Merge branch 'bb-10.2-mdev9543' of github.com:MariaDB/server into bb-10.2-mdev9543

Author: spetrunia

mysql-test/r/win.result

@@ -1401,3 +1401,105 @@ pk	c	CNT
 9	2	4
 10	2	3
 drop table t0,t1;
+#
+# EXPLAIN FORMAT=JSON support for window functions
+#
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+explain format=json select rank() over (order by a) from t0;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "window_functions_computation": {
+      "temporary_table": {
+        "table": {
+          "table_name": "t0",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100
+        }
+      }
+    }
+  }
+}
+create table t1 (a int, b int, c int);
+insert into t1 select a,a,a from t0;
+explain format=json
+select
+a,
+rank() over (order by sum(b))
+from t1
+group by a;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "filesort": {
+      "window_functions_computation": {
+        "temporary_table": {
+          "table": {
+            "table_name": "t1",
+            "access_type": "ALL",
+            "rows": 10,
+            "filtered": 100
+          }
+        }
+      }
+    }
+  }
+}
+explain format=json
+select
+a,
+rank() over (order by sum(b))
+from t1
+group by a
+order by null;
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "window_functions_computation": {
+      "temporary_table": {
+        "table": {
+          "table_name": "t1",
+          "access_type": "ALL",
+          "rows": 10,
+          "filtered": 100
+        }
+      }
+    }
+  }
+}
+#
+# Check how window function works together with GROUP BY and HAVING
+#
+select b,max(a) as MX, rank() over (order by b) from t1 group by b having MX in (3,5,7);
+b	MX	rank() over (order by b)
+3	3	1
+5	5	2
+7	7	3
+explain format=json
+select b,max(a) as MX, rank() over (order by b) from t1 group by b having MX in (3,5,7);
+EXPLAIN
+{
+  "query_block": {
+    "select_id": 1,
+    "having_condition": "(MX in (3,5,7))",
+    "filesort": {
+      "window_functions_computation": {
+        "temporary_table": {
+          "table": {
+            "table_name": "t1",
+            "access_type": "ALL",
+            "rows": 10,
+            "filtered": 100
+          }
+        }
+      }
+    }
+  }
+}
+drop table t1;
+drop table t0;

mysql-test/t/win.test

@@ -924,8 +924,40 @@ execute stmt;
 
 drop table t0,t1;
 
+--echo #
+--echo # EXPLAIN FORMAT=JSON support for window functions
+--echo #
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+
+explain format=json select rank() over (order by a) from t0;
+
+create table t1 (a int, b int, c int);
+insert into t1 select a,a,a from t0;
+
+explain format=json
+select
+  a,
+  rank() over (order by sum(b))
+from t1
+group by a;
 
+explain format=json
+select
+  a,
+  rank() over (order by sum(b))
+from t1
+group by a
+order by null;
 
+--echo #
+--echo # Check how window function works together with GROUP BY and HAVING
+--echo #
 
+select b,max(a) as MX, rank() over (order by b) from t1 group by b having MX in (3,5,7);
+explain format=json
+select b,max(a) as MX, rank() over (order by b) from t1 group by b having MX in (3,5,7);
 
+drop table t1;
+drop table t0;
 

sql/sql_explain.cc

@@ -884,6 +884,9 @@ void Explain_select::print_explain_json(Explain_query *query,
         case AGGR_OP_REMOVE_DUPLICATES:
           writer->add_member("duplicate_removal").start_object();
           break;
+        case AGGR_OP_WINDOW_FUNCS:
+          writer->add_member("window_functions_computation").start_object();
+          break;
         default:
           DBUG_ASSERT(0);
       }

sql/sql_explain.h

@@ -265,7 +265,8 @@ typedef enum
   AGGR_OP_TEMP_TABLE,
   AGGR_OP_FILESORT,
   //AGGR_OP_READ_SORTED_FILE, // need this?
-  AGGR_OP_REMOVE_DUPLICATES
+  AGGR_OP_REMOVE_DUPLICATES,
+  AGGR_OP_WINDOW_FUNCS
   //AGGR_OP_JOIN // Need this?
 } enum_explain_aggr_node_type;
 
@@ -297,6 +298,11 @@ class Explain_aggr_remove_dups : public Explain_aggr_node
   enum_explain_aggr_node_type get_type() { return AGGR_OP_REMOVE_DUPLICATES; }
 };
 
+class Explain_aggr_window_funcs : public Explain_aggr_node
+{
+public:
+  enum_explain_aggr_node_type get_type() { return AGGR_OP_WINDOW_FUNCS; }
+};
 
 /////////////////////////////////////////////////////////////////////////////
 

sql/sql_select.cc

@@ -2140,7 +2140,6 @@ bool JOIN::make_aggr_tables_info()
     All optimization is done. Check if we can use the storage engines
     group by handler to evaluate the group by
   */
-  group_by_handler *gbh= NULL;
   if (tables_list && (tmp_table_param.sum_func_count || group_list) &&
       !procedure)
   {
@@ -2339,14 +2338,6 @@ bool JOIN::make_aggr_tables_info()
     curr_tab->fields= &tmp_fields_list1;
     set_postjoin_aggr_write_func(curr_tab);
 
