Add postgres_fdw contrib module.

There's still a lot of room for improvement, but it basically works,
and we need this to be present before we can do anything much with the
writable-foreign-tables patch.  So let's commit it and get on with testing.

Shigeru Hanada, reviewed by KaiGai Kohei and Tom Lane

contrib/Makefile

@@ -43,6 +43,7 @@ SUBDIRS = \
 		pgcrypto	\
 		pgrowlocks	\
 		pgstattuple	\
+		postgres_fdw	\
 		seg		\
 		spi		\
 		tablefunc	\

contrib/postgres_fdw/.gitignore

+# Generated subdirectories
+/log/
+/results/
+/tmp_check/

contrib/postgres_fdw/Makefile

+# contrib/postgres_fdw/Makefile
+
+MODULE_big = postgres_fdw
+OBJS = postgres_fdw.o option.o deparse.o connection.o
+
+PG_CPPFLAGS = -I$(libpq_srcdir)
+SHLIB_LINK = $(libpq)
+SHLIB_PREREQS = submake-libpq
+
+EXTENSION = postgres_fdw
+DATA = postgres_fdw--1.0.sql
+
+REGRESS = postgres_fdw
+
+# the db name is hard-coded in the tests
+override USE_MODULE_DB =
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/postgres_fdw
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif

