host

Description

Name of host to connect to. If a host name looks like an absolute path name, it specifies Unix-domain communication rather than TCP/IP communication; the value is the name of the directory in which the socket file is stored. (On Unix, an absolute path name begins with a slash. On Windows, paths starting with drive letters are also recognized.) If the host name starts with @ , it is taken as a Unix-domain socket in the abstract namespace (currently supported on Linux and Windows). The default behavior when host is not specified, or is empty, is to connect to a Unix-domain socket in /tmp (or whatever socket directory was specified when PostgreSQL was built). On Windows, the default is to connect to localhost .

Client library

libpq 18.6

Manual definition

Documented

Source environment fallback

PGHOST

Compiled fallback expression

NULL

Usage

host

Default resolution and service-file precedence

The following environment variables can be used to select default connection parameter values, which will be used by PQconnectdb , PQsetdbLogin and PQsetdb if no value is directly specified by the calling code. These are useful to avoid hard-coding database connection information into simple client applications, for example.

Service names can be defined in either a per-user service file or a system-wide file. If the same service name exists in both the user and the system file, the user file takes precedence. By default, the per-user service file is named ~/.pg_service.conf . On Microsoft Windows, it is named %APPDATA%\postgresql\.pg_service.conf (where %APPDATA% refers to the Application Data subdirectory in the user's profile). A different file name can be specified by setting the environment variable PGSERVICEFILE . The system-wide file is named pg_service.conf . By default it is sought in the etc directory of the PostgreSQL installation (use pg_config --sysconfdir to identify this directory precisely). Another directory, but not a different file name, can be specified by setting the environment variable PGSYSCONFDIR .

Connection parameters obtained from a service file are combined with parameters obtained from other sources. A service file setting overrides the corresponding environment variable, and in turn can be overridden by a value given directly in the connection string. For example, using the above service file, a connection string service=mydb port=5434 will use host somehost , port 5434 , user admin , and other parameters as set by environment variables or built-in defaults.

Environment variable evidence

PGHOST behaves the same as the host connection parameter.

Related entries

• Connection service file
• Password file
• All libpq environment variables

Documentation and source

• 18.6 English manual · libpq-connect.html
• 18.6 libpq connection option declarations
• 18.6 English manual · libpq-envars.html
• 18.6 English manual · libpq-pgservice.html

Compare versions

PostgreSQL 15 → 16: changed.

--- PostgreSQL 15
+++ PostgreSQL 16
@@ -1,10 +1,10 @@
 {
   "compiled_default_expression": "NULL",
   "default_evidence": [
-    "Name of host to connect to. If a host name looks like an absolute path name, it specifies Unix-domain communication rather than TCP/IP communication; the value is the name of the directory in which the socket file is stored. (On Unix, an absolute path name begins with a slash. On Windows, paths starting with drive letters are also recognized.) If the host name starts with @ , it is taken as a Unix-domain socket in the abstract namespace (currently supported on Linux and Windows). The default behavior when host is not specified, or is empty, is to connect to a Unix-domain socket in /tmp (or whatever socket directory was specified when PostgreSQL was built). On Windows and on machines without Unix-domain sockets, the default is to connect to localhost .",
+    "Name of host to connect to. If a host name looks like an absolute path name, it specifies Unix-domain communication rather than TCP/IP communication; the value is the name of the directory in which the socket file is stored. (On Unix, an absolute path name begins with a slash. On Windows, paths starting with drive letters are also recognized.) If the host name starts with @ , it is taken as a Unix-domain socket in the abstract namespace (currently supported on Linux and Windows). The default behavior when host is not specified, or is empty, is to connect to a Unix-domain socket in /tmp (or whatever socket directory was specified when PostgreSQL was built). On Windows, the default is to connect to localhost .",
     "A comma-separated list of host names is also accepted, in which case each host name in the list is tried in order; an empty item in the list selects the default behavior as explained above. See Section 34.1.1.3 for details."
   ],
-  "definition": "Name of host to connect to. If a host name looks like an absolute path name, it specifies Unix-domain communication rather than TCP/IP communication; the value is the name of the directory in which the socket file is stored. (On Unix, an absolute path name begins with a slash. On Windows, paths starting with drive letters are also recognized.) If the host name starts with @ , it is taken as a Unix-domain socket in the abstract namespace (currently supported on Linux and Windows). The default behavior when host is not specified, or is empty, is to connect to a Unix-domain socket in /tmp (or whatever socket directory was specified when PostgreSQL was built). On Windows and on machines without Unix-domain sockets, the default is to connect to localhost . A comma-separated list of host names is also accepted, in which case each host name in the list is tried in order; an empty item in the list selects the default behavior as explained above. See Section 34.1.1.3 for details.",
+  "definition": "Name of host to connect to. If a host name looks like an absolute path name, it specifies Unix-domain communication rather than TCP/IP communication; the value is the name of the directory in which the socket file is stored. (On Unix, an absolute path name begins with a slash. On Windows, paths starting with drive letters are also recognized.) If the host name starts with @ , it is taken as a Unix-domain socket in the abstract namespace (currently supported on Linux and Windows). The default behavior when host is not specified, or is empty, is to connect to a Unix-domain socket in /tmp (or whatever socket directory was specified when PostgreSQL was built). On Windows, the default is to connect to localhost . A comma-separated list of host names is also accepted, in which case each host name in the list is tried in order; an empty item in the list selects the default behavior as explained above. See Section 34.1.1.3 for details.",
   "documented": true,
   "environment": "PGHOST",
   "keyword": "host"

Compares recorded interfaces and attributes. Source fingerprints and build metadata are excluded; an absent sample is not proof of the introduction or removal release.

Related entries

• dbname
• hostaddr
• load_balance_hosts
• port
• service
• target_session_attrs