Add Pebble SST ingest snapshot transfer

[bootjp]

Summary

• add an opt-in checkpoint-derived Pebble SST snapshot stream with a versioned integrity manifest
• restore verified SST files through DB.Ingest into a temporary database with atomic swap, rollback, and crash recovery
• retain legacy snapshot emission by default and fall back before streaming when SST preparation fails
• cover KV FSM and disk-spooled gRPC snapshot transport integration
• mark the focused design implemented and keep physical object offload out of scope

Safety and rollout

Set ELASTICKV_PEBBLE_SST_INGEST_SNAPSHOT=true only after every member runs a receiver-capable binary. Receivers always accept the new format. Invalid or unset values preserve legacy emission. Manifest, file bounds, exact lengths, SHA-256 digests, and EOF are verified before the live database is replaced.

The shared restore swap now retains the old database until the replacement opens and metadata verifies. Startup recovers a single interrupted rollback directory and preserves ambiguous backups instead of deleting them.

Tests

• go test ./store ./kv ./internal/raftengine/etcd -count=1 -timeout=20m
• go test -race ./store ./kv ./internal/raftengine/etcd -run 'TestPebbleStoreSST|TestSSTIngest|TestCountingWriter|TestSwapInTempDB|TestKVFSMSnapshotRoundTripsSSTIngestPayload|TestGRPCSnapshotTransportRoundTripsSSTIngestPayload|TestPebbleStore_SnapshotRestore|TestPebbleStore_Restore' -count=1 -timeout=15m\n- go test ./adapter -count=1 -timeout=20m\n- golangci-lint --config=.golangci.yaml run --fix

[coderabbitai]

Warning

Review limit reached

@bootjp, you've reached your PR review limit, so we couldn't start this review.

Next review available in:34 minutes

Enable usage-based reviews in Billing to review now. Otherwise, wait until the next included review is available.
You're only billed for reviews past your plan's rate limits ($0.25/file).

How can I continue?

After more reviews become available, a review can be triggered using the @coderabbitai review command as a PR comment. Alternatively, push new commits to this PR.

To avoid repeated limits, reduce automatic review volume by pausing incremental auto-reviews earlier, using label-based review opt-in, excluding WIP or generated PR titles, or requesting reviews manually when the PR is ready. If your team needs uninterrupted high-volume reviews, an organization admin can enable usage-based reviews.

How do review limits work?

CodeRabbit enforces per-developer PR review limits for each organization. Most developers receive the normal plan review availability.

For paid Pro and Pro+ PR reviews, CodeRabbit uses adaptive limits for sustained high-volume activity. When a developer's recent PR review activity reaches the 95th percentile or higher among CodeRabbit users, additional reviews become available more gradually as earlier reviews age out of the rolling window.

Please refer docs for additional details.

Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 9e97baa5-4303-496d-b18d-3f03a24b667f

📥 Commits

Reviewing files that changed from the base of the PR and between 915bc77 and 214a8cc.

📒 Files selected for processing (8)

• docs/design/2026_06_12_proposed_scaling_roadmap.md
• docs/design/2026_07_19_implemented_pebble_sst_ingest_snapshot_transfer.md
• internal/raftengine/etcd/grpc_transport_sst_snapshot_test.go
• kv/snapshot_sst_ingest_test.go
• store/lsm_store.go
• store/snapshot_pebble.go
• store/snapshot_pebble_sst.go
• store/snapshot_pebble_sst_test.go

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[bootjp]

Implementation and caller audit are complete on current HEAD 10491972bf234ed2253e18fef78a05d4699e7cd0.

Local evidence:

• go test ./store ./kv ./internal/raftengine/etcd -count=1 -timeout=20m
• focused go test -race across the SST, rollback, KV FSM, and gRPC transport paths
• go test ./adapter -count=1 -timeout=20m
• repository commit hook: golangci-lint with 0 issues
• old proposed design path references: none

Please review checkpoint consistency, manifest validation, atomic rollback/crash recovery, legacy fallback, and the audited native/MVCC/SST swap callers.

@codex review

[gemini-code-assist]

Code Review

This pull request implements Pebble SST Ingest Snapshot Transfer, introducing a new snapshot format (EKVSSTI1) that exports external SST files from a point-in-time checkpoint and ingests them atomically on the receiver side with rollback support. Feedback on these changes focuses on enhancing resource safety and robustness. Key recommendations include using defer (and wrapping loop bodies in anonymous functions) to prevent file descriptor leaks in the event of panics during file operations, avoiding global mutable state in tests to prevent data races, and replacing filepath.Glob with os.ReadDir to handle directory paths containing glob characters safely.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. You're on a roll.

Reviewed commit:10491972bf

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[bootjp]

Addressed and resolved all five current-head Gemini threads in signed commit 214a8ccf027a9190d7a5ec467f27a6ae3658c097:

• deferred, error-preserving file cleanup for inspect, stream, and receive paths
• instance-local SST target size with no mutable package test state
• literal os.ReadDir artifact discovery with a glob-character path regression

Verification on the new HEAD:

• go test ./store ./kv ./internal/raftengine/etcd -count=1 -timeout=20m
• focused go test -race across SST, rollback, KV FSM, and transport paths
• changed-package lint: 0 issues
• repository commit-hook lint: 0 issues

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. 🚀

Reviewed commit:214a8ccf02

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[bootjp]

Review-loop stop recorded for current HEAD 214a8ccf027a9190d7a5ec467f27a6ae3658c097:

• current-head review: no major issues
• current-head inline roots: none (all earlier Gemini roots are stale by original_commit_id and resolved)
• issue-style findings: none on the current head
• CI: all completed checks successful or intentionally skipped
• mergeability: mergeable

The PR remains open and was not merged.