Fixed some bugs in the function that calculated the selectivity

of the table conditions. 

sql/opt_range.cc

@@ -3324,9 +3324,8 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
 
   table->cond_selectivity= 1.0;
   
-  if (bitmap_is_clear_all(used_fields))
-    DBUG_RETURN(FALSE);
-
+  if (!bitmap_is_clear_all(used_fields))
+  {
     PARAM param;
     MEM_ROOT alloc;
     init_sql_alloc(&alloc, thd->variables.range_alloc_block_size, 0,
@@ -3358,8 +3357,7 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
     tree= get_mm_tree(&param, cond);
 
     if (!tree)
-    goto end;
-    
+      goto free_alloc;
     
     for (key= tree->keys, end= key + param.keys; key != end; key++, idx++)
     {
@@ -3380,6 +3378,12 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
         table->cond_selectivity*= table_field->cond_selectivity;
     }
 
+  free_alloc:
+    thd->mem_root= param.old_root;
+    free_root(&alloc, MYF(0));
+
+  }
+
   /* Calculate the selectivity of the range conditions supported by indexes */
 
   bitmap_clear_all(used_fields);
@@ -3411,18 +3415,19 @@ bool calculate_cond_selectivity_for_table(THD *thd, TABLE *table, Item *cond)
           bitmap_set_bit(used_fields, key_part->fieldnr-1);
         }
         if (i)
+        {
+          table->cond_selectivity*= quick_cond_selectivity;
+          if (i != used_key_parts)
 	  {
             double f1= key_info->actual_rec_per_key(i-1);
             double f2= key_info->actual_rec_per_key(i);
-          table->cond_selectivity*= quick_cond_selectivity * f1 / f2;
+            table->cond_selectivity*= f1 / f2;
+          }
         }
       } 
     }
   } 
 
-end:
-  thd->mem_root= param.old_root;
-  free_root(&alloc, MYF(0));
   DBUG_RETURN(FALSE);
 }
 

sql/sql_select.cc

@@ -6987,9 +6987,12 @@ double table_cond_selectivity(JOIN *join, uint idx, JOIN_TAB *s,
 
   /* Discount the selectivity of the access method used to join table s */
   if (s->quick && s->quick->index != MAX_KEY)
+  {
+    if (!ref)
     {
       /* A range scan by index s->quick->index is used to access table s */
-    sel*= table->quick_rows[s->quick->index]/table_records;
+      sel*= table_records/table->quick_rows[s->quick->index];
+    }
   }
   else if (ref)
   {