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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": ["PGGSSENCMODE behaves the same as the gssencmode connection parameter."]}], "signature": "gssencmode", "documented": true, "description": ["This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. 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There are three modes:</p>\n<div class=\"variablelist\">\n<dl class=\"variablelist\">\n<dt><span class=\"term\"><code class=\"literal\">disable</code></span></dt>\n<dd>\n<p>only try a non-GSSAPI-encrypted connection</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">prefer</code> (default)</span></dt>\n<dd>\n<p>if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI-encrypted connection; if that fails or there are no credentials, try a non-GSSAPI-encrypted connection. This is the default when <span class=\"productname\">PostgreSQL</span> has been compiled with GSSAPI support.</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">require</code></span></dt>\n<dd>\n<p>only try a GSSAPI-encrypted connection</p>\n</dd>\n</dl>\n</div>\n<p><code class=\"literal\">gssencmode</code> is ignored for Unix domain socket communication. 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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": ["PGGSSENCMODE behaves the same as the gssencmode connection parameter."]}], "signature": "gssencmode", "documented": true, "description": ["This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:"], "environment": [{"name": "PGGSSENCMODE", "source_url": "/docs/13/libpq-envars.html", "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-GSSENCMODE\"><span class=\"term\"><code class=\"literal\">gssencmode</code></span></dt><dd>\n<p>This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:</p>\n<div class=\"variablelist\">\n<dl class=\"variablelist\">\n<dt><span class=\"term\"><code class=\"literal\">disable</code></span></dt>\n<dd>\n<p>only try a non-GSSAPI-encrypted connection</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">prefer</code> (default)</span></dt>\n<dd>\n<p>if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI-encrypted connection; if that fails or there are no credentials, try a non-GSSAPI-encrypted connection. This is the default when <span class=\"productname\">PostgreSQL</span> has been compiled with GSSAPI support.</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">require</code></span></dt>\n<dd>\n<p>only try a GSSAPI-encrypted connection</p>\n</dd>\n</dl>\n</div>\n<p><code class=\"literal\">gssencmode</code> is ignored for Unix domain socket communication. 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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": ["PGGSSENCMODE behaves the same as the gssencmode connection parameter."]}], "signature": "gssencmode", "documented": true, "description": ["This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:"], "environment": [{"name": "PGGSSENCMODE", "source_url": "/docs/14/libpq-envars.html", "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-GSSENCMODE\"><span class=\"term\"><code class=\"literal\">gssencmode</code></span></dt><dd>\n<p>This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:</p>\n<div class=\"variablelist\">\n<dl class=\"variablelist\">\n<dt><span class=\"term\"><code class=\"literal\">disable</code></span></dt>\n<dd>\n<p>only try a non-GSSAPI-encrypted connection</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">prefer</code> (default)</span></dt>\n<dd>\n<p>if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI-encrypted connection; if that fails or there are no credentials, try a non-GSSAPI-encrypted connection. This is the default when <span class=\"productname\">PostgreSQL</span> has been compiled with GSSAPI support.</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">require</code></span></dt>\n<dd>\n<p>only try a GSSAPI-encrypted connection</p>\n</dd>\n</dl>\n</div>\n<p><code class=\"literal\">gssencmode</code> is ignored for Unix domain socket communication. If <span class=\"productname\">PostgreSQL</span> is compiled without GSSAPI support, using the <code class=\"literal\">require</code> option will cause an error, while <code class=\"literal\">prefer</code> will be accepted but <span class=\"application\">libpq</span> will not actually attempt a GSSAPI-encrypted connection.