Postgresql

001-psql.sql

--- connection count
SELECT sum(numbackends) FROM pg_stat_database;

---  long running queries
SELECT
  pid,
  now() - pg_stat_activity.query_start AS duration,
  query,
  state
FROM pg_stat_activity
WHERE (now() - pg_stat_activity.query_start) > interval '5 minutes';


--- long statements https://www.postgresql.org/docs/9.5/static/pgstatstatements.html
select pg_stat_statements_reset();

SELECT calls, total_time/1000, rows, 100.0 * shared_blks_hit /
               nullif(shared_blks_hit + shared_blks_read, 0) AS hit_percent, query
          FROM pg_stat_statements ORDER BY total_time DESC LIMIT 5;

--- blocks. From https://wiki.postgresql.org/wiki/Lock_Monitoring
  SELECT blocked_locks.pid     AS blocked_pid,
         blocked_activity.usename  AS blocked_user,
         blocking_locks.pid     AS blocking_pid,
         blocking_activity.usename AS blocking_user,
         blocked_activity.query    AS blocked_statement,
         blocking_activity.query   AS current_statement_in_blocking_process
   FROM  pg_catalog.pg_locks         blocked_locks
    JOIN pg_catalog.pg_stat_activity blocked_activity  ON blocked_activity.pid = blocked_locks.pid
    JOIN pg_catalog.pg_locks         blocking_locks 
        ON blocking_locks.locktype = blocked_locks.locktype
        AND blocking_locks.DATABASE IS NOT DISTINCT FROM blocked_locks.DATABASE
        AND blocking_locks.relation IS NOT DISTINCT FROM blocked_locks.relation
        AND blocking_locks.page IS NOT DISTINCT FROM blocked_locks.page
        AND blocking_locks.tuple IS NOT DISTINCT FROM blocked_locks.tuple
        AND blocking_locks.virtualxid IS NOT DISTINCT FROM blocked_locks.virtualxid
        AND blocking_locks.transactionid IS NOT DISTINCT FROM blocked_locks.transactionid
        AND blocking_locks.classid IS NOT DISTINCT FROM blocked_locks.classid
        AND blocking_locks.objid IS NOT DISTINCT FROM blocked_locks.objid
        AND blocking_locks.objsubid IS NOT DISTINCT FROM blocked_locks.objsubid
        AND blocking_locks.pid != blocked_locks.pid
 
    JOIN pg_catalog.pg_stat_activity blocking_activity ON blocking_activity.pid = blocking_locks.pid
   WHERE NOT blocked_locks.GRANTED;


--- Kill query
select pg_cancel_backend(1234); -- soft
select pg_terminate_backend(1234); -- hard

closing-pos-session.conf

# understanding wal and checkpoint:
#
# https://www.postgresql.org/docs/9.5/static/wal-intro.html
# https://blog.2ndquadrant.com/basics-of-tuning-checkpoints/

checkpoint_timeout=45min # default is 5 min

# To get more logs:
log_min_duration_statement='100333' # log quieres that are running more than 100 sec
log_checkpoints = 'on'
shared_preload_libraries = 'pg_stat_statements'
# pg_stat_statements also requires extra package to be installed:
# bash:   apt-get install postgresql-contrib
# psql:   CREATE EXTENSION pg_stat_statements;

closing-pos-session.sql

--- REINDEX accounting tables
REINDEX TABLE account_move;
REINDEX TABLE account_move_line;
REINDEX TABLE account_bank_statement_line;
REINDEX TABLE account_payment;

VACUUM FULL ANALYZE account_move_line;