted for various specific database products. These tools mostly share the administration features with the open source tools but offer improvements in data modeling, importing, exporting or reporting.


Notable users

Notable organizations and products that use PostgreSQL as the primary database include: *
Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...
, used for a petabyte-scale “Release Quality View” (RQV) analytics dashboard, which tracks quality of Windows updates analyzing 20K types of metrics from over 800M Windows devices. * In 2009, the social-networking website Myspace used
Aster Data Systems Aster Data Systems was a data management and analysis software company headquartered in San Carlos, California. It was founded in 2005 and acquired by Teradata in 2011. History Aster Data was co-founded in 2005 by Stanford University graduate s ...
's nCluster database for data warehousing, which was built on unmodified PostgreSQL. *
Geni.com Geni is an American commercial genealogy and social networking website, founded in 2006, and owned by MyHeritage, an Israeli private company, since November 2012. As of 2021, MyHeritage has kept its genealogical website separate from Geni's webs ...
uses PostgreSQL for their main genealogy database. * OpenStreetMap, a collaborative project to create a free editable map of the world. * Afilias, domain registries for
.org The domain name .org is a generic top-level domain (gTLD) of the Domain Name System (DNS) used on the Internet. The name is truncated from ''organization''. It was one of the original domains established in 1985, and has been operated by th ...
,
.info The domain name info is a generic top-level domain (gTLD) in the Domain Name System (DNS) of the Internet. The name is derived from ''information'', although registration requirements do not prescribe any particular purpose. The TLD ''info'' wa ...
and others. *
Sony Online Daybreak Game Company LLC is an American video game developer based in San Diego. The company was founded in December 1997 as Sony Online Entertainment, a subsidiary of Sony Computer Entertainment, but was spun off to an independent investor ...
multiplayer online games. * BASF, shopping platform for their agribusiness portal. *
Reddit Reddit (; stylized in all lowercase as reddit) is an American social news aggregation, content rating, and discussion website. Registered users (commonly referred to as "Redditors") submit content to the site such as links, text posts, imag ...
social news website. *
Skype Skype () is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for VoIP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, debi ...
VoIP application, central business databases. * Sun xVM, Sun's virtualization and datacenter automation suite. * MusicBrainz, open online music encyclopedia. * The
International Space Station The International Space Station (ISS) is the largest Modular design, modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos ( ...
– to collect telemetry data in orbit and replicate it to the ground. * MyYearbook social-networking site. *
Instagram Instagram is a photo and video sharing social networking service owned by American company Meta Platforms. The app allows users to upload media that can be edited with filters and organized by hashtags and geographical tagging. Posts can ...
, a mobile photo-sharing service. * Disqus, an online discussion and commenting service. * TripAdvisor, travel-information website of mostly user-generated content. * Yandex, a Russian internet company switched its Yandex.Mail service from Oracle to Postgres. * Amazon Redshift, part of AWS, a columnar online analytical processing (OLAP) system based on
ParAccel ParAccel, Inc. was a California-based software company. It provided a database management system designed to provide advanced analytics for business intelligence. ParAccel was acquired by Actian in April 2013. History ParAccel was a venture- ...
's Postgres modifications. *
National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditi ...
's (NOAA)
National Weather Service The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the ...
(NWS), Interactive Forecast Preparation System (IFPS), a system that integrates data from the NEXRAD weather radars, surface, and
hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is call ...
systems to build detailed localized forecast models. *
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and ...
's national weather service, Met Office, has begun swapping Oracle for PostgreSQL in a strategy to deploy more open source technology. * WhitePages.com had been using Oracle and
MySQL MySQL () is an open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, and "SQL", the acronym for Structured Query Language. A relational database ...
, but when it came to moving its core directories in-house, it turned to PostgreSQL. Because WhitePages.com needs to combine large sets of data from multiple sources, PostgreSQL's ability to load and index data at high rates was a key to its decision to use PostgreSQL. * FlightAware, a flight tracking website. *
Grofers Blink Commerce Private Limited, d/b/a Blinkit and formerly Grofers, is an Indian instant delivery service. It was founded in December 2013 and is based out of Gurgaon. Customers of the company use a mobile application to order groceries and es ...
, an online grocery delivery service. * ''
The Guardian ''The Guardian'' is a British daily newspaper. It was founded in 1821 as ''The Manchester Guardian'', and changed its name in 1959. Along with its sister papers '' The Observer'' and '' The Guardian Weekly'', ''The Guardian'' is part of the ...
'' migrated from
MongoDB MongoDB is a source-available cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with optional schemas. MongoDB is developed by MongoDB Inc. and licensed under the S ...
to PostgreSQL in 2018. * YugabyteDB implements the PostgreSQL query layer as its default SQL mode


