Datasets:

brianmcgee
/

nix-cache-dataset

	---
	license: mit
	language:
	- en
	tags:
	- nix
	- nixos
	size_categories:
	- 100M<n<1B
	- 1B<n<10B
	pretty_name: Nix Cache Dataset
	configs:
	- config_name: inventory
	data_files: datasets/inventory-2026-01-06T01-13Z.parquet
	- config_name: narinfos in the inventory
	data_files: datasets/narinfos-2026-01-06T01-13Z.parquet
	- config_name: narinfos in the inventory - nixos images only
	data_files: datasets/narinfos-nixos-images-2026-01-06T01-13Z.parquet
	- config_name: store paths affected by the removal of nixos images
	data_files: datasets/narinfos-nixos-images-dangling-refs-2026-01-06T01-13Z.parquet
	- config_name: buildstepoutputs
	data_files: datasets/buildstepoutputs-2025-12-05-17:38:30Z.csv.zst
	- config_name: narinfos in inventory but not in buildstepoutputs
	data_files: datasets/inventory-not-in-buildstepoutputs-2025-12-05-17:38:30Z.parquet

	---

	# Nix Cache Dataset

	This repository contains several datasets relating to the contents of https://cache.nixos.org:

	## Getting started

	To make it easier to explore the datasets, a [Nix] devshell is provided in `shell.nix`. To enter it, run

	```console
	❯ nix develop -f shell.nix

	[brian@saturn:~/Development/com/github/numtide/nix-cache-dataset]$
	```

	If you are a [Direnv] user, you can also run `direnv allow` to automatically load the devshell:

	```console
	❯ direnv allow
	direnv: loading ~/Development/com/github/numtide/nix-cache-dataset/.envrc
	direnv: using nix
	direnv: nix-direnv: Using cached dev shell
	direnv: export +AR +AS +CC +CONFIG_SHELL +CXX +HOST_PATH +IN_NIX_SHELL +LD +NIX_BINTOOLS +NIX_BINTOOLS_WRAPPER_TARGET_HOST_x86_64_unknown_linux_gnu +NIX_BUILD_CORES +NIX_CC +NIX_CC_WRAPPER_TARGET_HOST_x86_64_unknown_linux_gnu +NIX_CFLAGS_COMPILE +NIX_ENFORCE_NO_NATIVE +NIX_HARDENING_ENABLE +NIX_LDFLAGS +NIX_STORE +NM +OBJCOPY +OBJDUMP +RANLIB +READELF +SIZE +SOURCE_DATE_EPOCH +STRINGS +STRIP +__structuredAttrs +buildInputs +buildPhase +builder +cmakeFlags +configureFlags +depsBuildBuild +depsBuildBuildPropagated +depsBuildTarget +depsBuildTargetPropagated +depsHostHost +depsHostHostPropagated +depsTargetTarget +depsTargetTargetPropagated +doCheck +doInstallCheck +dontAddDisableDepTrack +mesonFlags +name +nativeBuildInputs +out +outputs +patches +phases +preferLocalBuild +propagatedBuildInputs +propagatedNativeBuildInputs +shell +shellHook +stdenv +strictDeps +system ~PATH ~XDG_DATA_DIRS

	brian@saturn ~/..../nix-cache-dataset  main* ⇡
	❯
	```

	The devshell contains a `duckdb` command which is pre-configured to load some helpful utility functions which reside in
	`./duckdb/init.sql`:

	* `nixbase32` which converts a fixed-size `byte[20]` column into nixbase32
	* `narURL` which recovers the URL of a NAR file from it's `file_hash` and `compression` columns.

	Both are necessary when introspecting any of the narinfo related datasets as their schema was optimized to reduce file
	sizes.

	## Contents

	> [!NOTE]
	> The primary datasets below were compiled with [Narwal].

