Monitor running/recent SQL in real time

Oracle

SET LONG 1000000 LONGCHUNKSIZE 1000000 LINESIZE 250 PAGESIZE 0
SELECT DBMS_SQLTUNE.REPORT_SQL_MONITOR(sql_id=>'&sql_id', type=>'TEXT') AS report FROM dual;
-- or: SELECT sql_id, status, elapsed_time FROM v$sql_monitor WHERE status='EXECUTING';

Real-Time SQL Monitoring shows long/parallel queries live (Tuning Pack).

PostgreSQL

SELECT pid, now()-query_start AS dur, state, wait_event, query
FROM pg_stat_activity WHERE state='active' ORDER BY query_start;

With auto_explain, plans of slow queries can be logged automatically.

MySQL

SELECT thread_id, event_name, timer_wait/1e9 AS ms, sql_text
FROM performance_schema.events_statements_current;

events_statements_current shows the statements currently running.

SQL Server

SELECT r.session_id, r.status, r.wait_type, r.percent_complete, t.text
FROM sys.dm_exec_requests r JOIN sys.dm_exec_sessions s ON s.session_id = r.session_id CROSS APPLY sys.dm_exec_sql_text(r.sql_handle) t
WHERE s.is_user_process = 1;

'Live Query Statistics' in SSMS shows plan progress live.

MongoDB

db.currentOp({ active: true, secs_running: { $gt: 1 } })

Shows long-running operations live; they can be terminated with killOp.

Redis

MONITOR

Streams ALL commands live — affects performance in production, use it only briefly. Prefer SLOWLOG instead.

Elasticsearch

GET _tasks?detailed=true&group_by=parents

Shows running tasks live; a long task is cancelled with POST _tasks/<id>/_cancel.