Service implementations

Some notable vendors offer PostgreSQL as
software as a service Software as a service (SaaS ) is a software licensing and delivery model in which software is licensed on a subscription basis and is centrally hosted. SaaS is also known as "on-demand software" and Web-based/Web-hosted software. SaaS is co ...
: * Heroku, a platform as a service provider, has supported PostgreSQL since the start in 2007. They offer value-add features like full database ''roll-back'' (ability to restore a database from any specified time), which is based on WAL-E, open-source software developed by Heroku. * In January 2012,
EnterpriseDB EnterpriseDB (EDB), a privately held company based in Massachusetts, provides software and services based on the open-source database PostgreSQL (also known as Postgres), and is one of the largest contributors to Postgres. EDB develops and int ...
released a cloud version of both PostgreSQL and their own proprietary Postgres Plus Advanced Server with automated provisioning for failover, replication, load-balancing, and scaling. It runs on Amazon Web Services. Since 2015, Postgres Advanced Server has been offered as ApsaraDB for PPAS, a relational database as a service on Alibaba Cloud. * VMware has offered vFabric Postgres (also termed vPostgres) for private clouds on
VMware vSphere VMware vSphere (formerly VMware Infrastructure 4) is VMware's cloud computing virtualization platform. It includes an updated vCenter Configuration Manager, as well as vCenter Application Discovery Manager, and the ability of vMotion to mov ...
since May 2012. The company announced End of Availability (EOA) of the product in 2014. * In November 2013, Amazon Web Services announced the addition of PostgreSQL to their Relational Database Service offering. * In November 2016, Amazon Web Services announced the addition of PostgreSQL compatibility to their cloud-native Amazon Aurora managed database offering. * In May 2017, Microsoft Azure announced Azure Databases for PostgreSQL * In May 2019, Alibaba Cloud announced PolarDB for PostgreSQL. * Jelastic
Multicloud Multicloud (also spelled multi-cloud or multi cloud) is a company's use of multiple cloud computing and storage services from different vendors in a single heterogeneous architecture to improve cloud infrastructure capabilities and cost. It also r ...
Platform as a Service provides container-based PostgreSQL support since 2011. They offer automated asynchronous master-slave replication of PostgreSQL available from marketplace. * In June 2019,
IBM Cloud IBM Cloud, (formerly known as Bluemix) is a set of cloud computing services for business offered by the information technology company IBM. Services As of 2021, IBM Cloud contains more than 170 services including compute, storage, network ...
announce
IBM Cloud Hyper Protect DBaaS for PostgreSQL
* In September 2020, Crunchy Data announce
Crunchy Bridge


Release history


See also

* Comparison of relational database management systems * Database scalability *
List of databases using MVCC The following database management systems and other software use multiversion concurrency control. Databases * Altibase * Berkeley DB * Cloudant * Cloud Spanner * Clustrix * CockroachDB * Couchbase * CouchDB * CUBRID * IBM Db2 – since IBM D ...
*
LLVM LLVM is a set of compiler and toolchain technologies that can be used to develop a front end for any programming language and a back end for any instruction set architecture. LLVM is designed around a language-independent intermediate repre ...
(llvmjit is the JIT engine used by PostgreSQL)


References


Further reading

* * * * * * * *


External links

* * * {{Software in the Public Interest Client-server database management systems Cross-platform software Free database management systems Free software programmed in C ORDBMS software for Linux Relational database management software for Linux