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The following SQL code displays the thresholds for when Autovacuum will clean up dead rows.
Dead rows (or tuples) occur in postgres when records are updated or deleted.

SELECT relname, n_live_tup, n_dead_tup, 
       FLOOR(current_setting('autovacuum_vacuum_threshold')::INTEGER + 
	    (current_setting('autovacuum_vacuum_scale_factor')::NUMERIC * 
	    (n_live_tup))) AS "Autovacuum Threshold",
       round(n_dead_tup / FLOOR(current_setting('autovacuum_vacuum_threshold')::INTEGER + 
	                       (current_setting('autovacuum_vacuum_scale_factor')::NUMERIC * 
		               (n_live_tup)))*100,2) AS "Percentage",
       last_vacuum, last_autovacuum 
FROM pg_stat_user_tables
WHERE n_live_tup > 0
ORDER BY 5 DESC LIMIT 10;

autovacuum_analyze_scale_factor       | Number of DML prior to analyze as a fraction of reltuples.
autovacuum_analyze_threshold          | Minimum number of DML prior to analyze.
autovacuum_vacuum_scale_factor        | Number of DML prior to vacuum as a fraction of reltuples.
autovacuum_vacuum_threshold           | Minimum number of tuple DML prior to vacuum.