MDEV-7674: ANALYZE shows r_rows=0

Change r_rows to be double

mysql-test/r/analyze_format_json.result

@@ -24,7 +24,7 @@ insert into t1 select A.a*10 + B.a, A.a*10 + B.a, A.a*10 + B.a from t0 A, t0 B;
 analyze
 select * from t0, t1 where t1.a=t0.a and t0.a > 9;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
-1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	10	100.00	0.00	Using where
+1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	10.00	100.00	0.00	Using where
 1	SIMPLE	t1	ref	a	a	5	test.t0.a	1	NULL	100.00	NULL	
 analyze format=json 
 select * from t0, t1 where t1.a=t0.a and t0.a > 9;
@@ -61,8 +61,8 @@ EXPLAIN
 analyze
 select * from t0, t1 where t1.a=t0.a and t1.b<4;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
-1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	10	100.00	100.00	Using where
-1	SIMPLE	t1	ref	a	a	5	test.t0.a	1	1	100.00	40.00	Using where
+1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	10.00	100.00	100.00	Using where
+1	SIMPLE	t1	ref	a	a	5	test.t0.a	1	1.00	100.00	40.00	Using where
 analyze format=json
 select * from t0, t1 where t1.a=t0.a and t1.b<4;
 EXPLAIN
@@ -99,8 +99,8 @@ EXPLAIN
 analyze 
 select * from t1 tbl1, t1 tbl2 where tbl1.b<2 and tbl2.b>5;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
-1	SIMPLE	tbl1	ALL	NULL	NULL	NULL	NULL	100	100	100.00	2.00	Using where
-1	SIMPLE	tbl2	ALL	NULL	NULL	NULL	NULL	100	100	100.00	94.00	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	tbl1	ALL	NULL	NULL	NULL	NULL	100	100.00	100.00	2.00	Using where
+1	SIMPLE	tbl2	ALL	NULL	NULL	NULL	NULL	100	100.00	100.00	94.00	Using where; Using join buffer (flat, BNL join)
 analyze format=json
 select * from t1 tbl1, t1 tbl2 where tbl1.b<20 and tbl2.b<60;
 EXPLAIN
@@ -170,3 +170,43 @@ EXPLAIN
 }
 drop table t1;
 drop table t0;
+#
+# MDEV-7674: ANALYZE shows r_rows=0
+#
+create table t1(a int);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t2 (a int, key(a));
+insert into t2 values (0),(1);
+analyze format=json select * from t1 straight_join t2 force index(a) where t2.a=t1.a;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "table": {
+      "table_name": "t1",
+      "access_type": "ALL",
+      "r_loops": 1,
+      "rows": 10,
+      "r_rows": 10,
+      "filtered": 100,
+      "r_filtered": 100,
+      "attached_condition": "(t1.a is not null)"
+    },
+    "table": {
+      "table_name": "t2",
+      "access_type": "ref",
+      "possible_keys": ["a"],
+      "key": "a",
+      "key_length": "5",
+      "used_key_parts": ["a"],
+      "ref": ["test.t1.a"],
+      "r_loops": 10,
+      "rows": 2,
+      "r_rows": 0.2,
+      "filtered": 100,
+      "r_filtered": 100,
+      "using_index": true
+    }
+  }
+}
+drop table t1,t2;

mysql-test/r/analyze_stmt_slow_query_log.result

@@ -10,6 +10,6 @@ drop table t1;
 # explain: id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
 # explain: 1	INSERT	t1	ALL	NULL	NULL	NULL	NULL	NULL	NULL	100.00	100.00	NULL
 # explain: id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
-# explain: 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	10	100.00	30.00	Using where
+# explain: 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	10.00	100.00	30.00	Using where
 # explain: id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
 # explain: 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used

mysql-test/t/analyze_format_json.test

@@ -36,3 +36,18 @@ select * from t1 tbl1, t1 tbl2 where tbl1.b<20 and tbl2.b<60 and tbl1.c > tbl2.c
 
 drop table t1;
 drop table t0;
+
+--echo #
+--echo # MDEV-7674: ANALYZE shows r_rows=0
+--echo #
+
+create table t1(a int);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+
+create table t2 (a int, key(a));
+insert into t2 values (0),(1);
+
+analyze format=json select * from t1 straight_join t2 force index(a) where t2.a=t1.a;
+
+drop table t1,t2;
+