contrib/postgres_fdw/option.c

+/*-------------------------------------------------------------------------
+ *
+ * option.c
+ *		  FDW option handling for postgres_fdw
+ *
+ * Portions Copyright (c) 2012-2013, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		  contrib/postgres_fdw/option.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "postgres_fdw.h"
+
+#include "access/reloptions.h"
+#include "catalog/pg_foreign_server.h"
+#include "catalog/pg_foreign_table.h"
+#include "catalog/pg_user_mapping.h"
+#include "commands/defrem.h"
+
+
+/*
+ * Describes the valid options for objects that this wrapper uses.
+ */
+typedef struct PgFdwOption
+{
+	const char *keyword;
+	Oid			optcontext;		/* OID of catalog in which option may appear */
+	bool		is_libpq_opt;	/* true if it's used in libpq */
+} PgFdwOption;
+
+/*
+ * Valid options for postgres_fdw.
+ * Allocated and filled in InitPgFdwOptions.
+ */
+static PgFdwOption *postgres_fdw_options;
+
+/*
+ * Valid options for libpq.
+ * Allocated and filled in InitPgFdwOptions.
+ */
+static PQconninfoOption *libpq_options;
+
+/*
+ * Helper functions
+ */
+static void InitPgFdwOptions(void);
+static bool is_valid_option(const char *keyword, Oid context);
+static bool is_libpq_option(const char *keyword);
+
+
+/*
+ * Validate the generic options given to a FOREIGN DATA WRAPPER, SERVER,
+ * USER MAPPING or FOREIGN TABLE that uses postgres_fdw.
+ *
+ * Raise an ERROR if the option or its value is considered invalid.
+ */
+extern Datum postgres_fdw_validator(PG_FUNCTION_ARGS);
+
+PG_FUNCTION_INFO_V1(postgres_fdw_validator);
+
+Datum
+postgres_fdw_validator(PG_FUNCTION_ARGS)
+{
+	List	   *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
+	Oid			catalog = PG_GETARG_OID(1);
+	ListCell   *cell;
+
+	/* Build our options lists if we didn't yet. */
+	InitPgFdwOptions();
+
+	/*
+	 * Check that only options supported by postgres_fdw, and allowed for the
+	 * current object type, are given.
+	 */
+	foreach(cell, options_list)
+	{
+		DefElem    *def = (DefElem *) lfirst(cell);
+
+		if (!is_valid_option(def->defname, catalog))
+		{
+			/*
+			 * Unknown option specified, complain about it. Provide a hint
+			 * with list of valid options for the object.
+			 */
+			PgFdwOption *opt;
+			StringInfoData buf;
+
+			initStringInfo(&buf);
+			for (opt = postgres_fdw_options; opt->keyword; opt++)
+			{
+				if (catalog == opt->optcontext)
+					appendStringInfo(&buf, "%s%s", (buf.len > 0) ? ", " : "",
+									 opt->keyword);
+			}
+
+			ereport(ERROR,
+					(errcode(ERRCODE_FDW_INVALID_OPTION_NAME),
+					 errmsg("invalid option \"%s\"", def->defname),
+					 errhint("Valid options in this context are: %s",
+							 buf.data)));
+		}
+
+		/*
+		 * Validate option value, when we can do so without any context.
+		 */
+		if (strcmp(def->defname, "use_remote_explain") == 0)
+		{
+			/* use_remote_explain accepts only boolean values */
+			(void) defGetBoolean(def);
+		}
+		else if (strcmp(def->defname, "fdw_startup_cost") == 0 ||
+				 strcmp(def->defname, "fdw_tuple_cost") == 0)
+		{
+			/* these must have a non-negative numeric value */
+			double		val;
+			char	   *endp;
+
+			val = strtod(defGetString(def), &endp);
+			if (*endp || val < 0)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("%s requires a non-negative numeric value",
+								def->defname)));
+		}
+	}
+
+	PG_RETURN_VOID();
+}
+
+/*
+ * Initialize option lists.
+ */
+static void
+InitPgFdwOptions(void)
+{
+	int			num_libpq_opts;
+	PQconninfoOption *lopt;
+	PgFdwOption *popt;
+
+	/* non-libpq FDW-specific FDW options */
+	static const PgFdwOption non_libpq_options[] = {
+		{"schema_name", ForeignTableRelationId, false},
+		{"table_name", ForeignTableRelationId, false},
+		{"column_name", AttributeRelationId, false},
+		/* use_remote_explain is available on both server and table */
+		{"use_remote_explain", ForeignServerRelationId, false},
+		{"use_remote_explain", ForeignTableRelationId, false},
+		/* cost factors */
