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Re: ERROR 1089 (HY000):
Posted by: Harrison Fisk
Date: February 15, 2005 08:10PM

Hi,

As the error message indicates and as http://dev.mysql.com/doc/mysql/en/mysql-cluster-limitations-in-4-1.html also mentions, Cluster does not support indexes on prefixes of columns. So you can not create a unique on the first 25 characters. As you indicated the 32 works because that is the entire column width (not a prefix).

The reason why this doesn't matter is because the UNIQUE is implemented as a hashed value. That means it will take up the same width in the index regardless of how many characters you use in it. Even non-unique indexes contain a direct pointer to the data rather than a copy since it is a t-tree.

Harrison Fisk, Trainer and Consultant
MySQL AB, www.mysql.com

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