From reading the source code (Table.doHeavyIndexing() in the generator), the heavy-indexing attribute of the table should create an index for every column for a composite primary key. It has the following flaws in 3.3:
- It is not documented what the attribute does.
- It currently does not work correctly. The first column of the composite primary key is left out (and the comment in the code why this is done is incorrect, because the database will automatically create a composite index for the combined columns, not an index for the first column).
- It would be much more transparent to list the indexed columns as <index-column>.
Therefore I propose to remove this attribute from the 4.0 schema without replacement. This would not remove any functionality.