Insert PostgreSQL table in to hypertable using multiple selects over disjoint time ranges

[sbahman]

For inserting very large PostgreSQL tables in to hypertables it would be useful to have a function which inserts it using multiple selects over disjoint time ranges. By tuning the timerange one can limit ram being used by the server and maybe improve the efficiency of the query.

[davidkohn88]

Hey @sbahman if you want to give it a try an initial version is up. Documentation isn't fully done yet, but something to work with.