[dataimport] massive_store: drop all constraints in __init__ and restore all in finish This should avoid dependency issues when dropping specific constraints (e.g. when dropping a primary constraint referenced by a foreign key constraint). We only do this in master mode, slave mode stores are supposed to work with an initialized db already.

[dataimport] massive_store: ignore primary key when requesting indexes on a table Primary keys show up in both lists of constraints and indexes. Pick a side and stick to it.