performance problems with bulk inserts/updates on tsrange with gist-based exclude constrains

Hi All,

I have quite a few tables that follow a pattern like this:

Table "public.my_model"
Column | Type | Modifiers
--------+-------------------+-----------
period | tsrange | not null
key | character varying | not null
value | integer |
Indexes:
"my_model_pkey" PRIMARY KEY, btree (period, key)
"my_model_period_key_excl" EXCLUDE USING gist (period WITH &&, key
WITH =)
Check constraints:
"my_model_period_check" CHECK (period <> 'empty'::tsrange)

So, a primary key of a period column and one or more other columns
(usually int or string) and an exclude constraint to prevent overlaps,
and a check constraint to prevent empty ranges.

However, I'm hitting performance problems on moderate bulk inserts and
updates, with ~700k rows taking around 13 minutes. Profiling my python
code suggests that most of the time is being taken by Postgres (9.4 in
this case...)

What can I do to speed things up? Is there a different type of index I
can use to achieve the same exclude constraint? Is there something I can
do to have the index changes only done on the commit of the bulk batches?

cheers,

Chris