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From Rick Hillegas <Richard.Hille...@Sun.COM>
Subject another question about optimizer documentation
Date Mon, 12 Jun 2006 16:06:17 GMT
I'm also puzzled by the following explanation from the Tuning Guide:

  Selectivity and cardinality statistics
    Working with cardinality statistics
      When cardinality statistics are automatically updated

        "For other operations, Derby automatically updates statistics 
for the table and all indexes on the table if they are already exist. 
Those operations are:

    * (all indexes) When you execute SYSCS_UTIL.SYSCS_COMPRESS_TABLE.
    * (index only) When you drop a column that is part of a table's 
index; the statistics for the affected index are dropped, and statistics 
for the other indexes on the table are updated.

What does the second bullet mean? Derby doesn't let you drop a column 
from a table right now.


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