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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . 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TCP/IP communication is always used when a nonempty string is specified for this parameter.</p>\n<p>Using <code class=\"literal\">hostaddr</code> instead of <code class=\"literal\">host</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. 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See <a class=\"xref\" href=\"/docs/10/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"33.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a033.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on machines without Unix-domain sockets, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . 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The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 33.15 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 33.1.1.3 for details. 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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/11/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span></dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter.</p>\n<p>Using <code class=\"literal\">hostaddr</code> instead of <code class=\"literal\">host</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/11/libpq-pgpass.html\" title=\"34.15.\u00a0The Password File\">Section\u00a034.15</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/11/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"34.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a034.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on machines without Unix-domain sockets, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . 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The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 34.15 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details. 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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."]}, "12": {"facts": [{"label": "Client library", "value": "libpq 12.22"}, {"label": "Manual definition", "value": "Documented"}, {"label": "Source environment fallback", "value": "PGHOSTADDR"}, {"label": "Compiled fallback expression", "value": "NULL"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/12/libpq-envars.html", "text": "PGHOSTADDR"}, "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. 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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/12/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span></dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter.</p>\n<p>Using <code class=\"literal\">hostaddr</code> instead of <code class=\"literal\">host</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/12/libpq-pgpass.html\" title=\"33.15.\u00a0The Password File\">Section\u00a033.15</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/12/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"33.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a033.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on machines without Unix-domain sockets, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. Using hostaddr instead of host allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 33.15 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 33.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on machines without Unix-domain sockets, it will attempt to connect to localhost .", "documented": true, "environment": "PGHOSTADDR", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 33.1.1.3 for details."], "compiled_default_expression": "NULL"}, "comparison_hash": "aa0196e3894c84a6023b6e5aed9e320ad635f4da9a533d414a09ed3e89411997", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 33.1.1.3 for details."], "precedence_evidence": ["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."]}, "13": {"facts": [{"label": "Client library", "value": "libpq 13.23"}, {"label": "Manual definition", "value": "Documented"}, {"label": "Source environment fallback", "value": "PGHOSTADDR"}, {"label": "Compiled fallback expression", "value": "NULL"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/13/libpq-envars.html", "text": "PGHOSTADDR"}, "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. 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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/13/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span></dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of <code class=\"literal\">host</code> will be looked up to find the corresponding IP address \u2014 or, if <code class=\"literal\">host</code> specifies an IP address, that value will be used directly.</p>\n<p>Using <code class=\"literal\">hostaddr</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/13/libpq-pgpass.html\" title=\"33.15.\u00a0The Password File\">Section\u00a033.15</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/13/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"33.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a033.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on Windows and on machines without Unix-domain sockets, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly. Using hostaddr allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 33.15 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 33.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on Windows and on machines without Unix-domain sockets, it will attempt to connect to localhost .", "documented": true, "environment": "PGHOSTADDR", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 33.1.1.3 for details."], "compiled_default_expression": "NULL"}, "comparison_hash": "0cb2000fc6c93e33090ff5ba26ba4e61ccdc21a377f9d27ff8a68917e0c7fe9a", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 33.1.1.3 for details."], "precedence_evidence": ["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."]}, "14": {"facts": [{"label": "Client library", "value": "libpq 14.24"}, {"label": "Manual definition", "value": "Documented"}, {"label": "Source environment fallback", "value": "PGHOSTADDR"}, {"label": "Compiled fallback expression", "value": "NULL"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/14/libpq-envars.html", "text": "PGHOSTADDR"}, "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. 