cleanup: remove TABLE::add_read_columns_used_by_index

TABLE::add_read_columns_used_by_index() is conceptually wrong,
it *adds* columns used by index to the bitmap, without clearing
it first. But it also enables keyread, meaning that *only* columns
from the index will be read. It is supposed to be used to
add columns used by an index to a bitmap that already has columns
of a primary key - for engines where a primary key is part of every
index.

The correct fix is to change mark_columns_used_by_index() to
take into account extended keys.

this reverts 1d0acc77 and cf97cbd1

sql/key.cc

@@ -467,17 +467,7 @@ bool is_key_used(TABLE *table, uint idx, const MY_BITMAP *fields)
 {
   bitmap_clear_all(&table->tmp_set);
   table->mark_columns_used_by_index_no_reset(idx, &table->tmp_set);
-  if (bitmap_is_overlapping(&table->tmp_set, fields))
-    return 1;
-
-  /*
-    If table handler has primary key as part of the index, check that primary
-    key is not updated
-  */
-  if (idx != table->s->primary_key && table->s->primary_key < MAX_KEY &&
-      (table->file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX))
-    return is_key_used(table, table->s->primary_key, fields);
-  return 0;
+  return bitmap_is_overlapping(&table->tmp_set, fields);
 }
 
 

sql/sql_update.cc

@@ -539,7 +539,7 @@ int mysql_update(THD *thd,
     MY_BITMAP *save_write_set= table->write_set;
 
     if (query_plan.index < MAX_KEY && old_covering_keys.is_set(query_plan.index))
-      table->add_read_columns_used_by_index(query_plan.index);
+      table->mark_columns_used_by_index(query_plan.index);
     else
       table->use_all_columns();
 

sql/table.cc

@@ -6093,28 +6093,6 @@ MY_BITMAP *TABLE::mark_columns_used_by_index_in_bitmap(uint index,
   DBUG_RETURN(backup);
 }
 
-
-/*
-  Add fields used by a specified index to the table's read_set.
-
-  NOTE:
-    The original state can be restored with
-    restore_column_maps_after_mark_index().
-*/
-
-void TABLE::add_read_columns_used_by_index(uint index)
-{
-  MY_BITMAP *bitmap= &tmp_set;
-  DBUG_ENTER("TABLE::add_read_columns_used_by_index");
-
-  file->ha_start_keyread();
-  bitmap_copy(bitmap, read_set);
-  mark_columns_used_by_index_no_reset(index, bitmap);
-  column_bitmaps_set(bitmap, write_set);
-  DBUG_VOID_RETURN;
-}
-
-
 /*
   Restore to use normal column maps after key read
 
@@ -6143,10 +6121,12 @@ void TABLE::restore_column_maps_after_mark_index(MY_BITMAP *backup)
 void TABLE::mark_columns_used_by_index_no_reset(uint index, MY_BITMAP *bitmap)
 {
   KEY_PART_INFO *key_part= key_info[index].key_part;
-  KEY_PART_INFO *key_part_end= (key_part +
-                                key_info[index].user_defined_key_parts);
+  KEY_PART_INFO *key_part_end= (key_part + key_info[index].user_defined_key_parts);
   for (;key_part != key_part_end; key_part++)
     bitmap_set_bit(bitmap, key_part->fieldnr-1);
+  if (file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX &&
+      s->primary_key != MAX_KEY && s->primary_key != index)
+    mark_columns_used_by_index_no_reset(s->primary_key, bitmap);
 }
 
 

sql/table.h

@@ -1310,7 +1310,6 @@ struct TABLE
   MY_BITMAP *mark_columns_used_by_index_in_bitmap(uint index, MY_BITMAP *map);
   MY_BITMAP *mark_columns_used_by_index(uint index)
   { return mark_columns_used_by_index_in_bitmap(index, &tmp_set); }
-  void add_read_columns_used_by_index(uint index);
   void restore_column_maps_after_mark_index(MY_BITMAP *backup);
   void mark_auto_increment_column(void);
   void mark_columns_needed_for_update(void);