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE", "source_option": {"keyword": "gssencmode", "declaration": "\"gssencmode\", \"PGGSSENCMODE\", DefaultGSSMode, NULL, \"GSSENC-Mode\", \"\", 8, offsetof(struct pg_conn, gssencmode)", "environment": "PGGSSENCMODE", "source_notes": [], "compiled_default_expression": "DefaultGSSMode"}, "comparison_data": {"keyword": "gssencmode", "definition": "This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes: disable only try a non- GSSAPI -encrypted connection prefer (default) if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support. require only try a GSSAPI -encrypted connection gssencmode is ignored for Unix domain socket communication. If PostgreSQL is compiled without GSSAPI support, using the require option will cause an error, while prefer will be accepted but libpq will not actually attempt a GSSAPI -encrypted connection.", "documented": true, "environment": "PGGSSENCMODE", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. 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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": "PGGSSENCMODE"}, {"label": "Compiled fallback expression", "value": "DefaultGSSMode"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/15/libpq-envars.html", "text": "PGGSSENCMODE"}, "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "title": "Environment fallback", "columns": [{"key": "name", "label": "Variable"}, {"key": "description", "label": "Documented behavior"}]}], "keyword": "gssencmode", "related": [{"url": "/docs/15/libpq-pgservice.html", "label": "Connection service file"}, {"url": "/docs/15/libpq-pgpass.html", "label": "Password file"}, {"url": "/docs/15/libpq-envars.html", "label": "All libpq environment variables"}], "release": {"ref": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "label": "15.19", "major": "15", "channel": "stable", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/15/postgresql-15-A4.pdf", "bytes": 14609140, "pages": 2987, "sha256": "66228564a4d16efb47d6a914085716ecfe22ca1566db56bc7c3d82f790646d72", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/15/postgresql-15-US.pdf", "bytes": 14495690, "pages": 3153, "sha256": "645a498c2390d47a6223ec74770631185807a19c484edb0fc5a295d9f460bc02", "built_at": "2026-09-26"}}, "tree": "15", "index": "index.html", "major": "15", "pages": 1168, "release": "15.19", "source_url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "svg_assets": 3, "source_mode": "en HTML verified against the pinned official archive", "source_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "revision": "6af958c6520151fc7697d56e0616b03fb00522c4568158674d452ae0644ba545", "evidence_kind": "English manual and source declarations", "source_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "sources": [{"url": "/docs/15/libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE", "file": "libpq-connect.html", "label": "15.19 English manual \u00b7 libpq-connect.html", "anchor": "LIBPQ-CONNECT-GSSENCMODE", "sha256": "64a9c015aa67f085bd343fc47439d7a15fd8b6583b0d6f3cf94d7bb94b6f544a"}, {"url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "file": "src/interfaces/libpq/fe-connect.c", "label": "15.19 libpq connection option declarations", "sha256": "63bd4ab01b7161916c0a86a4510f36d287c3ef4e78910568cde611bb925dd9f2", "archive_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, {"url": "/docs/15/libpq-envars.html", "file": "libpq-envars.html", "label": "15.19 English manual \u00b7 libpq-envars.html", "anchor": "", "sha256": "2744c085549e5c53c9cde2147b57b93387276297bb0f545bdf7838595878100d"}, {"url": "/docs/15/libpq-pgservice.html", "file": "libpq-pgservice.html", "label": "15.19 English manual \u00b7 libpq-pgservice.html", "anchor": "", "sha256": "7081175cdd79775d0be65f2af8751f386ea5a006c3f185699be5f7bd1097321b"}], "sections": [{"title": "Default resolution and service-file precedence", "paragraphs": ["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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGGSSENCMODE behaves the same as the gssencmode connection parameter."]}], "signature": "gssencmode", "documented": true, "description": ["This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:"], "environment": [{"name": "PGGSSENCMODE", "source_url": "/docs/15/libpq-envars.html", "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-GSSENCMODE\"><span class=\"term\"><code class=\"literal\">gssencmode</code></span></dt><dd>\n<p>This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:</p>\n<div class=\"variablelist\">\n<dl class=\"variablelist\">\n<dt><span class=\"term\"><code class=\"literal\">disable</code></span></dt>\n<dd>\n<p>only try a non-GSSAPI-encrypted connection</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">prefer</code> (default)</span></dt>\n<dd>\n<p>if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI-encrypted connection; if that fails or there are no credentials, try a non-GSSAPI-encrypted connection. This is the default when <span class=\"productname\">PostgreSQL</span> has been compiled with GSSAPI support.