-    // psergey-todo: this is probably an incorrect place:
-    if (select_lex->window_funcs.elements)
-    {
-      curr_tab->window_funcs= new Window_funcs_computation;
-      if (curr_tab->window_funcs->setup(thd, &select_lex->window_funcs))
-        DBUG_RETURN(true);
-    }
-
     tmp_table_param.func_count= 0;
     tmp_table_param.field_count+= tmp_table_param.func_count;
     if (sort_and_group || curr_tab->table->group)
@@ -2658,6 +2649,24 @@ bool JOIN::make_aggr_tables_info()
       skip_sort_order= true;
     }
   }
+
+  /*
+    Window functions computation step should be attached to the last join_tab
+    that's doing aggregation.
+    The last join_tab reads the data from the temp. table.  It also may do
+    - sorting
+    - duplicate value removal
+    Both of these operations are done after window function computation step.
+  */
+  curr_tab= join_tab + top_join_tab_count + aggr_tables - 1;
+  if (select_lex->window_funcs.elements)
+  {
+    curr_tab->window_funcs_step= new Window_funcs_computation;
+    if (curr_tab->window_funcs_step->setup(thd, &select_lex->window_funcs,
+                                           curr_tab))
+      DBUG_RETURN(true);
+  }
+
   fields= curr_fields_list;
   // Reset before execution
   set_items_ref_array(items0);
@@ -19137,7 +19146,10 @@ bool test_if_use_dynamic_range_scan(JOIN_TAB *join_tab)
 int join_init_read_record(JOIN_TAB *tab)
 {
   int error;
-
+  /* 
+    Note: the query plan tree for the below operations is constructed in
+    save_agg_explain_data.
+  */
   if (tab->distinct && tab->remove_duplicates())  // Remove duplicates.
     return 1;
   if (tab->filesort && tab->sort_table())     // Sort table.
@@ -24174,6 +24186,14 @@ void save_agg_explain_data(JOIN *join, Explain_select *xpl_sel)
     node= new Explain_aggr_tmp_table;
     node->child= prev_node;
 
+    if (join_tab->window_funcs_step)
+    {
+      prev_node=node;
+      node= new Explain_aggr_window_funcs;
+      node->child= prev_node;
+    }
+
+    /* The below matches execution in join_init_read_record() */
     if (join_tab->distinct)
     {
       prev_node= node;
@@ -25946,9 +25966,10 @@ AGGR_OP::end_send()
 
   // Update ref array
   join_tab->join->set_items_ref_array(*join_tab->ref_array);
-  if (join_tab->window_funcs)
+  if (join_tab->window_funcs_step)
   {
-    join_tab->window_funcs->exec(join);
+    if (join_tab->window_funcs_step->exec(join))
+      return NESTED_LOOP_ERROR;
   }
 
   table->reginfo.lock_type= TL_UNLOCK;

sql/sql_select.h

@@ -428,7 +428,7 @@ typedef struct st_join_table {
     Non-NULL value means this join_tab must do window function computation
     before reading.
   */
-  Window_funcs_computation* window_funcs;
+  Window_funcs_computation* window_funcs_step;
 
   /**
     List of topmost expressions in the select list. The *next* JOIN TAB

sql/sql_window.cc

@@ -1565,11 +1565,20 @@ bool Window_func_runner::exec(JOIN *join)
 
 
 bool Window_funcs_computation::setup(THD *thd,
-                                     List<Item_window_func> *window_funcs)
+                                     List<Item_window_func> *window_funcs,
+                                     JOIN_TAB *tab)
 {
   List_iterator_fast<Item_window_func> it(*window_funcs);
   Item_window_func *item_win;
   Window_func_runner *runner;
+
+  SQL_SELECT *sel= NULL;
+  if (tab->filesort && tab->filesort->select)
+  {
+    sel= tab->filesort->select;
+    DBUG_ASSERT(!sel->quick);
+  }
+
   // for each window function
   while ((item_win= it++))
   {
@@ -1579,6 +1588,8 @@ bool Window_funcs_computation::setup(THD *thd,
     {
       return true;
     }
+    /* Apply the same condition that the subsequent sort will */
+    runner->filesort->select= sel;
     win_func_runners.push_back(runner, thd->mem_root);
   }
   return false;

sql/sql_window.h

@@ -171,9 +171,11 @@ class Window_func_runner : public Sql_alloc
   bool exec(JOIN *join);
 
   void cleanup() { delete filesort; }
-};
 
+  friend class Window_funcs_computation;
+};
 
+struct st_join_table;
 /*
   This is a "window function computation phase": a single object of this class
   takes care of computing all window functions in a SELECT.
@@ -187,7 +189,7 @@ class Window_funcs_computation : public Sql_alloc
 {
   List<Window_func_runner> win_func_runners;
 public:
-  bool setup(THD *thd, List<Item_window_func> *window_funcs);
+  bool setup(THD *thd, List<Item_window_func> *window_funcs, st_join_table *tab);
   bool exec(JOIN *join);
   void cleanup();
 };