Hi guys. Is there any difference between these two queries regarding performance? Table stopvoip has several million records. I suspect using the aggregate function would be best, but benchmarking doesn't seem to confirm it. Both queries take around 150 - 175 ms once data has been cached.
Any hindsights? SELECT min(h323setuptime::date) FROM stopvoip WHERE callingstationid = '2941605118' AND h323setuptime >= '2007.07.01' AND h323disconnectcause = '10' AND acctsessiontime > 0 AND NOT calledstationid ~ '^99[89]#' "Aggregate (cost=11151.25..11151.27 rows=1 width=8)" " -> Bitmap Heap Scan on stopvoip (cost=29.29..11149.98 rows=507 width=8)" " Recheck Cond: ((callingstationid)::text = '2941605118'::text)" " Filter: ((h323setuptime >= '2007-07-01 00:00:00-03'::timestamp with time zone) AND ((h323disconnectcause)::text = '10'::text) AND (acctsessiontime > 0) AND ((calledstationid)::text !~ '^99[89]#'::text))" " -> Bitmap Index Scan on idx_stopvoip_callingid2 (cost=0.00..29.29 rows=2939 width=0)" " Index Cond: ((callingstationid)::text = '2941605118'::text)" SELECT h323setuptime::date FROM stopvoip WHERE callingstationid = '2941605118' AND h323setuptime >= '2007.07.01' AND h323disconnectcause = '10' AND acctsessiontime > 0 AND NOT calledstationid ~ '^99[89]#' ORDER BY 1 LIMIT 1 "Limit (cost=11174.03..11174.03 rows=1 width=8)" " -> Sort (cost=11174.03..11175.30 rows=507 width=8)" " Sort Key: (h323setuptime)::date" " -> Bitmap Heap Scan on stopvoip (cost=29.29..11151.25 rows=507 width=8)" " Recheck Cond: ((callingstationid)::text = '2941605118'::text)" " Filter: ((h323setuptime >= '2007-07-01 00:00:00-03'::timestamp with time zone) AND ((h323disconnectcause)::text = '10'::text) AND (acctsessiontime > 0) AND ((calledstationid)::text !~ '^99[89]#'::text))" " -> Bitmap Index Scan on idx_stopvoip_callingid2 (cost=0.00..29.29 rows=2939 width=0)" " Index Cond: ((callingstationid)::text = '2941605118'::text)" Thanks, Fernando.