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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/14/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span></dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of <code class=\"literal\">host</code> will be looked up to find the corresponding IP address \u2014 or, if <code class=\"literal\">host</code> specifies an IP address, that value will be used directly.</p>\n<p>Using <code class=\"literal\">hostaddr</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/14/libpq-pgpass.html\" title=\"34.16.\u00a0The Password File\">Section\u00a034.16</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/14/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"34.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a034.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on Windows and on machines without Unix-domain sockets, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly. Using hostaddr allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 34.16 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on Windows and on machines without Unix-domain sockets, it will attempt to connect to localhost .", "documented": true, "environment": "PGHOSTADDR", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details."], "compiled_default_expression": "NULL"}, "comparison_hash": "5e8e34fc4d76b3e7dccce9f5a30069984bbde8ebe8a1d1c450f33b007cbd91ce", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details."], "precedence_evidence": ["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."]}, "15": {"facts": [{"label": "Client library", "value": "libpq 15.19"}, {"label": "Manual definition", "value": "Documented"}, {"label": "Source environment fallback", "value": "PGHOSTADDR"}, {"label": "Compiled fallback expression", "value": "NULL"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/15/libpq-envars.html", "text": "PGHOSTADDR"}, "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. 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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/15/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span></dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of <code class=\"literal\">host</code> will be looked up to find the corresponding IP address \u2014 or, if <code class=\"literal\">host</code> specifies an IP address, that value will be used directly.</p>\n<p>Using <code class=\"literal\">hostaddr</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/15/libpq-pgpass.html\" title=\"34.16.\u00a0The Password File\">Section\u00a034.16</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/15/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"34.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a034.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on Windows and on machines without Unix-domain sockets, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly. Using hostaddr allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 34.16 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on Windows and on machines without Unix-domain sockets, it will attempt to connect to localhost .", "documented": true, "environment": "PGHOSTADDR", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details."], "compiled_default_expression": "NULL"}, "comparison_hash": "5e8e34fc4d76b3e7dccce9f5a30069984bbde8ebe8a1d1c450f33b007cbd91ce", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details."], "precedence_evidence": ["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."]}, "16": {"facts": [{"label": "Client library", "value": "libpq 16.15"}, {"label": "Manual definition", "value": "Documented"}, {"label": "Source environment fallback", "value": "PGHOSTADDR"}, {"label": "Compiled fallback expression", "value": "NULL"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/16/libpq-envars.html", "text": "PGHOSTADDR"}, "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. 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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/16/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span> </dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of <code class=\"literal\">host</code> will be looked up to find the corresponding IP address \u2014 or, if <code class=\"literal\">host</code> specifies an IP address, that value will be used directly.</p>\n<p>Using <code class=\"literal\">hostaddr</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/16/libpq-pgpass.html\" title=\"34.16.\u00a0The Password File\">Section\u00a034.16</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/16/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"34.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a034.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly. Using hostaddr allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 34.16 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to localhost .", "documented": true, "environment": "PGHOSTADDR", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details."], "compiled_default_expression": "NULL"}, "comparison_hash": "25a913ce915b0f8dcc1c7b1ea4c278b1a482d423bc53c2f0b9c1636e56eaf8a4", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details."], "precedence_evidence": ["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."]}, "17": {"facts": [{"label": "Client library", "value": "libpq 17.11"}, {"label": "Manual definition", "value": "Documented"}, {"label": "Source environment fallback", "value": "PGHOSTADDR"}, {"label": "Compiled fallback expression", "value": "NULL"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/17/libpq-envars.html", "text": "PGHOSTADDR"}, "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. 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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/17/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span> </dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of <code class=\"literal\">host</code> will be looked up to find the corresponding IP address \u2014 or, if <code class=\"literal\">host</code> specifies an IP address, that value will be used directly.