Date: Mon, 31 Aug 2020 00:00:47 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: pgsql-hackers@postgresql.org
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>,
	Tatsuro Yamada <tatsuro.yamada.tf@nttcom.co.jp>
Subject: v13: show extended stats target in \d
Message-ID: <20200831050047.GG5450@telsasoft.com>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="xesSdrSSBC0PokLI"
Content-Disposition: inline
User-Agent: Mutt/1.9.4 (2018-02-28)
Precedence: bulk


--xesSdrSSBC0PokLI
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

The stats target can be set since commit d06215d03, but wasn't shown by psql.
 ALTER STATISISTICS .. SET STATISTICS n.

Normal (1-D) stats targets are shown in \d+ table.
Stats objects are shown in \d (no plus).
Arguably, this should be shown only in "verbose" mode (\d+).

--xesSdrSSBC0PokLI
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="0001-Show-stats-target-of-extended-statistics.patch"

From 60a4033a04fbaafbb01c2bb2d73bb2fbe4d1da75 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 30 Aug 2020 23:38:17 -0500
Subject: [PATCH 1/1] Show stats target of extended statistics

This can be set since d06215d03, but wasn't shown by psql.
Normal (1-D) stats targets are shown in \d+ table.
---
 src/bin/psql/describe.c                 |  8 +++++++-
 src/test/regress/expected/stats_ext.out | 18 ++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      |  2 ++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index d81f1575bf..73befa36ee 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2683,10 +2683,12 @@ describeOneTableDetails(const char *schemaname,
 							  "        a.attnum = s.attnum AND NOT attisdropped)) AS columns,\n"
 							  "  'd' = any(stxkind) AS ndist_enabled,\n"
 							  "  'f' = any(stxkind) AS deps_enabled,\n"
-							  "  'm' = any(stxkind) AS mcv_enabled\n"
+							  "  'm' = any(stxkind) AS mcv_enabled,\n"
+							  "  %s"
 							  "FROM pg_catalog.pg_statistic_ext stat "
 							  "WHERE stxrelid = '%s'\n"
 							  "ORDER BY 1;",
+							  (pset.sversion >= 130000 ? "stxstattarget\n" : "-1\n"),
 							  oid);
 
 			result = PSQLexec(buf.data);
@@ -2732,6 +2734,10 @@ describeOneTableDetails(const char *schemaname,
 									  PQgetvalue(result, i, 4),
 									  PQgetvalue(result, i, 1));
 
+					if (strcmp(PQgetvalue(result, i, 8), "-1") != 0)
+						appendPQExpBuffer(&buf, " STATISTICS %s",
+									  PQgetvalue(result, i, 8));
+
 					printTableAddFooter(&cont, buf.data);
 				}
 			}
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 0ae779a3b9..4dea48a2e8 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -102,6 +102,15 @@ WARNING:  statistics object "public.ab1_a_b_stats" could not be computed for rel
 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
+                                    Table "public.ab1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           |          |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Statistics objects:
+    "public"."ab1_a_b_stats" (ndistinct, dependencies, mcv) ON a, b FROM ab1 STATISTICS 0
+
 ANALYZE ab1;
 SELECT stxname, stxdndistinct, stxddependencies, stxdmcv
   FROM pg_statistic_ext s, pg_statistic_ext_data d
@@ -113,6 +122,15 @@ SELECT stxname, stxdndistinct, stxddependencies, stxdmcv
 (1 row)
 
 ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
+\d+ ab1
+                                    Table "public.ab1"
+ Column |  Type   | Collation | Nullable | Default | Storage | Stats target | Description 
+--------+---------+-----------+----------+---------+---------+--------------+-------------
+ a      | integer |           |          |         | plain   |              | 
+ b      | integer |           |          |         | plain   |              | 
+Statistics objects:
+    "public"."ab1_a_b_stats" (ndistinct, dependencies, mcv) ON a, b FROM ab1
+
 -- 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"
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 2834a902a7..d1d49948b4 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -72,12 +72,14 @@ ANALYZE ab1;
 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
 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;
 ALTER STATISTICS ab1_a_b_stats SET STATISTICS -1;
+\d+ ab1
 -- partial analyze doesn't build stats either
 ANALYZE ab1 (a);
 ANALYZE ab1;
-- 
2.17.0


--xesSdrSSBC0PokLI--