</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">require</code></span></dt>\n<dd>\n<p>only try a GSSAPI-encrypted connection</p>\n</dd>\n</dl>\n</div>\n<p><code class=\"literal\">gssencmode</code> is ignored for Unix domain socket communication. If <span class=\"productname\">PostgreSQL</span> is compiled without GSSAPI support, using the <code class=\"literal\">require</code> option will cause an error, while <code class=\"literal\">prefer</code> will be accepted but <span class=\"application\">libpq</span> will not actually attempt a GSSAPI-encrypted connection.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE", "source_option": {"keyword": "gssencmode", "declaration": "\"gssencmode\", \"PGGSSENCMODE\", DefaultGSSMode, NULL, \"GSSENC-Mode\", \"\", 8, offsetof(struct pg_conn, gssencmode)", "environment": "PGGSSENCMODE", "source_notes": [], "compiled_default_expression": "DefaultGSSMode"}, "comparison_data": {"keyword": "gssencmode", "definition": "This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes: disable only try a non- GSSAPI -encrypted connection prefer (default) if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support. require only try a GSSAPI -encrypted connection gssencmode is ignored for Unix domain socket communication. If PostgreSQL is compiled without GSSAPI support, using the require option will cause an error, while prefer will be accepted but libpq will not actually attempt a GSSAPI -encrypted connection.", "documented": true, "environment": "PGGSSENCMODE", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "compiled_default_expression": "DefaultGSSMode"}, "comparison_hash": "402998f186138ef492d8315637bdecb8dd4b0e73f825d124c736b6a496a1cc09", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "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": "PGGSSENCMODE"}, {"label": "Compiled fallback expression", "value": "DefaultGSSMode"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/16/libpq-envars.html", "text": "PGGSSENCMODE"}, "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "title": "Environment fallback", "columns": [{"key": "name", "label": "Variable"}, {"key": "description", "label": "Documented behavior"}]}], "keyword": "gssencmode", "related": [{"url": "/docs/16/libpq-pgservice.html", "label": "Connection service file"}, {"url": "/docs/16/libpq-pgpass.html", "label": "Password file"}, {"url": "/docs/16/libpq-envars.html", "label": "All libpq environment variables"}], "release": {"ref": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "label": "16.15", "major": "16", "channel": "stable", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/16/postgresql-16-A4.pdf", "bytes": 15282337, "pages": 3055, "sha256": "4bb6c1f63deedac98736d8c4c7bc0fad0ac24e85b07e21ee10411872f06afd06", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/16/postgresql-16-US.pdf", "bytes": 15164148, "pages": 3220, "sha256": "5b6b6166c89991199e144bb0ae34c17a5f29826251dbf19db1abc0df3a3e771b", "built_at": "2026-09-26"}}, "tree": "16", "index": "index.html", "major": "16", "pages": 1169, "release": "16.15", "source_url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "svg_assets": 3, "source_mode": "en HTML verified against the pinned official archive", "source_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "revision": "3c21e58b35318021716440e67bb8bafd392b6a2b965a244d90e9e33c99e0bdef", "evidence_kind": "English manual and source declarations", "source_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "sources": [{"url": "/docs/16/libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE", "file": "libpq-connect.html", "label": "16.15 English manual \u00b7 libpq-connect.html", "anchor": "LIBPQ-CONNECT-GSSENCMODE", "sha256": "a88a6c8f0e2229b1e469ca3fcf95d6cba163af369f2c232c04c07ba0a5b64242"}, {"url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "file": "src/interfaces/libpq/fe-connect.c", "label": "16.15 libpq connection option