Improve test coverage for functional dependencies

The regression tests for functional dependencies were only using clauses
of the form (Var op Const), i.e. with Var on the left side. This adds
a couple of queries with Var on the right, to test other code paths.

It also prints one of the functional dependencies, to test the data type
output function. The functional dependencies are "perfect" with degree
of 1.0 so this should be stable.

Discussion: https://www.postgresql.org/message-id/flat/20200113230008.g67iyk4cs3xbnjju@development
Author: Tomas Vondra

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index 9fa659c71d13d006b6bad102a06b68d7a72d424b..e8439f5a3412fd46ab4a70f96063b3131dadce0a 100644 (file)
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -536,6 +536,13 @@ 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;
+-- print the detected dependencies
+SELECT dependencies FROM pg_stats_ext WHERE statistics_name = 'func_deps_stat';
+                                                dependencies                                                
+------------------------------------------------------------------------------------------------------------
+ {"3 => 4": 1.000000, "3 => 6": 1.000000, "4 => 6": 1.000000, "3, 4 => 6": 1.000000, "3, 6 => 4": 1.000000}
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
  estimated | actual 
 -----------+--------
@@ -697,6 +704,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi
        102 |    714
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND 0 = b');
+ estimated | actual 
+-----------+--------
+       102 |    714
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE c = 0 AND d = 0');
  estimated | actual 
 -----------+--------
@@ -709,6 +722,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi
          1 |     64
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND b = 0 AND 0 = c AND d = 0');
+ estimated | actual 
+-----------+--------
+         1 |     64
+(1 row)
+
 -- create separate functional dependencies
 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;
@@ -719,6 +738,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi
        714 |    714
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND 0 = b');
+ estimated | actual 
+-----------+--------
+       714 |    714
+(1 row)
+
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE c = 0 AND d = 0');
  estimated | actual 
 -----------+--------
@@ -731,6 +756,12 @@ SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi
         65 |     64
 (1 row)
 
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND b = 0 AND 0 = c AND d = 0');
+ estimated | actual 
+-----------+--------
+        65 |     64
+(1 row)
+
 DROP TABLE functional_dependencies_multi;
 -- MCV lists
 CREATE TABLE mcv_lists (

diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 0ece39a27979d8d4c826b1bf6b4d09bcbdc911a8..3e927822124de76187e0482c7693627205fec619 100644 (file)
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -318,6 +318,9 @@ CREATE STATISTICS func_deps_stat (dependencies) ON a, b, c FROM functional_depen
 
 ANALYZE functional_dependencies;
 
+-- print the detected dependencies
+SELECT dependencies FROM pg_stats_ext WHERE statistics_name = 'func_deps_stat';
+
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1''');
 
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies WHERE a = 1 AND b = ''1'' AND c = 1');
@@ -391,8 +394,10 @@ ANALYZE functional_dependencies_multi;
 
 -- estimates without any functional dependencies
 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');
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND b = 0 AND 0 = c AND d = 0');
 
 -- create separate functional dependencies
 CREATE STATISTICS functional_dependencies_multi_1 (dependencies) ON a, b FROM functional_dependencies_multi;
@@ -401,8 +406,10 @@ CREATE STATISTICS functional_dependencies_multi_2 (dependencies) ON c, d FROM fu
 ANALYZE 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');
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE c = 0 AND d = 0');
 SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE a = 0 AND b = 0 AND c = 0 AND d = 0');
+SELECT * FROM check_estimated_rows('SELECT * FROM functional_dependencies_multi WHERE 0 = a AND b = 0 AND 0 = c AND d = 0');
 
 DROP TABLE functional_dependencies_multi;