	### `datasets/inventory-2026-01-06T01-13Z.parquet`

	This is a complete inventory of the [S3 Bucket] which backs the cache as of `2026-01-06T01:13Z` and provided by the
	[S3 Inventory Service]. It has the following schema and is ordered by `key`:

	```console
	❯ duckdb -c "describe select * from 'datasets/inventory-2026-01-06T01-13Z.parquet'"
	┌────────────────────┬──────────────────────────┬─────────┬─────────┬─────────┬─────────┐
	│ column_name │ column_type │ null │ key │ default │ extra │
	│ varchar │ varchar │ varchar │ varchar │ varchar │ varchar │
	├────────────────────┼──────────────────────────┼─────────┼─────────┼─────────┼─────────┤
	│ key │ VARCHAR │ YES │ NULL │ NULL │ NULL │
	│ size │ BIGINT │ YES │ NULL │ NULL │ NULL │
	│ last_modified_date │ TIMESTAMP WITH TIME ZONE │ YES │ NULL │ NULL │ NULL │
	│ e_tag │ VARCHAR │ YES │ NULL │ NULL │ NULL │
	│ storage_class │ VARCHAR │ YES │ NULL │ NULL │ NULL │
	└────────────────────┴──────────────────────────┴─────────┴─────────┴─────────┴─────────┘
	```

	Here is the first 10 entries:

	```console
	❯ duckdb -c "select * from 'datasets/inventory-2026-01-06T01-13Z.parquet' limit 10"
	┌──────────────────────────────────────────┬───────┬──────────────────────────┬──────────────────────────────────┬───────────────┐
	│ key │ size │ last_modified_date │ e_tag │ storage_class │
	│ varchar │ int64 │ timestamp with time zone │ varchar │ varchar │
	├──────────────────────────────────────────┼───────┼──────────────────────────┼──────────────────────────────────┼───────────────┤
	│ .well-known/pki-validation/gsdv.txt │ 101 │ 2018-09-07 09:35:54+01 │ dcdfef6f1cdfeae2d2c9de7dab84292a │ STANDARD │
	│ 000003nzgismzlipaq0jnchpz65d65z7.ls │ 1228 │ 2024-06-21 17:17:36+01 │ bf47b9ab2ea7a795d15107d4dcf64697 │ STANDARD │
	│ 000003nzgismzlipaq0jnchpz65d65z7.narinfo │ 1452 │ 2024-06-21 17:17:37+01 │ 34997acded08172170eb1a4cde9456d1 │ STANDARD │
	│ 00000c8rdrjqkdxjpm5wrhl6sspapbmn.ls │ 97 │ 2019-11-06 19:35:06+00 │ ae368bafcfb9e5632acc57acf4f2a325 │ STANDARD │
	│ 00000c8rdrjqkdxjpm5wrhl6sspapbmn.narinfo │ 905 │ 2019-11-06 19:35:06+00 │ 0bf1c5c76cf15dd07c8c79eca27ebff4 │ STANDARD │
	│ 00000in9ndrbpshcibwfgsygx0xq069g.ls │ 329 │ 2025-11-07 18:40:26+00 │ f817f1b476fe0cb82ac2f5dbc19be620 │ STANDARD │
	│ 00000in9ndrbpshcibwfgsygx0xq069g.narinfo │ 732 │ 2025-11-07 18:40:28+00 │ 4037fbf8ab5484847756f0839c2c7245 │ STANDARD │
	│ 00000jipsrr2nfgn36w04xg2z6hnr7y0.ls │ 323 │ 2024-01-06 07:48:26+00 │ 8a3bad8cb3795080ccd636ef212c1878 │ STANDARD │
	│ 00000jipsrr2nfgn36w04xg2z6hnr7y0.narinfo │ 523 │ 2024-01-06 07:48:27+00 │ 997c5c9a6911bfadd7efcb9f845a4082 │ STANDARD │
	│ 00000lkv8yz6bsccrp03ppq71mzjdcpv.ls │ 396 │ 2022-05-10 03:33:54+01 │ 3284e9e9e5ae0a2562640e1f20af395d │ STANDARD │
	├──────────────────────────────────────────┴───────┴──────────────────────────┴──────────────────────────────────┴───────────────┤
	│ 10 rows 5 columns │
	└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
	```