</p>\n<p>Using <code class=\"literal\">hostaddr</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/17/libpq-pgpass.html\" title=\"32.16.\u00a0The Password File\">Section\u00a032.16</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/17/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"32.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a032.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly. Using hostaddr allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 32.16 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to localhost .", "documented": true, "environment": "PGHOSTADDR", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details."], "compiled_default_expression": "NULL"}, "comparison_hash": "90f4bd94bbe9a4e92674b61c49e3f961826253701d15eaf8cdabb29bbfb88b88", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. 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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/18/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span> </dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of <code class=\"literal\">host</code> will be looked up to find the corresponding IP address \u2014 or, if <code class=\"literal\">host</code> specifies an IP address, that value will be used directly.</p>\n<p>Using <code class=\"literal\">hostaddr</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/18/libpq-pgpass.html\" title=\"32.16.\u00a0The Password File\">Section\u00a032.16</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/18/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"32.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a032.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly. Using hostaddr allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 32.16 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to localhost .", "documented": true, "environment": "PGHOSTADDR", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details."], "compiled_default_expression": "NULL"}, "comparison_hash": "90f4bd94bbe9a4e92674b61c49e3f961826253701d15eaf8cdabb29bbfb88b88", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details."], "precedence_evidence": ["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."]}, "19": {"facts": [{"label": "Client library", "value": "libpq 19beta4"}, {"label": "Manual definition", "value": "Documented"}, {"label": "Source environment fallback", "value": "PGHOSTADDR"}, {"label": "Compiled fallback expression", "value": "NULL"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/19/libpq-envars.html", "text": "PGHOSTADDR"}, "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. 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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 using the servicefile key word in a libpq connection string or 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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/19/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span> </dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of <code class=\"literal\">host</code> will be looked up to find the corresponding IP address \u2014 or, if <code class=\"literal\">host</code> specifies an IP address, that value will be used directly.</p>\n<p>Using <code class=\"literal\">hostaddr</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/19/libpq-pgpass.html\" title=\"32.16.\u00a0The Password File\">Section\u00a032.16</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/19/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"32.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a032.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly. Using hostaddr allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 32.16 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details. 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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 using the servicefile key word in a libpq connection string or 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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/devel/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span> </dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of <code class=\"literal\">host</code> will be looked up to find the corresponding IP address \u2014 or, if <code class=\"literal\">host</code> specifies an IP address, that value will be used directly.</p>\n<p>Using <code class=\"literal\">hostaddr</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/devel/libpq-pgpass.html\" title=\"32.15.\u00a0The Password File\">Section\u00a032.15</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/devel/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"32.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a032.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. 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If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 32.15 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details. 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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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."]}], "signature": "hostaddr", "documented": true, "description": ["Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly."], "environment": [{"name": "PGHOSTADDR", "source_url": "/docs/18/libpq-envars.html", "description": "PGHOSTADDR behaves the same as the hostaddr connection parameter. This can be set instead of or in addition to PGHOST to avoid DNS lookup overhead."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-HOSTADDR\"><span class=\"term\"><code class=\"literal\">hostaddr</code></span> </dt><dd>\n<p>Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., <code class=\"literal\">172.28.40.9</code>. If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of <code class=\"literal\">host</code> will be looked up to find the corresponding IP address \u2014 or, if <code class=\"literal\">host</code> specifies an IP address, that value will be used directly.