name	monitor-sessions
description	Monitor active Teradata sessions using real-time resources, view SQL execution details, identify blocking issues, and optionally take control actions

Monitor Sessions

Monitor and analyze active sessions in the Teradata database system to identify performance issues, blocking problems, and resource consumption patterns using real-time MCP resources and tools.

🔍 Enhanced Capabilities

This skill now leverages real-time MCP resources for faster monitoring!

With tdwm-mcp v1.5.0, this skill provides:

✅ REAL-TIME RESOURCES - Instant session data without running queries
✅ SQL TEXT VISIBILITY - View query text and execution steps
✅ BLOCKING DETECTION - Identify lock chains and contention
✅ CONTROL ACTIONS - Optional session termination when needed
✅ INTEGRATED CONTEXT - Sessions + workload + resource data in one view

Instructions

When to Use This Skill

User asks to check active sessions or current database activity
Need to identify who is running what queries
Investigating performance issues or blocked sessions
Monitoring specific user activity
Response to complaints about slow queries or system unresponsiveness

Available MCP Tools

Session Monitoring:

list_sessions - List all active user sessions with details
show_session_sql_text - View full SQL text for specific session
show_session_sql_steps - View execution steps for session query
monitor_session_query_band - View query band settings for sessions
identify_blocking - Identify sessions blocking other sessions

Control Actions (Optional):

abort_sessions_user - Terminate all sessions for a specific user

Related Monitoring:

show_tdwm_summary - View workload distribution (context for sessions)
show_query_log - Historical query analysis

Available MCP Resources (NEW ✨)

Real-Time Session Data:

tdwm://system/sessions - Real-time snapshot of all active sessions
tdwm://system/summary - Workload distribution showing session context
tdwm://system/workloads - Active workloads (to understand session classification)

Query Analysis:

tdwm://system/delayed-queries - Sessions waiting in delay queues
tdwm://system/throttle-statistics - Throttle impact on sessions

Reference:

tdwm://reference/session-states - Explanation of session states
tdwm://reference/blocking-types - Types of blocking scenarios

Step-by-Step Workflow

Phase 1: Quick Assessment (Use Resources First)

Get Real-Time Session Overview
- Read resource: tdwm://system/sessions
- Provides instant snapshot of all active sessions
- Review session count, usernames, current states
- Identify sessions of interest (long-running, high CPU, blocked)
Understand Workload Context
- Read resource: tdwm://system/summary
- Shows how sessions are distributed across workloads
- Identifies which workloads are busy
- Provides system-wide context

Phase 2: Detailed Analysis (Use Tools)

List Active Sessions
- Use list_sessions for detailed, sortable session data
- Review session IDs, usernames, runtime, CPU time, I/O
- Filter by user, state, or runtime criteria
- Identify sessions requiring deeper investigation
Examine Session SQL
- For suspicious or long-running sessions:
  - Use show_session_sql_text to see full query text
  - Use show_session_sql_steps to see execution steps
- Analyze query complexity and optimization
- Check if queries match expected workload patterns
Check for Blocking
- Use identify_blocking to find lock contention
- Identify both blocking and blocked sessions
- Document blocking chains (Session A blocks B blocks C)
- Determine if blocking is normal (brief) or problematic (long)
Review Query Bands
- Use monitor_session_query_band to see session tags
- Verify queries are properly classified
- Check if query bands match expected application

Phase 3: Analysis and Reporting

Correlate Session Data
- Cross-reference sessions with workload summary
- Check if throttles are delaying sessions (resource: tdwm://system/throttle-statistics)
- Identify patterns: multiple users, same application, similar queries
Provide Recommendations
- Summarize active session count and patterns
- Highlight problematic sessions (blocking, long-running, high resource)
- Provide session IDs and usernames for follow-up
- Recommend actions: optimize query, adjust workload, abort session

Phase 4: Control Actions (Optional)

Take Action if Needed
- For runaway queries: Consider using abort_sessions_user
- For blocking issues: Identify which session to terminate
- Emergency situations: Act quickly to restore service
- Always document: Record what was terminated and why

Examples

Example 1: Quick Session Check Using Resources (Fast)

Scenario: "Show me what's currently running on the database"

Action (Resource-First Approach):

