Added r_table_loops to "ANALYZE FORMAT=JSON statement"

Author: Sergei Petrunia <sergey@mariadb.com>

mysql-test/main/rowid_filter.result

@@ -592,6 +592,7 @@ ANALYZE
           "ref": ["dbt3_s001.lineitem.l_orderkey"],
           "loops": 98,
           "r_loops": 98,
+          "r_table_loops": 96,
           "rows": 1,
           "r_rows": 1,
           "cost": "REPLACED",

mysql-test/main/rowid_filter_aria.result

@@ -450,6 +450,7 @@ ANALYZE
           },
           "loops": 92,
           "r_loops": 98,
+          "r_table_loops": 96,
           "rows": 1,
           "r_rows": 0.112244898,
           "cost": "REPLACED",
@@ -593,6 +594,7 @@ ANALYZE
           "ref": ["dbt3_s001.lineitem.l_orderkey"],
           "loops": 92,
           "r_loops": 98,
+          "r_table_loops": 96,
           "rows": 1,
           "r_rows": 1,
           "cost": "REPLACED",
@@ -765,6 +767,7 @@ ANALYZE
           "ref": ["dbt3_s001.lineitem.l_orderkey"],
           "loops": 56.90890924,
           "r_loops": 34,
+          "r_table_loops": 33,
           "rows": 1,
           "r_rows": 1,
           "cost": "REPLACED",
@@ -915,6 +918,7 @@ ANALYZE
           "ref": ["dbt3_s001.lineitem.l_orderkey"],
           "loops": 56.90890924,
           "r_loops": 34,
+          "r_table_loops": 33,
           "rows": 1,
           "r_rows": 1,
           "cost": "REPLACED",

mysql-test/main/rowid_filter_innodb.result

@@ -433,6 +433,7 @@ ANALYZE
           "ref": ["dbt3_s001.lineitem.l_orderkey"],
           "loops": 98,
           "r_loops": 98,
+          "r_table_loops": 96,
           "rows": 1,
           "r_rows": 1,
           "cost": "REPLACED",
@@ -578,6 +579,7 @@ ANALYZE
           "ref": ["dbt3_s001.lineitem.l_orderkey"],
           "loops": 98,
           "r_loops": 98,
+          "r_table_loops": 96,
           "rows": 1,
           "r_rows": 1,
           "cost": "REPLACED",

sql/sql_explain.cc

@@ -1922,7 +1922,15 @@ void Explain_table_access::print_explain_json(Explain_query *query,
   /* r_loops (not present in tabular output) */
   if (is_analyze)
   {
-    writer->add_member("r_loops").add_ll(tracker.get_loops());
+    ha_rows loops= tracker.get_loops();
+    writer->add_member("r_loops").add_ll(loops);
+
+    if (type == JT_EQ_REF) // max one row
+    {
+      ha_rows table_loops= op_tracker.get_loops();
+      if (table_loops != loops)
+        writer->add_member("r_table_loops").add_ll(table_loops);
+    }
   }
   
   /* `rows` */