Merge branch '11.0' into 11.1bb-11.1-release

1 files changed, 8 insertions, 42 deletions

diff --git a/sql/sql_statistics.cc b/sql/sql_statistics.cc
index ecde847c8d4..ccf1ebb9ef9 100644
--- a/sql/sql_statistics.cc
+++ b/sql/sql_statistics.cc
@@ -4029,50 +4029,16 @@ double Histogram_binary::point_selectivity(Field *field, key_range *endpoint,
   }
   else
   {
-    /* 
+    /*
       The value 'pos' fits within one single histogram bucket.
 
-      Histogram_binary buckets have the same numbers of rows, but they cover
-      different ranges of values.
-
-      We assume that values are uniformly distributed across the [0..1] value
-      range.
-    */
-
-    /* 
-      If all buckets covered value ranges of the same size, the width of
-      value range would be:
+      We also have avg_sel which is per-table average selectivity of col=const.
+      If there are popular values, this may be larger than one bucket, so 
+      cap the returned number by the selectivity of one bucket.
     */
     double avg_bucket_width= 1.0 / (get_width() + 1);
-    
-    /*
-      Let's see what is the width of value range that our bucket is covering.
-        (min==max currently. they are kept in the formula just in case we 
-         will want to extend it to handle multi-bucket case)
-    */
-    double inv_prec_factor= (double) 1.0 / prec_factor(); 
-    double current_bucket_width= 
-        (max + 1 == get_width() ?  1.0 : (get_value(max) * inv_prec_factor)) -
-        (min == 0 ?  0.0 : (get_value(min-1) * inv_prec_factor));
-
-    DBUG_ASSERT(current_bucket_width); /* We shouldn't get a one zero-width bucket */
-
-    /*
-      So:
-      - each bucket has the same #rows 
-      - values are unformly distributed across the [min_value,max_value] domain.
 
-      If a bucket has value range that's N times bigger then average, than
-      each value will have to have N times fewer rows than average.
-    */
-    sel= avg_sel * avg_bucket_width / current_bucket_width;
-
-    /*
-      (Q: if we just follow this proportion we may end up in a situation
-      where number of different values we expect to find in this bucket
-      exceeds the number of rows that this histogram has in a bucket. Are 
-      we ok with this or we would want to have certain caps?)
-    */
+    sel= MY_MIN(avg_bucket_width, avg_sel);
   }
   return sel;
 }
@@ -4147,7 +4113,7 @@ bool is_eits_usable(Field *field)
   if (!col_stats)
     return false;
 
-  DBUG_ASSERT(field->table->stats_is_read);
+  DBUG_ASSERT(field->orig_table->stats_is_read);
 
   /*
     (1): checks if we have EITS statistics for a particular column
@@ -4160,8 +4126,8 @@ bool is_eits_usable(Field *field)
   return !col_stats->no_stat_values_provided() &&        //(1)
     field->type() != MYSQL_TYPE_GEOMETRY &&              //(2)
 #ifdef WITH_PARTITION_STORAGE_ENGINE
-    (!field->table->part_info ||
-     !field->table->part_info->field_in_partition_expr(field)) &&     //(3)
+    (!field->orig_table->part_info ||
+     !field->orig_table->part_info->field_in_partition_expr(field)) &&     //(3)
 #endif
     true;
 }