1. Read real-time sessions:
   tdwm://system/sessions
   → Instant snapshot: 47 active sessions

2. Analyze resource data:
   - 23 sessions in ETL workload (expected for this time)
   - 15 sessions in INTERACTIVE workload
   - 9 sessions in DEFAULT workload
   - Most sessions <5 minutes runtime (normal)
   - 2 sessions running >30 minutes (investigate)

3. Get workload context:
   tdwm://system/summary
   → ETL workload using 60% of resources
   → Interactive workload using 30%
   → System healthy, no overload

4. Report:
   "47 active sessions, system healthy. ETL workload dominant (expected).
    2 long-running sessions (ID 1234, 5678) worth monitoring."

Result: Complete overview in seconds without running any queries

Example 2: Investigate Specific User (Detailed)

Scenario: "What is user john_smith doing right now?"

Action (Resource + Tool Approach):

1. Check resource first:
   tdwm://system/sessions
   → Filter for user='john_smith'
   → Found 3 active sessions: 1245, 1246, 1247

2. Get detailed session data:
   list_sessions()
   → Filter output for john_smith
   → Session 1245: Running 45 minutes, high CPU
   → Session 1246: Running 2 minutes, normal
   → Session 1247: Idle, 0 CPU

3. Examine long-running session 1245:
   show_session_sql_text(session_id=1245)
   → Query: Large aggregation on fact table
   → No obvious optimization issues

   show_session_sql_steps(session_id=1245)
   → Currently in step 5 of 8
   → Doing JOIN operation
   → No blocking detected

4. Check query band:
   monitor_session_query_band()
   → Filter for session 1245
   → Query band: APP=ANALYTICS_TOOL, USER=john_smith
   → Classified in ANALYTICS workload (correct)

5. Report:
   "john_smith has 3 sessions:
    - Session 1245: Long-running analytics query (45 min), progressing normally
    - Session 1246: Recent query, completing soon
    - Session 1247: Idle connection

    No issues detected. Long query is expected for analytics workload."

Result: Complete user activity profile with context

Example 3: Diagnose Blocking Issues (Critical)

Scenario: "Some queries seem stuck, check for blocking"

Action (Blocking Analysis):

1. Quick resource check:
   tdwm://system/sessions
   → 12 sessions in "blocked" state
   → Multiple sessions waiting on locks

2. Identify blocking chains:
   identify_blocking()
   → Blocking detected!
   → Session 2001 (user: etl_batch) is blocking 8 sessions
   → Session 2050 (user: report_user) is blocking 4 sessions

3. Analyze blocking session 2001:
   show_session_sql_text(session_id=2001)
   → UPDATE statement on CUSTOMER table
   → Has been running for 90 minutes
   → Holding exclusive table lock

   list_sessions()
   → Filter for session 2001
   → Started at 02:00 AM (ETL window)
   → Should have completed by now

4. Check blocked sessions:
   list_sessions()
   → Filter for blocked sessions
   → All trying to SELECT from CUSTOMER table
   → Waiting for lock release
   → Users complaining about reports not loading

5. Analyze second blocker (session 2050):
   show_session_sql_text(session_id=2050)
   → Long-running report query
   → Holding shared lock, blocking UPDATE attempts

6. Review reference:
   tdwm://reference/blocking-types
   → Scenario: ETL update blocking reports = Type 1 blocking
   → Recommendation: Complete ETL or abort if stuck

7. Report:
   "BLOCKING DETECTED - 12 sessions blocked:

    Primary blocker: Session 2001 (etl_batch)
    - Running 90 minutes (abnormally long)
    - UPDATE on CUSTOMER table
    - Blocking 8 report sessions
    - RECOMMENDATION: Check if ETL is stuck, may need to abort

    Secondary blocker: Session 2050 (report_user)
    - Long-running report (60 min)
    - Blocking 4 UPDATE attempts
    - RECOMMENDATION: Let complete or optimize query

    IMMEDIATE ACTION NEEDED for Session 2001"

Result: Clear identification of blocking issues with recommendations

Example 4: Emergency Session Termination (Control Action)

Scenario: "User adhoc_user01 is running runaway queries, kill all their sessions"

Action (Control Action):

