slow queries, by total time

Author: NikolayS

bloat/index_pgstattuple.sql

@@ -0,0 +1,41 @@
+-- In pg_stat_statements, there is a problem: sometimes (quite often), it registers the same query twice (or even more).
+-- It's easy to check in your DB: 
+--
+--   with heh as (
+--     select userid, dbid, query, count(*), array_agg(queryid) queryids
+--     from pg_stat_statements group by 1, 2, 3 having count(*) > 1
+--  ) select left(query, 85) || '...', userid, dbid, count, queryids from heh;
+--
+-- This query gives you "full picture", aggregating stats for each query-database-username ternary
+
+-- Works with Postgres 9.6
+
+select
+  sum(calls) as calls,
+  sum(total_time) as total_time,
+  sum(mean_time * calls) / sum(calls) as mean_time,
+  max(max_time) as max_time,
+  min(min_time) as min_time,
+  -- stddev_time, -- https://stats.stackexchange.com/questions/55999/is-it-possible-to-find-the-combined-standard-deviation
+  sum(rows) as rows,
+  userid,
+  dbid,
+  query,
+  sum(shared_blks_hit) as shared_blks_hit,
+  sum(shared_blks_read) as shared_blks_read,
+  sum(shared_blks_dirtied) as shared_blks_dirtied,
+  sum(shared_blks_written) as shared_blks_written,
+  sum(local_blks_hit) as local_blks_hit,
+  sum(local_blks_read) as local_blks_read,
+  sum(local_blks_dirtied) as local_blks_dirtied,
+  sum(local_blks_written) as local_blks_written,
+  sum(temp_blks_read) as temp_blks_read,
+  sum(temp_blks_written) as temp_blks_written,
+  sum(blk_read_time) as blk_read_time,
+  sum(blk_write_time) as blk_write_time,
+  array_agg(queryid) as queryids -- 9.4+
+from pg_stat_statements
+group by userid, dbid, query
+order by sum(total_time) desc
+limit 50;
+

slow/pg_stat_statements_top_total.sql

@@ -1,13 +1,13 @@
 \echo Menu:
 \echo '   1  – Basic Node Information (master/replica, lag, DB size, tmp files)'
 \echo '   2  – Sizes of tables'
-\echo '  b1  – Table bloat, rough estimation'
+\echo '  b1  – Tables bloat, rough estimation'
 \echo '  b2  – B-tree indexes bloat, rough estimation'
-\echo '  b3  – Table bloat, more precise (requires pgstattuple extension; expensive)'
-\echo '  b4  – Index bloat, more precise (requires pgstattuple extension; expensive)'
-\echo '   3  - Slowest Queries'
+\echo '  b3  – Tables bloat, more precise (requires pgstattuple extension; expensive)'
+\echo '  b4  – B-tree indexes bloat, more precise (requires pgstattuple extension; expensive)'
 \echo '  i1  - Unused/Redundant Indexes'
 \echo '  i2  - Rarely Used Indexes'
+\echo '  s1  - Slowest Queries, by Total Time (requires pg_stat_statements extension)'
 \echo '   q  – Quit'
 \echo
 \echo 'Type your choice and press <Enter>:'
@@ -20,9 +20,9 @@ select
   :d_stp::text = 'b2' as d_step_is_b2,
   :d_stp::text = 'b3' as d_step_is_b3,
   :d_stp::text = 'b4' as d_step_is_b4,
-  :d_stp::text = '3' as d_step_is_3,
   :d_stp::text = 'i1' as d_step_is_i1,
   :d_stp::text = 'i2' as d_step_is_i2,
+  :d_stp::text = 's1' as d_step_is_s1,
   :d_stp::text = 'q' as d_step_is_q \gset
 \if :d_step_is_1
   \i ./general/basic.sql
@@ -45,11 +45,7 @@ select
   \prompt 'Press <Enter> to continue…' d_dummy
   \i ./start.psql
 \elif :d_step_is_b4
-  \i ./bloat/index_pgstattuple.sql
-  \prompt 'Press <Enter> to continue…' d_dummy
-  \i ./start.psql
-\elif :d_step_is_3
-  \echo '      3 is chosen!'
+  \i ./bloat/btree_pgstattuple.sql
   \prompt 'Press <Enter> to continue…' d_dummy
   \i ./start.psql
 \elif :d_step_is_i1
@@ -60,6 +56,10 @@ select
   \i ./indexes/rare.sql
   \prompt 'Press <Enter> to continue…' d_dummy
   \i ./start.psql
+\elif :d_step_is_s1
+  \i ./slow/pg_stat_statements_top_total.sql
+  \prompt 'Press <Enter> to continue…' d_dummy
+  \i ./start.psql
 \elif :d_step_is_q
   \echo 'Bye!'
   \echo