L2 Application Support / SQL / OS / Autosys / Monitoring — Real Q&A (Concise Answers)

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Application Support – L2

1) How would you troubleshoot a web application that is running slow for some users but not all?

2) What is the first step if you receive an application “500 Internal Server Error”?

3) How would you approach repeated application crashes during peak hours?

4) A batch job failed with a “File not found” error. What’s your next step?

5) How do you handle a high-severity incident impacting multiple users?

SQL – L2

6) How do you find the top 5 slowest running queries (by average time) in SQL Server?

SELECT TOP 5
  qs.query_hash,
  qs.total_elapsed_time / NULLIF(qs.execution_count,0) AS avg_elapsed,
  SUBSTRING(st.text, 1, 4000) AS sample_sql
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS st
ORDER BY avg_elapsed DESC;

7) How can you check if a table is locked in Oracle or SQL Server?

-- Oracle (session + lock info)
SELECT s.sid, s.serial#, l.type, l.id1, l.id2, l.lmode, l.request
FROM v$lock l JOIN v$session s ON s.sid = l.sid;

-- SQL Server
SELECT * FROM sys.dm_tran_locks; -- or: EXEC sp_who2

8) What’s the difference between INNER JOIN and LEFT JOIN?

9) How do you identify and kill a long-running query in SQL Server?

-- Identify
SELECT session_id, status, wait_type, blocking_session_id, start_time, command
FROM sys.dm_exec_requests
WHERE status <> 'background';

-- Terminate
KILL <session_id>;

10) How can you optimize a query that is performing poorly?

Windows/Linux Troubleshooting – L2

11) A Linux service is not starting. How do you troubleshoot?

# Systemd basics
systemctl status <service>
journalctl -u <service> --since "30 min ago"

# Config & ports
ss -tulpen     # or: netstat -tulnp
sudo -u <svcuser> /path/to/binary --version  # sanity check

12) How do you check if a port is listening in Windows?

netstat -ano | findstr :<PORT>
tasklist /FI "PID eq <PID>"   # map PID to process

13) A Windows server shows 100% CPU usage. How do you proceed?

14) How do you check disk space usage in Linux?

df -h                   # filesystem usage
du -sh /var/* | sort -h # biggest directories

15) DNS resolution is failing on a Linux machine. Steps?

resolvectl status                 # or check /etc/resolv.conf on non-systemd
dig example.com @<dns>
nc -vz <dns_ip> 53                # reachability test

Autosys – L2

16) How do you check the status of a job in Autosys?

autorep -j <job_name> -q

17) How do you force start an Autosys job?

sendevent -E FORCE_STARTJOB -J <job_name>

18) What’s the difference between ON ICE and ON HOLD in Autosys?

19) How do you find the last run details of a job?

autorep -j <job_name> -r

20) How do you troubleshoot a job failure in Autosys?

Monitoring Tools – L2

21) What is the difference between threshold-based and anomaly-based alerts?

22) In Nagios, how do you check if a host is reachable?

23) How do you integrate monitoring alerts with ServiceNow?

24) In Splunk, how do you find events from the last 15 minutes for a specific error code?

index=app_logs error_code=500 earliest=-15m@m latest=now

25) What’s the difference between proactive and reactive monitoring?

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