</p>\n<p>Using <code class=\"literal\">hostaddr</code> allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for <code class=\"literal\">verify-full</code> SSL certificate verification. The following rules are used:</p>\n<div class=\"itemizedlist\">\n<ul class=\"itemizedlist\">\n<li class=\"listitem\">\n<p>If <code class=\"literal\">host</code> is specified without <code class=\"literal\">hostaddr</code>, a host name lookup occurs. (When using <code class=\"function\">PQconnectPoll</code>, the lookup occurs when <code class=\"function\">PQconnectPoll</code> first considers this host name, and it may cause <code class=\"function\">PQconnectPoll</code> to block for a significant amount of time.)</p>\n</li>\n<li class=\"listitem\">\n<p>If <code class=\"literal\">hostaddr</code> is specified without <code class=\"literal\">host</code>, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The connection attempt will fail if the authentication method requires a host name.</p>\n</li>\n<li class=\"listitem\">\n<p>If both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, the value for <code class=\"literal\">hostaddr</code> gives the server network address. The value for <code class=\"literal\">host</code> is ignored unless the authentication method requires it, in which case it will be used as the host name.</p>\n</li>\n</ul>\n</div>\n<p>Note that authentication is likely to fail if <code class=\"literal\">host</code> is not the name of the server at network address <code class=\"literal\">hostaddr</code>. Also, when both <code class=\"literal\">host</code> and <code class=\"literal\">hostaddr</code> are specified, <code class=\"literal\">host</code> is used to identify the connection in a password file (see <a class=\"xref\" href=\"/docs/18/libpq-pgpass.html\" title=\"32.16.\u00a0The Password File\">Section\u00a032.16</a>).</p>\n<p>A comma-separated list of <code class=\"literal\">hostaddr</code> values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See <a class=\"xref\" href=\"/docs/18/libpq-connect.html#LIBPQ-MULTIPLE-HOSTS\" title=\"32.1.1.3.\u00a0Specifying Multiple Hosts\">Section\u00a032.1.1.3</a> for details.</p>\n<p>Without either a host name or host address, <span class=\"application\">libpq</span> will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to <code class=\"literal\">localhost</code>.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-HOSTADDR", "source_option": {"keyword": "hostaddr", "declaration": "\"hostaddr\", \"PGHOSTADDR\", NULL, NULL, \"Database-Host-IP-Address\", \"\", 45, offsetof(struct pg_conn, pghostaddr)", "environment": "PGHOSTADDR", "source_notes": [], "compiled_default_expression": "NULL"}, "comparison_data": {"keyword": "hostaddr", "definition": "Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. If this parameter is not specified, the value of host will be looked up to find the corresponding IP address \u2014 or, if host specifies an IP address, that value will be used directly. Using hostaddr allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 32.16 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on Windows, it will attempt to connect to localhost .", "documented": true, "environment": "PGHOSTADDR", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details."], "compiled_default_expression": "NULL"}, "comparison_hash": "90f4bd94bbe9a4e92674b61c49e3f961826253701d15eaf8cdabb29bbfb88b88", "default_evidence": ["A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 32.1.1.3 for details."], "precedence_evidence": ["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."]}, "comparison": {"left": "11", "right": "12", "status": "changed", "diff": "--- PostgreSQL 11\n+++ PostgreSQL 12\n@@ -1,9 +1,9 @@\n {\n   \"compiled_default_expression\": \"NULL\",\n   \"default_evidence\": [\n-    \"A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details.\"\n+    \"A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 33.1.1.3 for details.\"\n   ],\n-  \"definition\": \"Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. Using hostaddr instead of host allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 34.15 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 34.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on machines without Unix-domain sockets, it will attempt to connect to localhost .\",\n+  \"definition\": \"Numeric IP address of host to connect to. This should be in the standard IPv4 address format, e.g., 172.28.40.9 . If your machine supports IPv6, you can also use those addresses. TCP/IP communication is always used when a nonempty string is specified for this parameter. Using hostaddr instead of host allows the application to avoid a host name look-up, which might be important in applications with time constraints. However, a host name is required for GSSAPI or SSPI authentication methods, as well as for verify-full SSL certificate verification. The following rules are used: If host is specified without hostaddr , a host name lookup occurs. (When using PQconnectPoll , the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block for a significant amount of time.) If hostaddr is specified without host , the value for hostaddr gives the server network address. The connection attempt will fail if the authentication method requires a host name. If both host and hostaddr are specified, the value for hostaddr gives the server network address. The value for host is ignored unless the authentication method requires it, in which case it will be used as the host name. Note that authentication is likely to fail if host is not the name of the server at network address hostaddr . Also, when both host and hostaddr are specified, host is used to identify the connection in a password file (see Section 33.15 ). A comma-separated list of hostaddr values is also accepted, in which case each host in the list is tried in order. An empty item in the list causes the corresponding host name to be used, or the default host name if that is empty as well. See Section 33.1.1.3 for details. Without either a host name or host address, libpq will connect using a local Unix-domain socket; or on machines without Unix-domain sockets, it will attempt to connect to localhost .\",\n   \"documented\": true,\n   \"environment\": \"PGHOSTADDR\",\n   \"keyword\": \"hostaddr\""}}