Alert Muting Feature — Implementation Plan

[HannahVernon]

Which component(s) does this affect?

• Full Dashboard
• Lite
• SQL collection scripts
• Installer
• Documentation

Problem Statement

Users cannot suppress specific recurring alerts. The only existing options are coarse-grained:

• Server silencing — suppresses ALL alerts for an entire server
• Acknowledgement — temporarily hides badges until conditions worsen
• Database exclusion — filters entire databases from blocking/deadlock counts

There is no way to say "stop alerting me about this specific long-running query" or "mute all blocking alerts from database X" while keeping other alerts active.

Proposed Solution

Add a mute rule system that sits between alert detection and notification. Muted alerts are still collected and logged (with a muted flag) but suppressed from tray notifications, emails, and UI badges.

Two muting modes:

• Pattern-based: match on server, metric type, database, query text substring, wait type, or job name (fields combined with AND logic)
• Instance-based: a tightly-scoped pattern rule auto-populated from a specific alert's context

Data Model

public class MuteRule
{
    public string Id { get; set; }               // GUID
    public bool Enabled { get; set; } = true;
    public DateTime CreatedAtUtc { get; set; }
    public DateTime? ExpiresAtUtc { get; set; }  // null = permanent
    public string? Reason { get; set; }          // user note

    // Match criteria — all non-null fields must match (AND)
    public string? ServerName { get; set; }      // exact match, null = any
    public string? MetricName { get; set; }      // exact: "Blocking", "Deadlocks", "High CPU", etc.
    public string? DatabasePattern { get; set; } // substring (case-insensitive)
    public string? QueryTextPattern { get; set; }// substring (case-insensitive)
    public string? WaitTypePattern { get; set; } // substring (case-insensitive)
    public string? JobNamePattern { get; set; }  // substring (case-insensitive)
}

Alert Context for Matching

public class AlertContext
{
    public string ServerName { get; set; }
    public string MetricName { get; set; }       // "Blocking", "Deadlocks", "High CPU", etc.
    public string? DatabaseName { get; set; }
    public string? QueryText { get; set; }
    public string? WaitType { get; set; }
    public string? JobName { get; set; }
}

Integration Points

Dashboard — EvaluateAlertConditionsAsync() in MainWindow.xaml.cs:

• After each metric's threshold check passes, before sending notifications
• Call _muteRuleService.IsAlertMuted(context) with available detail
• If muted: log alert with Muted=true, skip tray/email/badge

Lite — CheckPerformanceAlerts() in MainWindow.xaml.cs:

• Same pattern: check mute rules per-metric after threshold triggers
• If muted: log to DuckDB with muted=TRUE, skip tray/email

Persistence

Dashboard: alert_mute_rules.json in %APPDATA%\PerformanceMonitorDashboard\
Lite: New DuckDB table config_mute_rules

UI

• Alert History tab: right-click context menu → "Mute This Alert" / "Mute Similar Alerts..."
• Mute Rule Dialog: create/edit form with match fields, expiration picker (1h/24h/7d/permanent), reason text
• Manage Mute Rules Window: list all rules, enable/disable/delete, accessible from Settings
• Visual indicator: muted alerts shown grayed/italic in alert history with a "muted" label

Use Case

Alerts which happen frequently, and are well-known, but cannot be immediately actioned, could be muted for a period of time, or muted permanently on a case-by-case basis.

Alternatives Considered

No response

Additional Context

Phase 1: Core Model & Service

1. model-mute-rule — Create MuteRule model class (both editions)
2. service-mute-rule-dashboard — Create MuteRuleService for Dashboard (JSON persistence, match logic)
3. service-mute-rule-lite — Create MuteRuleService for Lite (DuckDB persistence, match logic)
4. lite-schema-update — Add config_mute_rules table + muted column to config_alert_log in Schema.cs

Phase 2: Alert Pipeline Integration

5. integrate-dashboard-eval — Wire mute checks into EvaluateAlertConditionsAsync (per-metric)
6. integrate-lite-eval — Wire mute checks into CheckPerformanceAlerts (per-metric)
7. alert-log-muted-flag-dashboard — Add Muted field to AlertLogEntry, pass through RecordAlert
8. alert-log-muted-flag-lite — Add muted column to DuckDB insert in EmailAlertService.LogAlertAsync

Phase 3: UI — Mute Rule Management

9. dialog-mute-rule-dashboard — Create MuteRuleDialog.xaml/.cs for creating/editing rules
10. dialog-mute-rule-lite — Create equivalent for Lite edition
11. window-manage-rules-dashboard — Create ManageMuteRulesWindow (list, enable/disable, delete)
12. window-manage-rules-lite — Create equivalent for Lite edition
13. settings-button-dashboard — Add "Manage Mute Rules..." button to Dashboard SettingsWindow
14. settings-button-lite — Add equivalent to Lite SettingsWindow

