Function to create calendar-based chunks

custom_create_chunk.sql

CREATE OR REPLACE PROCEDURE custom_create_chunk(hypertable REGCLASS, trunc_field TEXT DEFAULT 'month') AS
$$
DECLARE
  r RECORD;
  range_start BIGINT;
  range_end BIGINT;
  slices JSONB;
BEGIN

  SELECT
    d.column_name, ds.range_end
  INTO
    r
  FROM
    _timescaledb_catalog.hypertable h
    JOIN _timescaledb_catalog.dimension d ON d.hypertable_id = h.id
    LEFT JOIN _timescaledb_catalog.dimension_slice ds ON ds.dimension_id = d.id
  WHERE
    d.column_type = 'timestamp with time zone'::regtype
    AND format('%I.%I', h.schema_name, h.table_name)::regclass = hypertable
  ORDER BY
    ds.range_start DESC, ds.range_end DESC
  LIMIT 1;

  IF NOT FOUND THEN
    RETURN;
  END IF;

  RAISE DEBUG 'r: %', r;

  IF r.range_end IS NULL THEN
    range_start := _timescaledb_internal.time_to_internal(date_trunc(trunc_field, now()));
  ELSE
    range_start := r.range_end;
  END IF;

  RAISE INFO 'range_start: %', range_start;

  range_end := 
    _timescaledb_internal.time_to_internal(
      _timescaledb_internal.to_timestamp(range_start) + 
      format('1 %s', trunc_field)::interval
    );

  RAISE DEBUG 'range_end: %', range_end;
  slices    := jsonb_build_object(r.column_name, array[range_start, range_end]);
  RAISE DEBUG 'slices: %', slices;
  PERFORM _timescaledb_internal.create_chunk(hypertable, slices);

  RETURN;
END;
$$
LANGUAGE plpgsql;