declarations", "sha256": "ccc43473f7a01820f1ef625a8704548db03499bdee02ef943adbd1329f17f9e7", "archive_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, {"url": "/docs/16/libpq-envars.html", "file": "libpq-envars.html", "label": "16.15 English manual \u00b7 libpq-envars.html", "anchor": "", "sha256": "2dd3190c2f6b9e0d3051b7cc325bb30dad84b29e53035680aa622409ad00fe28"}, {"url": "/docs/16/libpq-pgservice.html", "file": "libpq-pgservice.html", "label": "16.15 English manual \u00b7 libpq-pgservice.html", "anchor": "", "sha256": "d636639599c1db7c0eb9da6c188abfbf7c590bb2ae9367e7fff05863bb9bd0db"}], "sections": [{"title": "Default resolution and service-file precedence", "paragraphs": ["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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGGSSENCMODE behaves the same as the gssencmode connection parameter."]}], "signature": "gssencmode", "documented": true, "description": ["This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:"], "environment": [{"name": "PGGSSENCMODE", "source_url": "/docs/16/libpq-envars.html", "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-GSSENCMODE\"><span class=\"term\"><code class=\"literal\">gssencmode</code></span> </dt><dd>\n<p>This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:</p>\n<div class=\"variablelist\">\n<dl class=\"variablelist\">\n<dt><span class=\"term\"><code class=\"literal\">disable</code></span></dt>\n<dd>\n<p>only try a non-GSSAPI-encrypted connection</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">prefer</code> (default)</span></dt>\n<dd>\n<p>if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI-encrypted connection; if that fails or there are no credentials, try a non-GSSAPI-encrypted connection. This is the default when <span class=\"productname\">PostgreSQL</span> has been compiled with GSSAPI support.</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">require</code></span></dt>\n<dd>\n<p>only try a GSSAPI-encrypted connection</p>\n</dd>\n</dl>\n</div>\n<p><code class=\"literal\">gssencmode</code> is ignored for Unix domain socket communication. If <span class=\"productname\">PostgreSQL</span> is compiled without GSSAPI support, using the <code class=\"literal\">require</code> option will cause an error, while <code class=\"literal\">prefer</code> will be accepted but <span class=\"application\">libpq</span> will not actually attempt a GSSAPI-encrypted connection.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE", "source_option": {"keyword": "gssencmode", "declaration": "\"gssencmode\", \"PGGSSENCMODE\", DefaultGSSMode, NULL, \"GSSENC-Mode\", \"\", 8, offsetof(struct pg_conn, gssencmode)", "environment": "PGGSSENCMODE", "source_notes": [], "compiled_default_expression": "DefaultGSSMode"}, "comparison_data": {"keyword": "gssencmode", "definition": "This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes: disable only try a non- GSSAPI -encrypted connection prefer (default) if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support. require only try a GSSAPI -encrypted connection gssencmode is ignored for Unix domain socket communication. If PostgreSQL is compiled without GSSAPI support, using the require option will cause an error, while prefer will be accepted but libpq will not actually attempt a GSSAPI -encrypted connection.", "documented": true, "environment": "PGGSSENCMODE", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "compiled_default_expression": "DefaultGSSMode"}, "comparison_hash": "402998f186138ef492d8315637bdecb8dd4b0e73f825d124c736b6a496a1cc09", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "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. 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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": ["PGGSSENCMODE behaves the same as the gssencmode connection parameter."]}], "signature": "gssencmode", "documented": true, "description": ["This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:"], "environment": [{"name": "PGGSSENCMODE", "source_url": "/docs/17/libpq-envars.html", "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-GSSENCMODE\"><span class=\"term\"><code class=\"literal\">gssencmode</code></span> </dt><dd>\n<p>This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:</p>\n<div class=\"variablelist\">\n<dl class=\"variablelist\">\n<dt><span class=\"term\"><code class=\"literal\">disable</code></span></dt>\n<dd>\n<p>only try a non-GSSAPI-encrypted connection</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">prefer</code> (default)</span></dt>\n<dd>\n<p>if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI-encrypted connection; if that fails or there are no credentials, try a non-GSSAPI-encrypted connection. This is the default when <span class=\"productname\">PostgreSQL</span> has been compiled with GSSAPI support.