Prevent InnoDB auto increment ON DUPLICATE KEY

I am currently having problems with a primary key ID which is set to auto increment. It keeps incrementing ON DUPLICATE KEY.

For Example:

ID | field1     | field2

1  | user       | value

5  | secondUser | value

86 | thirdUser  | value

From the description above, you’ll notice that I have 3 inputs in that table but due to auto increment on each update, ID has 86 for the third input.

Is there anyway to avoid this ?

Here’s what my mySQL query looks like:

INSERT INTO table ( field1, field2 ) VALUES (:value1, :value2)
            ON DUPLICATE KEY
            UPDATE field1 = :value1, field2 = :value2 

And here’s what my table looks like;

CREATE TABLE IF NOT EXISTS `table` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `field1` varchar(200) NOT NULL,
  `field2` varchar(255) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `field1` (`field1`),
  KEY `id` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;

Answer

You could set the innodb_autoinc_lock_mode config option to "0" for “traditional” auto-increment lock mode, which guarantees that all INSERT statements will assign consecutive values for AUTO_INCREMENT columns.

That said, you shouldn’t depend on the auto-increment IDs being consecutive in your application. Their purpose is to provide unique identifiers.