list of extended statistics on psql

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index fc16e6c..d4c9de9 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1909,6 +1909,18 @@ testdb=>
       </varlistentry>
 
       <varlistentry>
+        <term><literal>\dz [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        </para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><literal>\e</literal> or <literal>\edit</literal> <literal> <optional> <replaceable class="parameter">filename</replaceable> </optional> <optional> <replaceable class="parameter">line_number</replaceable> </optional> </literal></term>
 
         <listitem>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 9902a4a..dc36c98 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -932,6 +932,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
+			case 'z':			/* Extended Statistics */
+				success = listExtendedStats(pattern);
+				break;
 			default:
 				status = PSQL_CMD_UNKNOWN;
 		}
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index d81f157..c9d9e08 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4368,6 +4368,74 @@ listEventTriggers(const char *pattern, bool verbose)
 }
 
 /*
+ * \dz
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "stxnamespace::pg_catalog.regnamespace AS \"%s\", \n"
+					  "c.relname AS \"%s\", \n"
+					  "stxname AS \"%s\", \n"
+					  "(SELECT pg_catalog.string_agg(pg_catalog.quote_ident(attname),', ') \n"
+					  " FROM pg_catalog.unnest(stxkeys) s(attnum) \n"
+					  " JOIN pg_catalog.pg_attribute a ON (stxrelid = a.attrelid AND \n"
+					  " a.attnum = s.attnum AND NOT attisdropped)) AS \"%s\", \n"
+					  "'d' = any(stxkind) AS \"%s\", \n"
+					  "'f' = any(stxkind) AS \"%s\", \n"
+					  "'m' = any(stxkind) AS \"%s\"  \n"
+					  "FROM pg_catalog.pg_statistic_ext \n"
+					  "INNER JOIN pg_catalog.pg_class c \n"
+					  "ON stxrelid = c.oid \n",
+					  gettext_noop("Schema"),
+					  gettext_noop("Table"),
+					  gettext_noop("Name"),
+					  gettext_noop("Columns"),
+					  gettext_noop("Ndistinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("MCV"));
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2, 3, 4;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
+/*
  * \dC
  *
  * Describes casts.
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec9..6c16947 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -105,6 +105,9 @@ extern bool listExtensionContents(const char *pattern);
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
+/* \dz */
+extern bool listExtendedStats(const char *pattern);
+
 /* \dRp */
 bool		listPublications(const char *pattern);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af82928..78b30f2 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -268,6 +268,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
+	fprintf(output, _("  \\dz     [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
 	fprintf(output, _("  \\sv[+]  VIEWNAME       show a view's definition\n"));
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index 555d464..0c7c780 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5012,3 +5012,41 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+\dz
+                          List of extended statistics
+ Schema | Table |   Name    |     Columns      | Ndistinct | Dependencies | MCV 
+--------+-------+-----------+------------------+-----------+--------------+-----
+ public | hoge  | stts_hoge | col1, col2, col3 | t         | t            | t
+ public | t1    | stts_1    | a, b             | f         | t            | f
+ public | t1    | stts_2    | a, b             | t         | t            | f
+ public | t1    | stts_3    | a, b             | t         | t            | t
+ public | t2    | stts_4    | b, c             | t         | t            | t
+(5 rows)
+
+\dz stts_?
+                    List of extended statistics
+ Schema | Table |  Name  | Columns | Ndistinct | Dependencies | MCV 
+--------+-------+--------+---------+-----------+--------------+-----
+ public | t1    | stts_1 | a, b    | f         | t            | f
+ public | t1    | stts_2 | a, b    | t         | t            | f
+ public | t1    | stts_3 | a, b    | t         | t            | t
+ public | t2    | stts_4 | b, c    | t         | t            | t
+(4 rows)
+
+\dz *hoge
+                          List of extended statistics
+ Schema | Table |   Name    |     Columns      | Ndistinct | Dependencies | MCV 
+--------+-------+-----------+------------------+-----------+--------------+-----
+ public | hoge  | stts_hoge | col1, col2, col3 | t         | t            | t
+(1 row)
+
+drop table t1, t2, hoge;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 5a16080..d8c5688 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1207,3 +1207,20 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+\dz
+\dz stts_?
+\dz *hoge
+drop table t1, t2, hoge;

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index fc16e6c..ace8e5f 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1893,6 +1893,18 @@ testdb=>
         </para>
         </listitem>
       </varlistentry>
+      
+	  <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 9902a4a..dcc9fba 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -929,6 +929,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index d81f157..77b3074 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4368,6 +4368,74 @@ listEventTriggers(const char *pattern, bool verbose)
 }
 
 /*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "stxnamespace::pg_catalog.regnamespace AS \"%s\", \n"
+					  "c.relname AS \"%s\", \n"
+					  "stxname AS \"%s\", \n"
+					  "(SELECT pg_catalog.string_agg(pg_catalog.quote_ident(attname),', ') \n"
+					  " FROM pg_catalog.unnest(stxkeys) s(attnum) \n"
+					  " JOIN pg_catalog.pg_attribute a ON (stxrelid = a.attrelid AND \n"
+					  " a.attnum = s.attnum AND NOT attisdropped)) AS \"%s\", \n"
+					  "'d' = any(stxkind) AS \"%s\", \n"
+					  "'f' = any(stxkind) AS \"%s\", \n"
+					  "'m' = any(stxkind) AS \"%s\"  \n"
+					  "FROM pg_catalog.pg_statistic_ext \n"
+					  "INNER JOIN pg_catalog.pg_class c \n"
+					  "ON stxrelid = c.oid \n",
+					  gettext_noop("Schema"),
+					  gettext_noop("Table"),
+					  gettext_noop("Name"),
+					  gettext_noop("Columns"),
+					  gettext_noop("Ndistinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("MCV"));
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2, 3, 4;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
+/*
  * \dC
  *
  * Describes casts.
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec9..f0b3f91 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af82928..35c39db 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX     [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index 555d464..caad618 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5012,3 +5012,41 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+\dX
+                          List of extended statistics
+ Schema | Table |   Name    |     Columns      | Ndistinct | Dependencies | MCV 
+--------+-------+-----------+------------------+-----------+--------------+-----
+ public | hoge  | stts_hoge | col1, col2, col3 | t         | t            | t
+ public | t1    | stts_1    | a, b             | f         | t            | f
+ public | t1    | stts_2    | a, b             | t         | t            | f
+ public | t1    | stts_3    | a, b             | t         | t            | t
+ public | t2    | stts_4    | b, c             | t         | t            | t
+(5 rows)
+
+\dX stts_?
+                    List of extended statistics
+ Schema | Table |  Name  | Columns | Ndistinct | Dependencies | MCV 
+--------+-------+--------+---------+-----------+--------------+-----
+ public | t1    | stts_1 | a, b    | f         | t            | f
+ public | t1    | stts_2 | a, b    | t         | t            | f
+ public | t1    | stts_3 | a, b    | t         | t            | t
+ public | t2    | stts_4 | b, c    | t         | t            | t
+(4 rows)
+
+\dX *hoge
+                          List of extended statistics
+ Schema | Table |   Name    |     Columns      | Ndistinct | Dependencies | MCV 
+--------+-------+-----------+------------------+-----------+--------------+-----
+ public | hoge  | stts_hoge | col1, col2, col3 | t         | t            | t
+(1 row)
+
+drop table t1, t2, hoge;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 5a16080..163c1fb 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1207,3 +1207,20 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+\dX
+\dX stts_?
+\dX *hoge
+drop table t1, t2, hoge;

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index fc16e6c..8b0568c 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1893,6 +1893,18 @@ testdb=>
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 9902a4a..dcc9fba 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -929,6 +929,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index d81f157..e43241f 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4368,6 +4368,74 @@ listEventTriggers(const char *pattern, bool verbose)
 }
 
 /*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "stxnamespace::pg_catalog.regnamespace AS \"%s\", \n"
+					  "c.relname AS \"%s\", \n"
+					  "stxname AS \"%s\", \n"
+					  "(SELECT pg_catalog.string_agg(pg_catalog.quote_ident(attname),', ') \n"
+					  " FROM pg_catalog.unnest(stxkeys) s(attnum) \n"
+					  " JOIN pg_catalog.pg_attribute a ON (stxrelid = a.attrelid AND \n"
+					  " a.attnum = s.attnum AND NOT attisdropped)) AS \"%s\", \n"
+					  "'d' = any(stxkind) AS \"%s\", \n"
+					  "'f' = any(stxkind) AS \"%s\", \n"
+					  "'m' = any(stxkind) AS \"%s\"  \n"
+					  "FROM pg_catalog.pg_statistic_ext \n"
+					  "INNER JOIN pg_catalog.pg_class c \n"
+					  "ON stxrelid = c.oid \n",
+					  gettext_noop("Schema"),
+					  gettext_noop("Table"),
+					  gettext_noop("Name"),
+					  gettext_noop("Columns"),
+					  gettext_noop("Ndistinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("MCV"));
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2, 3;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
+/*
  * \dC
  *
  * Describes casts.
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec9..f0b3f91 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af82928..35c39db 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX     [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index 555d464..caad618 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5012,3 +5012,41 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+\dX
+                          List of extended statistics
+ Schema | Table |   Name    |     Columns      | Ndistinct | Dependencies | MCV 
+--------+-------+-----------+------------------+-----------+--------------+-----
+ public | hoge  | stts_hoge | col1, col2, col3 | t         | t            | t
+ public | t1    | stts_1    | a, b             | f         | t            | f
+ public | t1    | stts_2    | a, b             | t         | t            | f
+ public | t1    | stts_3    | a, b             | t         | t            | t
+ public | t2    | stts_4    | b, c             | t         | t            | t
+(5 rows)
+
+\dX stts_?
+                    List of extended statistics
+ Schema | Table |  Name  | Columns | Ndistinct | Dependencies | MCV 
+--------+-------+--------+---------+-----------+--------------+-----
+ public | t1    | stts_1 | a, b    | f         | t            | f
+ public | t1    | stts_2 | a, b    | t         | t            | f
+ public | t1    | stts_3 | a, b    | t         | t            | t
+ public | t2    | stts_4 | b, c    | t         | t            | t
+(4 rows)
+
+\dX *hoge
+                          List of extended statistics
+ Schema | Table |   Name    |     Columns      | Ndistinct | Dependencies | MCV 
+--------+-------+-----------+------------------+-----------+--------------+-----
+ public | hoge  | stts_hoge | col1, col2, col3 | t         | t            | t
+(1 row)
+
+drop table t1, t2, hoge;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 5a16080..163c1fb 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1207,3 +1207,20 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+\dX
+\dX stts_?
+\dX *hoge
+drop table t1, t2, hoge;

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index fc16e6c..5664c22 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1893,6 +1893,20 @@ testdb=>
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 9902a4a..077a585 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -929,6 +929,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index d81f157..d99e387 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4368,6 +4368,98 @@ listEventTriggers(const char *pattern, bool verbose)
 }
 
 /*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "stxnamespace::pg_catalog.regnamespace AS \"%s\", \n"
+					  "stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(attname),', ') \n"
+					  "   FROM pg_catalog.unnest(stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT attisdropped)), \n"
+					  "  stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(stxkind) THEN 'not built' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(stxkind) THEN 'not built' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(stxkind) THEN 'not built' \n"
+					  "END AS \"%s\" \n",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("N_distinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("Mcv"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\n pg_catalog.length(stxdndistinct) AS \"%s\", \n"
+						  "pg_catalog.length(stxddependencies) AS \"%s\", \n"
+						  "pg_catalog.length(stxdmcv) AS \"%s\" \n",
+						  gettext_noop("N_size"),
+						  gettext_noop("D_size"),
+						  gettext_noop("M_size"));
+
+	}
+
+	appendPQExpBufferStr(&buf,
+						 "FROM pg_catalog.pg_statistic_ext es \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON stxrelid = c.oid \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
+/*
  * \dC
  *
  * Describes casts.
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec9..89b13c3 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af82928..ea249bf 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index 555d464..76facc4 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5012,3 +5012,71 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+\dX
+                               List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |    Mcv    
+--------+-----------+----------------------------+------------+--------------+-----------
+ public | stts_1    | a, b FROM t1               |            | built        | 
+ public | stts_2    | a, b FROM t1               | built      | built        | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built
+ public | stts_4    | b, c FROM t2               | not built  | not built    | not built
+ public | stts_hoge | col1, col2, col3 FROM hoge | not built  | not built    | not built
+(5 rows)
+
+\dX stts_?
+                      List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |    Mcv    
+--------+--------+--------------+------------+--------------+-----------
+ public | stts_1 | a, b FROM t1 |            | built        | 
+ public | stts_2 | a, b FROM t1 | built      | built        | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built
+ public | stts_4 | b, c FROM t2 | not built  | not built    | not built
+(4 rows)
+
+\dX *hoge
+                               List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |    Mcv    
+--------+-----------+----------------------------+------------+--------------+-----------
+ public | stts_hoge | col1, col2, col3 FROM hoge | not built  | not built    | not built
+(1 row)
+
+\dX+
+                                            List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |    Mcv    | N_size | D_size | M_size 
+--------+-----------+----------------------------+------------+--------------+-----------+--------+--------+--------
+ public | stts_1    | a, b FROM t1               |            | built        |           |        |     40 |       
+ public | stts_2    | a, b FROM t1               | built      | built        |           |     13 |     40 |       
+ public | stts_3    | a, b FROM t1               | built      | built        | built     |     13 |     40 |   6126
+ public | stts_4    | b, c FROM t2               | not built  | not built    | not built |        |        |       
+ public | stts_hoge | col1, col2, col3 FROM hoge | not built  | not built    | not built |        |        |       
+(5 rows)
+
+\dX+ stts_?
+                                    List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |    Mcv    | N_size | D_size | M_size 
+--------+--------+--------------+------------+--------------+-----------+--------+--------+--------
+ public | stts_1 | a, b FROM t1 |            | built        |           |        |     40 |       
+ public | stts_2 | a, b FROM t1 | built      | built        |           |     13 |     40 |       
+ public | stts_3 | a, b FROM t1 | built      | built        | built     |     13 |     40 |   6126
+ public | stts_4 | b, c FROM t2 | not built  | not built    | not built |        |        |       
+(4 rows)
+
+\dX+ *hoge
+                                            List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |    Mcv    | N_size | D_size | M_size 
+--------+-----------+----------------------------+------------+--------------+-----------+--------+--------+--------
+ public | stts_hoge | col1, col2, col3 FROM hoge | not built  | not built    | not built |        |        |       
+(1 row)
+
+drop table t1, t2, hoge;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 5a16080..82f49a1 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1207,3 +1207,26 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+
+\dX
+\dX stts_?
+\dX *hoge
+\dX+
+\dX+ stts_?
+\dX+ *hoge
+drop table t1, t2, hoge;

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=>
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index c7a83d5dfc..c6f1653cb7 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -930,6 +930,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 07d640021c..e0ca32d34b 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4397,6 +4397,98 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "stxnamespace::pg_catalog.regnamespace AS \"%s\", \n"
+					  "stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("N_distinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("Mcv"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCOALESCE(pg_catalog.length(stxdndistinct), 0) AS \"%s\", \n"
+						  "COALESCE(pg_catalog.length(stxddependencies), 0) AS \"%s\", \n"
+						  "COALESCE(pg_catalog.length(stxdmcv), 0) AS \"%s\"",
+						  gettext_noop("N_size"),
+						  gettext_noop("D_size"),
+						  gettext_noop("M_size"));
+
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index daac0ff49d..ec6edaf174 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5072,3 +5072,71 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+\dX
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ public | stts_1    | a, b FROM t1               |            | built        | 
+ public | stts_2    | a, b FROM t1               | built      | built        | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+(5 rows)
+
+\dX stts_?
+                     List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   
+--------+--------+--------------+------------+--------------+---------
+ public | stts_1 | a, b FROM t1 |            | built        | 
+ public | stts_2 | a, b FROM t1 | built      | built        | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined
+(4 rows)
+
+\dX *hoge
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+(1 row)
+
+\dX+
+                                           List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size | D_size | M_size 
+--------+-----------+----------------------------+------------+--------------+---------+--------+--------+--------
+ public | stts_1    | a, b FROM t1               |            | built        |         |      0 |     40 |      0
+ public | stts_2    | a, b FROM t1               | built      | built        |         |     13 |     40 |      0
+ public | stts_3    | a, b FROM t1               | built      | built        | built   |     13 |     40 |   6126
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined |      0 |      0 |      0
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined |      0 |      0 |      0
+(5 rows)
+
+\dX+ stts_?
+                                   List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   | N_size | D_size | M_size 
+--------+--------+--------------+------------+--------------+---------+--------+--------+--------
+ public | stts_1 | a, b FROM t1 |            | built        |         |      0 |     40 |      0
+ public | stts_2 | a, b FROM t1 | built      | built        |         |     13 |     40 |      0
+ public | stts_3 | a, b FROM t1 | built      | built        | built   |     13 |     40 |   6126
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined |      0 |      0 |      0
+(4 rows)
+
+\dX+ *hoge
+                                           List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size | D_size | M_size 
+--------+-----------+----------------------------+------------+--------------+---------+--------+--------+--------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined |      0 |      0 |      0
+(1 row)
+
+drop table t1, t2, hoge;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 47b28d2a07..7f8aeaea8d 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1225,3 +1225,26 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+
+\dX
+\dX stts_?
+\dX *hoge
+\dX+
+\dX+ stts_?
+\dX+ *hoge
+drop table t1, t2, hoge;

