Commit 7f20ecc7 authored by unknown's avatar unknown
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BUG#17001 - Table and server crash on ALTER TABLE 

frm and data files for tables created by earlier MySQL
versions becomes out of sync after certain ALTER TABLE statements:
- One that changes column default value;
- One that changes table comment;
- One that changes table password.

As a result one can expirience either server crash or data corruption/loss.

This fix ensures that running ALTER TABLE on tables created by earlier
MySQL versions recreates data files.


sql/sql_table.cc:
  Ensure that running ALTER TABLE on tables created by earlier
  MySQL versions recreates data files.
parent 18b25158

sql/sql_table.cc

+10 −2
Original line number Diff line number Diff line
@@ -3197,7 +3197,7 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name, 
  uint db_create_options, used_fields;

  enum db_type old_db_type,new_db_type;

  bool need_copy_table;

  bool no_table_reopen= FALSE;

  bool no_table_reopen= FALSE, varchar= FALSE;

  DBUG_ENTER("mysql_alter_table");



  thd->proc_info="init";
@@ -3399,6 +3399,8 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name, 
  Field **f_ptr,*field;

  for (f_ptr=table->field ; (field= *f_ptr) ; f_ptr++)

  {

    if (field->type() == MYSQL_TYPE_STRING)

      varchar= TRUE;

    /* Check if field should be dropped */

    Alter_drop *drop;

    drop_it.rewind();
@@ -3660,12 +3662,18 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name, 
    better have a negative test here, instead of positive, like

    alter_info->flags & ALTER_ADD_COLUMN|ALTER_ADD_INDEX|...

    so that ALTER TABLE won't break when somebody will add new flag



    MySQL uses frm version to determine the type of the data fields and

    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.

  */

  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->tmp_table ||

                    (table->s->frm_version < FRM_VER_TRUE_VARCHAR && varchar));

  create_info->frm_only= !need_copy_table;



  /*