Manage Queues

Manage Queues

Monitor and manage delayed request queues to handle queued queries, release blocked requests, and abort unnecessary items to maintain system flow and meet SLAs.

Instructions

When to Use This Skill

• Queries are stuck in queues and need intervention
• Users report excessive wait times
• Need to release specific queued requests
• Emergency situation requires clearing problematic queue items
• Regular queue maintenance and monitoring

Available MCP Tools

• show_delayed_queue - View delayed requests by type (workload, system, utility)
• release_delayed_request - Release a blocked request from queue
• abort_delayed_request - Abort/cancel a delayed request

Step-by-Step Workflow

1. Assess Queue Status

   • Use show_delayed_queue with type='ALL' to see all queued items
   • Identify queue types: workload (throttled), system (locks), utility (maintenance)
   • Note queue depths and wait times

2. Analyze Queued Requests

   • Review each delayed request: who, what, how long
   • Identify legitimate delays vs stuck requests
   • Prioritize based on business impact and wait time

3. Determine Root Cause

   • Workload queue: Throttle limits or resource constraints
   • System queue: Lock conflicts or blocking sessions
   • Utility queue: Concurrent maintenance operations
   • Cross-reference with session and workload monitoring

4. Take Appropriate Action

   For Releasing Requests:

   • Use when request is valid but delayed too long
   • Verify adequate resources before release
   • Release highest priority items first
   • Monitor system impact after release

   For Aborting Requests:

   • Use when request is no longer needed or problematic
   • Confirm with request owner if possible
   • Abort lowest priority or stuck items
   • Document reason for abort

5. Monitor Results

   • Check queue depth after actions
   • Verify released queries execute successfully
   • Ensure no cascade effects from releases
   • Track if queuing recurs (indicates systemic issue)

6. Address Underlying Issues

   • If queues persistently fill, investigate root cause
   • May need workload tuning, throttle adjustment, or capacity
   • Document patterns for long-term optimization

Examples

Example 1: Check Queue Status

User: "Are there any queries waiting in queue?"

Action:
1. Call show_delayed_queue with type='ALL'
2. Summarize: "5 workload queue, 2 system queue, 0 utility queue"
3. Report wait times and affected users
4. Flag any excessive waits (>SLA threshold)

Example 2: Release Priority Request

User: "The CEO's dashboard query is stuck, can you release it?"

Action:
1. Use show_delayed_queue to locate the request
2. Verify it's in queue (not executing or blocked)
3. Confirm system has capacity for release
4. Call release_delayed_request with request ID
5. Monitor to ensure it executes: "Request released and now executing"
6. If still blocked, investigate further

Example 3: Clear Abandoned Requests

User: "There are old queries in queue from last night, clean them up"

Action:
1. Show delayed queue and identify old requests
2. Check request age and originating user
3. Verify users are no longer waiting (offline, session closed)
4. Call abort_delayed_request for each abandoned item
5. Report: "Aborted 12 requests older than 8 hours"
6. Investigate why they were delayed so long

Example 4: Manage Queue During Peak

User: "Month-end queue is backing up, help manage it"

Action:
1. Check show_delayed_queue for workload distribution
2. Identify critical vs non-critical delayed requests
3. Release critical month-end reports selectively
4. Abort or delay non-critical ad-hoc queries
5. Monitor queue depth trends
6. Communicate with users about delays
7. Recommend: "Consider temporary throttle adjustment for peak period"

Example 5: Resolve Lock-Related Queue

User: "Queries are stuck in system queue"

Action:
1. Use show_delayed_queue with type='SYSTEM'
2. Identify requests waiting on locks
3. Use detect_blocking to find blocking sessions
4. Options:
   a. Wait for blocker to complete (if nearly done)
   b. Terminate blocking session (if stuck/problematic)
   c. Abort delayed request (if blocker will run long)
5. Take action and verify queue clears
6. Report resolution and prevent recurrence

Best Practices

• Check queues proactively, don't wait for user complaints
• Workload queues are usually intentional (throttles working)
• System queues often indicate blocking - find and resolve blocker
• Utility queues are typically brief unless maintenance stuck
• Always verify why request is queued before releasing or aborting
• Communicate with users before aborting their requests when possible
• Release requests cautiously - could overload system if many released at once
• Document queue management actions for audit trail
• Track queue patterns to identify systemic issues
• Long queues may indicate need for capacity or workload tuning
• Emergency releases should be followed by root cause analysis
• Consider impact on other queued items when releasing selectively
• Set SLA thresholds for queue wait times and alert when exceeded
• Coordinate with DBAs before making major queue management decisions