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=>
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index c7a83d5dfc..c6f1653cb7 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -930,6 +930,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 07d640021c..e0ca32d34b 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4397,6 +4397,98 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "stxnamespace::pg_catalog.regnamespace AS \"%s\", \n"
+					  "stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("N_distinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("Mcv"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCOALESCE(pg_catalog.length(stxdndistinct), 0) AS \"%s\", \n"
+						  "COALESCE(pg_catalog.length(stxddependencies), 0) AS \"%s\", \n"
+						  "COALESCE(pg_catalog.length(stxdmcv), 0) AS \"%s\"",
+						  gettext_noop("N_size"),
+						  gettext_noop("D_size"),
+						  gettext_noop("M_size"));
+
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index daac0ff49d..ec6edaf174 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5072,3 +5072,71 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+\dX
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ public | stts_1    | a, b FROM t1               |            | built        | 
+ public | stts_2    | a, b FROM t1               | built      | built        | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+(5 rows)
+
+\dX stts_?
+                     List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   
+--------+--------+--------------+------------+--------------+---------
+ public | stts_1 | a, b FROM t1 |            | built        | 
+ public | stts_2 | a, b FROM t1 | built      | built        | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined
+(4 rows)
+
+\dX *hoge
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+(1 row)
+
+\dX+
+                                           List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size | D_size | M_size 
+--------+-----------+----------------------------+------------+--------------+---------+--------+--------+--------
+ public | stts_1    | a, b FROM t1               |            | built        |         |      0 |     40 |      0
+ public | stts_2    | a, b FROM t1               | built      | built        |         |     13 |     40 |      0
+ public | stts_3    | a, b FROM t1               | built      | built        | built   |     13 |     40 |   6126
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined |      0 |      0 |      0
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined |      0 |      0 |      0
+(5 rows)
+
+\dX+ stts_?
+                                   List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   | N_size | D_size | M_size 
+--------+--------+--------------+------------+--------------+---------+--------+--------+--------
+ public | stts_1 | a, b FROM t1 |            | built        |         |      0 |     40 |      0
+ public | stts_2 | a, b FROM t1 | built      | built        |         |     13 |     40 |      0
+ public | stts_3 | a, b FROM t1 | built      | built        | built   |     13 |     40 |   6126
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined |      0 |      0 |      0
+(4 rows)
+
+\dX+ *hoge
+                                           List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size | D_size | M_size 
+--------+-----------+----------------------------+------------+--------------+---------+--------+--------+--------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined |      0 |      0 |      0
+(1 row)
+
+drop table t1, t2, hoge;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 47b28d2a07..7f8aeaea8d 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1225,3 +1225,26 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+
+\dX
+\dX stts_?
+\dX *hoge
+\dX+
+\dX+ stts_?
+\dX+ *hoge
+drop table t1, t2, hoge;

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=>
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index c7a83d5dfc..c6f1653cb7 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -930,6 +930,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 07d640021c..484f011792 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4397,6 +4397,98 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("N_distinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("Mcv"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCOALESCE(pg_catalog.length(esd.stxdndistinct), 0) AS \"%s\", \n"
+						  "COALESCE(pg_catalog.length(esd.stxddependencies), 0) AS \"%s\", \n"
+						  "COALESCE(pg_catalog.length(esd.stxdmcv), 0) AS \"%s\"",
+						  gettext_noop("N_size"),
+						  gettext_noop("D_size"),
+						  gettext_noop("M_size"));
+
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index daac0ff49d..f30df047e1 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5072,3 +5072,80 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+create schema foo;
+create schema yama;
+create statistics foo.stts_foo on col1, col2 from hoge;
+create statistics yama.stts_yama on col1, col3 from hoge;
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+\dX
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined
+ public | stts_1    | a, b FROM t1               |            | built        | 
+ public | stts_2    | a, b FROM t1               | built      | built        | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+ yama   | stts_yama | col1, col3 FROM hoge       | defined    | defined      | defined
+(7 rows)
+
+\dX stts_?
+                     List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   
+--------+--------+--------------+------------+--------------+---------
+ public | stts_1 | a, b FROM t1 |            | built        | 
+ public | stts_2 | a, b FROM t1 | built      | built        | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined
+(4 rows)
+
+\dX *hoge
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+(1 row)
+
+\dX+
+                                           List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size | D_size | M_size 
+--------+-----------+----------------------------+------------+--------------+---------+--------+--------+--------
+ foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined |      0 |      0 |      0
+ public | stts_1    | a, b FROM t1               |            | built        |         |      0 |     40 |      0
+ public | stts_2    | a, b FROM t1               | built      | built        |         |     13 |     40 |      0
+ public | stts_3    | a, b FROM t1               | built      | built        | built   |     13 |     40 |   6126
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined |      0 |      0 |      0
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined |      0 |      0 |      0
+ yama   | stts_yama | col1, col3 FROM hoge       | defined    | defined      | defined |      0 |      0 |      0
+(7 rows)
+
+\dX+ stts_?
+                                   List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   | N_size | D_size | M_size 
+--------+--------+--------------+------------+--------------+---------+--------+--------+--------
+ public | stts_1 | a, b FROM t1 |            | built        |         |      0 |     40 |      0
+ public | stts_2 | a, b FROM t1 | built      | built        |         |     13 |     40 |      0
+ public | stts_3 | a, b FROM t1 | built      | built        | built   |     13 |     40 |   6126
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined |      0 |      0 |      0
+(4 rows)
+
+\dX+ *hoge
+                                           List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size | D_size | M_size 
+--------+-----------+----------------------------+------------+--------------+---------+--------+--------+--------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined |      0 |      0 |      0
+(1 row)
+
+drop table t1, t2, hoge;
+drop schema foo, yama;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 47b28d2a07..747e23a02a 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1225,3 +1225,32 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+create schema foo;
+create schema yama;
+create statistics foo.stts_foo on col1, col2 from hoge;
+create statistics yama.stts_yama on col1, col3 from hoge;
+
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+
+\dX
+\dX stts_?
+\dX *hoge
+\dX+
+\dX+ stts_?
+\dX+ *hoge
+drop table t1, t2, hoge;
+drop schema foo, yama;

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=>
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index c7a83d5dfc..c6f1653cb7 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -930,6 +930,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 07d640021c..1807324542 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4397,6 +4397,106 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("N_distinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("Mcv"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxddependencies)::bigint) \n"
+						  "     WHEN 'f' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdmcv)::bigint) \n"
+						  "     WHEN 'm' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("N_size"),
+						  gettext_noop("D_size"),
+						  gettext_noop("M_size"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index daac0ff49d..701f2dbe59 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5072,3 +5072,80 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+create schema foo;
+create schema yama;
+create statistics foo.stts_foo on col1, col2 from hoge;
+create statistics yama.stts_yama (ndistinct, mcv) on col1, col3 from hoge;
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+\dX
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined
+ public | stts_1    | a, b FROM t1               |            | built        | 
+ public | stts_2    | a, b FROM t1               | built      | built        | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+ yama   | stts_yama | col1, col3 FROM hoge       | defined    |              | defined
+(7 rows)
+
+\dX stts_?
+                     List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   
+--------+--------+--------------+------------+--------------+---------
+ public | stts_1 | a, b FROM t1 |            | built        | 
+ public | stts_2 | a, b FROM t1 | built      | built        | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined
+(4 rows)
+
+\dX *hoge
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+(1 row)
+
+\dX+
+                                               List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+--------+-----------+----------------------------+------------+--------------+---------+----------+----------+------------
+ foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ public | stts_1    | a, b FROM t1               |            | built        |         |          | 40 bytes | 
+ public | stts_2    | a, b FROM t1               | built      | built        |         | 13 bytes | 40 bytes | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ yama   | stts_yama | col1, col3 FROM hoge       | defined    |              | defined | 0 bytes  |          | 0 bytes
+(7 rows)
+
+\dX+ stts_?
+                                       List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+--------+--------+--------------+------------+--------------+---------+----------+----------+------------
+ public | stts_1 | a, b FROM t1 |            | built        |         |          | 40 bytes | 
+ public | stts_2 | a, b FROM t1 | built      | built        |         | 13 bytes | 40 bytes | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+(4 rows)
+
+\dX+ *hoge
+                                             List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
+--------+-----------+----------------------------+------------+--------------+---------+---------+---------+---------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
+(1 row)
+
+drop table t1, t2, hoge;
+drop schema foo, yama;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 47b28d2a07..dc9f4b2159 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1225,3 +1225,32 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+create schema foo;
+create schema yama;
+create statistics foo.stts_foo on col1, col2 from hoge;
+create statistics yama.stts_yama (ndistinct, mcv) on col1, col3 from hoge;
+
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+
+\dX
+\dX stts_?
+\dX *hoge
+\dX+
+\dX+ stts_?
+\dX+ *hoge
+drop table t1, t2, hoge;
+drop schema foo, yama;

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=>
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index c7a83d5dfc..c6f1653cb7 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -930,6 +930,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 07d640021c..1807324542 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4397,6 +4397,106 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("N_distinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("Mcv"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxddependencies)::bigint) \n"
+						  "     WHEN 'f' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdmcv)::bigint) \n"
+						  "     WHEN 'm' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("N_size"),
+						  gettext_noop("D_size"),
+						  gettext_noop("M_size"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 5238a960f7..30a8ada7d2 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3851,6 +3851,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index daac0ff49d..701f2dbe59 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5072,3 +5072,80 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+create schema foo;
+create schema yama;
+create statistics foo.stts_foo on col1, col2 from hoge;
+create statistics yama.stts_yama (ndistinct, mcv) on col1, col3 from hoge;
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+\dX
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined
+ public | stts_1    | a, b FROM t1               |            | built        | 
+ public | stts_2    | a, b FROM t1               | built      | built        | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+ yama   | stts_yama | col1, col3 FROM hoge       | defined    |              | defined
+(7 rows)
+
+\dX stts_?
+                     List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   
+--------+--------+--------------+------------+--------------+---------
+ public | stts_1 | a, b FROM t1 |            | built        | 
+ public | stts_2 | a, b FROM t1 | built      | built        | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined
+(4 rows)
+
+\dX *hoge
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+(1 row)
+
+\dX+
+                                               List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+--------+-----------+----------------------------+------------+--------------+---------+----------+----------+------------
+ foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ public | stts_1    | a, b FROM t1               |            | built        |         |          | 40 bytes | 
+ public | stts_2    | a, b FROM t1               | built      | built        |         | 13 bytes | 40 bytes | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ yama   | stts_yama | col1, col3 FROM hoge       | defined    |              | defined | 0 bytes  |          | 0 bytes
+(7 rows)
+
+\dX+ stts_?
+                                       List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+--------+--------+--------------+------------+--------------+---------+----------+----------+------------
+ public | stts_1 | a, b FROM t1 |            | built        |         |          | 40 bytes | 
+ public | stts_2 | a, b FROM t1 | built      | built        |         | 13 bytes | 40 bytes | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+(4 rows)
+
+\dX+ *hoge
+                                             List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
+--------+-----------+----------------------------+------------+--------------+---------+---------+---------+---------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
+(1 row)
+
+drop table t1, t2, hoge;
+drop schema foo, yama;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 47b28d2a07..dc9f4b2159 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1225,3 +1225,32 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+create schema foo;
+create schema yama;
+create statistics foo.stts_foo on col1, col2 from hoge;
+create statistics yama.stts_yama (ndistinct, mcv) on col1, col3 from hoge;
+
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+
+\dX
+\dX stts_?
+\dX *hoge
+\dX+
+\dX+ stts_?
+\dX+ *hoge
+drop table t1, t2, hoge;
+drop schema foo, yama;

From 1a7e99c931c0b3ed5560abd3ff656412f8b353f1 Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas@2ndquadrant.com>
Date: Sun, 8 Nov 2020 21:53:54 +0100
Subject: [PATCH 1/2] v7

---
 doc/src/sgml/ref/psql-ref.sgml     |  14 ++++
 src/bin/psql/command.c             |   3 +
 src/bin/psql/describe.c            | 100 +++++++++++++++++++++++++++++
 src/bin/psql/describe.h            |   3 +
 src/bin/psql/help.c                |   1 +
 src/bin/psql/tab-complete.c        |   4 +-
 src/test/regress/expected/psql.out |  77 ++++++++++++++++++++++
 src/test/regress/sql/psql.sql      |  29 +++++++++
 8 files changed, 230 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index c7a83d5dfc..c6f1653cb7 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -930,6 +930,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 07d640021c..1807324542 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4397,6 +4397,106 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("N_distinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("Mcv"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxddependencies)::bigint) \n"
+						  "     WHEN 'f' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdmcv)::bigint) \n"
+						  "     WHEN 'm' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("N_size"),
+						  gettext_noop("D_size"),
+						  gettext_noop("M_size"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 5238a960f7..30a8ada7d2 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3851,6 +3851,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index daac0ff49d..701f2dbe59 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5072,3 +5072,80 @@ List of access methods
  hash  | uuid_ops        | uuid                 | uuid                  |      2 | uuid_hash_extended
 (5 rows)
 
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+create schema foo;
+create schema yama;
+create statistics foo.stts_foo on col1, col2 from hoge;
+create statistics yama.stts_yama (ndistinct, mcv) on col1, col3 from hoge;
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+\dX
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined
+ public | stts_1    | a, b FROM t1               |            | built        | 
+ public | stts_2    | a, b FROM t1               | built      | built        | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+ yama   | stts_yama | col1, col3 FROM hoge       | defined    |              | defined
+(7 rows)
+
+\dX stts_?
+                     List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   
+--------+--------+--------------+------------+--------------+---------
+ public | stts_1 | a, b FROM t1 |            | built        | 
+ public | stts_2 | a, b FROM t1 | built      | built        | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined
+(4 rows)
+
+\dX *hoge
+                              List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
+--------+-----------+----------------------------+------------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+(1 row)
+
+\dX+
+                                               List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+--------+-----------+----------------------------+------------+--------------+---------+----------+----------+------------
+ foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ public | stts_1    | a, b FROM t1               |            | built        |         |          | 40 bytes | 
+ public | stts_2    | a, b FROM t1               | built      | built        |         | 13 bytes | 40 bytes | 
+ public | stts_3    | a, b FROM t1               | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public | stts_4    | b, c FROM t2               | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ yama   | stts_yama | col1, col3 FROM hoge       | defined    |              | defined | 0 bytes  |          | 0 bytes
+(7 rows)
+
+\dX+ stts_?
+                                       List of extended statistics
+ Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+--------+--------+--------------+------------+--------------+---------+----------+----------+------------
+ public | stts_1 | a, b FROM t1 |            | built        |         |          | 40 bytes | 
+ public | stts_2 | a, b FROM t1 | built      | built        |         | 13 bytes | 40 bytes | 
+ public | stts_3 | a, b FROM t1 | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public | stts_4 | b, c FROM t2 | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+(4 rows)
+
+\dX+ *hoge
+                                             List of extended statistics
+ Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
+--------+-----------+----------------------------+------------+--------------+---------+---------+---------+---------
+ public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
+(1 row)
+
+drop table t1, t2, hoge;
+drop schema foo, yama;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 47b28d2a07..dc9f4b2159 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1225,3 +1225,32 @@ drop role regress_partitioning_role;
 \dAo * pg_catalog.jsonb_path_ops
 \dAp+ btree float_ops
 \dAp * pg_catalog.uuid_ops
+
+-- check printing info about extended statistics
+create table t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+
+create table t2 (a int, b int, c int);
+create statistics stts_4 on b, c from t2;
+
+create table hoge (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from hoge;
+
+create schema foo;
+create schema yama;
+create statistics foo.stts_foo on col1, col2 from hoge;
+create statistics yama.stts_yama (ndistinct, mcv) on col1, col3 from hoge;
+
+insert into t1 select i,i from generate_series(1,100) i;
+analyze t1;
+
+\dX
+\dX stts_?
+\dX *hoge
+\dX+
+\dX+ stts_?
+\dX+ *hoge
+drop table t1, t2, hoge;
+drop schema foo, yama;
-- 
2.26.2

From 9a6f15a7d531afa28f8cd8f67edbe301a8ea7ed5 Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas@2ndquadrant.com>
Date: Sun, 8 Nov 2020 22:37:29 +0100
Subject: [PATCH 2/2] rename objects in regression test

---
 src/test/regress/expected/psql.out | 120 ++++++++++++++---------------
 src/test/regress/sql/psql.sql      |  36 ++++-----
 2 files changed, 78 insertions(+), 78 deletions(-)

diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index 701f2dbe59..27c73445d5 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -5073,79 +5073,79 @@ List of access methods
 (5 rows)
 
 -- check printing info about extended statistics
-create table t1 (a int, b int);
-create statistics stts_1 (dependencies) on a, b from t1;
-create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
-create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
-create table t2 (a int, b int, c int);
-create statistics stts_4 on b, c from t2;
-create table hoge (col1 int, col2 int, col3 int);
-create statistics stts_hoge on col1, col2, col3 from hoge;
-create schema foo;
-create schema yama;
-create statistics foo.stts_foo on col1, col2 from hoge;
-create statistics yama.stts_yama (ndistinct, mcv) on col1, col3 from hoge;
-insert into t1 select i,i from generate_series(1,100) i;
-analyze t1;
+create table stts_t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from stts_t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from stts_t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (ndistinct, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
 \dX
-                              List of extended statistics
- Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
---------+-----------+----------------------------+------------+--------------+---------
- foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined
- public | stts_1    | a, b FROM t1               |            | built        | 
- public | stts_2    | a, b FROM t1               | built      | built        | 
- public | stts_3    | a, b FROM t1               | built      | built        | built
- public | stts_4    | b, c FROM t2               | defined    | defined      | defined
- public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
- yama   | stts_yama | col1, col3 FROM hoge       | defined    |              | defined
+                                List of extended statistics
+ Schema  |   Name    |          Definition           | N_distinct | Dependencies |   Mcv   
+---------+-----------+-------------------------------+------------+--------------+---------
+ public  | stts_1    | a, b FROM stts_t1             |            | built        | 
+ public  | stts_2    | a, b FROM stts_t1             | built      | built        | 
+ public  | stts_3    | a, b FROM stts_t1             | built      | built        | built
+ public  | stts_4    | b, c FROM stts_t2             | defined    | defined      | defined
+ public  | stts_hoge | col1, col2, col3 FROM stts_t3 | defined    | defined      | defined
+ stts_s1 | stts_foo  | col1, col2 FROM stts_t3       | defined    | defined      | defined
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3       | defined    |              | defined
 (7 rows)
 