1. Verify problem first:
   tdwm://system/sessions
   → User adhoc_user01 has 15 active sessions
   → All running identical query
   → System CPU at 95% (critical)

2. Get detailed view:
   list_sessions()
   → Filter for adhoc_user01
   → 15 sessions, each using 6% CPU
   → Total: 90% of system CPU
   → All started within 5 minutes (query blast)

3. Check query:
   show_session_sql_text(session_id=3001)  # Pick one session
   → SELECT with CROSS JOIN (Cartesian product!)
   → Missing WHERE clause
   → Generating billions of rows

4. Confirm termination decision:
   - Runaway query confirmed
   - No business justification for Cartesian product
   - System critically overloaded
   - User needs to be stopped

5. Execute termination:
   abort_sessions_user(username="adhoc_user01")
   → Terminating all 15 sessions for adhoc_user01
   → Result: "15 sessions terminated"

6. Monitor recovery:
   tdwm://system/summary
   → Wait 30 seconds
   → CPU dropping from 95% to 45%
   → System recovering

7. Document incident:
   "Emergency termination of adhoc_user01 sessions at 14:23:
    - 15 runaway queries with Cartesian product
    - Consuming 90% of system CPU
    - Missing WHERE clause in query
    - System returned to normal after termination
    - User notified to fix query before resubmitting"

Result: System stabilized, incident documented

Example 5: Routine Session Audit (Proactive)

Scenario: Daily morning check of overnight session activity

Action (Comprehensive Audit):

1. Get high-level overview:
   tdwm://system/summary
   → 34 active sessions (normal for 8 AM)
   → ETL workload: 12 sessions
   → Interactive: 18 sessions
   → Ad-hoc: 4 sessions

2. Check real-time sessions:
   tdwm://system/sessions
   → No sessions running >2 hours (good)
   → No blocked sessions
   → Resource usage balanced

3. Review delayed queries:
   tdwm://system/delayed-queries
   → 3 queries in delay queue (acceptable)
   → All from ad-hoc workload (expected throttling)

4. Check throttle statistics:
   tdwm://system/throttle-statistics
   → ETL throttle: 0 delayed (nighttime processing complete)
   → Ad-hoc throttle: 3 delayed (working as designed)
   → Interactive throttle: 0 delayed (good performance)

5. List all sessions for record:
   list_sessions()
   → Full session inventory captured
   → No anomalies detected

6. Check for any blocking:
   identify_blocking()
   → No blocking detected

7. Report:
   "Morning session audit - 8:00 AM:
    ✅ 34 active sessions (normal)
    ✅ No blocking issues
    ✅ No long-running sessions (all <2 hours)
    ✅ Throttles working as expected
    ✅ System healthy

    Overnight ETL completed successfully.
    Interactive users beginning morning queries.
    No issues requiring attention."

Result: Clean bill of health, documented baseline

Best Practices

Resource-First Approach (NEW ✨)

START with resources for instant overview (tdwm://system/sessions)
Resources are faster than running queries
Use tools for detailed analysis only when needed
Resources provide point-in-time snapshot

Investigation Workflow

Always start with system-wide view before drilling into specifics
Cross-reference session data with workload summary for context
Document session IDs prominently for easy reference
Consider time of day and expected workload patterns

Blocking Analysis

Check for blocking proactively during performance investigations
Analyze blocking chains to find root cause (first blocker)
Understand business impact (how many users affected)
Distinguish normal brief locks from problematic long locks

Control Actions

ONLY abort sessions when necessary (runaway queries, system emergency)
Always document what was terminated and why
Notify users when their sessions are terminated
Consider less drastic options first (throttling, priority adjustment)

Session State Understanding

Reference tdwm://reference/session-states for state meanings
"Active" = currently executing
"Blocked" = waiting on lock
"Idle" = connected but not executing

Monitoring Frequency

Critical systems: Check every 15-30 minutes
Normal systems: Check 2-3 times per day
Always check during peak hours (morning, midday)
Set up alerts for blocking or long-running sessions

Related Skills

Use monitor-queries skill for historical query analysis
Use control-sessions skill for detailed session management
Use monitor-resources skill for CPU/memory/I/O correlation
Use emergency-response skill for crisis situations

monitor-sessions

Install Skill

SKILL.md