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| author | Sergey Petrunya <psergey@askmonty.org> | 2011-09-06 17:06:04 +0400 |
|---|---|---|
| committer | Sergey Petrunya <psergey@askmonty.org> | 2011-09-06 17:06:04 +0400 |
| commit | fc6b6435b4c3f5203e6ffc3de289f0413a7ef33f (patch) | |
| tree | ea2257094662595e5841c7fa1f25efa5720c3d23 /sql/opt_subselect.cc | |
| parent | e1435a51786f7975da79f62fc430fc3b3bf1a45f (diff) | |
| download | mariadb-git-fc6b6435b4c3f5203e6ffc3de289f0413a7ef33f.tar.gz | |
BUG#823930: Wrong result with semijoin materialization and blob fields
- Make subquery_types_allow_materialization() detect a case where
create_tmp_table() would create a blob column which would make it
impossible to use materialization
Non-semi-join materialization worked because it detected that this case
and felt back to use IN->EXISTS. Semi-join Materialization cannot easily
fallback, so we have to detect this case early.
Diffstat (limited to 'sql/opt_subselect.cc')
| -rw-r--r-- | sql/opt_subselect.cc | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/sql/opt_subselect.cc b/sql/opt_subselect.cc index 9ea55390fc5..3cb13b0b88c 100644 --- a/sql/opt_subselect.cc +++ b/sql/opt_subselect.cc @@ -559,6 +559,16 @@ bool subquery_types_allow_materialization(Item_in_subselect *in_subs) if (inner->field_type() == MYSQL_TYPE_BLOB || inner->field_type() == MYSQL_TYPE_GEOMETRY) DBUG_RETURN(FALSE); + /* + Materialization also is unable to work when create_tmp_table() will + create a blob column because item->max_length is too big. + The following check is copied from Item::make_string_field(): + */ + if (inner->max_length / inner->collation.collation->mbmaxlen > + CONVERT_IF_BIGGER_TO_BLOB) + { + DBUG_RETURN(FALSE); + } break; case TIME_RESULT: if (mysql_type_to_time_type(outer->field_type()) != |