Releasing disk space after delete data (1 reply)

In http://dev.mysql.com/doc/refman/5.1/en/optimize-table.html it says:

"After doing substantial insert, update, or delete operations on an InnoDB table that has its own .ibd file because it was created with the innodb_file_per_table option enabled. The table and indexes are reorganized, and disk space can be reclaimed for use by the operating system"

So with the innodb_file_per_table parameter we can release disk space with the optimize-table function. Why does that not work without the innodb_file_per_table option enabled with a shared table space? Is there maybe any other way?

Thanks in advance!

Best regards
Lars Werdes