+		{"fdw_startup_cost", ForeignServerRelationId, false},
+		{"fdw_tuple_cost", ForeignServerRelationId, false},
+		{NULL, InvalidOid, false}
+	};
+
+	/* Prevent redundant initialization. */
+	if (postgres_fdw_options)
+		return;
+
+	/*
+	 * Get list of valid libpq options.
+	 *
+	 * To avoid unnecessary work, we get the list once and use it throughout
+	 * the lifetime of this backend process.  We don't need to care about
+	 * memory context issues, because PQconndefaults allocates with malloc.
+	 */
+	libpq_options = PQconndefaults();
+	if (!libpq_options)			/* assume reason for failure is OOM */
+		ereport(ERROR,
+				(errcode(ERRCODE_FDW_OUT_OF_MEMORY),
+				 errmsg("out of memory"),
+			 errdetail("could not get libpq's default connection options")));
+
+	/* Count how many libpq options are available. */
+	num_libpq_opts = 0;
+	for (lopt = libpq_options; lopt->keyword; lopt++)
+		num_libpq_opts++;
+
+	/*
+	 * Construct an array which consists of all valid options for
+	 * postgres_fdw, by appending FDW-specific options to libpq options.
+	 *
+	 * We use plain malloc here to allocate postgres_fdw_options because it
+	 * lives as long as the backend process does.  Besides, keeping
+	 * libpq_options in memory allows us to avoid copying every keyword
+	 * string.
+	 */
+	postgres_fdw_options = (PgFdwOption *)
+		malloc(sizeof(PgFdwOption) * num_libpq_opts +
+			   sizeof(non_libpq_options));
+	if (postgres_fdw_options == NULL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FDW_OUT_OF_MEMORY),
+				 errmsg("out of memory")));
+
+	popt = postgres_fdw_options;
+	for (lopt = libpq_options; lopt->keyword; lopt++)
+	{
+		/* Hide debug options, as well as settings we override internally. */
+		if (strchr(lopt->dispchar, 'D') ||
+			strcmp(lopt->keyword, "fallback_application_name") == 0 ||
+			strcmp(lopt->keyword, "client_encoding") == 0)
+			continue;
+
+		/* We don't have to copy keyword string, as described above. */
+		popt->keyword = lopt->keyword;
+
+		/*
+		 * "user" and any secret options are allowed only on user mappings.
+		 * Everything else is a server option.
+		 */
+		if (strcmp(lopt->keyword, "user") == 0 || strchr(lopt->dispchar, '*'))
+			popt->optcontext = UserMappingRelationId;
+		else
+			popt->optcontext = ForeignServerRelationId;
+		popt->is_libpq_opt = true;
+
+		popt++;
+	}
+
+	/* Append FDW-specific options and dummy terminator. */
+	memcpy(popt, non_libpq_options, sizeof(non_libpq_options));
+}
+
+/*
+ * Check whether the given option is one of the valid postgres_fdw options.
+ * context is the Oid of the catalog holding the object the option is for.
+ */
+static bool
+is_valid_option(const char *keyword, Oid context)
+{
+	PgFdwOption *opt;
+
+	Assert(postgres_fdw_options);		/* must be initialized already */
+
+	for (opt = postgres_fdw_options; opt->keyword; opt++)
+	{
+		if (context == opt->optcontext && strcmp(opt->keyword, keyword) == 0)
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * Check whether the given option is one of the valid libpq options.
+ */
+static bool
+is_libpq_option(const char *keyword)
+{
+	PgFdwOption *opt;
+
+	Assert(postgres_fdw_options);		/* must be initialized already */
+
+	for (opt = postgres_fdw_options; opt->keyword; opt++)
+	{
+		if (opt->is_libpq_opt && strcmp(opt->keyword, keyword) == 0)
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * Generate key-value arrays which include only libpq options from the
+ * given list (which can contain any kind of options).	Caller must have
+ * allocated large-enough arrays.  Returns number of options found.
+ */
+int
+ExtractConnectionOptions(List *defelems, const char **keywords,
+						 const char **values)
+{
+	ListCell   *lc;
+	int			i;
+
+	/* Build our options lists if we didn't yet. */
+	InitPgFdwOptions();
+
+	i = 0;
+	foreach(lc, defelems)
+	{
+		DefElem    *d = (DefElem *) lfirst(lc);
+
+		if (is_libpq_option(d->defname))
+		{
+			keywords[i] = d->defname;
+			values[i] = defGetString(d);
+			i++;
+		}
+	}
+	return i;
+}

