sql: introduce index_recommendations_enabled session variable

This commit introduces a session variable to control whether or not index recommendations are shown at the bottom of the EXPLAIN plan. If `index_recommendations_enabled` is set to true, index recommendations are shown. Otherwise, they are not shown. This variable defaults to true. Release note (sql change): Index recommendations can be omitted from the EXPLAIN plan if the `index_recommendations_enabled` session variable is set to false.
cockroachdb · Dec 14, 2021 · 94f69be · 94f69be
1 parent d411bd0
commit 94f69be
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Showing 10 changed files with 234 additions and 124 deletions.
diff --git a/pkg/sql/exec_util.go b/pkg/sql/exec_util.go
@@ -2710,6 +2710,10 @@ func (m *sessionDataMutator) SetZigzagJoinEnabled(val bool) {
 	m.data.ZigzagJoinEnabled = val
 }
 
+func (m *sessionDataMutator) SetIndexRecommendationsEnabled(val bool) {
+	m.data.IndexRecommendationsEnabled = val
+}
+
 func (m *sessionDataMutator) SetExperimentalDistSQLPlanning(
 	val sessiondatapb.ExperimentalDistSQLPlanningMode,
 ) {

diff --git a/pkg/sql/logictest/testdata/logic_test/information_schema b/pkg/sql/logictest/testdata/logic_test/information_schema
@@ -4659,6 +4659,7 @@ force_savepoint_restart                               off
 foreign_key_cascades_limit                            10000
 idle_in_session_timeout                               0
 idle_in_transaction_session_timeout                   0
+index_recommendations_enabled                         on
 inject_retry_errors_enabled                           off
 integer_datetimes                                     on
 intervalstyle                                         postgres

diff --git a/pkg/sql/logictest/testdata/logic_test/pg_catalog b/pkg/sql/logictest/testdata/logic_test/pg_catalog
@@ -4062,6 +4062,7 @@ force_savepoint_restart                               off                 NULL
 foreign_key_cascades_limit                            10000               NULL      NULL        NULL        string
 idle_in_session_timeout                               0                   NULL      NULL        NULL        string
 idle_in_transaction_session_timeout                   0                   NULL      NULL        NULL        string
+index_recommendations_enabled                         on                  NULL      NULL        NULL        string
 inject_retry_errors_enabled                           off                 NULL      NULL        NULL        string
 integer_datetimes                                     on                  NULL      NULL        NULL        string
 intervalstyle                                         postgres            NULL      NULL        NULL        string
@@ -4168,6 +4169,7 @@ force_savepoint_restart                               off                 NULL
 foreign_key_cascades_limit                            10000               NULL  user     NULL      10000               10000
 idle_in_session_timeout                               0                   NULL  user     NULL      0s                  0s
 idle_in_transaction_session_timeout                   0                   NULL  user     NULL      0s                  0s
+index_recommendations_enabled                         on                  NULL  user     NULL      on                  on
 inject_retry_errors_enabled                           off                 NULL  user     NULL      off                 off
 integer_datetimes                                     on                  NULL  user     NULL      on                  on
 intervalstyle                                         postgres            NULL  user     NULL      postgres            postgres
@@ -4269,6 +4271,7 @@ force_savepoint_restart                               NULL    NULL     NULL
 foreign_key_cascades_limit                            NULL    NULL     NULL     NULL        NULL
 idle_in_session_timeout                               NULL    NULL     NULL     NULL        NULL
 idle_in_transaction_session_timeout                   NULL    NULL     NULL     NULL        NULL
+index_recommendations_enabled                         NULL    NULL     NULL     NULL        NULL
 inject_retry_errors_enabled                           NULL    NULL     NULL     NULL        NULL
 integer_datetimes                                     NULL    NULL     NULL     NULL        NULL
 intervalstyle                                         NULL    NULL     NULL     NULL        NULL

diff --git a/pkg/sql/logictest/testdata/logic_test/set b/pkg/sql/logictest/testdata/logic_test/set
@@ -558,6 +558,12 @@ SET disable_plan_gists = 'true'
 statement ok
 SET disable_plan_gists = 'false'
 
+statement ok
+SET index_recommendations_enabled = 'true'
+
+statement ok
+SET index_recommendations_enabled = 'false'
+
 query T
 SHOW LC_COLLATE
 ----

diff --git a/pkg/sql/logictest/testdata/logic_test/show_source b/pkg/sql/logictest/testdata/logic_test/show_source
@@ -65,6 +65,7 @@ force_savepoint_restart                               off
 foreign_key_cascades_limit                            10000
 idle_in_session_timeout                               0
 idle_in_transaction_session_timeout                   0
+index_recommendations_enabled                         on
 inject_retry_errors_enabled                           off
 integer_datetimes                                     on
 intervalstyle                                         postgres

diff --git a/pkg/sql/opt/exec/execbuilder/testdata/explain b/pkg/sql/opt/exec/execbuilder/testdata/explain
@@ -785,6 +785,39 @@ index recommendations: 1
 1. type: index replacement
    SQL commands: DROP INDEX tc@c; CREATE INDEX ON tc (a) STORING (b);
 
+# Ensure that the query above no longer has index recommendations if they are
+# disabled.
+statement ok
+SET index_recommendations_enabled = 'false'
+
+query T
+EXPLAIN (VERBOSE) SELECT * FROM tc WHERE a = 10 ORDER BY b
+----
+distribution: local
+vectorized: true
+·
+• sort
+│ columns: (a, b)
+│ ordering: +b
+│ estimated row count: 10 (missing stats)
+│ order: +b
+│
+└── • index join
+    │ columns: (a, b)
+    │ estimated row count: 10 (missing stats)
+    │ table: tc@tc_pkey
+    │ key columns: rowid
+    │
+    └── • scan
+          columns: (a, rowid)
+          estimated row count: 10 (missing stats)
+          table: tc@c
+          spans: /10-/11
+
+# Reset index_recommendations_enabled to its default setting.
+statement ok
+SET index_recommendations_enabled = 'true'
+
 query T
 EXPLAIN (TYPES) INSERT INTO t VALUES (1, 2)
 ----

diff --git a/pkg/sql/plan_opt.go b/pkg/sql/plan_opt.go
@@ -525,7 +525,8 @@ func (opc *optPlanningCtx) buildExecMemo(ctx context.Context) (_ *memo.Memo, _ e
 
 	// For index recommendations, after building we must interrupt the flow to
 	// find potential index candidates in the memo.
-	if _, isExplain := opc.p.stmt.AST.(*tree.Explain); isExplain {
+	_, isExplain := opc.p.stmt.AST.(*tree.Explain)
+	if isExplain && p.SessionData().IndexRecommendationsEnabled {
 		if err := opc.makeQueryIndexRecommendation(); err != nil {
 			return nil, err
 		}