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| -rw-r--r-- | sql/sql_table.cc | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/sql/sql_table.cc b/sql/sql_table.cc index 9ec8e8db1fb..275cfbaa088 100644 --- a/sql/sql_table.cc +++ b/sql/sql_table.cc @@ -3614,12 +3614,21 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name, their layout. See Field_string::type() for details. Thus, if the table is too old we may have to rebuild the data to update the layout. + + There was a bug prior to mysql-4.0.25. Number of null fields was + calculated incorrectly. As a result frm and data files gets out of + sync after fast alter table. There is no way to determine by which + mysql version (in 4.0 and 4.1 branches) table was created, thus we + disable fast alter table for all tables created by mysql versions + prior to 5.0 branch. + See BUG#6236. */ need_copy_table= (alter_info->flags & ~(ALTER_CHANGE_COLUMN_DEFAULT|ALTER_OPTIONS) || (create_info->used_fields & ~(HA_CREATE_USED_COMMENT|HA_CREATE_USED_PASSWORD)) || table->s->tmp_table || + !table->s->mysql_version || (table->s->frm_version < FRM_VER_TRUE_VARCHAR && varchar)); create_info->frm_only= !need_copy_table; |