contrib/postgres_fdw/postgres_fdw--1.0.sql

+/* contrib/postgres_fdw/postgres_fdw--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION postgres_fdw" to load this file. \quit
+
+CREATE FUNCTION postgres_fdw_handler()
+RETURNS fdw_handler
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT;
+
+CREATE FUNCTION postgres_fdw_validator(text[], oid)
+RETURNS void
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT;
+
+CREATE FOREIGN DATA WRAPPER postgres_fdw
+  HANDLER postgres_fdw_handler
+  VALIDATOR postgres_fdw_validator;

contrib/postgres_fdw/postgres_fdw.control

+# postgres_fdw extension
+comment = 'foreign-data wrapper for remote PostgreSQL servers'
+default_version = '1.0'
+module_pathname = '$libdir/postgres_fdw'
+relocatable = true

contrib/postgres_fdw/postgres_fdw.h

+/*-------------------------------------------------------------------------
+ *
+ * postgres_fdw.h
+ *		  Foreign-data wrapper for remote PostgreSQL servers
+ *
+ * Portions Copyright (c) 2012-2013, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		  contrib/postgres_fdw/postgres_fdw.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef POSTGRES_FDW_H
+#define POSTGRES_FDW_H
+
+#include "foreign/foreign.h"
+#include "lib/stringinfo.h"
+#include "nodes/relation.h"
+#include "utils/rel.h"
+
+#include "libpq-fe.h"
+
+/* in connection.c */
+extern PGconn *GetConnection(ForeignServer *server, UserMapping *user);
+extern void ReleaseConnection(PGconn *conn);
+extern unsigned int GetCursorNumber(PGconn *conn);
+extern void pgfdw_report_error(int elevel, PGresult *res, bool clear,
+				   const char *sql);
+
+/* in option.c */
+extern int ExtractConnectionOptions(List *defelems,
+						 const char **keywords,
+						 const char **values);
+
+/* in deparse.c */
+extern void classifyConditions(PlannerInfo *root,
+				   RelOptInfo *baserel,
+				   List **remote_conds,
+				   List **param_conds,
+				   List **local_conds,
+				   List **param_numbers);
+extern void deparseSimpleSql(StringInfo buf,
+				 PlannerInfo *root,
+				 RelOptInfo *baserel,
+				 List *local_conds);
+extern void appendWhereClause(StringInfo buf,
+				  bool has_where,
+				  List *exprs,
+				  PlannerInfo *root);
+extern void deparseAnalyzeSql(StringInfo buf, Relation rel);
+
+#endif   /* POSTGRES_FDW_H */

doc/src/sgml/client-auth.sgml

@@ -1098,7 +1098,7 @@ omicron         bryanh                  guest1
     <replaceable>servicename</> can be set on the server side using the
     <xref linkend="guc-krb-srvname"> configuration parameter, and on the
     client side using the <literal>krbsrvname</> connection parameter. (See
-    also <xref linkend="libpq-connect">.)  The installation default can be
+    also <xref linkend="libpq-paramkeywords">.) The installation default can be
     changed from the default <literal>postgres</literal> at build time using
     <literal>./configure --with-krb-srvnam=</><replaceable>whatever</>.
     In most environments,

doc/src/sgml/contrib.sgml

@@ -132,6 +132,7 @@ CREATE EXTENSION <replaceable>module_name</> FROM unpackaged;
  &pgstatstatements;
  &pgstattuple;
  &pgtrgm;
+ &postgres-fdw;
  &seg;
  &sepgsql;
  &contrib-spi;

doc/src/sgml/dblink.sgml

@@ -8,11 +8,16 @@
  </indexterm>
 
  <para>
-  <filename>dblink</> is a module which supports connections to
+  <filename>dblink</> is a module that supports connections to
   other <productname>PostgreSQL</> databases from within a database
   session.
  </para>
 
+ <para>
+  See also <xref linkend="postgres-fdw">, which provides roughly the same
+  functionality using a more modern and standards-compliant infrastructure.
+ </para>
+
  <refentry id="CONTRIB-DBLINK-CONNECT">
   <refmeta>
    <refentrytitle>dblink_connect</refentrytitle>
@@ -47,12 +52,10 @@ dblink_connect(text connname, text connstr) returns text
    <para>
     The connection string may also be the name of an existing foreign
     server.  It is recommended to use the foreign-data wrapper
-    <literal>dblink_fdw</literal> when defining the corresponding foreign
-    server.  See the example below, as well as the following:
-    <simplelist type="inline">
-     <member><xref linkend="sql-createserver"></member>
-     <member><xref linkend="sql-createusermapping"></member>
-    </simplelist>
+    <literal>dblink_fdw</literal> when defining the foreign
+    server.  See the example below, as well as
+    <xref linkend="sql-createserver"> and
+    <xref linkend="sql-createusermapping">.
    </para>
 
   </refsect1>
@@ -77,8 +80,8 @@ dblink_connect(text connname, text connstr) returns text
       <para><application>libpq</>-style connection info string, for example
        <literal>hostaddr=127.0.0.1 port=5432 dbname=mydb user=postgres
        password=mypasswd</>.
-       For details see <function>PQconnectdb</> in
-       <xref linkend="libpq-connect">.
+       For details see <xref linkend="libpq-connstring">.
+       Alternatively, the name of a foreign server.
       </para>
      </listitem>
     </varlistentry>
@@ -133,9 +136,10 @@ SELECT dblink_connect('myconn', 'dbname=postgres');
 --       ERROR:  password is required
 --       DETAIL:  Non-superuser cannot connect if the server does not request a password.
 --       HINT:  Target server's authentication method must be changed.
-CREATE USER dblink_regression_test WITH PASSWORD 'secret';
+
 CREATE SERVER fdtest FOREIGN DATA WRAPPER dblink_fdw OPTIONS (hostaddr '127.0.0.1', dbname 'contrib_regression');
 
