To find blocking locks:
select a.txn_owner, a.txn_db, a.xid, a.pid, a.txn_start, a.lock_mode, a.relation as table_id,nvl(trim(c."name"),d.relname) as tablename, a.granted,b.pid as blocking_pid ,datediff(s,a.txn_start,getdate())/86400||' days '||datediff(s,a.txn_start,getdate())%86400/3600||' hrs '||datediff(s,a.txn_start,getdate())%3600/60||' mins '||datediff(s,a.txn_start,getdate())%60||' secs' as txn_duration from svv_transactions a left join (select pid,relation,granted from pg_locks group by 1,2,3) b on a.relation=b.relation and a.granted='f' and b.granted='t' left join (select * from stv_tbl_perm where slice=0) c on a.relation=c.id left join pg_class d on a.relation=d.oid where a.relation is not null;
The output may look something like this:
txn_owner | txn_db | xid | pid | txn_start | lock_mode | table_id | tablename | granted | blocking_pid | txn_duration | ----------+--------+---------+-------+----------------------------+---------------------+----------+-----------+---------+--------------+-----------------------------+ usr1 | db1 | 5559898 | 19813 | 2018-06-30 10:51:57.485722 | AccessExclusiveLock | 351959 | lineorder | t | | 0 days 0 hrs 0 mins 52 secs | usr1 | db1 | 5559927 | 20450 | 2018-06-30 10:52:19.761199 | AccessShareLock | 351959 | lineorder | f | 19813 | 0 days 0 hrs 0 mins 30 secs | usr1 | db1 | 5559898 | 19813 | 2018-06-30 10:51:57.485722 | AccessShareLock | 351959 | lineorder | t | | 0 days 0 hrs 0 mins 52 secs |
Once you’ve found the process id you want to kill then do this:
select pg_terminate_backend(PID);
At that point you can rerun your blocking lock query, and the lock should be released. Sometime pg_terminate_backend(PID) does not work, querying STV_SESSIONS can display stubborn Redshift backend processes that refuse to be killed.