 \dX stts_?
-                     List of extended statistics
- Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   
---------+--------+--------------+------------+--------------+---------
- public | stts_1 | a, b FROM t1 |            | built        | 
- public | stts_2 | a, b FROM t1 | built      | built        | 
- public | stts_3 | a, b FROM t1 | built      | built        | built
- public | stts_4 | b, c FROM t2 | defined    | defined      | defined
+                        List of extended statistics
+ Schema |  Name  |    Definition     | N_distinct | Dependencies |   Mcv   
+--------+--------+-------------------+------------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 |            | built        | 
+ public | stts_2 | a, b FROM stts_t1 | built      | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built      | built        | built
+ public | stts_4 | b, c FROM stts_t2 | defined    | defined      | defined
 (4 rows)
 
-\dX *hoge
-                              List of extended statistics
- Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   
---------+-----------+----------------------------+------------+--------------+---------
- public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | N_distinct | Dependencies |   Mcv   
+--------+-----------+-------------------------------+------------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined    | defined      | defined
 (1 row)
 
 \dX+
-                                               List of extended statistics
- Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
---------+-----------+----------------------------+------------+--------------+---------+----------+----------+------------
- foo    | stts_foo  | col1, col2 FROM hoge       | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
- public | stts_1    | a, b FROM t1               |            | built        |         |          | 40 bytes | 
- public | stts_2    | a, b FROM t1               | built      | built        |         | 13 bytes | 40 bytes | 
- public | stts_3    | a, b FROM t1               | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
- public | stts_4    | b, c FROM t2               | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
- public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
- yama   | stts_yama | col1, col3 FROM hoge       | defined    |              | defined | 0 bytes  |          | 0 bytes
+                                                 List of extended statistics
+ Schema  |   Name    |          Definition           | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+---------+-----------+-------------------------------+------------+--------------+---------+----------+----------+------------
+ public  | stts_1    | a, b FROM stts_t1             |            | built        |         |          | 40 bytes | 
+ public  | stts_2    | a, b FROM stts_t1             | built      | built        |         | 13 bytes | 40 bytes | 
+ public  | stts_3    | a, b FROM stts_t1             | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public  | stts_4    | b, c FROM stts_t2             | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ public  | stts_hoge | col1, col2, col3 FROM stts_t3 | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ stts_s1 | stts_foo  | col1, col2 FROM stts_t3       | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3       | defined    |              | defined | 0 bytes  |          | 0 bytes
 (7 rows)
 
 \dX+ stts_?
-                                       List of extended statistics
- Schema |  Name  |  Definition  | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
---------+--------+--------------+------------+--------------+---------+----------+----------+------------
- public | stts_1 | a, b FROM t1 |            | built        |         |          | 40 bytes | 
- public | stts_2 | a, b FROM t1 | built      | built        |         | 13 bytes | 40 bytes | 
- public | stts_3 | a, b FROM t1 | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
- public | stts_4 | b, c FROM t2 | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+                                         List of extended statistics
+ Schema |  Name  |    Definition     | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+--------+--------+-------------------+------------+--------------+---------+----------+----------+------------
+ public | stts_1 | a, b FROM stts_t1 |            | built        |         |          | 40 bytes | 
+ public | stts_2 | a, b FROM stts_t1 | built      | built        |         | 13 bytes | 40 bytes | 
+ public | stts_3 | a, b FROM stts_t1 | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
 (4 rows)
 
-\dX+ *hoge
-                                             List of extended statistics
- Schema |   Name    |         Definition         | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
---------+-----------+----------------------------+------------+--------------+---------+---------+---------+---------
- public | stts_hoge | col1, col2, col3 FROM hoge | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
+\dX+ *stts_hoge
+                                              List of extended statistics
+ Schema |   Name    |          Definition           | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
+--------+-----------+-------------------------------+------------+--------------+---------+---------+---------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
 (1 row)
 
-drop table t1, t2, hoge;
-drop schema foo, yama;
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2;
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index dc9f4b2159..5ebfe184a4 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1227,30 +1227,30 @@ drop role regress_partitioning_role;
 \dAp * pg_catalog.uuid_ops
 
 -- check printing info about extended statistics
-create table t1 (a int, b int);
-create statistics stts_1 (dependencies) on a, b from t1;
-create statistics stts_2 (dependencies, ndistinct) on a, b from t1;
-create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from t1;
+create table stts_t1 (a int, b int);
+create statistics stts_1 (dependencies) on a, b from stts_t1;
+create statistics stts_2 (dependencies, ndistinct) on a, b from stts_t1;
+create statistics stts_3 (dependencies, ndistinct, mcv) on a, b from stts_t1;
 
-create table t2 (a int, b int, c int);
-create statistics stts_4 on b, c from t2;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
 
-create table hoge (col1 int, col2 int, col3 int);
-create statistics stts_hoge on col1, col2, col3 from hoge;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
 
-create schema foo;
-create schema yama;
-create statistics foo.stts_foo on col1, col2 from hoge;
-create statistics yama.stts_yama (ndistinct, mcv) on col1, col3 from hoge;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (ndistinct, mcv) on col1, col3 from stts_t3;
 
-insert into t1 select i,i from generate_series(1,100) i;
-analyze t1;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
 
 \dX
 \dX stts_?
-\dX *hoge
+\dX *stts_hoge
 \dX+
 \dX+ stts_?
-\dX+ *hoge
-drop table t1, t2, hoge;
-drop schema foo, yama;
+\dX+ *stts_hoge
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2;
-- 
2.26.2

From 11c088cb43cdb13e445e246d0529d5721cf3bb10 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Tue, 10 Nov 2020 11:39:14 +0900
Subject: [PATCH] Add regression test of \dX to stats_ext.sql

---
 src/test/regress/expected/stats_ext.out | 94 +++++++++++++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      | 31 +++++++++++
 2 files changed, 125 insertions(+)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 4c3edd213f..0ec4e24960 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1550,6 +1550,100 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | N_distinct | Dependencies |   Mcv   
+----------+------------------------+--------------------------------------+------------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |            | built        | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |            |              | built
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |            |              | built
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |            |              | built
+ public   | stts_1                 | a, b FROM stts_t1                    | built      |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built      | built        | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built      | built        | built
+ public   | stts_4                 | b, c FROM stts_t2                    | defined    | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined    | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined    | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |            | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |            |              | built
+(12 rows)
+
+\dX stts_?
+                        List of extended statistics
+ Schema |  Name  |    Definition     | N_distinct | Dependencies |   Mcv   
+--------+--------+-------------------+------------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | built      |              | 
+ public | stts_2 | a, b FROM stts_t1 | built      | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built      | built        | built
+ public | stts_4 | b, c FROM stts_t2 | defined    | defined      | defined
+(4 rows)
+
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | N_distinct | Dependencies |   Mcv   
+--------+-----------+-------------------------------+------------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined    | defined      | defined
+(1 row)
+
+\dX+
+                                                            List of extended statistics
+  Schema  |          Name          |              Definition              | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size   |   M_size   
+----------+------------------------+--------------------------------------+------------+--------------+---------+----------+-----------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |            | built        |         |          | 106 bytes | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |            |              | built   |          |           | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |            |              | built   |          |           | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |            |              | built   |          |           | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built      |              |         | 13 bytes |           | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built      | built        |         | 13 bytes | 40 bytes  | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built      | built        | built   | 13 bytes | 40 bytes  | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | defined    | defined      | defined | 0 bytes  | 0 bytes   | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined    | defined      | defined | 0 bytes  | 0 bytes   | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined    | defined      | defined | 0 bytes  | 0 bytes   | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |            | defined      | defined |          | 0 bytes   | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |            |              | built   |          |           | 686 bytes
+(12 rows)
+
+\dX+ stts_?
+                                         List of extended statistics
+ Schema |  Name  |    Definition     | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+--------+--------+-------------------+------------+--------------+---------+----------+----------+------------
+ public | stts_1 | a, b FROM stts_t1 | built      |              |         | 13 bytes |          | 
+ public | stts_2 | a, b FROM stts_t1 | built      | built        |         | 13 bytes | 40 bytes | 
+ public | stts_3 | a, b FROM stts_t1 | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+(4 rows)
+
+\dX+ *stts_hoge
+                                              List of extended statistics
+ Schema |   Name    |          Definition           | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
+--------+-----------+-------------------------------+------------+--------------+---------+---------+---------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                                           List of extended statistics
+ Schema  |   Name    |       Definition        | N_distinct | Dependencies |   Mcv   | N_size | D_size  | M_size  
+---------+-----------+-------------------------+------------+--------------+---------+--------+---------+---------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |            | defined      | defined |        | 0 bytes | 0 bytes
+(1 row)
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 9781e590a3..2b90471a4b 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -833,6 +833,37 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.16.5

From 6de4684532f7cdf5451f4969ab83514fa5bb19d3 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Mon, 9 Nov 2020 11:25:14 +0900
Subject: [PATCH] Add \dX command on psql

---
 doc/src/sgml/ref/psql-ref.sgml |  14 ++++++
 src/bin/psql/command.c         |   3 ++
 src/bin/psql/describe.c        | 100 +++++++++++++++++++++++++++++++++++++++++
 src/bin/psql/describe.h        |   3 ++
 src/bin/psql/help.c            |   1 +
 src/bin/psql/tab-complete.c    |   4 +-
 6 files changed, 124 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index c7a83d5dfc..c6f1653cb7 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -930,6 +930,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 07d640021c..1807324542 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4397,6 +4397,106 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("N_distinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("Mcv"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxddependencies)::bigint) \n"
+						  "     WHEN 'f' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdmcv)::bigint) \n"
+						  "     WHEN 'm' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("N_size"),
+						  gettext_noop("D_size"),
+						  gettext_noop("M_size"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 5238a960f7..30a8ada7d2 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3851,6 +3851,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
-- 
2.16.5

From b22ebf34fc09e246f8d4cf408f76a6753f3d6bcb Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Tue, 10 Nov 2020 16:47:45 +0900
Subject: [PATCH] Add regression test of \dX to stats_ext.sql (another version)

---
 src/test/regress/sql/stats_ext.sql | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 9781e590a3..c590dcc90a 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -49,6 +49,7 @@ CREATE STATISTICS regress_schema_2.ab1_a_b_stats ON a, b FROM ab1;
 
 -- Let's also verify the pg_get_statisticsobjdef output looks sane.
 SELECT pg_get_statisticsobjdef(oid) FROM pg_statistic_ext WHERE stxname = 'ab1_a_b_stats';
+\dX
 
 DROP STATISTICS regress_schema_2.ab1_a_b_stats;
 
@@ -60,9 +61,10 @@ ALTER TABLE ab1 DROP COLUMN a;
 \d ab1
 -- Ensure statistics are dropped when table is
 SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
+\dX
 DROP TABLE ab1;
 SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
-
+\dX
 -- Ensure things work sanely with SET STATISTICS 0
 CREATE TABLE ab1 (a INTEGER, b INTEGER);
 ALTER TABLE ab1 ALTER a SET STATISTICS 0;
@@ -73,13 +75,16 @@ ALTER TABLE ab1 ALTER a SET STATISTICS -1;
 -- setting statistics target 0 skips the statistics, without printing any message, so check catalog
 ALTER STATISTICS ab1_a_b_stats SET STATISTICS 0;
 \d ab1
+\dX+ ab1_a_b_stats
 ANALYZE ab1;
 SELECT stxname, stxdndistinct, stxddependencies, stxdmcv
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxname = 'ab1_a_b_stats'
    AND d.stxoid = s.oid;
+\dX+ ab1_a_b_stats
 ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
 \d+ ab1
+\dX+ ab1_a_b_stats
 -- partial analyze doesn't build stats either
 ANALYZE ab1 (a);
 ANALYZE ab1;
@@ -93,6 +98,7 @@ CREATE TABLE ab1c () INHERITS (ab1);
 INSERT INTO ab1 VALUES (1,1);
 CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
 ANALYZE ab1;
+\dX+ ab1_a_b_stats
 DROP TABLE ab1 CASCADE;
 
 -- Verify supported object types for extended statistics
@@ -171,6 +177,7 @@ SELECT s.stxkind, d.stxdndistinct
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxrelid = 'ndistinct'::regclass
    AND d.stxoid = s.oid;
+\dX+ s10
 
 -- minor improvement, make sure the ctid does not break the matching
 SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY ctid, a, b');
@@ -202,6 +209,7 @@ SELECT s.stxkind, d.stxdndistinct
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxrelid = 'ndistinct'::regclass
    AND d.stxoid = s.oid;
+\dX+ s10
 
 -- correct estimates
 SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
@@ -220,6 +228,7 @@ SELECT s.stxkind, d.stxdndistinct
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxrelid = 'ndistinct'::regclass
    AND d.stxoid = s.oid;
+\dX+
 
 -- dropping the statistics results in under-estimates
 SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
@@ -261,6 +270,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
 CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
 
 ANALYZE functional_dependencies;
+\dX+ func_deps_stat
 
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
 
@@ -274,6 +284,7 @@ INSERT INTO functional_dependencies (a, b, c, filler1)
      SELECT mod(i,100), mod(i,50), mod(i,25), i FROM generate_series(1,5000) s(i);
 
 ANALYZE functional_dependencies;
+\dX+ func_deps_stat
 
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
 
@@ -335,6 +346,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
 CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
 
 ANALYZE functional_dependencies;
+\dx+ func_deps_stat
 
 -- print the detected dependencies
 SELECT dependencies FROM pg_stats_ext WHERE statistics_name = 'func_deps_stat';
@@ -437,6 +449,7 @@ CREATE STATISTICS functional_dependencies_multi_1 (dependencies) ON a, b FROM fu
 CREATE STATISTICS functional_dependencies_multi_2 (dependencies) ON c, d FROM functional_dependencies_multi;
 
 ANALYZE functional_dependencies_multi;
+\dX+ functional_dependencies_multi_*
 
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND 0 = b');
@@ -472,6 +485,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
 
@@ -536,6 +550,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
 
@@ -591,6 +606,7 @@ SELECT d.stxdmcv IS NOT NULL
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxname = 'mcv_lists_stats'
    AND d.stxoid = s.oid;
+\dX+ mcv_lists_stats
 
 -- check change of column type resets the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN c TYPE numeric;
@@ -598,6 +614,7 @@ ALTER TABLE mcv_lists ALTER COLUMN c TYPE numeric;
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
 
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
 
@@ -629,6 +646,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (0, 1) AN
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND b IS NULL');
 
@@ -650,6 +668,7 @@ SELECT m.*
        pg_mcv_list_items(d.stxdmcv) m
  WHERE s.stxname = 'mcv_lists_stats'
    AND d.stxoid = s.oid;
+\dX+ mcv_lists_stats
 
 -- 2 distinct combinations with NULL values, all in the MCV list
 TRUNCATE mcv_lists;
@@ -682,6 +701,7 @@ SELECT m.*
        pg_mcv_list_items(d.stxdmcv) m
  WHERE s.stxname = 'mcv_lists_stats'
    AND d.stxoid = s.oid;
+\dx+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
@@ -714,6 +734,7 @@ CREATE STATISTICS mcv_lists_uuid_stats (mcv) ON a, b, c
   FROM mcv_lists_uuid;
 
 ANALYZE mcv_lists_uuid;
+\dX+ mcv_lists_uuid_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_uuid WHERE a = ''1679091c-5a88-0faf-6fb5-e6087eb1b2dc'' AND b = ''1679091c-5a88-0faf-6fb5-e6087eb1b2dc''');
 
@@ -740,6 +761,7 @@ CREATE STATISTICS mcv_lists_arrays_stats (mcv) ON a, b, c
   FROM mcv_lists_arrays;
 
 ANALYZE mcv_lists_arrays;
+\dX+ mcv_lists_arrays_stats
 
 -- mcv with bool
 CREATE TABLE mcv_lists_bool (
@@ -768,6 +790,7 @@ CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 
 ANALYZE mcv_lists_bool;
+\dX+ mcv_lists_bool_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE a AND b AND c');
 
@@ -806,6 +829,7 @@ CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
 CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi;
 
 ANALYZE mcv_lists_multi;
+\dX+ mcv_lists_multi_*
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
@@ -832,6 +856,7 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 
 ANALYZE tststats.priv_test_tbl;
+\dX+ tststats.priv_test_stats
 
 -- User with no access
 CREATE USER regress_stats_user1;
-- 
2.16.5

From e552a17a9c74952a002e6dabe8d57c9ab787addb Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Mon, 9 Nov 2020 11:25:14 +0900
Subject: [PATCH 1/3] Add \dX command on psql

---
 doc/src/sgml/ref/psql-ref.sgml |  14 +++++
 src/bin/psql/command.c         |   3 +
 src/bin/psql/describe.c        | 100 +++++++++++++++++++++++++++++++++
 src/bin/psql/describe.h        |   3 +
 src/bin/psql/help.c            |   1 +
 src/bin/psql/tab-complete.c    |   4 +-
 6 files changed, 124 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index c7a83d5dfc..c6f1653cb7 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -930,6 +930,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 07d640021c..1807324542 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4397,6 +4397,106 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("N_distinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("Mcv"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxddependencies)::bigint) \n"
+						  "     WHEN 'f' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdmcv)::bigint) \n"
+						  "     WHEN 'm' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("N_size"),
+						  gettext_noop("D_size"),
+						  gettext_noop("M_size"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 5238a960f7..30a8ada7d2 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3851,6 +3851,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
-- 
2.26.2

From 3daa574b29b77b1d9586e32c1c2a9b27a7e3565d Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Tue, 10 Nov 2020 11:39:14 +0900
Subject: [PATCH 2/3] Add regression test of \dX to stats_ext.sql