</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">require</code></span></dt>\n<dd>\n<p>only try a GSSAPI-encrypted connection</p>\n</dd>\n</dl>\n</div>\n<p><code class=\"literal\">gssencmode</code> is ignored for Unix domain socket communication. If <span class=\"productname\">PostgreSQL</span> is compiled without GSSAPI support, using the <code class=\"literal\">require</code> option will cause an error, while <code class=\"literal\">prefer</code> will be accepted but <span class=\"application\">libpq</span> will not actually attempt a GSSAPI-encrypted connection.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE", "source_option": {"keyword": "gssencmode", "declaration": "\"gssencmode\", \"PGGSSENCMODE\", DefaultGSSMode, NULL, \"GSSENC-Mode\", \"\", 8, offsetof(struct pg_conn, gssencmode)", "environment": "PGGSSENCMODE", "source_notes": [], "compiled_default_expression": "DefaultGSSMode"}, "comparison_data": {"keyword": "gssencmode", "definition": "This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes: disable only try a non- GSSAPI -encrypted connection prefer (default) if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support. require only try a GSSAPI -encrypted connection gssencmode is ignored for Unix domain socket communication. If PostgreSQL is compiled without GSSAPI support, using the require option will cause an error, while prefer will be accepted but libpq will not actually attempt a GSSAPI -encrypted connection.", "documented": true, "environment": "PGGSSENCMODE", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "compiled_default_expression": "DefaultGSSMode"}, "comparison_hash": "402998f186138ef492d8315637bdecb8dd4b0e73f825d124c736b6a496a1cc09", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "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. 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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": ["PGGSSENCMODE behaves the same as the gssencmode connection parameter."]}], "signature": "gssencmode", "documented": true, "description": ["This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:"], "environment": [{"name": "PGGSSENCMODE", "source_url": "/docs/18/libpq-envars.html", "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-GSSENCMODE\"><span class=\"term\"><code class=\"literal\">gssencmode</code></span> </dt><dd>\n<p>This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:</p>\n<div class=\"variablelist\">\n<dl class=\"variablelist\">\n<dt><span class=\"term\"><code class=\"literal\">disable</code></span></dt>\n<dd>\n<p>only try a non-GSSAPI-encrypted connection</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">prefer</code> (default)</span></dt>\n<dd>\n<p>if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI-encrypted connection; if that fails or there are no credentials, try a non-GSSAPI-encrypted connection. This is the default when <span class=\"productname\">PostgreSQL</span> has been compiled with GSSAPI support.</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">require</code></span></dt>\n<dd>\n<p>only try a GSSAPI-encrypted connection</p>\n</dd>\n</dl>\n</div>\n<p><code class=\"literal\">gssencmode</code> is ignored for Unix domain socket communication. If <span class=\"productname\">PostgreSQL</span> is compiled without GSSAPI support, using the <code class=\"literal\">require</code> option will cause an error, while <code class=\"literal\">prefer</code> will be accepted but <span class=\"application\">libpq</span> will not actually attempt a GSSAPI-encrypted connection.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE", "source_option": {"keyword": "gssencmode", "declaration": "\"gssencmode\", \"PGGSSENCMODE\", DefaultGSSMode, NULL, \"GSSENC-Mode\", \"\", 8, offsetof(struct pg_conn, gssencmode)", "environment": "PGGSSENCMODE", "source_notes": [], "compiled_default_expression": "DefaultGSSMode"}, "comparison_data": {"keyword": "gssencmode", "definition": "This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes: disable only try a non- GSSAPI -encrypted connection prefer (default) if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support. require only try a GSSAPI -encrypted connection gssencmode is ignored for Unix domain socket communication. If PostgreSQL is compiled without GSSAPI support, using the require option will cause an error, while prefer will be accepted but libpq will not actually attempt a GSSAPI -encrypted connection.", "documented": true, "environment": "PGGSSENCMODE", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "compiled_default_expression": "DefaultGSSMode"}, "comparison_hash": "402998f186138ef492d8315637bdecb8dd4b0e73f825d124c736b6a496a1cc09", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "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. 