Phase 4: UI — Alert History Integration

15. context-menu-dashboard — Add right-click "Mute" options to Dashboard alert history
16. context-menu-lite — Add right-click "Mute" options to Lite AlertsHistoryTab
17. visual-indicator-dashboard — Show muted alerts with distinct styling in alert history
18. visual-indicator-lite — Same for Lite

Phase 5: MCP & Polish

19. mcp-tools-dashboard — Add get_mute_rules to Dashboard McpAlertTools
20. mcp-tools-lite — Add get_mute_rules to Lite McpAlertTools
21. docs-readme — Update README alert section with mute rule documentation

Dependencies

• Phase 2 depends on Phase 1
• Phase 3 depends on Phase 1
• Phase 4 depends on Phase 2 + Phase 3
• Phase 5 depends on Phase 1

Notes

• Match logic uses AND across non-null fields (all specified fields must match)
• Instance-based muting is just a pattern rule with all fields populated from context
• Expired rules are automatically skipped during matching and can be cleaned up periodically
• Existing server silencing / acknowledgement / cooldown mechanisms remain unchanged
• Muted alerts are still written to the alert log for auditability — they just don't trigger notifications
• DuckDB schema version will need to be bumped for the Lite table changes

[HannahVernon]

Work is happening on https://github.com/HannahVernon/PerformanceMonitor/tree/feature/alert-muting

[HannahVernon]

Alert Muting & Alert Detail Window — Feature Branch Summary

Branch: feature/alert-muting (off dev)
37 files changed, +2,453 / -146 lines across 14 commits

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Alert Muting

Overview

Users can create rules to mute specific recurring alerts. Muted alerts are still collected and logged for auditability, but suppressed from tray notifications and email alerts. Muted alerts appear grayed out (dimmed, italic) in the Alert History tab.

Mute Rule Matching

Rules match using AND logic across any combination of:

• Server Name — exact match
• Metric Name — exact match (one of the 7 alert metrics)
• Database — substring match
• Query Text — substring match
• Wait Type — substring match
• Job Name — substring match

Blank fields match any value. All populated fields must match for the rule to apply.

Creating Mute Rules

• Settings → Manage Mute Rules → Add Rule... — create a rule from scratch
• Right-click alert → Mute This Alert... — pre-fills server name + metric (targeted rule for one server)
• Right-click alert → Mute Similar Alerts... — pre-fills metric only (matches across all servers)

The Create/Edit Mute Rule dialog is context-sensitive: it only shows pattern fields relevant to the selected metric type. For example, selecting "High CPU" or "TempDB Space" hides all pattern fields since those metrics have no filterable sub-properties. Selecting "Long-Running Query" shows Database, Query Text, and Wait Type fields.

Mute Rule Expiration

Rules support optional expiration:

• 1 hour
• 24 hours
• 7 days
• Never (permanent)

Expired rules can be bulk-removed via "Purge Expired" in the Manage Mute Rules window.

Manage Mute Rules Window

• DataGrid showing all rules with Enabled checkbox, Metric, Server, Reason, and Expires columns
• Enabled checkbox is single-click interactive and persists immediately across app restarts
• Double-click a rule to edit it
• Toggle and Delete buttons return focus to the grid and preserve selection for repeated operations
• Close button in bottom-right corner

Persistence

• Dashboard (Full Edition): JSON file at %APPDATA%\PerformanceMonitorDashboard\alert_mute_rules.json
• Lite Edition: DuckDB table config_mute_rules with in-memory cache

MCP Integration

• New get_mute_rules MCP tool returns all current mute rules (both editions)

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Alert Detail Window

Overview

A popup window showing full details about a specific alert from the Alert History tab.

Access

• Right-click → View Details... on any alert row
• Double-click any alert row

Core Fields (all metrics)

• Alert Time (local)
• Server Name
• Metric
• Current Value
• Threshold
• Notification Type
• Status (e.g., "Email Sent", "Tray Only", "Muted")
• Muted banner (shown when alert was suppressed by a mute rule)

Context-Sensitive Details

The Detail Window shows a "Details" section with rich contextual information that varies by metric type:

• Blocking Detected: Session IDs (blocked and blocking), database name, query text, wait time, lock mode, client application (up to 3 blocking events)
• Deadlocks Detected: Victim/survivor session IDs, database names, query text (up to 3 deadlock events)
• High CPU: No additional detail (core fields only — CPU % and threshold)
• Poison Wait: Per-wait-type breakdown showing wait type name, average ms per wait, delta wait ms, and delta tasks
• Long-Running Query: Session ID, database name, query text, CPU time, reads, writes, wait type, blocking session, program name (up to 3 queries)
• TempDB Space: Usage percentage, total reserved MB, unallocated MB, user objects MB, internal objects MB, version store MB
• Long-Running Agent Job: Job name, current duration, average duration, P95 duration, percentage of average, start time (up to 3 jobs)

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Schema Changes

Lite DuckDB

• Schema version bumped from 19 → 21
• v20: Added muted BOOLEAN NOT NULL DEFAULT false column to config_alert_log; added config_mute_rules table
• v21: Added detail_text VARCHAR column to config_alert_log

