PowerShell CMTrace Log Tool

A high-performance, WPF-based log viewer for PowerShell, specifically engineered to handle massive log files (up to 10 million lines) with minimal memory overhead and near-instant parsing. It mimics the functionality of the classic CMTrace utility while providing modern customization, multithreaded file tailing, and regex/keyword-based highlighting.

Key Features

• Massive Log Support: Capable of seamlessly loading, retaining, and viewing up to 10,000,000 log lines in memory without crashing, trimming, or freezing the UI.
• Crash-Proof Bulk UI Updates: Implements a custom ObservableRangeCollection<T> that properly suppresses individual notifications during bulk adds, preventing WPF ItemsControl inconsistency exceptions and massive layout thrashing.
• Multithreaded Performance: Uses a dedicated background Runspace with a highly tuned 10,000-item drain limit per 50ms tick to tail files, preventing UI freezes during massive log reads.
• WPF-Powered UI: Modern DataGrid interface with strict item-level virtualization, ensuring smooth scrolling even with millions of log entries.
• Throttled UI Rendering: Intelligent UI update throttling ensures the statistics panel recalculates at a maximum of 1Hz during continuous heavy tailing, keeping the interface buttery smooth.
• Optimized Initial Load: Real-time total line count updates without triggering heavy layout recalculations during the initial file flush, keeping the window draggable and responsive.
• Zero-Cost Timestamp Parsing: High-speed C# log parsing integrated directly into the script. Extracts timestamps via direct string slicing instead of DateTime.TryParse, yielding a ~5x parsing speedup.
• Customizable Highlighting: Define custom keywords and color schemes (Red, Orange, Yellow, Green, Blue, Purple, White) to instantly spot errors and warnings.
• Detail Formatting: Includes intelligent JSON formatting and delimiter splitting (comma, space, period) in the bottom detail panel for easier log analysis.
• Persistent Configuration: Automatically saves user settings, window state, and keyword preferences to an .ini file in AppData.

Architecture Highlights

• Optimized Tailer: Uses a System.IO.StreamReader with a 64KB buffer and FileShare.ReadWrite to reliably tail active log files at maximum disk I/O speeds without locking them.
• High-Capacity Memory Management: Pre-allocates 500,000 initial entries and dynamically scales up to 11 million items before trimming, drastically reducing array resizing overhead and GC pressure.
• O(1) Auto-Scrolling: Caches the WPF ScrollViewer reference and uses ScrollToEnd() instead of ScrollIntoView(), bypassing expensive visual tree realization and layout calculations.
• Smart Filtering Bypass: Automatically skips the C# filtering logic and injects raw batches directly into the UI collection if no level filters are active.
• Zero-GC Pressure: Uses StringBuilder and efficient string slicing (avoiding unnecessary concatenations and date parsing) to parse logs with minimal garbage collection.
• Mouse-Wheel Smoothing: Features custom PreviewMouseWheel handling to provide granular, "slow" scrolling for precise log investigation.

Getting Started

1. Requirements: PowerShell 5.1 or later (64-bit host required for large memory allocations).
2. Run: Simply execute the script in a PowerShell host capable of rendering WPF (e.g., powershell.exe or pwsh.exe).
3. Opening Logs: Use File > Open... to select a .log or .txt file.

Settings & Configuration

The application allows full customization of:

• Visuals: Font family, font size, and window layout.
• Highlighting: Add, remove, or modify keyword/color mappings in the Settings menu.
• Formatting: Toggle JSON beautification or add custom delimiters for parsing complex message strings.

Recent Optimizations & New Features

• 10 Million Line Capacity: MaxRetainedEntries increased to 10,000,000. InitialCapacity increased to 500,000 to prevent constant array resizing during massive file loads.
• WPF Crash Fix: Completely rewrote ObservableRangeCollection to fire a single Reset event after bulk additions, fixing the "ItemsControl is inconsistent with its items source" crash when ingesting hundreds of thousands of lines per second.
• 5x Faster Parsing: Replaced DateTime.TryParse with direct Substring extraction for CMTrace timestamps.
• High-Throughput I/O: Increased StreamReader buffer size to 64KB to minimize system calls during initial file reads.
• Instant Auto-Scroll: Replaced DataGrid.ScrollIntoView() with cached ScrollViewer.ScrollToEnd() for O(1) scrolling performance.
• UI Thread Protection: Tuned MaxDrainPerTick to 10,000 and the refresh timer to 50ms, ensuring the UI thread is never starved even if the background parser ingests 50,000+ logs/sec.

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Developed for high-performance systems administration and rapid troubleshooting of massive log files.