---
 src/test/regress/expected/stats_ext.out | 94 +++++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      | 31 ++++++++
 2 files changed, 125 insertions(+)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 4c3edd213f..0ec4e24960 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1550,6 +1550,100 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | N_distinct | Dependencies |   Mcv   
+----------+------------------------+--------------------------------------+------------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |            | built        | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |            |              | built
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |            |              | built
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |            |              | built
+ public   | stts_1                 | a, b FROM stts_t1                    | built      |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built      | built        | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built      | built        | built
+ public   | stts_4                 | b, c FROM stts_t2                    | defined    | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined    | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined    | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |            | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |            |              | built
+(12 rows)
+
+\dX stts_?
+                        List of extended statistics
+ Schema |  Name  |    Definition     | N_distinct | Dependencies |   Mcv   
+--------+--------+-------------------+------------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | built      |              | 
+ public | stts_2 | a, b FROM stts_t1 | built      | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built      | built        | built
+ public | stts_4 | b, c FROM stts_t2 | defined    | defined      | defined
+(4 rows)
+
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | N_distinct | Dependencies |   Mcv   
+--------+-----------+-------------------------------+------------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined    | defined      | defined
+(1 row)
+
+\dX+
+                                                            List of extended statistics
+  Schema  |          Name          |              Definition              | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size   |   M_size   
+----------+------------------------+--------------------------------------+------------+--------------+---------+----------+-----------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |            | built        |         |          | 106 bytes | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |            |              | built   |          |           | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |            |              | built   |          |           | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |            |              | built   |          |           | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built      |              |         | 13 bytes |           | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built      | built        |         | 13 bytes | 40 bytes  | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built      | built        | built   | 13 bytes | 40 bytes  | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | defined    | defined      | defined | 0 bytes  | 0 bytes   | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined    | defined      | defined | 0 bytes  | 0 bytes   | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined    | defined      | defined | 0 bytes  | 0 bytes   | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |            | defined      | defined |          | 0 bytes   | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |            |              | built   |          |           | 686 bytes
+(12 rows)
+
+\dX+ stts_?
+                                         List of extended statistics
+ Schema |  Name  |    Definition     | N_distinct | Dependencies |   Mcv   |  N_size  |  D_size  |   M_size   
+--------+--------+-------------------+------------+--------------+---------+----------+----------+------------
+ public | stts_1 | a, b FROM stts_t1 | built      |              |         | 13 bytes |          | 
+ public | stts_2 | a, b FROM stts_t1 | built      | built        |         | 13 bytes | 40 bytes | 
+ public | stts_3 | a, b FROM stts_t1 | built      | built        | built   | 13 bytes | 40 bytes | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | defined    | defined      | defined | 0 bytes  | 0 bytes  | 0 bytes
+(4 rows)
+
+\dX+ *stts_hoge
+                                              List of extended statistics
+ Schema |   Name    |          Definition           | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
+--------+-----------+-------------------------------+------------+--------------+---------+---------+---------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                                           List of extended statistics
+ Schema  |   Name    |       Definition        | N_distinct | Dependencies |   Mcv   | N_size | D_size  | M_size  
+---------+-----------+-------------------------+------------+--------------+---------+--------+---------+---------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |            | defined      | defined |        | 0 bytes | 0 bytes
+(1 row)
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 9781e590a3..2b90471a4b 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -833,6 +833,37 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.26.2

From 62ef3806a959929c37d0847cffefc8e57e56c235 Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas@2ndquadrant.com>
Date: Sun, 15 Nov 2020 19:00:23 +0100
Subject: [PATCH 3/3] Add regression test of \dX to stats_ext.sql (another
 version)

---
 src/test/regress/expected/stats_ext.out | 181 ++++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      |  27 +++-
 2 files changed, 207 insertions(+), 1 deletion(-)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 0ec4e24960..fb10ee2237 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -64,6 +64,13 @@ SELECT pg_get_statisticsobjdef(oid) FROM pg_statistic_ext WHERE stxname = 'ab1_a
  CREATE STATISTICS regress_schema_2.ab1_a_b_stats ON a, b FROM ab1
 (1 row)
 
+\dX
+                              List of extended statistics
+      Schema      |     Name      |  Definition   | N_distinct | Dependencies |   Mcv   
+------------------+---------------+---------------+------------+--------------+---------
+ regress_schema_2 | ab1_a_b_stats | a, b FROM ab1 | defined    | defined      | defined
+(1 row)
+
 DROP STATISTICS regress_schema_2.ab1_a_b_stats;
 -- Ensure statistics are dropped when columns are
 CREATE STATISTICS ab1_b_c_stats ON b, c FROM ab1;
@@ -86,12 +93,25 @@ SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
  ab1_b_c_stats
 (1 row)
 
+\dX
+                         List of extended statistics
+ Schema |     Name      |  Definition   | N_distinct | Dependencies |   Mcv   
+--------+---------------+---------------+------------+--------------+---------
+ public | ab1_b_c_stats | b, c FROM ab1 | defined    | defined      | defined
+(1 row)
+
 DROP TABLE ab1;
 SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
  stxname 
 ---------
 (0 rows)
 
+\dX
+                 List of extended statistics
+ Schema | Name | Definition | N_distinct | Dependencies | Mcv 
+--------+------+------------+------------+--------------+-----
+(0 rows)
+
 -- Ensure things work sanely with SET STATISTICS 0
 CREATE TABLE ab1 (a INTEGER, b INTEGER);
 ALTER TABLE ab1 ALTER a SET STATISTICS 0;
@@ -111,6 +131,13 @@ ALTER STATISTICS ab1_a_b_stats SET STATISTICS 0;
 Statistics objects:
     "public"."ab1_a_b_stats" (ndistinct, dependencies, mcv) ON a, b FROM ab1; STATISTICS 0
 
+\dX+ ab1_a_b_stats
+                                        List of extended statistics
+ Schema |     Name      |  Definition   | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
+--------+---------------+---------------+------------+--------------+---------+---------+---------+---------
+ public | ab1_a_b_stats | a, b FROM ab1 | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
+(1 row)
+
 ANALYZE ab1;
 SELECT stxname, stxdndistinct, stxddependencies, stxdmcv
   FROM pg_statistic_ext s, pg_statistic_ext_data d
@@ -121,6 +148,13 @@ SELECT stxname, stxdndistinct, stxddependencies, stxdmcv
  ab1_a_b_stats |               |                  | 
 (1 row)
 
+\dX+ ab1_a_b_stats
+                                        List of extended statistics
+ Schema |     Name      |  Definition   | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
+--------+---------------+---------------+------------+--------------+---------+---------+---------+---------
+ public | ab1_a_b_stats | a, b FROM ab1 | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
+(1 row)
+
 ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
 \d+ ab1
                                     Table "public.ab1"
@@ -131,6 +165,13 @@ ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
 Statistics objects:
     "public"."ab1_a_b_stats" (ndistinct, dependencies, mcv) ON a, b FROM ab1
 
+\dX+ ab1_a_b_stats
+                                        List of extended statistics
+ Schema |     Name      |  Definition   | N_distinct | Dependencies |   Mcv   | N_size  | D_size  | M_size  
+--------+---------------+---------------+------------+--------------+---------+---------+---------+---------
+ public | ab1_a_b_stats | a, b FROM ab1 | defined    | defined      | defined | 0 bytes | 0 bytes | 0 bytes
+(1 row)
+
 -- partial analyze doesn't build stats either
 ANALYZE ab1 (a);
 WARNING:  statistics object "public.ab1_a_b_stats" could not be computed for relation "public.ab1"
@@ -146,6 +187,13 @@ CREATE TABLE ab1c () INHERITS (ab1);
 INSERT INTO ab1 VALUES (1,1);
 CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
 ANALYZE ab1;
+\dX+ ab1_a_b_stats
+                                         List of extended statistics
+ Schema |     Name      |  Definition   | N_distinct | Dependencies |  Mcv  |  N_size  |  D_size  |  M_size   
+--------+---------------+---------------+------------+--------------+-------+----------+----------+-----------
+ public | ab1_a_b_stats | a, b FROM ab1 | built      | built        | built | 11 bytes | 40 bytes | 186 bytes
+(1 row)
+
 DROP TABLE ab1 CASCADE;
 NOTICE:  drop cascades to table ab1c
 -- Verify supported object types for extended statistics
@@ -254,6 +302,13 @@ SELECT s.stxkind, d.stxdndistinct
  {d,f,m} | {"3, 4": 11, "3, 6": 11, "4, 6": 11, "3, 4, 6": 11}
 (1 row)
 
+\dX+ s10
+                                          List of extended statistics
+ Schema | Name |       Definition       | N_distinct | Dependencies |  Mcv  |  N_size  |  D_size   |  M_size   
+--------+------+------------------------+------------+--------------+-------+----------+-----------+-----------
+ public | s10  | a, b, c FROM ndistinct | built      | built        | built | 51 bytes | 189 bytes | 988 bytes
+(1 row)
+
 -- minor improvement, make sure the ctid does not break the matching
 SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY ctid, a, b');
  estimated | actual 
@@ -310,6 +365,13 @@ SELECT s.stxkind, d.stxdndistinct
  {d,f,m} | {"3, 4": 2550, "3, 6": 800, "4, 6": 1632, "3, 4, 6": 5000}
 (1 row)
 
+\dX+ s10
+                                          List of extended statistics
+ Schema | Name |       Definition       | N_distinct | Dependencies |  Mcv  |  N_size  |  D_size  |   M_size   
+--------+------+------------------------+------------+--------------+-------+----------+----------+------------
+ public | s10  | a, b, c FROM ndistinct | built      | built        | built | 58 bytes | 23 bytes | 5718 bytes
+(1 row)
+
 -- correct estimates
 SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
  estimated | actual 
@@ -350,6 +412,12 @@ SELECT s.stxkind, d.stxdndistinct
 ---------+---------------
 (0 rows)
 
+\dX+
+                               List of extended statistics
+ Schema | Name | Definition | N_distinct | Dependencies | Mcv | N_size | D_size | M_size 
+--------+------+------------+------------+--------------+-----+--------+--------+--------
+(0 rows)
+
 -- dropping the statistics results in under-estimates
 SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
  estimated | actual 
@@ -413,6 +481,13 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
 -- create statistics
 CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
 ANALYZE functional_dependencies;
+\dX+ func_deps_stat
+                                                 List of extended statistics
+ Schema |      Name      |              Definition              | N_distinct | Dependencies | Mcv | N_size | D_size  | M_size 
+--------+----------------+--------------------------------------+------------+--------------+-----+--------+---------+--------
+ public | func_deps_stat | a, b, c FROM functional_dependencies |            | defined      |     |        | 0 bytes | 
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
  estimated | actual 
 -----------+--------
@@ -431,6 +506,12 @@ DROP STATISTICS func_deps_stat;
 INSERT INTO functional_dependencies (a, b, c, filler1)
      SELECT mod(i,100), mod(i,50), mod(i,25), i FROM generate_series(1,5000) s(i);
 ANALYZE functional_dependencies;
+\dX+ func_deps_stat
+                               List of extended statistics
+ Schema | Name | Definition | N_distinct | Dependencies | Mcv | N_size | D_size | M_size 
+--------+------+------------+------------+--------------+-----+--------+--------+--------
+(0 rows)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
  estimated | actual 
 -----------+--------
@@ -590,6 +671,13 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
 -- create statistics
 CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
 ANALYZE functional_dependencies;
+\dX+ func_deps_stat
+                                                  List of extended statistics
+ Schema |      Name      |              Definition              | N_distinct | Dependencies | Mcv | N_size |  D_size   | M_size 
+--------+----------------+--------------------------------------+------------+--------------+-----+--------+-----------+--------
+ public | func_deps_stat | a, b, c FROM functional_dependencies |            | built        |     |        | 106 bytes | 
+(1 row)
+
 -- print the detected dependencies
 SELECT dependencies FROM pg_stats_ext WHERE statistics_name = 'func_deps_stat';
                                                 dependencies                                                
@@ -821,6 +909,14 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi
 CREATE STATISTICS functional_dependencies_multi_1 (dependencies) ON a, b FROM functional_dependencies_multi;
 CREATE STATISTICS functional_dependencies_multi_2 (dependencies) ON c, d FROM functional_dependencies_multi;
 ANALYZE functional_dependencies_multi;
+\dX+ functional_dependencies_multi_*
+                                                            List of extended statistics
+ Schema |              Name               |               Definition                | N_distinct | Dependencies | Mcv | N_size |  D_size  | M_size 
+--------+---------------------------------+-----------------------------------------+------------+--------------+-----+--------+----------+--------
+ public | functional_dependencies_multi_1 | a, b FROM functional_dependencies_multi |            | built        |     |        | 40 bytes | 
+ public | functional_dependencies_multi_2 | c, d FROM functional_dependencies_multi |            | built        |     |        | 40 bytes | 
+(2 rows)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE a = 0 AND b = 0');
  estimated | actual 
 -----------+--------
@@ -882,6 +978,13 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
+                                             List of extended statistics
+ Schema |      Name       |       Definition       | N_distinct | Dependencies |  Mcv  | N_size | D_size |   M_size   
+--------+-----------------+------------------------+------------+--------------+-------+--------+--------+------------
+ public | mcv_lists_stats | a, b, c FROM mcv_lists |            |              | built |        |        | 5890 bytes
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
  estimated | actual 
 -----------+--------
@@ -1041,6 +1144,13 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
+                                             List of extended statistics
+ Schema |      Name       |       Definition       | N_distinct | Dependencies |  Mcv  | N_size | D_size |   M_size   
+--------+-----------------+------------------------+------------+--------------+-------+--------+--------+------------
+ public | mcv_lists_stats | a, b, c FROM mcv_lists |            |              | built |        |        | 6754 bytes
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
  estimated | actual 
 -----------+--------
@@ -1191,6 +1301,13 @@ SELECT d.stxdmcv IS NOT NULL
  t
 (1 row)
 
+\dX+ mcv_lists_stats
+                                             List of extended statistics
+ Schema |      Name       |       Definition       | N_distinct | Dependencies |  Mcv  | N_size | D_size |   M_size   
+--------+-----------------+------------------------+------------+--------------+-------+--------+--------+------------
+ public | mcv_lists_stats | a, b, c FROM mcv_lists |            |              | built |        |        | 6754 bytes
+(1 row)
+
 -- check change of column type resets the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN c TYPE numeric;
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
@@ -1200,6 +1317,13 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
 (1 row)
 
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
+                                             List of extended statistics
+ Schema |      Name       |       Definition       | N_distinct | Dependencies |  Mcv  | N_size | D_size |   M_size   
+--------+-----------------+------------------------+------------+--------------+-------+--------+--------+------------
+ public | mcv_lists_stats | a, b, c FROM mcv_lists |            |              | built |        |        | 6950 bytes
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
  estimated | actual 
 -----------+--------
@@ -1250,6 +1374,13 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (0, 1) AN
 -- create statistics
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
+                                             List of extended statistics
+ Schema |      Name       |       Definition       | N_distinct | Dependencies |  Mcv  | N_size | D_size |   M_size   
+--------+-----------------+------------------------+------------+--------------+-------+--------+--------+------------
+ public | mcv_lists_stats | a, b, c FROM mcv_lists |            |              | built |        |        | 6916 bytes
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND b IS NULL');
  estimated | actual 
 -----------+--------
@@ -1294,6 +1425,13 @@ SELECT m.*
      0 | {1,2,3} | {f,f,f} |         1 |              1
 (1 row)
 
+\dX+ mcv_lists_stats
+                                             List of extended statistics
+ Schema |      Name       |       Definition       | N_distinct | Dependencies |  Mcv  | N_size | D_size |  M_size   
+--------+-----------------+------------------------+------------+--------------+-------+--------+--------+-----------
+ public | mcv_lists_stats | a, b, c FROM mcv_lists |            |              | built |        |        | 258 bytes
+(1 row)
+
 -- 2 distinct combinations with NULL values, all in the MCV list
 TRUNCATE mcv_lists;
 DROP STATISTICS mcv_lists_stats;
@@ -1338,6 +1476,13 @@ SELECT m.*
      1 | {NULL,NULL,NULL} | {t,t,t} |       0.5 |           0.25
 (2 rows)
 
+\dX+ mcv_lists_stats
+                                             List of extended statistics
+ Schema |      Name       |       Definition       | N_distinct | Dependencies |  Mcv  | N_size | D_size |  M_size   
+--------+-----------------+------------------------+------------+--------------+-------+--------+--------+-----------
+ public | mcv_lists_stats | a, b, d FROM mcv_lists |            |              | built |        |        | 294 bytes
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
  estimated | actual 
 -----------+--------
@@ -1385,6 +1530,13 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_uuid WHERE a = ''167
 CREATE STATISTICS mcv_lists_uuid_stats (mcv) ON a, b, c
   FROM mcv_lists_uuid;
 ANALYZE mcv_lists_uuid;
+\dX+ mcv_lists_uuid_stats
+                                                List of extended statistics
+ Schema |         Name         |         Definition          | N_distinct | Dependencies |  Mcv  | N_size | D_size | M_size 
+--------+----------------------+-----------------------------+------------+--------------+-------+--------+--------+--------
+ public | mcv_lists_uuid_stats | a, b, c FROM mcv_lists_uuid |            |              | built |        |        | 11 kB
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_uuid WHERE a = ''1679091c-5a88-0faf-6fb5-e6087eb1b2dc'' AND b = ''1679091c-5a88-0faf-6fb5-e6087eb1b2dc''');
  estimated | actual 
 -----------+--------
@@ -1414,6 +1566,13 @@ INSERT INTO mcv_lists_arrays (a, b, c)
 CREATE STATISTICS mcv_lists_arrays_stats (mcv) ON a, b, c
   FROM mcv_lists_arrays;
 ANALYZE mcv_lists_arrays;
+\dX+ mcv_lists_arrays_stats
+                                                  List of extended statistics
+ Schema |          Name          |          Definition           | N_distinct | Dependencies |  Mcv  | N_size | D_size | M_size 
+--------+------------------------+-------------------------------+------------+--------------+-------+--------+--------+--------
+ public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays |            |              | built |        |        | 24 kB
+(1 row)
+
 -- mcv with bool
 CREATE TABLE mcv_lists_bool (
     a BOOL,
@@ -1453,6 +1612,13 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE NOT a AND
 CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 ANALYZE mcv_lists_bool;
+\dX+ mcv_lists_bool_stats
+                                                  List of extended statistics
+ Schema |         Name         |         Definition          | N_distinct | Dependencies |  Mcv  | N_size | D_size |  M_size   
+--------+----------------------+-----------------------------+------------+--------------+-------+--------+--------+-----------
+ public | mcv_lists_bool_stats | a, b, c FROM mcv_lists_bool |            |              | built |        |        | 386 bytes
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE a AND b AND c');
  estimated | actual 
 -----------+--------
@@ -1516,6 +1682,14 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AN
 CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
 CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi;
 ANALYZE mcv_lists_multi;
+\dX+ mcv_lists_multi_*
+                                               List of extended statistics
+ Schema |       Name        |        Definition         | N_distinct | Dependencies |  Mcv  | N_size | D_size |  M_size   
+--------+-------------------+---------------------------+------------+--------------+-------+--------+--------+-----------
+ public | mcv_lists_multi_1 | a, b FROM mcv_lists_multi |            |              | built |        |        | 426 bytes
+ public | mcv_lists_multi_2 | c, d FROM mcv_lists_multi |            |              | built |        |        | 546 bytes
+(2 rows)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
  estimated | actual 
 -----------+--------
@@ -1550,6 +1724,13 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+\dX+ tststats.priv_test_stats
+                                                   List of extended statistics
+  Schema  |      Name       |            Definition            | N_distinct | Dependencies |  Mcv  | N_size | D_size |  M_size   
+----------+-----------------+----------------------------------+------------+--------------+-------+--------+--------+-----------
+ tststats | priv_test_stats | a, b FROM tststats.priv_test_tbl |            |              | built |        |        | 686 bytes
+(1 row)
+
 -- Check printing info about extended statistics by \dX
 create table stts_t1 (a int, b int);
 create statistics stts_1 (ndistinct) on a, b from stts_t1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 2b90471a4b..40da1dcbb5 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -49,6 +49,7 @@ CREATE STATISTICS regress_schema_2.ab1_a_b_stats ON a, b FROM ab1;
 
