diff options
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 1ea738d976c..d635eec0e28 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -6158,7 +6158,11 @@ best_access_path(JOIN *join, else { /* Estimate cost of reading table. */ - tmp= s->scan_time(); + if (s->table->force_index && !best_key) // index scan + tmp= s->table->file->read_time(s->ref.key, 1, s->records); + else // table scan + tmp= s->scan_time(); + if ((s->table->map & join->outer_join) || disable_jbuf) // Can't use join cache { /* @@ -7611,7 +7615,11 @@ best_extension_by_limited_search(JOIN *join, if (join->sort_by_table && join->sort_by_table != join->positions[join->const_tables].table->table) - /* We have to make a temp table */ + /* + We may have to make a temp table, note that this is only a + heuristic since we cannot know for sure at this point. + Hence it may be wrong. + */ current_read_time+= current_record_count; if (current_read_time < join->best_read) { |