How do I interpret the number of rows displayed as synchronized on my team usage page?

Issue

When you view your team usage page, it shows you an unexpected value for "Heroku Connect rows synced" and you want to understand how this number is calculated.

Resolution

This number is the total number of rows being kept in sync across all of your connections, including connections to both production and sandbox organizations. Even if your objects don't see many updates throughout a month, the number will be the sum of the number of rows across all tables.

You can verify these numbers by issuing COUNT(*) queries against your mapped tables, e.g.,

-- Find the number of synchronized rows in the Connection with schema "salesforce" and table "account" 
SELECT 
  COUNT(*)
FROM
  salesforce.account
;

This process could be labor intensive though, so to get an estimate one could do something like:

SELECT
  SUM(reltuples::BIGINT) as approximate_usage
FROM
  pg_class
WHERE
  relname IN (
      SELECT
        CONCAT(table_schema, '.', table_name) as fq_name 
      FROM
        information_schema.tables
      WHERE
        table_schema = 'salesforce'
      AND
        -- ignore Connect system tables
        table_name NOT LIKE '\_%'
   )
OR 
  relname IN (
      SELECT
        table_name 
      FROM 
        information_schema.tables
      WHERE
        table_schema = 'salesforce'
      AND
        table_name NOT LIKE '\_%'
  )
;

It's important to note that even if your current usage exceeds the amount granted by your license or contract, you'll still be able to use Heroku Connect normally. (See: What happens if I exceed my row limit on Heroku Connect?)