Memory Snapshot Report

Memory Snapshot Report

This is the analysis workflow for the tool (export → validate → report, plus ad-hoc SQL). To build, launch, and screenshot the tool end-to-end from a clean checkout, use the run-memory-snapshot-data-tool skill and its driver.

When to use

• User wants to analyze a Unity memory snapshot (.snap file).
• User wants to export a snapshot to a DuckDB or SQLite database.
• User wants to generate or view an HTML report from an exported snapshot database.
• User wants to validate an export against Unity golden values.

Prerequisites

• .NET 10 SDK.
• Run commands from the repo root (the directory containing MemorySnapshotDataTools.sln).

Steps

1. Export snapshot to database

From the repo root:

dotnet run --project Cli/MemorySnapshotDataTools.Cli.csproj -- export <path/to/snapshot.snap> <path/to/output.duckdb> --validate minimal --verbose

• Use .duckdb for DuckDB (recommended) or .db for SQLite.
• For SQLite add --destination sqlite.
• --verbose prints progress and timings (parse+extract vs. write).

Batch export every .snap in a directory to <basename>.duckdb alongside each file:

dotnet run --project Cli/MemorySnapshotDataTools.Cli.csproj -- batch-export <directory> \
  --filter MyGame \
  --skip-existing \
  --verbose

• --filter is optional (case-insensitive substring on filenames).
• --skip-existing skips when the output DB is newer than the snap.
• Exit code 0 = all succeeded, 1 = one or more failures, 2 = cancelled.

2. Validate export against Unity golden JSON

For the full validation workflow (extracting golden values in Unity, every compared metric, tolerances, and failure formats) use the validate-golden skill and docs/golden-validation.md. Quick path:

The golden extractor lives in the com.unity.memory-snapshot-data-tools package under UnityPackage/ in this repo, imported into a Unity project via a local file: path in that project's Packages/manifest.json. After extracting *_golden.json in Unity (Tools → Memory Snapshot Validation → Extract Golden Values):

dotnet run --project Cli/MemorySnapshotDataTools.Cli.csproj -- validate \
  <path/to/snapshot_golden.json> \
  <path/to/exported.duckdb>

• Compares AssetBundle, SerializedFile (Unity Subsystems native roots), and Remapper metrics.
• Also compares the MemoryProfiler Summary page metrics from the summary_metrics table:
  • Allocated Memory Distribution: Total Allocated, Total Resident, Native, Managed, Executables & Mapped, Graphics (Estimated), Untracked.
  • Managed Heap Utilization: Virtual Machine, Objects, Empty Heap Space.
  • Committed bytes use a 1% / 64 KB tolerance (5% / 1 MB for the estimated Graphics and Untracked rows); resident bytes use 1% / 64 KB and are skipped for Graphics and Untracked (resident unavailable).
• Writes *_validation_result.json next to the golden file unless --out is set.
• Exit code 0 = pass, 1 = metric mismatch, 3 = error.

3. Generate HTML report

dotnet run --project Cli/MemorySnapshotDataTools.Cli.csproj -- report <path/to/output.duckdb> --out report.html --verbose

• Omit --out to write to a temp file and open in the browser.
• Use --title "My Report" to set the report title.
• Report works with either DuckDB or SQLite databases produced by the export command. Prefer DuckDB — the SQLite report query is dramatically slower (seconds → minutes).

4. Optional

• Open the generated HTML file or DB in the user’s preferred viewer.
• For ad-hoc SQL, use the same DB path; tables are schema_meta, snapshot_info, native_objects, managed_objects, connections, native_roots, memory_regions, native_allocations, system_memory_regions, and summary_metrics (MemoryProfiler Summary-page breakdown). Analysis views (v_allocation_enriched, v_system_region_summary, v_region_owner_breakdown) and DuckDB macros (region_allocations, region_page_density) simplify native-memory/region queries. For schema details, join keys, and version compatibility, use the memory-db-sql skill and docs/database-schema.md.

Domain

• The tool supports DuckDB (default) and SQLite; report can be generated from either.
• The CLI reports timings: export shows parse+extract vs. write; report shows query vs. render vs. write. Use --verbose to see them.