mysql-test/t/analyze_stmt.test

@@ -244,3 +244,18 @@ create table t1(a int);
 prepare stmt from "analyze select * from t1";
 execute stmt;
 drop table t1;
+
+--echo #
+--echo # MDEV-7674: ANALYZE shows r_rows=0
+--echo #
+
+create table t1(a int);
+insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+
+create table t2 (a int, key(a));
+insert into t2 values (0),(1);
+
+analyze select * from t1 straight_join t2 force index(a) where t2.a=t1.a;
+
+drop table t1,t2;
+

sql/sql_class.cc

@@ -2454,8 +2454,7 @@ void THD::make_explain_field_list(List<Item> &field_list, uint8 explain_flags,
                                                  MYSQL_TYPE_LONGLONG));
   if (is_analyze)
   {
-    field_list.push_back(item= new Item_return_int("r_rows", 10,
-                                                   MYSQL_TYPE_LONGLONG));
+    field_list.push_back(item= new Item_float("r_rows", 0.1234, 10, 4));
     item->maybe_null=1;
   }
 

sql/sql_explain.cc

@@ -298,7 +298,7 @@ int print_explain_row(select_result_sink *result,
                       const char *key_len,
                       const char *ref,
                       ha_rows *rows,
-                      ha_rows *r_rows,
+                      double *r_rows,
                       double r_filtered,
                       const char *extra)
 {
@@ -356,10 +356,7 @@ int print_explain_row(select_result_sink *result,
   if (is_analyze)
   {
     if (r_rows)
-    {
-      item_list.push_back(new Item_int(*r_rows, 
-                                       MY_INT64_NUM_DECIMAL_DIGITS));
-    }
+      item_list.push_back(new Item_float(*r_rows, 2));
     else
       item_list.push_back(item_null);
   }
@@ -472,9 +469,8 @@ int Explain_union::print_explain(Explain_query *query,
   /* `r_rows` */
   if (is_analyze)
   {
-    ha_rows avg_rows= fake_select_lex_tracker.get_avg_rows();
-    item_list.push_back(new Item_int((longlong) (ulonglong) avg_rows,
-                                      MY_INT64_NUM_DECIMAL_DIGITS));
+    double avg_rows= fake_select_lex_tracker.get_avg_rows();
+    item_list.push_back(new Item_float(avg_rows, 2));
   }
 
   /* `filtered` */
@@ -1004,9 +1000,8 @@ int Explain_table_access::print_explain(select_result_sink *output, uint8 explai
     }
     else
     {
-      ha_rows avg_rows= tracker.get_avg_rows();
-      item_list.push_back(new Item_int((longlong) (ulonglong) avg_rows,
-                                        MY_INT64_NUM_DECIMAL_DIGITS));
+      double avg_rows= tracker.get_avg_rows();
+      item_list.push_back(new Item_float(avg_rows, 2));
     }
   }
 
@@ -1289,8 +1284,8 @@ void Explain_table_access::print_explain_json(Explain_query *query,
     writer->add_member("r_rows");
     if (tracker.has_scans())
     {
-      ha_rows avg_rows= tracker.get_avg_rows();
-      writer->add_ll(avg_rows);
+      double avg_rows= tracker.get_avg_rows();
+      writer->add_double(avg_rows);
     }
     else
       writer->add_null();
@@ -1756,7 +1751,7 @@ int Explain_update::print_explain(Explain_query *query,
     "Using index condition" is also not possible (which is an unjustified limitation)
   */
   double r_filtered= 100 * tracker.get_filtered_after_where();
-  ha_rows r_rows= tracker.get_avg_rows();
+  double r_rows= tracker.get_avg_rows();
 
   print_explain_row(output, explain_flags, is_analyze,
                     1, /* id */
@@ -1877,8 +1872,8 @@ void Explain_update::print_explain_json(Explain_query *query,
   /* `r_rows` */
   if (is_analyze && tracker.has_scans())
   {
-    ha_rows avg_rows= tracker.get_avg_rows();
-    writer->add_member("r_rows").add_ll(avg_rows);
+    double avg_rows= tracker.get_avg_rows();
+    writer->add_member("r_rows").add_double(avg_rows);
   }
  
   /* UPDATE/DELETE do not produce `filtered` estimate */

sql/sql_explain.h

@@ -44,9 +44,9 @@ public:
 
   bool has_scans() { return (r_scans != 0); }
   ha_rows get_loops() { return r_scans; }
-  ha_rows get_avg_rows()
+  double get_avg_rows()
   {
-    return r_scans ? (ha_rows)rint((double) r_rows / r_scans): 0;
+    return r_scans ? ((double)r_rows / r_scans): 0;
   }
 
   double get_filtered_after_where()