 -- Let's also verify the pg_get_statisticsobjdef output looks sane.
 SELECT pg_get_statisticsobjdef(oid) FROM pg_statistic_ext WHERE stxname = 'ab1_a_b_stats';
+\dX
 
 DROP STATISTICS regress_schema_2.ab1_a_b_stats;
 
@@ -60,9 +61,10 @@ ALTER TABLE ab1 DROP COLUMN a;
 \d ab1
 -- Ensure statistics are dropped when table is
 SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
+\dX
 DROP TABLE ab1;
 SELECT stxname FROM pg_statistic_ext WHERE stxname LIKE 'ab1%';
-
+\dX
 -- Ensure things work sanely with SET STATISTICS 0
 CREATE TABLE ab1 (a INTEGER, b INTEGER);
 ALTER TABLE ab1 ALTER a SET STATISTICS 0;
@@ -73,13 +75,16 @@ ALTER TABLE ab1 ALTER a SET STATISTICS -1;
 -- setting statistics target 0 skips the statistics, without printing any message, so check catalog
 ALTER STATISTICS ab1_a_b_stats SET STATISTICS 0;
 \d ab1
+\dX+ ab1_a_b_stats
 ANALYZE ab1;
 SELECT stxname, stxdndistinct, stxddependencies, stxdmcv
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxname = 'ab1_a_b_stats'
    AND d.stxoid = s.oid;
+\dX+ ab1_a_b_stats
 ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
 \d+ ab1
+\dX+ ab1_a_b_stats
 -- partial analyze doesn't build stats either
 ANALYZE ab1 (a);
 ANALYZE ab1;
@@ -93,6 +98,7 @@ CREATE TABLE ab1c () INHERITS (ab1);
 INSERT INTO ab1 VALUES (1,1);
 CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1;
 ANALYZE ab1;
+\dX+ ab1_a_b_stats
 DROP TABLE ab1 CASCADE;
 
 -- Verify supported object types for extended statistics
@@ -171,6 +177,7 @@ SELECT s.stxkind, d.stxdndistinct
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxrelid = 'ndistinct'::regclass
    AND d.stxoid = s.oid;
+\dX+ s10
 
 -- minor improvement, make sure the ctid does not break the matching
 SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY ctid, a, b');
@@ -202,6 +209,7 @@ SELECT s.stxkind, d.stxdndistinct
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxrelid = 'ndistinct'::regclass
    AND d.stxoid = s.oid;
+\dX+ s10
 
 -- correct estimates
 SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
@@ -220,6 +228,7 @@ SELECT s.stxkind, d.stxdndistinct
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxrelid = 'ndistinct'::regclass
    AND d.stxoid = s.oid;
+\dX+
 
 -- dropping the statistics results in under-estimates
 SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
@@ -261,6 +270,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
 CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
 
 ANALYZE functional_dependencies;
+\dX+ func_deps_stat
 
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
 
@@ -274,6 +284,7 @@ INSERT INTO functional_dependencies (a, b, c, filler1)
      SELECT mod(i,100), mod(i,50), mod(i,25), i FROM generate_series(1,5000) s(i);
 
 ANALYZE functional_dependencies;
+\dX+ func_deps_stat
 
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
 
@@ -335,6 +346,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE
 CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_dependencies;
 
 ANALYZE functional_dependencies;
+\dX+ func_deps_stat
 
 -- print the detected dependencies
 SELECT dependencies FROM pg_stats_ext WHERE statistics_name = 'func_deps_stat';
@@ -437,6 +449,7 @@ CREATE STATISTICS functional_dependencies_multi_1 (dependencies) ON a, b FROM fu
 CREATE STATISTICS functional_dependencies_multi_2 (dependencies) ON c, d FROM functional_dependencies_multi;
 
 ANALYZE functional_dependencies_multi;
+\dX+ functional_dependencies_multi_*
 
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND 0 = b');
@@ -472,6 +485,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b =
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
 
@@ -536,6 +550,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a < ALL (ARRAY
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
 
@@ -591,6 +606,7 @@ SELECT d.stxdmcv IS NOT NULL
   FROM pg_statistic_ext s, pg_statistic_ext_data d
  WHERE s.stxname = 'mcv_lists_stats'
    AND d.stxoid = s.oid;
+\dX+ mcv_lists_stats
 
 -- check change of column type resets the MCV statistics
 ALTER TABLE mcv_lists ALTER COLUMN c TYPE numeric;
@@ -598,6 +614,7 @@ ALTER TABLE mcv_lists ALTER COLUMN c TYPE numeric;
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
 
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a = 1 AND b = ''1''');
 
@@ -629,6 +646,7 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IN (0, 1) AN
 CREATE STATISTICS mcv_lists_stats (mcv) ON a, b, c FROM mcv_lists;
 
 ANALYZE mcv_lists;
+\dX+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND b IS NULL');
 
@@ -650,6 +668,7 @@ SELECT m.*
        pg_mcv_list_items(d.stxdmcv) m
  WHERE s.stxname = 'mcv_lists_stats'
    AND d.stxoid = s.oid;
+\dX+ mcv_lists_stats
 
 -- 2 distinct combinations with NULL values, all in the MCV list
 TRUNCATE mcv_lists;
@@ -682,6 +701,7 @@ SELECT m.*
        pg_mcv_list_items(d.stxdmcv) m
  WHERE s.stxname = 'mcv_lists_stats'
    AND d.stxoid = s.oid;
+\dX+ mcv_lists_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE b = ''x'' OR d = ''x''');
 
@@ -714,6 +734,7 @@ CREATE STATISTICS mcv_lists_uuid_stats (mcv) ON a, b, c
   FROM mcv_lists_uuid;
 
 ANALYZE mcv_lists_uuid;
+\dX+ mcv_lists_uuid_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_uuid WHERE a = ''1679091c-5a88-0faf-6fb5-e6087eb1b2dc'' AND b = ''1679091c-5a88-0faf-6fb5-e6087eb1b2dc''');
 
@@ -740,6 +761,7 @@ CREATE STATISTICS mcv_lists_arrays_stats (mcv) ON a, b, c
   FROM mcv_lists_arrays;
 
 ANALYZE mcv_lists_arrays;
+\dX+ mcv_lists_arrays_stats
 
 -- mcv with bool
 CREATE TABLE mcv_lists_bool (
@@ -768,6 +790,7 @@ CREATE STATISTICS mcv_lists_bool_stats (mcv) ON a, b, c
   FROM mcv_lists_bool;
 
 ANALYZE mcv_lists_bool;
+\dX+ mcv_lists_bool_stats
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_bool WHERE a AND b AND c');
 
@@ -806,6 +829,7 @@ CREATE STATISTICS mcv_lists_multi_1 (mcv) ON a, b FROM mcv_lists_multi;
 CREATE STATISTICS mcv_lists_multi_2 (mcv) ON c, d FROM mcv_lists_multi;
 
 ANALYZE mcv_lists_multi;
+\dX+ mcv_lists_multi_*
 
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE a = 0 AND b = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists_multi WHERE c = 0 AND d = 0');
@@ -832,6 +856,7 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 
 ANALYZE tststats.priv_test_tbl;
+\dX+ tststats.priv_test_stats
 
 -- Check printing info about extended statistics by \dX
 create table stts_t1 (a int, b int);
-- 
2.26.2

From 85fe05c3020cd595ae8d5c2cc6f695b39f4a6e03 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Tue, 17 Nov 2020 13:30:57 +0900
Subject: [PATCH 2/2] Recreate regression test

---
 src/test/regress/expected/stats_ext.out | 94 +++++++++++++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      | 31 +++++++++++
 2 files changed, 125 insertions(+)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 4c3edd213f..27ca54a8f3 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1550,6 +1550,100 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
+----------+------------------------+--------------------------------------+-----------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built
+(12 rows)
+
+\dX stts_?
+                       List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
+--------+--------+-------------------+-----------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | built     |              | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+(4 rows)
+
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
+--------+-----------+-------------------------------+-----------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+(1 row)
+
+\dX+
+                                                                   List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+----------+------------------------+--------------------------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |         |                | 106 bytes         | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built   |                |                   | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built   |                |                   | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built   |                |                   | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              |         | 13 bytes       |                   | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined |                | 0 bytes           | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built   |                |                   | 686 bytes
+(12 rows)
+
+\dX+ stts_?
+                                                List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+--------+--------+-------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public | stts_1 | a, b FROM stts_t1 | built     |              |         | 13 bytes       |                   | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(4 rows)
+
+\dX+ *stts_hoge
+                                                       List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+--------+-----------+-------------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                                                    List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+---------+-----------+-------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined |                | 0 bytes           | 0 bytes
+(1 row)
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 9781e590a3..2b90471a4b 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -833,6 +833,37 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.16.5

From b093c5cc9b6376809123ca90bec3f330109935b8 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Tue, 17 Nov 2020 13:28:50 +0900
Subject: [PATCH 1/2] Replace column names with long names.

For example, s/N_size/Ndistinct_size/.
---
 doc/src/sgml/ref/psql-ref.sgml |  14 ++++++
 src/bin/psql/command.c         |   3 ++
 src/bin/psql/describe.c        | 100 +++++++++++++++++++++++++++++++++++++++++
 src/bin/psql/describe.h        |   3 ++
 src/bin/psql/help.c            |   1 +
 src/bin/psql/tab-complete.c    |   4 +-
 6 files changed, 124 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index c7a83d5dfc..c6f1653cb7 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -930,6 +930,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 07d640021c..3eb3b94b14 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4397,6 +4397,106 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("Ndistinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("MCV"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxddependencies)::bigint) \n"
+						  "     WHEN 'f' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdmcv)::bigint) \n"
+						  "     WHEN 'm' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("Ndistinct_size"),
+						  gettext_noop("Dependencies_size"),
+						  gettext_noop("MCV_size"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 5238a960f7..30a8ada7d2 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3851,6 +3851,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
-- 
2.16.5

From 91c09db61c2891cf83b3151f51348dfd02e09744 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Mon, 30 Nov 2020 11:09:00 +0900
Subject: [PATCH 1/2] Add \dX command on psql (rebased on 7e5e1bba03)

---
 doc/src/sgml/ref/psql-ref.sgml |  14 ++++++
 src/bin/psql/command.c         |   3 ++
 src/bin/psql/describe.c        | 100 +++++++++++++++++++++++++++++++++++++++++
 src/bin/psql/describe.h        |   3 ++
 src/bin/psql/help.c            |   1 +
 src/bin/psql/tab-complete.c    |   4 +-
 6 files changed, 124 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 38b588882d..46a6d0df76 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -928,6 +928,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 14150d05a9..7dac038f1b 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4401,6 +4401,106 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("Ndistinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("MCV"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxddependencies)::bigint) \n"
+						  "     WHEN 'f' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(stxdmcv)::bigint) \n"
+						  "     WHEN 'm' = any(stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("Ndistinct_size"),
+						  gettext_noop("Dependencies_size"),
+						  gettext_noop("MCV_size"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index f0e3ec957c..89b13c3f0c 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index af829282e6..ea249bf96d 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 8afc780acc..0112363b10 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3898,6 +3898,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
-- 
2.16.5

From da9c7378c7d049758d8d74798e7076f00e4f07c6 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Mon, 30 Nov 2020 11:10:45 +0900
Subject: [PATCH 2/2] Add regression test for \dX (rebased on 7e5e1bba03)

---
 src/test/regress/expected/stats_ext.out | 94 +++++++++++++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      | 31 +++++++++++
 2 files changed, 125 insertions(+)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 4c3edd213f..27ca54a8f3 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1550,6 +1550,100 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
+----------+------------------------+--------------------------------------+-----------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built
+(12 rows)
+
+\dX stts_?
+                       List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
+--------+--------+-------------------+-----------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | built     |              | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+(4 rows)
+
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
+--------+-----------+-------------------------------+-----------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+(1 row)
+
+\dX+
+                                                                   List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+----------+------------------------+--------------------------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |         |                | 106 bytes         | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built   |                |                   | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built   |                |                   | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built   |                |                   | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              |         | 13 bytes       |                   | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined |                | 0 bytes           | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built   |                |                   | 686 bytes
+(12 rows)
+
+\dX+ stts_?
+                                                List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+--------+--------+-------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public | stts_1 | a, b FROM stts_t1 | built     |              |         | 13 bytes       |                   | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(4 rows)
+
+\dX+ *stts_hoge
+                                                       List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+--------+-----------+-------------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                                                    List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+---------+-----------+-------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined |                | 0 bytes           | 0 bytes
+(1 row)
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 9781e590a3..2b90471a4b 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -833,6 +833,37 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.16.5

From 9f36a9df0c2803f5554b951e37ba5969c2744e3b Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Tue, 5 Jan 2021 12:34:16 +0900
Subject: [PATCH 2/2] Add regression test for \dX on psql

---
 src/test/regress/expected/stats_ext.out | 94 +++++++++++++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      | 31 +++++++++++
 2 files changed, 125 insertions(+)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 7bfeaf85f0..8c8a0afcf6 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1725,6 +1725,100 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
+----------+------------------------+--------------------------------------+-----------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built
+(12 rows)
+
+\dX stts_?
+                       List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
+--------+--------+-------------------+-----------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | built     |              | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+(4 rows)
+
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
+--------+-----------+-------------------------------+-----------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+(1 row)
+
+\dX+
+                                                                   List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+----------+------------------------+--------------------------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |         |                | 106 bytes         | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built   |                |                   | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built   |                |                   | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built   |                |                   | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              |         | 13 bytes       |                   | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined |                | 0 bytes           | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built   |                |                   | 686 bytes
+(12 rows)
+
+\dX+ stts_?
+                                                List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+--------+--------+-------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public | stts_1 | a, b FROM stts_t1 | built     |              |         | 13 bytes       |                   | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(4 rows)
+
+\dX+ *stts_hoge
+                                                       List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+--------+-----------+-------------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                                                    List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+---------+-----------+-------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined |                | 0 bytes           | 0 bytes
+(1 row)
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 7912e733ae..db6e3e1ba3 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -912,6 +912,37 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.16.5

From fe32b38c7b0d2ce2c4238eba91a2a8ba9229e994 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Tue, 5 Jan 2021 12:32:45 +0900
Subject: [PATCH 1/2] Add \dX command on psql

---
 doc/src/sgml/ref/psql-ref.sgml |  14 ++++++
 src/bin/psql/command.c         |   3 ++
 src/bin/psql/describe.c        | 100 +++++++++++++++++++++++++++++++++++++++++
 src/bin/psql/describe.h        |   3 ++
 src/bin/psql/help.c            |   1 +
 src/bin/psql/tab-complete.c    |   4 +-
 6 files changed, 124 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 303e7c3ad8..c5ebc1c3f4 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -928,6 +928,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 52c6de51b6..f90070a064 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4401,6 +4401,106 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\", \n"
+					  "CASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+					  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"),
+					  gettext_noop("Ndistinct"),
+					  gettext_noop("Dependencies"),
+					  gettext_noop("MCV"));
+
+	if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxddependencies)::bigint) \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdmcv)::bigint) \n"
+						  "     WHEN 'm' = any(es.stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("Ndistinct_size"),
+						  gettext_noop("Dependencies_size"),
+						  gettext_noop("MCV_size"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n"
+						 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+						 "ON es.oid = esd.stxoid \n"
+						 "INNER JOIN pg_catalog.pg_class c \n"
+						 "ON es.stxrelid = c.oid \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 6044e3a082..867e57d851 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 9ec1c4e810..e42bc8c54e 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 9dcab0d2fa..611f1efb15 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3910,6 +3910,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
-- 
2.16.5

From 9f36a9df0c2803f5554b951e37ba5969c2744e3b Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Tue, 5 Jan 2021 12:34:16 +0900
Subject: [PATCH 2/2] Add regression test for \dX on psql

---
 src/test/regress/expected/stats_ext.out | 94 +++++++++++++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      | 31 +++++++++++
 2 files changed, 125 insertions(+)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 7bfeaf85f0..8c8a0afcf6 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1725,6 +1725,100 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
+----------+------------------------+--------------------------------------+-----------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built
+(12 rows)
+
+\dX stts_?
+                       List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
+--------+--------+-------------------+-----------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | built     |              | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+(4 rows)
+
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
+--------+-----------+-------------------------------+-----------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+(1 row)
+
+\dX+
+                                                                   List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+----------+------------------------+--------------------------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |         |                | 106 bytes         | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built   |                |                   | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built   |                |                   | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built   |                |                   | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              |         | 13 bytes       |                   | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined |                | 0 bytes           | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built   |                |                   | 686 bytes
+(12 rows)
+
+\dX+ stts_?
+                                                List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+--------+--------+-------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public | stts_1 | a, b FROM stts_t1 | built     |              |         | 13 bytes       |                   | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(4 rows)
+
+\dX+ *stts_hoge
+                                                       List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+--------+-----------+-------------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                                                    List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+---------+-----------+-------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined |                | 0 bytes           | 0 bytes
+(1 row)
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 7912e733ae..db6e3e1ba3 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -912,6 +912,37 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.16.5

