diff options
Diffstat (limited to 'sql/opt_table_elimination.cc')
| -rw-r--r-- | sql/opt_table_elimination.cc | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/sql/opt_table_elimination.cc b/sql/opt_table_elimination.cc index ef2a92f1797..5d952021365 100644 --- a/sql/opt_table_elimination.cc +++ b/sql/opt_table_elimination.cc @@ -1220,8 +1220,16 @@ void build_eq_mods_for_cond(Dep_analysis_context *ctx, bound_item= item; } } - exchange_sort<Dep_value_field>(fvl, compare_field_values, NULL); - add_module_expr(ctx, eq_mod, *and_level, NULL, bound_item, fvl); + /* + Multiple equality is only useful if it includes at least one field from + the table that we could potentially eliminate: + */ + if (fvl->elements) + { + + exchange_sort<Dep_value_field>(fvl, compare_field_values, NULL); + add_module_expr(ctx, eq_mod, *and_level, NULL, bound_item, fvl); + } break; } default: |