百科 / 连接参数 / 连接目标

host

要连接的主机名。如果主机名看起来像绝对路径名，则指定的是 Unix 域通信，而非 TCP/IP 通信；此值是存放套接字文件的目录名。（在 Unix 上，绝对路径名以斜杠开头。在 Windows 上，也会识别以驱动器号开头的路径。）如果主机名以 @ 开头，则将其视为抽象命名空间中的 Unix 域套接字（目前在 Linux 和 Windows 上支持）。当未指定 host 或其值为空时，默认连接到 /tmp （或构建 PostgreSQL 时指定的套接字目录）中的 Unix 域套接字。在 Wi…

当前查看 PostgreSQL 18.6。

说明

客户端库: libpq 18.6
手册定义: 手册已记载
源码中的环境变量回退: PGHOST
编译时回退表达式: NULL

用法

host

默认值解析与服务文件优先级

以下环境变量可用于选择连接参数的默认值，供 PQconnectdb 、 PQsetdbLogin 和 PQsetdb 在调用代码未直接指定参数值时使用。例如，这样可以避免在简单的客户端应用程序中硬编码数据库连接信息。

服务名称可以在每个用户的服务文件或系统范围的文件中定义。如果同一个服务名称存在于用户文件和系统文件中，则用户文件优先。默认情况下，每个用户的服务文件名为 ~/.pg_service.conf 。在Microsoft Windows上，它的名称为 %APPDATA%\postgresql\.pg_service.conf （其中 %APPDATA% 指用户配置文件夹中的应用数据子目录）。可以通过设置环境变量 PGSERVICEFILE 来指定不同的文件名。系统范围的文件名为 pg_service.conf 。默认情况下，在 PostgreSQL 安装的 etc 目录中寻找（使用 pg_config --sysconfdir 来准确识别此目录）。可以通过设置环境变量 PGSYSCONFDIR 来指定另一个目录，但不能指定不同的文件名。

从服务文件中获取的连接参数会与其他来源的参数合并。服务文件中的设置会覆盖相应的环境变量，而连接字符串中直接给出的值又会覆盖服务文件中的设置。例如，使用上述服务文件时，连接字符串 service=mydb port=5434 将使用主机 somehost 、端口 5434 、用户 admin ，以及由环境变量或内置默认值设置的其他参数。

环境变量证据

PGHOST 的行为与 host 连接参数相同。

环境变量回退

变量	手册记载的行为
PGHOST	PGHOST 的行为与 host 连接参数相同。

手册定义

host

要连接的主机名。如果主机名看起来像绝对路径名，则指定的是 Unix 域通信，而非 TCP/IP 通信；此值是存放套接字文件的目录名。（在 Unix 上，绝对路径名以斜杠开头。在 Windows 上，也会识别以驱动器号开头的路径。）如果主机名以 @ 开头，则将其视为抽象命名空间中的 Unix 域套接字（目前在 Linux 和 Windows 上支持）。当未指定 host 或其值为空时，默认连接到 /tmp（或构建 PostgreSQL 时指定的套接字目录）中的 Unix 域套接字。在 Windows 上，默认连接到 localhost。

也可以接受一个逗号分隔的主机名列表，此时列表中的每个主机名将按顺序尝试；列表中的空项将选择上述默认行为。详细信息请参见第 32.1.1.3 节。

文档与源码

来源构建

版本: 18.6
构建: https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2
来源指纹: ee8d1a3612338fd9adf250730cb640fcc5233b5491337cc00a316a44e3a0b9f8

版本比较

PostgreSQL 13 → 14: 属性变化。

以下差异保留原始字段名与英文源描述。

--- PostgreSQL 13
+++ PostgreSQL 14
@@ -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.) 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 33.1.1.3 for details."
+    "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.) 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 33.1.1.3 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.",
   "documented": true,
   "environment": "PGHOST",
   "keyword": "host"

比较已记录的接口与属性，排除来源指纹和构建元数据。某个样本中没有记录，不能据此判断实际引入或移除的版本。

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