perf(dash-spv)!: persist the masternode list engine instead of replaying its messages by ZocoLini · Pull Request #1221 · dashpay/rust-dashcore

ZocoLini · 2026-10-26T16:48:03Z

Replaces the stored MnListDiff/QRInfo log, which every start replayed and
re-validated in full. Nothing pruned that log, so startup got slower the longer
a wallet was used (~2–3.5 s on mainnet with only 28 messages).

The storage now owns the engine and keeps a single snapshot of it
(masternodes/engine.dat). Restoring it on mainnet takes ~30 ms. The snapshot
is written once per QRInfo, on stop and after a reorg truncation. A migration
drops the old messages, so the first start after it syncs the masternode lists
from the network once.

Breaking: get_quorum_at_height no longer rebuilds quorums the engine has
pruned from stored messages (#1075); only heights within the engine's retention
window resolve.

Closes #1215

PR Hygiene · `ebe1fa3`

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- dash-spv (dash-spv/Cargo.toml, dash-spv/src/client/core.rs, dash-spv/src/client/lifecycle.rs and 10 more) — QuantumExplorer or xdustinface

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github-actions · 2026-10-26T16:48:48Z

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coderabbitai · 2026-10-26T16:49:00Z

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Source mode: Auto
Repository: dashpay/rust-dashcore
Branch: perf/masternode-engine-snapshot
File: .coderabbit.yaml
Commit: ebe1fa3
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Run ID: 4397dbcc-184c-46bb-a585-2973fad2008f

Commits

Reviewing files that changed from the base of the PR and between 22104eb and ebe1fa3.

Files selected for processing: 2

dash-spv/src/client/lifecycle.rs
dash-spv/src/sml_engine.rs

Walkthrough

Masternode storage now persists engine snapshots instead of individual diff and QRInfo messages. The client restores and uses the shared storage engine, and quorum lookups search its in-memory lists. A storage migration removes the previous masternode message directory.

Changes: Masternode engine snapshots

Layer / File(s)	Summary
Snapshot storage and migration `dash-spv/Cargo.toml`, `dash-spv/src/sml_engine.rs`, `dash-spv/src/storage/masternode.rs`, `dash-spv/src/storage/mod.rs`, `dash-spv/src/storage/migrator/*`	The engine can encode and decode snapshots. Persistent storage validates restored snapshots against the header chain, persists non-empty engines, and truncates or clears the shared engine. Storage version 3 removes the previous `masternodes` directory.
Persisting the engine after sync `dash-spv/src/sync/masternodes/manager.rs`, `dash-spv/src/sync/masternodes/sync_manager.rs`	The manager persists the engine after quorum validation. Sync response handling no longer stores individual diffs or QRInfo messages.
Client engine access and lookup `dash-spv/src/client/core.rs`, `dash-spv/src/client/lifecycle.rs`, `dash-spv/src/client/queries.rs`, `dash-spv/tests/dashd_masternode/*`	The client obtains its engine from storage and no longer rebuilds or separately truncates it. Quorum lookup uses in-memory lists only. Restart tests check that the engine tip is restored.

Priority: Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant MasternodesManager
  participant PersistentMasternodeStorage
  participant MasternodeListEngine
  participant engine.dat
  MasternodesManager->>PersistentMasternodeStorage: Persist engine
  PersistentMasternodeStorage->>MasternodeListEngine: Create snapshot
  MasternodeListEngine-->>PersistentMasternodeStorage: Encoded snapshot bytes
  PersistentMasternodeStorage->>engine.dat: Atomically write snapshot

Possibly related issues

dash-spv: the masternode message-log replay in DashSpvClient::new adds 7–12 s to every start #1215: This change replaces message-log replay on startup with restoration from an engine snapshot.

Possibly related PRs

dashpay/rust-dashcore#1211: That PR preserves engine state when feeds are refused or interrupted; this change persists the resulting engine state in a snapshot.

Suggested reviewers: xdustinface, shumkov, quantumexplorer

Merge Risk: Low · up to 22104

The change restores the masternode engine from a snapshot on startup instead of replaying stored messages. One narrow gap remains: if a storage write fails partway through a fork truncation, stale masternode lists from the abandoned branch can stay in the engine and be saved. Fix the truncation ordering before merging or accept it as a rare edge case.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 43.18% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 44 functions across 11 files. (1 skipped:…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: persisting the masternode list engine instead of replaying stored messages. The breaking-change marker is appropriate because the PR changes …
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title clearly and concisely describes the main change: persisting the masternode list engine instead of replaying stored messages. The breaking-change marker is appropriate because the PR changes quorum lookup behavior and storage APIs.

Full details: Docstring Coverage

Explanation

Docstring coverage is 43.18% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 44 functions across 11 files. (1 skipped: 1 unsupported.)

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

Finishing Touches: 💡 1

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Actionable comments posted: 2

🪄 Fix comments: Fix CodeRabbit comments on this PR

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Inline comments:
Review comments at @dash-spv/src/client/lifecycle.rs:
- Line 286: Update DiskStorageManager::truncate_above to attempt
MasternodeStorage::truncate_above after the other storage truncations regardless
of their result, while preserving the existing order and returning the first
error.

Review comments at @dash-spv/src/sml_engine.rs:
- Around line 247-269: Update from_snapshot to retain the number of bytes
consumed by decode_from_slice and reject the snapshot with a DecodeError if that
count differs from bytes.len(); preserve the existing decoded-value construction
when all bytes are consumed.

