By the numbers

A quantitative snapshot of the Neon repository.

Data collected on 2026-04-30 against commit 6a35a3e9f on main.

Size

Lines of code by language (excluding vendor/, target/, and lock files):

xychart-beta horizontal
    title "Lines of code by language"
    x-axis [Rust, Python, C, SQL, Shell, "Markdown (docs)"]
    y-axis "Lines of code (thousands)"
    bar [302, 77, 25, 4, 1, 21]

Language	Files	Lines	Notes
Rust	698	302,334	All services, libraries, and tools
Python	268	77,475	Integration tests in test_runner/
C	30	24,600	Inside pgxn/neon/ (extension + walproposer)
C headers	24	2,275	Postgres extension headers and walproposer
SQL	241	3,861	Migrations and Postgres regression fixtures
Markdown	131	20,725	docs/, READMEs, RFCs
Shell	—	1,118	scripts/, run_clippy.sh, pre-commit.py shim

The vendor/postgres-v{14,15,16,17} trees are vendored upstream Postgres and are excluded from the counts above.

Workspace structure

The Cargo workspace declares 51 member crates in Cargo.toml. They split into:

Group	Count	Examples
Top-level services	8	pageserver, safekeeper, proxy, storage_broker, storage_controller, storage_scrubber, compute_tools, endpoint_storage
Pageserver helpers	5	pageserver/compaction, pageserver/ctl, pageserver/client, pageserver/client_grpc, pageserver/page_api, pageserver/pagebench
Service clients / CLIs	3	safekeeper/client, storage_controller/client, control_plane/storcon_cli
Shared libraries (libs/)	25	utils, metrics, postgres_ffi, pq_proto, pageserver_api, safekeeper_api, walproposer, wal_decoder, remote_storage, vm_monitor, …
Build/dependency hack	1	workspace_hack
Postgres extension support	1	pgxn/neon/communicator

Largest source files

The biggest files are also the most central. They are good candidates for refactoring.

File	Lines
pageserver/src/tenant.rs	12,926
storage_controller/src/service.rs	10,544
pageserver/src/tenant/timeline.rs	8,326
pageserver/src/metrics.rs	4,671
pageserver/src/page_service.rs	4,662
pageserver/src/tenant/timeline/compaction.rs	4,584
pageserver/src/http/routes.rs	4,276
pageserver/src/pgdatadir_mapping.rs	3,489
pageserver/src/tenant/remote_timeline_client.rs	3,304
storage_controller/src/tenant_shard.rs	3,220

TODO / FIXME / HACK

The Rust codebase contains 785 comments matching TODO|FIXME|XXX|HACK, broken down as:

Marker	Count
TODO	654
FIXME	83
Other (XXX, HACK)	48

Activity

Commits per calendar year on main:

Year	Commits
2021	1,146
2022	1,429
2023	1,709
2024	2,539
2025	1,647
2026 (partial, through Mar)	3

Total commits across history: 18,944.

In the trailing 365 days the repo has roughly 648 commits authored by 55 distinct people or service accounts. Cumulative distinct authors over the full history: 175.

Bot-attributed commits

Bot accounts (e.g. dependabot[bot], github-actions[bot], renovate[bot]) appear in roughly 8 of the last 647 commits (about 1.2%). Neon does not currently use Factory Droid or Copilot in a way that leaves git-history traces, so AI-assisted contribution rates cannot be reliably extracted from history alone.

Postgres versions supported

Makefile declares POSTGRES_VERSIONS = v17 v16 v15 v14. Each version has its own vendored tree under vendor/postgres-v* and a per-version build of the neon extension.

Cargo dependency footprint

Cargo.lock is 213 KB and tracks ~600 transitive dependencies. The workspace_hack crate (managed by cargo-hakari) pins versions across the workspace to keep build times reasonable.

Test surface

Area	Files	LOC
Rust unit tests (in-tree #[cfg(test)] and tests/)	many	counted in Rust LOC above
Python integration tests (test_runner/)	268 .py	77,475
Postgres regression test fixtures (test_runner/sql_regress/)	241 .sql	3,861

The CI runs both debug and release builds across all four supported Postgres versions; see .github/workflows/build_and_test.yml (the largest workflow, ~73 KB).

Where this stops being a snapshot

This page captures a single moment. For an evolving narrative — what was added, what was rewritten, what was removed — see lore. For ownership maps see maintainers.