	### `datasets/narinfos-2026-01-06T01-13Z.parquet``

	This is a complete download of all `.narinfo` files within the S3 bucket as of `2026-01-06T01:13Z`. It has the following
	schema:

	```console
	❯ duckdb -c "describe select * from 'datasets/narinfos-2026-01-06T01-13Z.parquet'
	┌───────────────────────────────┬─────────────┬─────────┬─────────┬─────────┬─────────┐
	│ column_name │ column_type │ null │ key │ default │ extra │
	│ varchar │ varchar │ varchar │ varchar │ varchar │ varchar │
	├───────────────────────────────┼─────────────┼─────────┼─────────┼─────────┼─────────┤
	│ hash │ BLOB │ YES │ NULL │ NULL │ NULL │
	│ pname │ VARCHAR │ YES │ NULL │ NULL │ NULL │
	│ compression │ VARCHAR │ YES │ NULL │ NULL │ NULL │
	│ file_hash │ BLOB │ YES │ NULL │ NULL │ NULL │
	│ file_size │ UBIGINT │ YES │ NULL │ NULL │ NULL │
	│ nar_hash │ BLOB │ YES │ NULL │ NULL │ NULL │
	│ nar_size │ UBIGINT │ YES │ NULL │ NULL │ NULL │
	│ references │ BLOB[] │ YES │ NULL │ NULL │ NULL │
	│ deriver │ BLOB │ YES │ NULL │ NULL │ NULL │
	│ deriver_pname │ VARCHAR │ YES │ NULL │ NULL │ NULL │
	│ system │ VARCHAR │ YES │ NULL │ NULL │ NULL │
	│ signature_domains │ VARCHAR[] │ YES │ NULL │ NULL │ NULL │
	│ signature_values │ BLOB[] │ YES │ NULL │ NULL │ NULL │
	│ ca_algo │ VARCHAR │ YES │ NULL │ NULL │ NULL │
	│ ca_hash │ BLOB │ YES │ NULL │ NULL │ NULL │
	│ quirk_references_out_of_order │ BOOLEAN │ YES │ NULL │ NULL │ NULL │
	├───────────────────────────────┴─────────────┴─────────┴─────────┴─────────┴─────────┤
	│ 16 rows 6 columns │
	└─────────────────────────────────────────────────────────────────────────────────────┘
	```

	The schema is the same as the contents of a `.narinfo` file with some notable differences:

	* `StorePath` has been split into `hash` and `pname`, with the `/nix/store/` prefix omitted.
	* In addition, `hash` has been decoded from its original 32-byte `nixbase32` format into a 20-byte fixed-size `byte[20]`
	column to save space. As mentioned in [Getting Started](#Getting-started), there is a `nixbase32` utility function for
	`duckdb` which can be used to convert it back into it's original format.
	* `URL` is not included. Instead, it can be recovered from the `file_hash` and `compression` columns using the `narURL`
	utility function. Again, this was to save space.
	* `quirk_references_out_of_order` indicates whether the `references` column was not canonically sorted as is required by
	the narinfo format.

	Here is an example of using both:

	```console
	❯ duckdb -c " select nixbase32(hash) as hash, pname, narURL(file_hash, compression) as URL from 'datasets/narinfos-2026-01-06T01-13Z.parquet' where pname like 'nixos-%.iso' limit 10"
	┌──────────────────────────────────┬──────────────────────────────────────────────────────────────────────┬─────────────────────────────────────────────────────────────────┐
	│ hash │ pname │ URL │
	│ varchar │ varchar │ varchar │
	├──────────────────────────────────┼──────────────────────────────────────────────────────────────────────┼─────────────────────────────────────────────────────────────────┤
	│ 8s2i888nxl44dvrqkszyhm9wagx21cv8 │ nixos-21.11pre-git-aarch64-linux.iso │ nar/01i2cax5rgfirdnqy3gk0fam1jxjqzydlm6fmydqcr2rppzfgpyc.nar.xz │
	│ 8s2nl0q5l0qjwj4mdh47b32abd7dkb37 │ nixos-plasma5-23.11pre525972.ace5093e36ab-x86_64-linux.iso │ nar/03wiqhgkgbwr6lz6jlhnq9d4swjahdw32ylixshmpy25wmnhkg83.nar.xz │
	│ 8s308z464is6rbnn1wglws37bz5cxhi3 │ nixos-minimal-new-kernel-21.03pre253346.87e9b49fc78-x86_64-linux.iso │ nar/1ppngdicfkydg44hbyc6s77f40qk15a8r370a02yg06y4w7fscp3.nar.xz │
	│ 8s37vnmdg68z51s81lp7pfclkp0ljl7v │ nixos-plasma5-21.11.335288.3ddd960a3b5-x86_64-linux.iso │ nar/04pic41qkjib69bl1yk48w5bdnb0jj4jfzljmfxsx3c9sr966m71.nar.xz │
	│ 8s4yq0kgvw7d34jzd6j256n8rhqdncag │ nixos-18.03pre-git-x86_64-linux.iso │ nar/11m49i89vpm8mjq2khpiy9p4br3fkvk57nmi6narmxbih9lahg45.nar.xz │
	│ 8s4zyq65nl0d5jjd28pvm8rih78khhlx │ nixos-21.03pre-git-x86_64-linux.iso │ nar/00ivaz2lwdvqcg7c64l9ikgk0njcphad4h69z2hvih7xrrzvwbb0.nar.xz │
	│ 8s5577gfk2makszs3bnpfzf8h477ywwd │ nixos-minimal-17.03.1730.dad3c2231c-i686-linux.iso │ nar/074d9323apli87919s8rr8rfa0javdqvk24r4siclq1ysg67gp38.nar.xz │
	│ 8s580im104kqdf873sc1bqanp5x7mvjn │ nixos-18.09pre-git-x86_64-linux.iso │ nar/0nw2zmxw3bhn9ixx66n9vfhk81qvr88yh1a3dxyv1qi5xbqv8fgz.nar.xz │
	│ 8s5wj1h8hcvhiqxghlgblxnsi8lccrs7 │ nixos-graphical-25.11pre819493.4206c4cb5675-x86_64-linux.iso │ nar/0mnwc0lpxf4hllv97gc58rd7m0rkph03cg2b35zmarq1kcd1ihq5.nar.xz │
	│ 8s616arfxnpgz8grd3rggm9ahgk5wvn7 │ nixos-minimal-19.09pre174421.b306b4cf1a9-x86_64-linux.iso │ nar/1qxcksrfa9nv10ln5kf2mcx2jndx4hyf34x594779f0lh4rlfw68.nar.xz │
	├──────────────────────────────────┴──────────────────────────────────────────────────────────────────────┴─────────────────────────────────────────────────────────────────┤
	│ 10 rows 3 columns │
	└───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
	```

