Bug #6166 index prefix length of 0 not rejected

• Submitted: 19 Oct 2004 21:27
• Modified: 26 Oct 2004 7:03
• Reporter: Paul DuBois
• Status: Closed
• Category: MySQL Server
• Severity: S3 (Non-critical)
• Version: 4.0,4.1,...
• Assigned to: Sergei Glukhov
• CPU Architecture: Any

[19 Oct 2004 21:27] Paul DuBois

Description:
MySQL correctly catches when you attempt to index a column prefix
that is longer than the column itself: 

mysql> create table t (c char(10), index (c(11)));
ERROR 1089 (HY000): Incorrect sub part key; the used key part isn't a string,
the used length is longer than the key part, or the storage engine doesn't
support unique sub keys

However, it doesn't catch when the prefix length is 0.  Instead, it acts as
though no prefix was specified.

mysql> create table t (c char(10), index (c(0)));
Query OK, 0 rows affected (0.01 sec)

mysql> show create table t;
+-------
+--------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------
+--------------------------------------------------------------------------------------------------------+
| t     | CREATE TABLE `t` (
  `c` char(10) default NULL,   
  KEY `c` (`c`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 |
+-------
+--------------------------------------------------------------------------------------------------------+
1 row in set (0.08 sec)

How to repeat:
See above.

[22 Oct 2004 13:37] Sergei Glukhov

ChangeSet
  1.2124 04/10/22
  Fix for bug #6166: index prefix length of 0 not rejected

[26 Oct 2004 7:03] Sergei Glukhov

Fixed in 4.1 source tree
ChangeSet
  1.2043 04/10/26
  Fix for bug #6166: index prefix length of 0 not rejected