Dashboard

• Added Muted and DetailText properties to AlertLogEntry (in-memory alert log)
• RecordAlert method accepts new optional parameters: bool muted = false, string? detailText = null

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README Documentation

• Added all 7 alert metrics to the thresholds table (previously only had 4)
• Documented the three poison wait types with links to Microsoft Docs:
  • THREADPOOL (worker thread exhaustion)
  • RESOURCE_SEMAPHORE (memory grant pressure)
  • RESOURCE_SEMAPHORE_QUERY_COMPILE (compilation memory pressure)
• Documented alert muting feature (rule matching, access points, expiration)
• Documented the difference between "Mute This Alert" and "Mute Similar Alerts"
• Documented the Alert Detail Window and its context-sensitive details

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Files Changed

New Files (18)

• Dashboard/Models/MuteRule.cs — MuteRule + AlertMuteContext model classes
• Dashboard/Services/MuteRuleService.cs — JSON-persisted mute rule management
• Dashboard/MuteRuleDialog.xaml + .cs — Create/edit mute rule dialog
• Dashboard/ManageMuteRulesWindow.xaml + .cs — Manage all mute rules window
• Dashboard/AlertDetailWindow.xaml + .cs — Alert detail popup window
• Lite/Models/MuteRule.cs — MuteRule + AlertMuteContext (file-scoped namespace)
• Lite/Services/MuteRuleService.cs — DuckDB-persisted mute rule management
• Lite/Windows/MuteRuleDialog.xaml + .cs — Create/edit mute rule dialog
• Lite/Windows/ManageMuteRulesWindow.xaml + .cs — Manage all mute rules window
• Lite/Windows/AlertDetailWindow.xaml + .cs — Alert detail popup window

Modified Files (19)

• Dashboard/MainWindow.xaml.cs — Mute checks in all 7 metrics, context builders moved for richer detail text
• Dashboard/Controls/AlertsHistoryContent.xaml — Context menu items, muted row styling
• Dashboard/Controls/AlertsHistoryContent.xaml.cs — MuteRuleService property, handlers, DetailText on DisplayItem
• Dashboard/Services/EmailAlertService.cs — DetailText on AlertLogEntry, detailText param on RecordAlert
• Dashboard/SettingsWindow.xaml + .cs — "Alert Muting" section with Manage button
• Dashboard/Mcp/McpAlertTools.cs — get_mute_rules MCP tool
• Dashboard/Mcp/McpHostService.cs — MuteRuleService DI
• Lite/MainWindow.xaml.cs — Mute checks in all 7 metrics, detail text building
• Lite/Controls/AlertsHistoryTab.xaml — Context menu items, muted row styling
• Lite/Controls/AlertsHistoryTab.xaml.cs — MuteRuleService property, handlers, DetailText on AlertHistoryRow
• Lite/Services/EmailAlertService.cs — detailText param on TrySendAlertEmailAsync + LogAlertAsync
• Lite/Services/LocalDataService.AlertHistory.cs — detail_text in SQL queries + reader mapping
• Lite/Database/Schema.cs — detail_text column in CreateAlertLogTable
• Lite/Database/DuckDbInitializer.cs — Schema v19→21, migrations for muted + detail_text columns
• Lite/Windows/SettingsWindow.xaml + .cs — "Alert Muting" section with Manage button
• Lite/Mcp/McpAlertTools.cs — get_mute_rules MCP tool
• Lite/Mcp/McpHostService.cs — MuteRuleService DI
• Lite.Tests/DuckDbSchemaTests.cs — Updated table count for config_mute_rules
• README.md — Full documentation of alert muting, detail window, metrics, poison waits

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Test Results

• 6/6 unit tests passing
• Build: 0 errors across all 5 projects
• Both Dashboard and Lite editions have feature parity

[HannahVernon]

Screenshots from the feature branch:

Settings Dialog for 'Alert Muting' entry-point:

Manage Mute Rules dialog box:

Edit Mute Rule dialog box for "Long Running Job" rule, showing a filter for Job Name:

Mute Rule dialog for "High CPU" mute rule, with filter for Server Name:

Mute Rule dialog for "Blocking Detected" mute rule with filters by Database Name and Query Text:

Alert History window showing muted and active alerts, along with a sample details window for a 'Long-Running Alert' that has been muted:

Alert Details window showing a delivered Long-Running Jobs Cleared alert:

A Long-Running Job alert showing details of the job:

Poision Waits details:

Long-Running Query details:

[HannahVernon]

Screenshots from Lite:

Access point for the Alert Muting dialog:

Create Mute Rule dialog showing an entire server being muted, with options to filter muted alerting by "Database", "Wait Type", "Query Text", and "Job Name":

Edit Mute rule for "Long Running Query" showing exclusions by Query Text, with options to exclude by Database Name and Wait Types:

[HannahVernon]

Lite, showing Alert Details on double-click of an item in the "Alert History" tab:

And, a "muted" alert in the same tab (top row "Long-Running Job" in italics):