Remove and re-add foreign key constraints and indexes, allow binary format

[wpfl-dbt]

Suspect I'm not going to be sharing anything you haven't considered but thought I'd chip in anyway.

Was just browsing SO answers about inserting data quickly and it seems like there's a couple of tips that we could implement here:

• Remove and re-add foreign key constraints and indexes, from the population docs
  • Could deferring constraints help?
• Allow binary encoding on copy from, from the SQL copy docs: "it is somewhat faster than the text and CSV formats"

[1lliter8]

Was randomly thinking about this today and had another thought: where moving large volumes of data over the wire is the constraint, would copy from program 'gzip > ...' and sending up a compressed volume speed things up.