+CREATE USER dblink_regression_test WITH PASSWORD 'secret';
 CREATE USER MAPPING FOR dblink_regression_test SERVER fdtest OPTIONS (user 'dblink_regression_test', password 'secret');
 GRANT USAGE ON FOREIGN SERVER fdtest TO dblink_regression_test;
 GRANT SELECT ON TABLE foo TO dblink_regression_test;

doc/src/sgml/filelist.sgml

@@ -134,6 +134,7 @@
 <!ENTITY pgtesttiming    SYSTEM "pgtesttiming.sgml">
 <!ENTITY pgtrgm          SYSTEM "pgtrgm.sgml">
 <!ENTITY pgupgrade       SYSTEM "pgupgrade.sgml">
+<!ENTITY postgres-fdw    SYSTEM "postgres-fdw.sgml">
 <!ENTITY seg             SYSTEM "seg.sgml">
 <!ENTITY contrib-spi     SYSTEM "contrib-spi.sgml">
 <!ENTITY sepgsql         SYSTEM "sepgsql.sgml">

doc/src/sgml/libpq.sgml

@@ -6941,7 +6941,7 @@ myEventProc(PGEventId evtId, void *evtInfo, void *passThrough)
   <para>
    The file uses an <quote>INI file</quote> format where the section
    name is the service name and the parameters are connection
-   parameters; see <xref linkend="libpq-connect"> for a list.  For
+   parameters; see <xref linkend="libpq-paramkeywords"> for a list.  For
    example:
 <programlisting>
 # comment

doc/src/sgml/queries.sgml

@@ -699,7 +699,7 @@ SELECT *
     WHERE proname LIKE 'bytea%';
 </programlisting>
      The <xref linkend="CONTRIB-DBLINK-FUNCTION"> function
-     (part of the <xref linkend="dblink"> module>) executes
+     (part of the <xref linkend="dblink"> module) executes
      a remote query.  It is declared to return
      <type>record</> since it might be used for any kind of query.
      The actual column set must be specified in the calling query so

doc/src/sgml/recovery-config.sgml

@@ -314,8 +314,7 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
          <para>
           Specifies a connection string to be used for the standby server
           to connect with the primary. This string is in the format
-          accepted by the libpq <function>PQconnectdb</function> function,
-          described in <xref linkend="libpq-connect">. If any option is
+          described in <xref linkend="libpq-connstring">. If any option is
           unspecified in this string, then the corresponding environment
           variable (see <xref linkend="libpq-envars">) is checked. If the
           environment variable is not set either, then

doc/src/sgml/ref/create_foreign_data_wrapper.sgml

@@ -121,14 +121,6 @@ CREATE FOREIGN DATA WRAPPER <replaceable class="parameter">name</replaceable>
    There is no support for updating a foreign table, and optimization of
    queries is primitive (and mostly left to the wrapper, too).
   </para>
-
-  <para>
-   There is one built-in foreign-data wrapper validator function
-   provided:
-   <filename>postgresql_fdw_validator</filename>, which accepts
-   options corresponding to <application>libpq</> connection
-   parameters.
-  </para>
  </refsect1>
 
  <refsect1>

doc/src/sgml/ref/create_foreign_table.sgml

@@ -32,7 +32,7 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name
   <title>Description</title>
 
   <para>
-   <command>CREATE FOREIGN TABLE</command> will create a new foreign table
+   <command>CREATE FOREIGN TABLE</command> creates a new foreign table
    in the current database. The table will be owned by the user issuing the
    command.
   </para>
@@ -54,8 +54,9 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name
   </para>
 