From c8be51a52a381a6e9c7be62022f5fc48b5915bd0 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Thu, 7 Jan 2021 14:28:20 +0900
Subject: [PATCH] Add \dX command on psql

This patch includes the version check in the logic building query.
---
 doc/src/sgml/ref/psql-ref.sgml |  14 ++++
 src/bin/psql/command.c         |   3 +
 src/bin/psql/describe.c        | 141 +++++++++++++++++++++++++++++++++++++++++
 src/bin/psql/describe.h        |   3 +
 src/bin/psql/help.c            |   1 +
 src/bin/psql/tab-complete.c    |   4 +-
 6 files changed, 165 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..fd860776af 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the pattern
+        are listed.
+        If <literal>+</literal> is appended to the command name, each extended statistics
+        is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 303e7c3ad8..c5ebc1c3f4 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -928,6 +928,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 52c6de51b6..0ccd9ed286 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4401,6 +4401,147 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Briefly describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"));
+
+	if (pset.sversion < 120000)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN es.stxdependencies IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct"),
+						  gettext_noop("Dependencies"));
+	}
+	else
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct"),
+						  gettext_noop("Dependencies"),
+						  gettext_noop("MCV"));
+	}
+
+	if (verbose && pset.sversion < 120000)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(es.stxndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN es.stxdependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(es.stxdependencies)::bigint) \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct_size"),
+						  gettext_noop("Dependencies_size"));
+	}
+	else if (verbose)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdndistinct)::bigint) \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxddependencies)::bigint) \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+						  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdmcv)::bigint) \n"
+						  "     WHEN 'm' = any(es.stxkind) THEN '0 bytes' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct_size"),
+						  gettext_noop("Dependencies_size"),
+						  gettext_noop("MCV_size"));
+	}
+
+	if (pset.sversion < 120000)
+	{
+		appendPQExpBufferStr(&buf,
+							 " \nFROM pg_catalog.pg_statistic_ext es \n"
+							 "INNER JOIN pg_catalog.pg_class c \n"
+							 "ON es.stxrelid = c.oid \n");
+	}
+	else
+	{
+		appendPQExpBufferStr(&buf,
+							 " \nFROM pg_catalog.pg_statistic_ext es \n"
+							 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+							 "ON es.oid = esd.stxoid \n"
+							 "INNER JOIN pg_catalog.pg_class c \n"
+							 "ON es.stxrelid = c.oid \n");
+	}
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 6044e3a082..867e57d851 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 9ec1c4e810..e42bc8c54e 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 9dcab0d2fa..611f1efb15 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3910,6 +3910,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
-- 
2.16.5

From 3d2f4ef2ecba9fd7987df665237add6fc4ec03c1 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Thu, 7 Jan 2021 14:28:20 +0900
Subject: [PATCH 1/2] psql \dX: list extended statistics objects

The new command lists extended statistics objects, possibly with their
sizes. All past releases with extended statistics are supported.

Author: Tatsuro Yamada
Reviewed-by: Julien Rouhaud, Alvaro Herrera, Tomas Vondra
Discussion: https://postgr.es/m/c027a541-5856-75a5-0868-341301e1624b%40nttcom.co.jp_1
---
 doc/src/sgml/ref/psql-ref.sgml          |  14 +++
 src/bin/psql/command.c                  |   3 +
 src/bin/psql/describe.c                 | 150 ++++++++++++++++++++++++
 src/bin/psql/describe.h                 |   3 +
 src/bin/psql/help.c                     |   1 +
 src/bin/psql/tab-complete.c             |   4 +-
 src/test/regress/expected/stats_ext.out |  94 +++++++++++++++
 src/test/regress/sql/stats_ext.sql      |  31 +++++
 8 files changed, 299 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..d01acc92b8 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the
+        pattern are listed.
+        If <literal>+</literal> is appended to the command name, each extended
+        statistics is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 303e7c3ad8..c5ebc1c3f4 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -928,6 +928,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index caf97563f4..46f54199fb 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4392,6 +4392,156 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"));
+
+	/*
+	 * Since 12 there are two catalogs - one for the definition, one for the
+	 * data built by ANALYZE. Older releases use a single catalog. Also, 12
+	 * adds the MCV statistics kind.
+	 */
+	if (pset.sversion < 120000)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN es.stxdependencies IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct"),
+						  gettext_noop("Dependencies"));
+	}
+	else
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct"),
+						  gettext_noop("Dependencies"),
+						  gettext_noop("MCV"));
+	}
+
+	/* In verbose mode, print sizes of the extended statistics objects. */
+	if (verbose)
+	{
+		if (pset.sversion < 120000)
+		{
+			appendPQExpBuffer(&buf,
+							  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(es.stxndistinct)::bigint) \n"
+							  "     WHEN 'd' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\", \n"
+							  "CASE WHEN es.stxdependencies IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(es.stxdependencies)::bigint) \n"
+							  "     WHEN 'f' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\"",
+							  gettext_noop("Ndistinct_size"),
+							  gettext_noop("Dependencies_size"));
+		}
+		else
+		{
+			appendPQExpBuffer(&buf,
+							  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdndistinct)::bigint) \n"
+							  "     WHEN 'd' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\", \n"
+							  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxddependencies)::bigint) \n"
+							  "     WHEN 'f' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\", \n"
+							  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdmcv)::bigint) \n"
+							  "     WHEN 'm' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\"",
+							  gettext_noop("Ndistinct_size"),
+							  gettext_noop("Dependencies_size"),
+							  gettext_noop("MCV_size"));
+		}
+	}
+
+	if (pset.sversion < 120000)
+	{
+		appendPQExpBufferStr(&buf,
+							 " \nFROM pg_catalog.pg_statistic_ext es \n"
+							 "INNER JOIN pg_catalog.pg_class c \n"
+							 "ON es.stxrelid = c.oid \n");
+	}
+	else
+	{
+		appendPQExpBufferStr(&buf,
+							 " \nFROM pg_catalog.pg_statistic_ext es \n"
+							 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+							 "ON es.oid = esd.stxoid \n"
+							 "INNER JOIN pg_catalog.pg_class c \n"
+							 "ON es.stxrelid = c.oid \n");
+	}
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 6044e3a082..867e57d851 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 9ec1c4e810..e42bc8c54e 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 9dcab0d2fa..611f1efb15 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3910,6 +3910,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 7bfeaf85f0..8c8a0afcf6 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1725,6 +1725,100 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
+----------+------------------------+--------------------------------------+-----------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built
+(12 rows)
+
+\dX stts_?
+                       List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
+--------+--------+-------------------+-----------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | built     |              | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+(4 rows)
+
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
+--------+-----------+-------------------------------+-----------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+(1 row)
+
+\dX+
+                                                                   List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+----------+------------------------+--------------------------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |         |                | 106 bytes         | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built   |                |                   | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built   |                |                   | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built   |                |                   | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              |         | 13 bytes       |                   | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined |                | 0 bytes           | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built   |                |                   | 686 bytes
+(12 rows)
+
+\dX+ stts_?
+                                                List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+--------+--------+-------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public | stts_1 | a, b FROM stts_t1 | built     |              |         | 13 bytes       |                   | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(4 rows)
+
+\dX+ *stts_hoge
+                                                       List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+--------+-----------+-------------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                                                    List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+---------+-----------+-------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined |                | 0 bytes           | 0 bytes
+(1 row)
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 7912e733ae..db6e3e1ba3 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -912,6 +912,37 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.26.2

From 1ff2e77fd2472700a4a89699d8afed8679e38c7e Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas@2ndquadrant.com>
Date: Sat, 9 Jan 2021 00:56:43 +0100
Subject: [PATCH 2/2] fixup: rename defined to requested

---
 src/bin/psql/describe.c                 | 10 +--
 src/test/regress/expected/stats_ext.out | 90 ++++++++++++-------------
 2 files changed, 50 insertions(+), 50 deletions(-)

diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 46f54199fb..83084f79d0 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4440,10 +4440,10 @@ listExtendedStats(const char *pattern, bool verbose)
 	{
 		appendPQExpBuffer(&buf,
 						  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\", \n"
 						  "CASE WHEN es.stxdependencies IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\"",
 						  gettext_noop("Ndistinct"),
 						  gettext_noop("Dependencies"));
@@ -4452,13 +4452,13 @@ listExtendedStats(const char *pattern, bool verbose)
 	{
 		appendPQExpBuffer(&buf,
 						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\", \n"
 						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\", \n"
 						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'm' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\"",
 						  gettext_noop("Ndistinct"),
 						  gettext_noop("Dependencies"),
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 8c8a0afcf6..b3ae4de185 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1741,9 +1741,9 @@ create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_
 insert into stts_t1 select i,i from generate_series(1,100) i;
 analyze stts_t1;
 \dX
-                                          List of extended statistics
-  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
-----------+------------------------+--------------------------------------+-----------+--------------+---------
+                                           List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |    MCV    
+----------+------------------------+--------------------------------------+-----------+--------------+-----------
  public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        | 
  public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built
  public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built
@@ -1751,70 +1751,70 @@ analyze stts_t1;
  public   | stts_1                 | a, b FROM stts_t1                    | built     |              | 
  public   | stts_2                 | a, b FROM stts_t1                    | built     | built        | 
  public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built
- public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
- public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
- stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
- stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ public   | stts_4                 | b, c FROM stts_t2                    | requested | requested    | requested
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | requested | requested    | requested
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | requested | requested    | requested
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | requested    | requested
  tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built
 (12 rows)
 
 \dX stts_?
-                       List of extended statistics
- Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
---------+--------+-------------------+-----------+--------------+---------
+                        List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |    MCV    
+--------+--------+-------------------+-----------+--------------+-----------
  public | stts_1 | a, b FROM stts_t1 | built     |              | 
  public | stts_2 | a, b FROM stts_t1 | built     | built        | 
  public | stts_3 | a, b FROM stts_t1 | built     | built        | built
- public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+ public | stts_4 | b, c FROM stts_t2 | requested | requested    | requested
 (4 rows)
 
 \dX *stts_hoge
-                               List of extended statistics
- Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
---------+-----------+-------------------------------+-----------+--------------+---------
- public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+                                List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |    MCV    
+--------+-----------+-------------------------------+-----------+--------------+-----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | requested | requested    | requested
 (1 row)
 
 \dX+
-                                                                   List of extended statistics
-  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
-----------+------------------------+--------------------------------------+-----------+--------------+---------+----------------+-------------------+------------
- public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |         |                | 106 bytes         | 
- public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built   |                |                   | 24 kB
- public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built   |                |                   | 386 bytes
- public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built   |                |                   | 294 bytes
- public   | stts_1                 | a, b FROM stts_t1                    | built     |              |         | 13 bytes       |                   | 
- public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |         | 13 bytes       | 40 bytes          | 
- public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
- public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
- public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
- stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
- stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined |                | 0 bytes           | 0 bytes
- tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built   |                |                   | 686 bytes
+                                                                    List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size |  MCV_size  
+----------+------------------------+--------------------------------------+-----------+--------------+-----------+----------------+-------------------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |           |                | 106 bytes         | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built     |                |                   | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built     |                |                   | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built     |                |                   | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              |           | 13 bytes       |                   | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |           | 13 bytes       | 40 bytes          | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built     | 13 bytes       | 40 bytes          | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | requested    | requested |                | 0 bytes           | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built     |                |                   | 686 bytes
 (12 rows)
 
 \dX+ stts_?
-                                                List of extended statistics
- Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
---------+--------+-------------------+-----------+--------------+---------+----------------+-------------------+------------
- public | stts_1 | a, b FROM stts_t1 | built     |              |         | 13 bytes       |                   | 
- public | stts_2 | a, b FROM stts_t1 | built     | built        |         | 13 bytes       | 40 bytes          | 
- public | stts_3 | a, b FROM stts_t1 | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
- public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+                                                 List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size |  MCV_size  
+--------+--------+-------------------+-----------+--------------+-----------+----------------+-------------------+------------
+ public | stts_1 | a, b FROM stts_t1 | built     |              |           | 13 bytes       |                   | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        |           | 13 bytes       | 40 bytes          | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built     | 13 bytes       | 40 bytes          | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
 (4 rows)
 
 \dX+ *stts_hoge
-                                                       List of extended statistics
- Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
---------+-----------+-------------------------------+-----------+--------------+---------+----------------+-------------------+----------
- public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+                                                        List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size | MCV_size 
+--------+-----------+-------------------------------+-----------+--------------+-----------+----------------+-------------------+----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
 (1 row)
 
 \dX+ stts_s2.stts_yama
-                                                    List of extended statistics
- Schema  |   Name    |       Definition        | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
----------+-----------+-------------------------+-----------+--------------+---------+----------------+-------------------+----------
- stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined |                | 0 bytes           | 0 bytes
+                                                     List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size | MCV_size 
+---------+-----------+-------------------------+-----------+--------------+-----------+----------------+-------------------+----------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | requested    | requested |                | 0 bytes           | 0 bytes
 (1 row)
 
 drop table stts_t1, stts_t2, stts_t3;
-- 
2.26.2

>From 3d2f4ef2ecba9fd7987df665237add6fc4ec03c1 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Thu, 7 Jan 2021 14:28:20 +0900
Subject: [PATCH 1/2] psql \dX: list extended statistics objects

The new command lists extended statistics objects, possibly with their
sizes. All past releases with extended statistics are supported.

Author: Tatsuro Yamada
Reviewed-by: Julien Rouhaud, Alvaro Herrera, Tomas Vondra
Discussion: https://postgr.es/m/c027a541-5856-75a5-0868-341301e1624b%40nttcom.co.jp_1
---
 doc/src/sgml/ref/psql-ref.sgml          |  14 +++
 src/bin/psql/command.c                  |   3 +
 src/bin/psql/describe.c                 | 150 ++++++++++++++++++++++++
 src/bin/psql/describe.h                 |   3 +
 src/bin/psql/help.c                     |   1 +
 src/bin/psql/tab-complete.c             |   4 +-
 src/test/regress/expected/stats_ext.out |  94 +++++++++++++++
 src/test/regress/sql/stats_ext.sql      |  31 +++++
 8 files changed, 299 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..d01acc92b8 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,20 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the
+        pattern are listed.
+        If <literal>+</literal> is appended to the command name, each extended
+        statistics is listed with its size.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 303e7c3ad8..c5ebc1c3f4 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -928,6 +928,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index caf97563f4..46f54199fb 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4392,6 +4392,156 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"));
+
+	/*
+	 * Since 12 there are two catalogs - one for the definition, one for the
+	 * data built by ANALYZE. Older releases use a single catalog. Also, 12
+	 * adds the MCV statistics kind.
+	 */
+	if (pset.sversion < 120000)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN es.stxdependencies IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct"),
+						  gettext_noop("Dependencies"));
+	}
+	else
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct"),
+						  gettext_noop("Dependencies"),
+						  gettext_noop("MCV"));
+	}
+
+	/* In verbose mode, print sizes of the extended statistics objects. */
+	if (verbose)
+	{
+		if (pset.sversion < 120000)
+		{
+			appendPQExpBuffer(&buf,
+							  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(es.stxndistinct)::bigint) \n"
+							  "     WHEN 'd' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\", \n"
+							  "CASE WHEN es.stxdependencies IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(es.stxdependencies)::bigint) \n"
+							  "     WHEN 'f' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\"",
+							  gettext_noop("Ndistinct_size"),
+							  gettext_noop("Dependencies_size"));
+		}
+		else
+		{
+			appendPQExpBuffer(&buf,
+							  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdndistinct)::bigint) \n"
+							  "     WHEN 'd' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\", \n"
+							  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxddependencies)::bigint) \n"
+							  "     WHEN 'f' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\", \n"
+							  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdmcv)::bigint) \n"
+							  "     WHEN 'm' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\"",
+							  gettext_noop("Ndistinct_size"),
+							  gettext_noop("Dependencies_size"),
+							  gettext_noop("MCV_size"));
+		}
+	}
+
+	if (pset.sversion < 120000)
+	{
+		appendPQExpBufferStr(&buf,
+							 " \nFROM pg_catalog.pg_statistic_ext es \n"
+							 "INNER JOIN pg_catalog.pg_class c \n"
+							 "ON es.stxrelid = c.oid \n");
+	}
+	else
+	{
+		appendPQExpBufferStr(&buf,
+							 " \nFROM pg_catalog.pg_statistic_ext es \n"
+							 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+							 "ON es.oid = esd.stxoid \n"
+							 "INNER JOIN pg_catalog.pg_class c \n"
+							 "ON es.stxrelid = c.oid \n");
+	}
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "es.stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 6044e3a082..867e57d851 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 9ec1c4e810..e42bc8c54e 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 9dcab0d2fa..611f1efb15 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3910,6 +3910,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 7bfeaf85f0..8c8a0afcf6 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1725,6 +1725,100 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
+----------+------------------------+--------------------------------------+-----------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built
+(12 rows)
+
+\dX stts_?
+                       List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
+--------+--------+-------------------+-----------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | built     |              | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+(4 rows)
+
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
+--------+-----------+-------------------------------+-----------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+(1 row)
+
+\dX+
+                                                                   List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+----------+------------------------+--------------------------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |         |                | 106 bytes         | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built   |                |                   | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built   |                |                   | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built   |                |                   | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              |         | 13 bytes       |                   | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined |                | 0 bytes           | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built   |                |                   | 686 bytes
+(12 rows)
+
+\dX+ stts_?
+                                                List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
+--------+--------+-------------------+-----------+--------------+---------+----------------+-------------------+------------
+ public | stts_1 | a, b FROM stts_t1 | built     |              |         | 13 bytes       |                   | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        |         | 13 bytes       | 40 bytes          | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(4 rows)
+
+\dX+ *stts_hoge
+                                                       List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+--------+-----------+-------------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                                                    List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
+---------+-----------+-------------------------+-----------+--------------+---------+----------------+-------------------+----------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined |                | 0 bytes           | 0 bytes
+(1 row)
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 7912e733ae..db6e3e1ba3 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -912,6 +912,37 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.26.2