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There are three modes: disable only try a non- GSSAPI -encrypted connection prefer (default) if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support. require only try a GSSAPI -encrypted connection gssencmode is ignored for Unix domain socket communication. If PostgreSQL is compiled without GSSAPI support, using the require option will cause an error, while prefer will be accepted but libpq will not actually attempt a GSSAPI -encrypted connection.", "documented": true, "environment": "PGGSSENCMODE", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. 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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": ["PGGSSENCMODE behaves the same as the gssencmode connection parameter."]}], "signature": "gssencmode", "documented": true, "description": ["This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. 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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."]}}}, "snapshot": {"facts": [{"label": "Client library", "value": "libpq 18.6"}, {"label": "Manual definition", "value": "Documented"}, {"label": "Source environment fallback", "value": "PGGSSENCMODE"}, {"label": "Compiled fallback expression", "value": "DefaultGSSMode"}], "tables": [{"key": "environment", "rows": [{"name": {"url": "/docs/18/libpq-envars.html", "text": "PGGSSENCMODE"}, "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "title": "Environment fallback", "columns": [{"key": "name", "label": "Variable"}, {"key": "description", "label": "Documented behavior"}]}], "keyword": "gssencmode", "related": [{"url": "/docs/18/libpq-pgservice.html", "label": "Connection service file"}, {"url": "/docs/18/libpq-pgpass.html", "label": "Password file"}, {"url": "/docs/18/libpq-envars.html", "label": "All libpq environment variables"}], "release": {"ref": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "label": "18.6", "major": "18", "channel": "stable", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/18/postgresql-18-A4.pdf", "bytes": 15865106, "pages": 3154, "sha256": "19512c405da53f9f7fcf0abba359223aa65f021be025bf3411381918f92e3190", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/18/postgresql-18-US.pdf", "bytes": 15748059, "pages": 3328, "sha256": "facbe6c229e598b872d3d98bef53308f46e06746006fa4590de9a7de9dd46319", "built_at": "2026-09-26"}}, "tree": "18", "index": "index.html", "major": "18", "pages": 1148, "release": "18.6", "source_url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "svg_assets": 3, "source_mode": "en SGML built with pinned official archive", "source_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "revision": "ee8d1a3612338fd9adf250730cb640fcc5233b5491337cc00a316a44e3a0b9f8", "evidence_kind": "English manual and source declarations", "source_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "sources": [{"url": "/docs/18/libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE", "file": "libpq-connect.html", "label": "18.6 English manual \u00b7 libpq-connect.html", "anchor": "LIBPQ-CONNECT-GSSENCMODE", "sha256": "c26a7fc3dcda6066cfe540641ae2690faf3d3c03277f30b4dfc2328ab45c212f"}, {"url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "file": "src/interfaces/libpq/fe-connect.c", "label": "18.6 libpq connection option declarations", "sha256": "44a6e386cbfd67ebe768d6ef5493098119c2e6b4796239d53e5ed7b122b206a5", "archive_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, {"url": "/docs/18/libpq-envars.html", "file": "libpq-envars.html", "label": "18.6 English manual \u00b7 libpq-envars.html", "anchor": "", "sha256": "d64db73f3d48127bb984a5f775e77b7bcca2ba4bd218333cf24a45fcdd7c4363"}, {"url": "/docs/18/libpq-pgservice.html", "file": "libpq-pgservice.html", "label": "18.6 English manual \u00b7 libpq-pgservice.html", "anchor": "", "sha256": "6035a3f0ee1d0fd80db5bf58834390b884eecd23206659bdf6f07560deea5aa7"}], "sections": [{"title": "Default resolution and service-file precedence", "paragraphs": ["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."]