   <para>
-   To be able to create a table, you must have <literal>USAGE</literal>
-   privilege on all column types.
+   To be able to create a foreign table, you must have <literal>USAGE</literal>
+   privilege on the foreign server, as well as <literal>USAGE</literal>
+   privilege on all column types used in the table.
   </para>
  </refsect1>
 
@@ -134,7 +135,7 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name
     <term><replaceable class="PARAMETER">server_name</replaceable></term>
     <listitem>
      <para>
-      The name of an existing server for the foreign table.
+      The name of an existing foreign server to use for the foreign table.
       For details on defining a server, see <xref
       linkend="SQL-CREATESERVER">.
      </para>
@@ -164,7 +165,8 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name
   <title>Examples</title>
 
   <para>
-   Create foreign table <structname>films</> with <structname>film_server</>:
+   Create foreign table <structname>films</>, which will be accessed through
+   the server <structname>film_server</>:
 
 <programlisting>
 CREATE FOREIGN TABLE films (

doc/src/sgml/ref/create_server.sgml

@@ -110,11 +110,10 @@ CREATE SERVER <replaceable class="parameter">server_name</replaceable> [ TYPE '<
   <title>Notes</title>
 
   <para>
-   When using the <application>dblink</application> module
-   (see <xref linkend="dblink">), the foreign server name can be used
+   When using the <xref linkend="dblink"> module,
+   a foreign server's name can be used
    as an argument of the <xref linkend="contrib-dblink-connect">
-   function to indicate the connection parameters.  See also there for
-   more examples.  It is necessary to have
+   function to indicate the connection parameters.  It is necessary to have
    the <literal>USAGE</literal> privilege on the foreign server to be
    able to use it in this way.
   </para>
@@ -124,19 +123,13 @@ CREATE SERVER <replaceable class="parameter">server_name</replaceable> [ TYPE '<
   <title>Examples</title>
 
   <para>
-   Create a server <literal>foo</> that uses the built-in foreign-data
-   wrapper <literal>default</>:
+   Create a server <literal>myserver</> that uses the
+   foreign-data wrapper <literal>postgres_fdw</>:
 <programlisting>
-CREATE SERVER foo FOREIGN DATA WRAPPER "default";
+CREATE SERVER myserver FOREIGN DATA WRAPPER postgres_fdw OPTIONS (host 'foo', dbname 'foodb', port '5432');
 </programlisting>
+   See <xref linkend="postgres-fdw"> for more details.
   </para>
-
-  <para>
-   Create a server <literal>myserver</> that uses the
-   foreign-data wrapper <literal>pgsql</>:
-<programlisting>
-CREATE SERVER myserver FOREIGN DATA WRAPPER pgsql OPTIONS (host 'foo', dbname 'foodb', port '5432');
-</programlisting></para>
  </refsect1>
 
  <refsect1>
@@ -154,6 +147,7 @@ CREATE SERVER myserver FOREIGN DATA WRAPPER pgsql OPTIONS (host 'foo', dbname 'f
    <member><xref linkend="sql-alterserver"></member>
    <member><xref linkend="sql-dropserver"></member>
    <member><xref linkend="sql-createforeigndatawrapper"></member>
+   <member><xref linkend="sql-createforeigntable"></member>
    <member><xref linkend="sql-createusermapping"></member>
   </simplelist>
  </refsect1>

doc/src/sgml/ref/grant.sgml

@@ -357,10 +357,9 @@ GRANT <replaceable class="PARAMETER">role_name</replaceable> [, ...] TO <replace
        to create new servers using that foreign-data wrapper.
       </para>
       <para>
-       For servers, this privilege enables the grantee to create,
-       alter, and drop his own user's user mappings associated with
-       that server.  Also, it enables the grantee to query the options
-       of the server and associated user mappings.
+       For servers, this privilege enables the grantee to create foreign
+       tables using the server, and also to create, alter, or drop his own
+       user's user mappings associated with that server.
       </para>
      </listitem>
     </varlistentry>