>From 1ff2e77fd2472700a4a89699d8afed8679e38c7e Mon Sep 17 00:00:00 2001
From: Tomas Vondra <tomas@2ndquadrant.com>
Date: Sat, 9 Jan 2021 00:56:43 +0100
Subject: [PATCH 2/2] fixup: rename defined to requested

---
 src/bin/psql/describe.c                 | 10 +--
 src/test/regress/expected/stats_ext.out | 90 ++++++++++++-------------
 2 files changed, 50 insertions(+), 50 deletions(-)

diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 46f54199fb..83084f79d0 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4440,10 +4440,10 @@ listExtendedStats(const char *pattern, bool verbose)
 	{
 		appendPQExpBuffer(&buf,
 						  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\", \n"
 						  "CASE WHEN es.stxdependencies IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\"",
 						  gettext_noop("Ndistinct"),
 						  gettext_noop("Dependencies"));
@@ -4452,13 +4452,13 @@ listExtendedStats(const char *pattern, bool verbose)
 	{
 		appendPQExpBuffer(&buf,
 						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\", \n"
 						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\", \n"
 						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
-						  "     WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+						  "     WHEN 'm' = any(es.stxkind) THEN 'requested' \n"
 						  "END AS \"%s\"",
 						  gettext_noop("Ndistinct"),
 						  gettext_noop("Dependencies"),
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 8c8a0afcf6..b3ae4de185 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1741,9 +1741,9 @@ create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_
 insert into stts_t1 select i,i from generate_series(1,100) i;
 analyze stts_t1;
 \dX
-                                          List of extended statistics
-  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
-----------+------------------------+--------------------------------------+-----------+--------------+---------
+                                           List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |    MCV    
+----------+------------------------+--------------------------------------+-----------+--------------+-----------
  public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        | 
  public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built
  public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built
@@ -1751,70 +1751,70 @@ analyze stts_t1;
  public   | stts_1                 | a, b FROM stts_t1                    | built     |              | 
  public   | stts_2                 | a, b FROM stts_t1                    | built     | built        | 
  public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built
- public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
- public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
- stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
- stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ public   | stts_4                 | b, c FROM stts_t2                    | requested | requested    | requested
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | requested | requested    | requested
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | requested | requested    | requested
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | requested    | requested
  tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built
 (12 rows)
 
 \dX stts_?
-                       List of extended statistics
- Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
---------+--------+-------------------+-----------+--------------+---------
+                        List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |    MCV    
+--------+--------+-------------------+-----------+--------------+-----------
  public | stts_1 | a, b FROM stts_t1 | built     |              | 
  public | stts_2 | a, b FROM stts_t1 | built     | built        | 
  public | stts_3 | a, b FROM stts_t1 | built     | built        | built
- public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+ public | stts_4 | b, c FROM stts_t2 | requested | requested    | requested
 (4 rows)
 
 \dX *stts_hoge
-                               List of extended statistics
- Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
---------+-----------+-------------------------------+-----------+--------------+---------
- public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+                                List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |    MCV    
+--------+-----------+-------------------------------+-----------+--------------+-----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | requested | requested    | requested
 (1 row)
 
 \dX+
-                                                                   List of extended statistics
-  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
-----------+------------------------+--------------------------------------+-----------+--------------+---------+----------------+-------------------+------------
- public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |         |                | 106 bytes         | 
- public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built   |                |                   | 24 kB
- public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built   |                |                   | 386 bytes
- public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built   |                |                   | 294 bytes
- public   | stts_1                 | a, b FROM stts_t1                    | built     |              |         | 13 bytes       |                   | 
- public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |         | 13 bytes       | 40 bytes          | 
- public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
- public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
- public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
- stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
- stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined |                | 0 bytes           | 0 bytes
- tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built   |                |                   | 686 bytes
+                                                                    List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size |  MCV_size  
+----------+------------------------+--------------------------------------+-----------+--------------+-----------+----------------+-------------------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |           |                | 106 bytes         | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built     |                |                   | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built     |                |                   | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built     |                |                   | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              |           | 13 bytes       |                   | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |           | 13 bytes       | 40 bytes          | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built     | 13 bytes       | 40 bytes          | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | requested    | requested |                | 0 bytes           | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built     |                |                   | 686 bytes
 (12 rows)
 
 \dX+ stts_?
-                                                List of extended statistics
- Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size |  MCV_size  
---------+--------+-------------------+-----------+--------------+---------+----------------+-------------------+------------
- public | stts_1 | a, b FROM stts_t1 | built     |              |         | 13 bytes       |                   | 
- public | stts_2 | a, b FROM stts_t1 | built     | built        |         | 13 bytes       | 40 bytes          | 
- public | stts_3 | a, b FROM stts_t1 | built     | built        | built   | 13 bytes       | 40 bytes          | 6126 bytes
- public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+                                                 List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size |  MCV_size  
+--------+--------+-------------------+-----------+--------------+-----------+----------------+-------------------+------------
+ public | stts_1 | a, b FROM stts_t1 | built     |              |           | 13 bytes       |                   | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        |           | 13 bytes       | 40 bytes          | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built     | 13 bytes       | 40 bytes          | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
 (4 rows)
 
 \dX+ *stts_hoge
-                                                       List of extended statistics
- Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
---------+-----------+-------------------------------+-----------+--------------+---------+----------------+-------------------+----------
- public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined | 0 bytes        | 0 bytes           | 0 bytes
+                                                        List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size | MCV_size 
+--------+-----------+-------------------------------+-----------+--------------+-----------+----------------+-------------------+----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
 (1 row)
 
 \dX+ stts_s2.stts_yama
-                                                    List of extended statistics
- Schema  |   Name    |       Definition        | Ndistinct | Dependencies |   MCV   | Ndistinct_size | Dependencies_size | MCV_size 
----------+-----------+-------------------------+-----------+--------------+---------+----------------+-------------------+----------
- stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined |                | 0 bytes           | 0 bytes
+                                                     List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size | MCV_size 
+---------+-----------+-------------------------+-----------+--------------+-----------+----------------+-------------------+----------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | requested    | requested |                | 0 bytes           | 0 bytes
 (1 row)
 
 drop table stts_t1, stts_t2, stts_t3;
-- 
2.26.2

From 4dfc49faf0db33dfa5e4fa9bf38d31e4170ac459 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Wed, 13 Jan 2021 09:47:48 +0900
Subject: [PATCH 1/2] psql \dX: list extended statistics objects

The new command lists extended statistics objects, possibly with their
sizes. All past releases with extended statistics are supported.

Author: Tatsuro Yamada
Reviewed-by: Julien Rouhaud, Alvaro Herrera, Tomas Vondra
Discussion: https://postgr.es/m/c027a541-5856-75a5-0868-341301e1624b%40nttcom.co.jp_1
---
 doc/src/sgml/ref/psql-ref.sgml |  22 ++++++
 src/bin/psql/command.c         |   3 +
 src/bin/psql/describe.c        | 150 +++++++++++++++++++++++++++++++++++++++++
 src/bin/psql/describe.h        |   3 +
 src/bin/psql/help.c            |   1 +
 src/bin/psql/tab-complete.c    |   4 +-
 6 files changed, 182 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..aaf55df921 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,28 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the
+        pattern are listed.
+        If <literal>+</literal> is appended to the command name, each extended
+        statistics is listed with its size.
+        </para>
+
+        <para>
+        The column of the kind of extended stats (e.g. Ndistinct) shows some statuses.
+        "requested" means that it needs to collect statistics by <link
+        linkend="sql-analyze"><command>ANALYZE</command></link>. 
+        "built" means <link linkend="sql-analyze"><command>ANALYZE</command></link> was 
+        finished, and the planner can use it. NULL means that it doesn't exists. 
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 303e7c3ad8..c5ebc1c3f4 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -928,6 +928,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern, show_verbose);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index caf97563f4..c2051ee820 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4392,6 +4392,156 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern, bool verbose)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"));
+
+	/*
+	 * Since 12 there are two catalogs - one for the definition, one for the
+	 * data built by ANALYZE. Older releases use a single catalog. Also, 12
+	 * adds the MCV statistics kind.
+	 */
+	if (pset.sversion < 120000)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'requested' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN es.stxdependencies IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'requested' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct"),
+						  gettext_noop("Dependencies"));
+	}
+	else
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'd' = any(es.stxkind) THEN 'requested' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxddependencies IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'f' = any(es.stxkind) THEN 'requested' \n"
+						  "END AS \"%s\", \n"
+						  "CASE WHEN esd.stxdmcv IS NOT NULL THEN 'built' \n"
+						  "     WHEN 'm' = any(es.stxkind) THEN 'requested' \n"
+						  "END AS \"%s\"",
+						  gettext_noop("Ndistinct"),
+						  gettext_noop("Dependencies"),
+						  gettext_noop("MCV"));
+	}
+
+	/* In verbose mode, print sizes of the extended statistics objects. */
+	if (verbose)
+	{
+		if (pset.sversion < 120000)
+		{
+			appendPQExpBuffer(&buf,
+							  ",\nCASE WHEN es.stxndistinct IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(es.stxndistinct)::bigint) \n"
+							  "     WHEN 'd' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\", \n"
+							  "CASE WHEN es.stxdependencies IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(es.stxdependencies)::bigint) \n"
+							  "     WHEN 'f' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\"",
+							  gettext_noop("Ndistinct_size"),
+							  gettext_noop("Dependencies_size"));
+		}
+		else
+		{
+			appendPQExpBuffer(&buf,
+							  ",\nCASE WHEN esd.stxdndistinct IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdndistinct)::bigint) \n"
+							  "     WHEN 'd' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\", \n"
+							  "CASE WHEN esd.stxddependencies IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxddependencies)::bigint) \n"
+							  "     WHEN 'f' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\", \n"
+							  "CASE WHEN esd.stxdmcv IS NOT NULL THEN \n"
+							  "          pg_catalog.pg_size_pretty(pg_catalog.length(esd.stxdmcv)::bigint) \n"
+							  "     WHEN 'm' = any(es.stxkind) THEN '0 bytes' \n"
+							  "END AS \"%s\"",
+							  gettext_noop("Ndistinct_size"),
+							  gettext_noop("Dependencies_size"),
+							  gettext_noop("MCV_size"));
+		}
+	}
+
+	if (pset.sversion < 120000)
+	{
+		appendPQExpBufferStr(&buf,
+							 " \nFROM pg_catalog.pg_statistic_ext es \n"
+							 "INNER JOIN pg_catalog.pg_class c \n"
+							 "ON es.stxrelid = c.oid \n");
+	}
+	else
+	{
+		appendPQExpBufferStr(&buf,
+							 " \nFROM pg_catalog.pg_statistic_ext es \n"
+							 "LEFT JOIN pg_catalog.pg_statistic_ext_data esd \n"
+							 "ON es.oid = esd.stxoid \n"
+							 "INNER JOIN pg_catalog.pg_class c \n"
+							 "ON es.stxrelid = c.oid \n");
+	}
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "es.stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 6044e3a082..867e57d851 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern, bool verbose);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 9ec1c4e810..e42bc8c54e 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX[+]  [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 9dcab0d2fa..611f1efb15 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1500,7 +1500,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3910,6 +3910,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
-- 
2.16.5

From 5542fb4bb93df99dc7d0cc91489016f3609aff02 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Wed, 13 Jan 2021 09:51:39 +0900
Subject: [PATCH 2/2] regression test for psql \dX

---
 src/test/regress/expected/stats_ext.out | 94 +++++++++++++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      | 31 +++++++++++
 2 files changed, 125 insertions(+)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 7bfeaf85f0..b3ae4de185 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1725,6 +1725,100 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                           List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |    MCV    
+----------+------------------------+--------------------------------------+-----------+--------------+-----------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built
+ public   | stts_4                 | b, c FROM stts_t2                    | requested | requested    | requested
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | requested | requested    | requested
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | requested | requested    | requested
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | requested    | requested
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built
+(12 rows)
+
+\dX stts_?
+                        List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |    MCV    
+--------+--------+-------------------+-----------+--------------+-----------
+ public | stts_1 | a, b FROM stts_t1 | built     |              | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built
+ public | stts_4 | b, c FROM stts_t2 | requested | requested    | requested
+(4 rows)
+
+\dX *stts_hoge
+                                List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |    MCV    
+--------+-----------+-------------------------------+-----------+--------------+-----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | requested | requested    | requested
+(1 row)
+
+\dX+
+                                                                    List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size |  MCV_size  
+----------+------------------------+--------------------------------------+-----------+--------------+-----------+----------------+-------------------+------------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | built        |           |                | 106 bytes         | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | built     |                |                   | 24 kB
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | built     |                |                   | 386 bytes
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | built     |                |                   | 294 bytes
+ public   | stts_1                 | a, b FROM stts_t1                    | built     |              |           | 13 bytes       |                   | 
+ public   | stts_2                 | a, b FROM stts_t1                    | built     | built        |           | 13 bytes       | 40 bytes          | 
+ public   | stts_3                 | a, b FROM stts_t1                    | built     | built        | built     | 13 bytes       | 40 bytes          | 6126 bytes
+ public   | stts_4                 | b, c FROM stts_t2                    | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | requested    | requested |                | 0 bytes           | 0 bytes
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | built     |                |                   | 686 bytes
+(12 rows)
+
+\dX+ stts_?
+                                                 List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size |  MCV_size  
+--------+--------+-------------------+-----------+--------------+-----------+----------------+-------------------+------------
+ public | stts_1 | a, b FROM stts_t1 | built     |              |           | 13 bytes       |                   | 
+ public | stts_2 | a, b FROM stts_t1 | built     | built        |           | 13 bytes       | 40 bytes          | 
+ public | stts_3 | a, b FROM stts_t1 | built     | built        | built     | 13 bytes       | 40 bytes          | 6126 bytes
+ public | stts_4 | b, c FROM stts_t2 | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+(4 rows)
+
+\dX+ *stts_hoge
+                                                        List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size | MCV_size 
+--------+-----------+-------------------------------+-----------+--------------+-----------+----------------+-------------------+----------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | requested | requested    | requested | 0 bytes        | 0 bytes           | 0 bytes
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                                                     List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |    MCV    | Ndistinct_size | Dependencies_size | MCV_size 
+---------+-----------+-------------------------+-----------+--------------+-----------+----------------+-------------------+----------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | requested    | requested |                | 0 bytes           | 0 bytes
+(1 row)
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 7912e733ae..db6e3e1ba3 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -912,6 +912,37 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.16.5

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..36a79d9e3f 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,26 @@ testdb=>
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the
+        pattern are listed.
+        </para>
+
+        <para>
+        The column of the kind of extended stats (e.g. Ndistinct) shows its status.
+        NULL means that it doesn't exists. "defined" means that it is declared.
+        You can use pg_stats_ext if you'd like to know whether <link linkend="sql-analyze">
+        <command>ANALYZE</command></link> was run and statistics are available to the
+        planner.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 303e7c3ad8..c98e3d31d0 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -928,6 +928,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index caf97563f4..899fe5d85c 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4392,6 +4392,89 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"));
+
+	appendPQExpBuffer(&buf,
+					  ",\nCASE WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Ndistinct"),
+					  gettext_noop("Dependencies"));
+
+	/*
+	 * Add the MCV statistics kind.
+	 */ 	
+	if (pset.sversion >= 120000)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("MCV"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, false,
+						  false, NULL,
+						  "es.stxname", NULL,
+						  NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 6044e3a082..39856a0c7e 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 9ec1c4e810..4883ebd2ed 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX     [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 6abcbea963..17f7265038 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1505,7 +1505,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3974,6 +3974,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))

From 1aac3df2af2f6c834ffab10ddd1be1dee5970eb3 Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Wed, 20 Jan 2021 15:33:04 +0900
Subject: [PATCH 2/2] psql \dX regression test

Add a test by non-superuser
---
 src/test/regress/expected/stats_ext.out | 116 ++++++++++++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      |  37 ++++++++++
 2 files changed, 153 insertions(+)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index f094731e32..0ff4e51055 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -1727,6 +1727,122 @@ INSERT INTO tststats.priv_test_tbl
 CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
   FROM tststats.priv_test_tbl;
 ANALYZE tststats.priv_test_tbl;
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
+----------+------------------------+--------------------------------------+-----------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | defined      | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | defined
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | defined
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | defined
+ public   | stts_1                 | a, b FROM stts_t1                    | defined   |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | defined   | defined      | 
+ public   | stts_3                 | a, b FROM stts_t1                    | defined   | defined      | defined
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | defined
+(12 rows)
+
+\dX stts_?
+                       List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
+--------+--------+-------------------+-----------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | defined   |              | 
+ public | stts_2 | a, b FROM stts_t1 | defined   | defined      | 
+ public | stts_3 | a, b FROM stts_t1 | defined   | defined      | defined
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+(4 rows)
+
+\dX *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
+--------+-----------+-------------------------------+-----------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+(1 row)
+
+\dX+
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
+----------+------------------------+--------------------------------------+-----------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | defined      | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | defined
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | defined
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | defined
+ public   | stts_1                 | a, b FROM stts_t1                    | defined   |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | defined   | defined      | 
+ public   | stts_3                 | a, b FROM stts_t1                    | defined   | defined      | defined
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | defined
+(12 rows)
+
+\dX+ stts_?
+                       List of extended statistics
+ Schema |  Name  |    Definition     | Ndistinct | Dependencies |   MCV   
+--------+--------+-------------------+-----------+--------------+---------
+ public | stts_1 | a, b FROM stts_t1 | defined   |              | 
+ public | stts_2 | a, b FROM stts_t1 | defined   | defined      | 
+ public | stts_3 | a, b FROM stts_t1 | defined   | defined      | defined
+ public | stts_4 | b, c FROM stts_t2 | defined   | defined      | defined
+(4 rows)
+
+\dX+ *stts_hoge
+                               List of extended statistics
+ Schema |   Name    |          Definition           | Ndistinct | Dependencies |   MCV   
+--------+-----------+-------------------------------+-----------+--------------+---------
+ public | stts_hoge | col1, col2, col3 FROM stts_t3 | defined   | defined      | defined
+(1 row)
+
+\dX+ stts_s2.stts_yama
+                            List of extended statistics
+ Schema  |   Name    |       Definition        | Ndistinct | Dependencies |   MCV   
+---------+-----------+-------------------------+-----------+--------------+---------
+ stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined
+(1 row)
+
+create user non_superuser password 'hoge';
+\connect regression non_superuser
+\dX
+                                          List of extended statistics
+  Schema  |          Name          |              Definition              | Ndistinct | Dependencies |   MCV   
+----------+------------------------+--------------------------------------+-----------+--------------+---------
+ public   | func_deps_stat         | a, b, c FROM functional_dependencies |           | defined      | 
+ public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays        |           |              | defined
+ public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool          |           |              | defined
+ public   | mcv_lists_stats        | a, b, d FROM mcv_lists               |           |              | defined
+ public   | stts_1                 | a, b FROM stts_t1                    | defined   |              | 
+ public   | stts_2                 | a, b FROM stts_t1                    | defined   | defined      | 
+ public   | stts_3                 | a, b FROM stts_t1                    | defined   | defined      | defined
+ public   | stts_4                 | b, c FROM stts_t2                    | defined   | defined      | defined
+ public   | stts_hoge              | col1, col2, col3 FROM stts_t3        | defined   | defined      | defined
+ stts_s1  | stts_foo               | col1, col2 FROM stts_t3              | defined   | defined      | defined
+ stts_s2  | stts_yama              | col1, col3 FROM stts_t3              |           | defined      | defined
+ tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl     |           |              | defined
+(12 rows)
+
+\connect regression postgres
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+drop user non_superuser;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index cb08b478a4..a946c350bd 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -914,6 +914,43 @@ CREATE STATISTICS tststats.priv_test_stats (mcv) ON a, b
 
