MDEV-7648: Extra data in ANALYZE FORMAT=JSON $stmt

Show total execution time (r_total_time_ms) for various parts of the
query:
1. time spent in SELECTs
2. time spent reading rows from storage engines

#2 currently gets the data from P_S.

1 files changed, 46 insertions, 1 deletions

diff --git a/sql/sql_explain.cc b/sql/sql_explain.cc
index aa16a744e83..873ed74a1a2 100644
--- a/sql/sql_explain.cc
+++ b/sql/sql_explain.cc
@@ -732,7 +732,12 @@ void Explain_select::print_explain_json(Explain_query *query,
     */
     writer->add_member("query_block").start_object();
     writer->add_member("select_id").add_ll(select_id);
-    
+     
+    if (is_analyze && time_tracker.get_loops())
+    {
+      writer->add_member("r_loops").add_ll(time_tracker.get_loops());
+      writer->add_member("r_total_time_ms").add_double(time_tracker.get_time_ms());
+    }
     if (exec_const_cond)
     {
       writer->add_member("const_condition");
@@ -1289,6 +1294,9 @@ void Explain_table_access::print_explain_json(Explain_query *query,
     }
     else
       writer->add_null();
+
+    op_tracker.end_tracking();
+    op_tracker.print_json(writer);
   }
   
   /* `filtered` */
@@ -1971,3 +1979,40 @@ void create_explain_query_if_not_exists(LEX *lex, MEM_ROOT *mem_root)
     create_explain_query(lex, mem_root);
 }
 
+//////////////////////////////////////////////////////////////////////////////
+// 
+//////////////////////////////////////////////////////////////////////////////
+
+void Table_op_tracker::start_tracking(TABLE *table)
+{
+  //TODO: will this compile without P_S ?
+  start_count= end_count= 0;
+  if ((psi_table= table->file->m_psi))
+  {
+    PSI_CALL_get_table_current_stats(psi_table, &start_count, &start_sum);
+  }
+}
+
+
+void Table_op_tracker::end_tracking()
+{
+  if (psi_table)
+  {
+    PSI_CALL_get_table_current_stats(psi_table, &end_count, &end_sum);
+  }
+}
+
+void Table_op_tracker::print_json(Json_writer *writer)
+{
+  if (start_count != end_count)
+  {
+    /*
+      We have time in picoseconds, we want to print in milli-seconds
+       picosecond is sec* 10^ -12
+       millisecond is sec * 10^-3
+    */
+    double ms= double(end_sum - start_sum) / 1e9;
+    writer->add_member("r_total_time_ms").add_double(ms);
+  }
+}
+