}, {"title": "Environment variable evidence", "paragraphs": ["PGGSSENCMODE behaves the same as the gssencmode connection parameter."]}], "signature": "gssencmode", "documented": true, "description": ["This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:"], "environment": [{"name": "PGGSSENCMODE", "source_url": "/docs/18/libpq-envars.html", "description": "PGGSSENCMODE behaves the same as the gssencmode connection parameter."}], "manual_html": "<div><dl class=\"variablelist\"><dt id=\"LIBPQ-CONNECT-GSSENCMODE\"><span class=\"term\"><code class=\"literal\">gssencmode</code></span> </dt><dd>\n<p>This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes:</p>\n<div class=\"variablelist\">\n<dl class=\"variablelist\">\n<dt><span class=\"term\"><code class=\"literal\">disable</code></span></dt>\n<dd>\n<p>only try a non-GSSAPI-encrypted connection</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">prefer</code> (default)</span></dt>\n<dd>\n<p>if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI-encrypted connection; if that fails or there are no credentials, try a non-GSSAPI-encrypted connection. This is the default when <span class=\"productname\">PostgreSQL</span> has been compiled with GSSAPI support.</p>\n</dd>\n<dt><span class=\"term\"><code class=\"literal\">require</code></span></dt>\n<dd>\n<p>only try a GSSAPI-encrypted connection</p>\n</dd>\n</dl>\n</div>\n<p><code class=\"literal\">gssencmode</code> is ignored for Unix domain socket communication. If <span class=\"productname\">PostgreSQL</span> is compiled without GSSAPI support, using the <code class=\"literal\">require</code> option will cause an error, while <code class=\"literal\">prefer</code> will be accepted but <span class=\"application\">libpq</span> will not actually attempt a GSSAPI-encrypted connection.</p>\n</dd></dl></div>", "manual_path": "libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE", "source_option": {"keyword": "gssencmode", "declaration": "\"gssencmode\", \"PGGSSENCMODE\", DefaultGSSMode, NULL, \"GSSENC-Mode\", \"\", 8, offsetof(struct pg_conn, gssencmode)", "environment": "PGGSSENCMODE", "source_notes": [], "compiled_default_expression": "DefaultGSSMode"}, "comparison_data": {"keyword": "gssencmode", "definition": "This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes: disable only try a non- GSSAPI -encrypted connection prefer (default) if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support. require only try a GSSAPI -encrypted connection gssencmode is ignored for Unix domain socket communication. If PostgreSQL is compiled without GSSAPI support, using the require option will cause an error, while prefer will be accepted but libpq will not actually attempt a GSSAPI -encrypted connection.", "documented": true, "environment": "PGGSSENCMODE", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "compiled_default_expression": "DefaultGSSMode"}, "comparison_hash": "402998f186138ef492d8315637bdecb8dd4b0e73f825d124c736b6a496a1cc09", "default_evidence": ["if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support."], "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": "added", "diff": "--- PostgreSQL 11\n+++ PostgreSQL 12\n@@ -1 +1,10 @@\n-Not recorded in this version\n+{\n+  \"compiled_default_expression\": \"DefaultGSSMode\",\n+  \"default_evidence\": [\n+    \"if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support.\"\n+  ],\n+  \"definition\": \"This option determines whether or with what priority a secure GSS TCP/IP connection will be negotiated with the server. There are three modes: disable only try a non- GSSAPI -encrypted connection prefer (default) if there are GSSAPI credentials present (i.e., in a credentials cache), first try a GSSAPI -encrypted connection; if that fails or there are no credentials, try a non- GSSAPI -encrypted connection. This is the default when PostgreSQL has been compiled with GSSAPI support. require only try a GSSAPI -encrypted connection gssencmode is ignored for Unix domain socket communication. If PostgreSQL is compiled without GSSAPI support, using the require option will cause an error, while prefer will be accepted but libpq will not actually attempt a GSSAPI -encrypted connection.\",\n+  \"documented\": true,\n+  \"environment\": \"PGGSSENCMODE\",\n+  \"keyword\": \"gssencmode\"\n+}"}}