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Review info

Run configuration

Source mode: Auto
Repository: dashpay/rust-dashcore
Branch: perf/masternode-engine-snapshot
File: .coderabbit.yaml
Commit: 22104eb
Layers: Repository YAML
Review profile: CHILL
Plan: Advanced
Run ID: 1146a890-4e42-4c6d-b6f9-498294a86577

Commits

Reviewing files that changed from the base of the PR and between 22f52ac and 22104eb.

Files selected for processing: 13

dash-spv/Cargo.toml
dash-spv/src/client/core.rs
dash-spv/src/client/lifecycle.rs
dash-spv/src/client/queries.rs
dash-spv/src/sml_engine.rs
dash-spv/src/storage/masternode.rs
dash-spv/src/storage/migrator/mod.rs
dash-spv/src/storage/migrator/v3.rs
dash-spv/src/storage/mod.rs
dash-spv/src/sync/masternodes/manager.rs
dash-spv/src/sync/masternodes/sync_manager.rs
dash-spv/tests/dashd_masternode/helpers.rs
dash-spv/tests/dashd_masternode/tests_sync.rs

Files with no reviewable changes: 1

dash-spv/src/client/core.rs

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github-actions · 2026-10-26T16:57:19Z

Your move: coderabbitai requested changes on this head; dismiss the review or push a fix; coderabbitai left review threads unresolved; resolve them.
Full checklist in the description.

…, reject trailing snapshot bytes Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

github-actions · 2026-10-26T17:13:19Z

Waiting for bot review — coderabbitai not yet. Wait for the missing reviews, or a writer can post /skip-bots to proceed without them; blocking findings still need addressing.
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codecov · 2026-10-26T17:28:46Z

Codecov Report

❌ Patch coverage is 93.22034% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.79%. Comparing base (22f52ac) to head (ebe1fa3).

Files with missing lines	Patch %	Lines
dash-spv/src/client/queries.rs	0.00%	6 Missing ⚠️
dash-spv/src/storage/masternode.rs	97.70%	3 Missing ⚠️
dash-spv/src/sync/masternodes/manager.rs	77.77%	2 Missing ⚠️
dash-spv/src/sml_engine.rs	95.45%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1221      +/-   ##
==========================================
- Coverage   78.88%   78.79%   -0.09%     
==========================================
  Files         304      305       +1     
  Lines       81331    81004     -327     
==========================================
- Hits        64155    63830     -325     
+ Misses      17176    17174       -2

Flag	Coverage Δ
core	`77.75% <ø> (ø)`
ffi	`50.54% <ø> (ø)`
rpc	`52.05% <ø> (ø)`
spv	`92.38% <93.22%> (-0.10%)`	⬇️
wallet	`82.54% <ø> (ø)`

Files with missing lines	Coverage Δ
dash-spv/src/client/core.rs	`60.86% <ø> (+2.04%)`	⬆️
dash-spv/src/client/lifecycle.rs	`90.87% <100.00%> (-0.04%)`	⬇️
dash-spv/src/storage/migrator/mod.rs	`39.28% <ø> (ø)`
dash-spv/src/storage/migrator/v3.rs	`100.00% <100.00%> (ø)`
dash-spv/src/storage/mod.rs	`90.25% <100.00%> (+1.02%)`	⬆️
dash-spv/src/sync/masternodes/sync_manager.rs	`98.78% <100.00%> (-0.08%)`	⬇️
dash-spv/src/sml_engine.rs	`97.23% <95.45%> (-0.03%)`	⬇️
dash-spv/src/sync/masternodes/manager.rs	`96.44% <77.77%> (-0.59%)`	⬇️
dash-spv/src/storage/masternode.rs	`98.23% <97.70%> (-1.33%)`	⬇️
dash-spv/src/client/queries.rs	`42.50% <0.00%> (-1.05%)`	⬇️

... and 5 files with indirect coverage changes

github-actions · 2026-10-26T20:20:18Z

Bots are done — your move: post /self-reviewed.
Full checklist in the description.

feat: persist masternode list engine state

22104eb

github-actions Bot added the waiting-bots Waiting for the review bots to report on this head label Oct 26, 2026

ZocoLini mentioned this pull request Oct 26, 2026

dash-spv: the masternode message-log replay in DashSpvClient::new adds 7–12 s to every start #1215

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Comment thread dash-spv/src/client/lifecycle.rs Resolved

Comment thread dash-spv/src/sml_engine.rs Resolved

github-actions Bot added waiting-self-review Waiting for the author to post /self-reviewed and removed waiting-bots Waiting for the review bots to report on this head labels Oct 26, 2026

fix(dash-spv): truncate the engine even when storage truncation fails…

ebe1fa3

…, reject trailing snapshot bytes Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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coderabbitai Bot mentioned this pull request Oct 26, 2026

fix(dash-spv)!: verify MnListDiff against its block's coinbase before applying #1200

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xdustinface approved these changes Oct 28, 2026

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xdustinface merged commit 7329126 into dev Oct 28, 2026
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xdustinface deleted the perf/masternode-engine-snapshot branch October 28, 2026 06:52

xdustinface mentioned this pull request Oct 28, 2026

refactor(dash-spv): snapshot the masternode engine without copying shared entries #1227

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coderabbitai Bot mentioned this pull request Oct 30, 2026

feat(dash-spv): expose the coinbase payload of the newest validated diff #1202

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perf(dash-spv)!: persist the masternode list engine instead of replaying its messages - #1221

perf(dash-spv)!: persist the masternode list engine instead of replaying its messages#1221
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