Cache file->index_flags(index, 0, 1) in table->key_info[index].index_flags

The reason for this is that we call file->index_flags(index, 0, 1)
multiple times in best_access_patch()when optimizing a table.
For example, in InnoDB, the calls is not trivial (4 if's and 2 assignments)
Now the function is inlined and is just a memory reference.

Other things:
- handler::is_clustering_key() and pk_is_clustering_key() are now inline.
- Added TABLE::can_use_rowid_filter() to simplify some code.
- Test if we should use a rowid_filter only if can_use_rowid_filter() is
  true.
- Added TABLE::is_clustering_key() to avoid a memory reference.
- Simplify some code using the fact that HA_KEYREAD_ONLY is true implies
  that HA_CLUSTERED_INDEX is false.
- Added DBUG_ASSERT to TABLE::best_range_rowid_filter() to ensure we
  do not call it with a clustering key.
- Reorginized elements in struct st_key to get better memory alignment.
- Updated ha_innobase::index_flags() to not have
  HA_DO_RANGE_FILTER_PUSHDOWN for clustered index

1 files changed, 6 insertions, 1 deletions

diff --git a/sql/table.cc b/sql/table.cc
index 0e196b64379..df4d88a1527 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -7411,7 +7411,7 @@ MY_BITMAP *TABLE::prepare_for_keyread(uint index, MY_BITMAP *map)
   DBUG_ENTER("TABLE::prepare_for_keyread");
   if (!no_keyread)
     file->ha_start_keyread(index);
-  if (map != read_set || !(file->index_flags(index, 0, 1) & HA_CLUSTERED_INDEX))
+  if (map != read_set || !is_clustering_key(index))
   {
     mark_index_columns(index, map);
     column_bitmaps_set(map);
@@ -8342,6 +8342,11 @@ bool TABLE::add_tmp_key(uint key, uint key_parts,
     key_start= FALSE;
     key_part_info++;
   }
+  /*
+    We have to cache index_flags here as the table may be used by the
+    optimizer before it's opened.
+  */
+  keyinfo->index_flags= file->index_flags(key, 0, 1);
 
   /*
     For the case when there is a derived table that would give distinct rows,