How to list partition tables? about pg_party

[rkrage]

Programmatically, there isn't currently a way to figure out the range for a given partition. From a psql console, though, you should be able to see attached partitions and their associated metadata:

psql=# \d+ bigint_date_ranges

   Column   |            Type             | Collation | Nullable |                    Default                     | Storage | Stats target | Description
------------+-----------------------------+-----------+----------+------------------------------------------------+---------+--------------+-------------
 id         | bigint                      |           | not null | nextval('bigint_date_ranges_id_seq'::regclass) | plain   |              |
 created_at | timestamp without time zone |           | not null |                                                | plain   |              |
 updated_at | timestamp without time zone |           | not null |                                                | plain   |              |
Partition key: RANGE (((created_at)::date))
Partitions: bigint_date_ranges_a FOR VALUES FROM ('2018-03-26') TO ('2018-03-27'),
            bigint_date_ranges_b FOR VALUES FROM ('2018-03-27') TO ('2018-03-28')

Also, keep in mind that it is possible to manually name your child partitions to avoid these cryptic names:

create_range_partition_of \
  :some_range_records,
  name: :some_range_records_descriptive_partition_name,
  partition_key: "created_at::date",
  start_range: current_date,
  end_range: current_date + 1.day

Generally, it's a good idea to create necessary partitions ahead of time (via cron or some other scheduling service). As far as automatic partition creation goes, that isn't natively supported but can be accomplished with the rescuing you described. Example:

user_item = UserItem.new(user_id: 1)

begin
  user_item.save!
rescue ActiveRecord::StatementInvalid => e
  if e.message =~ /no partition of relation/
    UserItem.create_partition(values: user_item.user_id)
    user_item.save!
  else
    raise e
  end
end