persistence_and_poll_rates.sql

WITH persisted_rate AS (
    SELECT
      date_trunc('minute', persisted_time) AS persisted_minute,
      count(*)                             AS num_persisted
    FROM persistent_queue_table
    GROUP BY persisted_minute
),
    polled_rate AS (
      SELECT
        date_trunc('minute', poll_time) AS poll_minute,
        count(*)                        AS num_polled
      FROM persistent_queue_table
      GROUP BY poll_minute
  ),
SELECT
  persisted_minute AS minute,
  num_persisted,
  num_polled
FROM persisted_rate
  INNER JOIN polled_rate ON persisted_minute = poll_minute
ORDER BY minute;