 ANALYZE tststats.priv_test_tbl;
 
+-- Check printing info about extended statistics by \dX
+create table stts_t1 (a int, b int);
+create statistics stts_1 (ndistinct) on a, b from stts_t1;
+create statistics stts_2 (ndistinct, dependencies) on a, b from stts_t1;
+create statistics stts_3 (ndistinct, dependencies, mcv) on a, b from stts_t1;
+
+create table stts_t2 (a int, b int, c int);
+create statistics stts_4 on b, c from stts_t2;
+
+create table stts_t3 (col1 int, col2 int, col3 int);
+create statistics stts_hoge on col1, col2, col3 from stts_t3;
+
+create schema stts_s1;
+create schema stts_s2;
+create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
+create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
+
+insert into stts_t1 select i,i from generate_series(1,100) i;
+analyze stts_t1;
+
+\dX
+\dX stts_?
+\dX *stts_hoge
+\dX+
+\dX+ stts_?
+\dX+ *stts_hoge
+\dX+ stts_s2.stts_yama
+
+create user non_superuser password 'hoge';
+\connect regression non_superuser
+\dX
+\connect regression postgres
+
+drop table stts_t1, stts_t2, stts_t3;
+drop schema stts_s1, stts_s2 cascade;
+drop user non_superuser;
+
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
-- 
2.16.5

From e42b671f930765e16491f0dee5c1cfc1e57a9daa Mon Sep 17 00:00:00 2001
From: Tatsuro Yamada <yamatattsu@gmail.com>
Date: Wed, 20 Jan 2021 15:09:27 +0900
Subject: [PATCH 1/2] psql \dX: list extended statistics objects take2

The new command lists extended statistics objects.
All past releases with extended statistics are supported.

Author: Tatsuro Yamada
Reviewed-by: Julien Rouhaud, Alvaro Herrera, Tomas Vondra, Justin Pryzby
Discussion: https://postgr.es/m/c027a541-5856-75a5-0868-341301e1624b%40nttcom.co.jp_1
---
 doc/src/sgml/ref/psql-ref.sgml | 20 ++++++++++
 src/bin/psql/command.c         |  3 ++
 src/bin/psql/describe.c        | 83 ++++++++++++++++++++++++++++++++++++++++++
 src/bin/psql/describe.h        |  3 ++
 src/bin/psql/help.c            |  1 +
 src/bin/psql/tab-complete.c    |  4 +-
 6 files changed, 113 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 221a967bfe..36a79d9e3f 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1918,6 +1918,26 @@ testdb=&gt;
         </para>
         </listitem>
       </varlistentry>
+      
+      <varlistentry>
+        <term><literal>\dX [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
+        <listitem>
+        <para>
+        Lists extended statistics.
+        If <replaceable class="parameter">pattern</replaceable>
+        is specified, only those extended statistics whose names match the
+        pattern are listed.
+        </para>
+
+        <para>
+        The column of the kind of extended stats (e.g. Ndistinct) shows its status.
+        NULL means that it doesn't exists. "defined" means that it is declared.
+        You can use pg_stats_ext if you'd like to know whether <link linkend="sql-analyze">
+        <command>ANALYZE</command></link> was run and statistics are available to the
+        planner.
+        </para>
+        </listitem>
+      </varlistentry>
 
       <varlistentry>
         <term><literal>\dy[+] [ <link linkend="app-psql-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index 303e7c3ad8..c98e3d31d0 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -928,6 +928,9 @@ exec_command_d(PsqlScanState scan_state, bool active_branch, const char *cmd)
 				else
 					success = listExtensions(pattern);
 				break;
+			case 'X':			/* Extended Statistics */
+				success = listExtendedStats(pattern);
+				break;
 			case 'y':			/* Event Triggers */
 				success = listEventTriggers(pattern, show_verbose);
 				break;
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index caf97563f4..95954fc319 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4392,6 +4392,89 @@ listEventTriggers(const char *pattern, bool verbose)
 	return true;
 }
 
+/*
+ * \dX
+ *
+ * Describes extended statistics.
+ */
+bool
+listExtendedStats(const char *pattern)
+{
+	PQExpBufferData buf;
+	PGresult   *res;
+	printQueryOpt myopt = pset.popt;
+
+	if (pset.sversion < 100000)
+	{
+		char		sverbuf[32];
+
+		pg_log_error("The server (version %s) does not support extended statistics.",
+					 formatPGVersionNumber(pset.sversion, false,
+										   sverbuf, sizeof(sverbuf)));
+		return true;
+	}
+
+	initPQExpBuffer(&buf);
+	printfPQExpBuffer(&buf,
+					  "SELECT \n"
+					  "es.stxnamespace::pg_catalog.regnamespace::text AS \"%s\", \n"
+					  "es.stxname AS \"%s\", \n"
+					  "pg_catalog.format('%%s FROM %%s', \n"
+					  "  (SELECT pg_catalog.string_agg(pg_catalog.quote_ident(a.attname),', ') \n"
+					  "   FROM pg_catalog.unnest(es.stxkeys) s(attnum) \n"
+					  "   JOIN pg_catalog.pg_attribute a \n"
+					  "   ON (es.stxrelid = a.attrelid \n"
+					  "   AND a.attnum = s.attnum \n"
+					  "   AND NOT a.attisdropped)), \n"
+					  "es.stxrelid::regclass) AS \"%s\"",
+					  gettext_noop("Schema"),
+					  gettext_noop("Name"),
+					  gettext_noop("Definition"));
+
+	appendPQExpBuffer(&buf,
+					  ",\nCASE WHEN 'd' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\", \n"
+					  "CASE WHEN 'f' = any(es.stxkind) THEN 'defined' \n"
+					  "END AS \"%s\"",
+					  gettext_noop("Ndistinct"),
+					  gettext_noop("Dependencies"));
+
+	/*
+	 * Add the MCV statistics kind.
+	 */
+	if (pset.sversion >= 120000)
+	{
+		appendPQExpBuffer(&buf,
+						  ",\nCASE WHEN 'm' = any(es.stxkind) THEN 'defined' \n"
+						  "END AS \"%s\" ",
+						  gettext_noop("MCV"));
+	}
+
+	appendPQExpBufferStr(&buf,
+						 " \nFROM pg_catalog.pg_statistic_ext es \n");
+
+	processSQLNamePattern(pset.db, &buf, pattern,
+						  false, false,
+						  "es.stxnamespace::pg_catalog.regnamespace::text", "es.stxname",
+						  NULL, NULL);
+
+	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
+
+	res = PSQLexec(buf.data);
+	termPQExpBuffer(&buf);
+	if (!res)
+		return false;
+
+	myopt.nullPrint = NULL;
+	myopt.title = _("List of extended statistics");
+	myopt.translate_header = true;
+
+	printQuery(res, &myopt, pset.queryFout, false, pset.logfile);
+
+	PQclear(res);
+	return true;
+}
+
 /*
  * \dC
  *
diff --git a/src/bin/psql/describe.h b/src/bin/psql/describe.h
index 6044e3a082..39856a0c7e 100644
--- a/src/bin/psql/describe.h
+++ b/src/bin/psql/describe.h
@@ -102,6 +102,9 @@ extern bool listExtensions(const char *pattern);
 /* \dx+ */
 extern bool listExtensionContents(const char *pattern);
 
+/* \dX */
+extern bool listExtendedStats(const char *pattern);
+
 /* \dy */
 extern bool listEventTriggers(const char *pattern, bool verbose);
 
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 9ec1c4e810..4883ebd2ed 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -267,6 +267,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\du[S+] [PATTERN]      list roles\n"));
 	fprintf(output, _("  \\dv[S+] [PATTERN]      list views\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
+	fprintf(output, _("  \\dX     [PATTERN]      list extended statistics\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
 	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+]  FUNCNAME       show a function's definition\n"));
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 6abcbea963..17f7265038 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1505,7 +1505,7 @@ psql_completion(const char *text, int start, int end)
 		"\\dF", "\\dFd", "\\dFp", "\\dFt", "\\dg", "\\di", "\\dl", "\\dL",
 		"\\dm", "\\dn", "\\do", "\\dO", "\\dp", "\\dP", "\\dPi", "\\dPt",
 		"\\drds", "\\dRs", "\\dRp", "\\ds", "\\dS",
-		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dy",
+		"\\dt", "\\dT", "\\dv", "\\du", "\\dx", "\\dX", "\\dy",
 		"\\e", "\\echo", "\\ef", "\\elif", "\\else", "\\encoding",
 		"\\endif", "\\errverbose", "\\ev",
 		"\\f",
@@ -3974,6 +3974,8 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_views, NULL);
 	else if (TailMatchesCS("\\dx*"))
 		COMPLETE_WITH_QUERY(Query_for_list_of_extensions);
+	else if (TailMatchesCS("\\dX*"))
+		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_statistics, NULL);
 	else if (TailMatchesCS("\\dm*"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_matviews, NULL);
 	else if (TailMatchesCS("\\dE*"))
-- 
2.16.5

diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 2abf255798..eba659705e 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -4774,7 +4774,7 @@ listExtendedStats(const char *pattern)
 	processSQLNamePattern(pset.db, &buf, pattern,
 						  false, false,
 						  "es.stxnamespace::pg_catalog.regnamespace::text", "es.stxname",
-						  NULL, NULL);
+						  NULL, "pg_catalog.pg_statistics_obj_is_visible(es.oid)");
 
 	appendPQExpBufferStr(&buf, "ORDER BY 1, 2;");
 
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 8c214d8dfc..fa9fa9c8f0 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -2987,6 +2987,7 @@ create statistics stts_s1.stts_foo on col1, col2 from stts_t3;
 create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_t3;
 insert into stts_t1 select i,i from generate_series(1,100) i;
 analyze stts_t1;
+set search_path to public, stts_s1, stts_s2, tststats;
 \dX
                                                            List of extended statistics
   Schema  |          Name          |                               Definition                               | Ndistinct | Dependencies |   MCV   
@@ -3002,7 +3003,7 @@ analyze stts_t1;
  public   | stts_hoge              | col1, col2, col3 FROM stts_t3                                          | defined   | defined      | defined
  stts_s1  | stts_foo               | col1, col2 FROM stts_t3                                                | defined   | defined      | defined
  stts_s2  | stts_yama              | col1, col3 FROM stts_t3                                                |           | defined      | defined
- tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl                                       |           |              | defined
+ tststats | priv_test_stats        | a, b FROM priv_test_tbl                                                |           |              | defined
 (12 rows)
 
 \dX stts_?
@@ -3037,7 +3038,7 @@ analyze stts_t1;
  public   | stts_hoge              | col1, col2, col3 FROM stts_t3                                          | defined   | defined      | defined
  stts_s1  | stts_foo               | col1, col2 FROM stts_t3                                                | defined   | defined      | defined
  stts_s2  | stts_yama              | col1, col3 FROM stts_t3                                                |           | defined      | defined
- tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl                                       |           |              | defined
+ tststats | priv_test_stats        | a, b FROM priv_test_tbl                                                |           |              | defined
 (12 rows)
 
 \dX+ stts_?
@@ -3064,30 +3065,45 @@ analyze stts_t1;
  stts_s2 | stts_yama | col1, col3 FROM stts_t3 |           | defined      | defined
 (1 row)
 
+set search_path to public, stts_s1;
+\dX
+                                                          List of extended statistics
+ Schema  |          Name          |                               Definition                               | Ndistinct | Dependencies |   MCV   
+---------+------------------------+------------------------------------------------------------------------+-----------+--------------+---------
+ public  | func_deps_stat         | ((a * 2)), upper(b), ((c + (1)::numeric)) FROM functional_dependencies |           | defined      | 
+ public  | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays                                          |           |              | defined
+ public  | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool                                            |           |              | defined
+ public  | mcv_lists_stats        | a, b, d FROM mcv_lists                                                 |           |              | defined
+ public  | stts_1                 | a, b FROM stts_t1                                                      | defined   |              | 
+ public  | stts_2                 | a, b FROM stts_t1                                                      | defined   | defined      | 
+ public  | stts_3                 | a, b FROM stts_t1                                                      | defined   | defined      | defined
+ public  | stts_4                 | b, c FROM stts_t2                                                      | defined   | defined      | defined
+ public  | stts_hoge              | col1, col2, col3 FROM stts_t3                                          | defined   | defined      | defined
+ stts_s1 | stts_foo               | col1, col2 FROM stts_t3                                                | defined   | defined      | defined
+(10 rows)
+
 create role regress_stats_ext nosuperuser;
 set role regress_stats_ext;
 \dX
-                                                           List of extended statistics
-  Schema  |          Name          |                               Definition                               | Ndistinct | Dependencies |   MCV   
-----------+------------------------+------------------------------------------------------------------------+-----------+--------------+---------
- public   | func_deps_stat         | ((a * 2)), upper(b), ((c + (1)::numeric)) FROM functional_dependencies |           | defined      | 
- public   | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays                                          |           |              | defined
- public   | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool                                            |           |              | defined
- public   | mcv_lists_stats        | a, b, d FROM mcv_lists                                                 |           |              | defined
- public   | stts_1                 | a, b FROM stts_t1                                                      | defined   |              | 
- public   | stts_2                 | a, b FROM stts_t1                                                      | defined   | defined      | 
- public   | stts_3                 | a, b FROM stts_t1                                                      | defined   | defined      | defined
- public   | stts_4                 | b, c FROM stts_t2                                                      | defined   | defined      | defined
- public   | stts_hoge              | col1, col2, col3 FROM stts_t3                                          | defined   | defined      | defined
- stts_s1  | stts_foo               | col1, col2 FROM stts_t3                                                | defined   | defined      | defined
- stts_s2  | stts_yama              | col1, col3 FROM stts_t3                                                |           | defined      | defined
- tststats | priv_test_stats        | a, b FROM tststats.priv_test_tbl                                       |           |              | defined
-(12 rows)
+                                                          List of extended statistics
+ Schema |          Name          |                               Definition                               | Ndistinct | Dependencies |   MCV   
+--------+------------------------+------------------------------------------------------------------------+-----------+--------------+---------
+ public | func_deps_stat         | ((a * 2)), upper(b), ((c + (1)::numeric)) FROM functional_dependencies |           | defined      | 
+ public | mcv_lists_arrays_stats | a, b, c FROM mcv_lists_arrays                                          |           |              | defined
+ public | mcv_lists_bool_stats   | a, b, c FROM mcv_lists_bool                                            |           |              | defined
+ public | mcv_lists_stats        | a, b, d FROM mcv_lists                                                 |           |              | defined
+ public | stts_1                 | a, b FROM stts_t1                                                      | defined   |              | 
+ public | stts_2                 | a, b FROM stts_t1                                                      | defined   | defined      | 
+ public | stts_3                 | a, b FROM stts_t1                                                      | defined   | defined      | defined
+ public | stts_4                 | b, c FROM stts_t2                                                      | defined   | defined      | defined
+ public | stts_hoge              | col1, col2, col3 FROM stts_t3                                          | defined   | defined      | defined
+(9 rows)
 
 reset role;
 drop table stts_t1, stts_t2, stts_t3;
 drop schema stts_s1, stts_s2 cascade;
 drop user regress_stats_ext;
+reset search_path;
 -- User with no access
 CREATE USER regress_stats_user1;
 GRANT USAGE ON SCHEMA tststats TO regress_stats_user1;
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index e033080d4f..d563c4654c 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -1529,6 +1529,7 @@ create statistics stts_s2.stts_yama (dependencies, mcv) on col1, col3 from stts_
 
 insert into stts_t1 select i,i from generate_series(1,100) i;
 analyze stts_t1;
+set search_path to public, stts_s1, stts_s2, tststats;
 
 \dX
 \dX stts_?
@@ -1538,6 +1539,9 @@ analyze stts_t1;
 \dX+ *stts_hoge
 \dX+ stts_s2.stts_yama
 
+set search_path to public, stts_s1;
+\dX
+
 create role regress_stats_ext nosuperuser;
 set role regress_stats_ext;
 \dX
@@ -1546,6 +1550,7 @@ reset role;
 drop table stts_t1, stts_t2, stts_t3;
 drop schema stts_s1, stts_s2 cascade;
 drop user regress_stats_ext;
+reset search_path;
 
 -- User with no access
 CREATE USER regress_stats_user1;