	### `datasets/narinfos-nixos-2026-01-06T01-13Z.parquet`

	This is a subset of the `narinfos-2026-01-06T01-13Z.parquet` dataset which is attempting to identify any narinfos related
	to NixOS ISOs and other images which have been uploaded to the cache. These are candidates for removal from the cache as
	they are stored elsewhere.

	It was compiled using `./duckdb/nixos-images.sql`;

	### `datasets/narinfos-nixos-images-dangling-refs-2026-01-06T01-13Z.parquet`

	This is a list of store paths which reference one or more of the store paths contained in `datasets/narinfos-nixos-images-2026-01-06T01-13Z.parquet`,
	which will be affected by their removal from https://cache.nixos.org.

	It was compiled using `bin/dangling-references.py`.

	### `datasets/buildstepoutputs-2025-12-05-17:38:30Z.csv.zst`

	This is a dump of the `buildstepoutputs` table taken from [Hydra] on `2025-12-05T17:38:30Z`. It can be thought of as a
	record of every output path that [Hydra] has ever built and looks like this:

	```console
	❯ head datasets/buildstepoutputs-2025-12-05-17:38:30Z.csv
	build,stepnr,name,path
	684,2,out,/nix/store/mnkbj3aziazk2ijadn23cpwarm6bfmh8-nixos-install
	683,5,out,/nix/store/172yppi4bklbs1cyh91wqwpyyfbkvgds-system-path
	684,3,out,/nix/store/dxi8ij2la8in64mclyjslgs04nylcsa2-upstart-manual
	685,1,out,/nix/store/isaw8s240isvg06pimbr1wj12wxs9glv-hydra-build
	684,4,out,/nix/store/qcpb0179capgcyij03xk6fqhlwbafjr0-upstart-jobs
	686,1,out,/nix/store/07syvqz4w8n0z3alfm4kg5i46v3wbidx-checkinstall-1.6.1
	686,2,out,/nix/store/1g5nks931nirya16hmw2l1lg0jwazmsw-e2fslibs_1.39+1.40-WIP-2006.11.14+dfsg-2etch1_amd64.deb
	686,3,out,/nix/store/0dgvq0q33sniq77kq9150shj0jqllzh0-file_4.17-5etch3_amd64.deb
	686,4,out,/nix/store/7f03xxka0l0h623ydvqsjvqf6w1vvhzv-heimdal-1.0.2.tar.gz
	```

	### `datasets/inventory-not-in-buildstepoutputs-2025-12-05-17:38:30Z.parquet`

	This file contains a list of all the `.narinfo` files within `datasets/inventory-2026-01-06T01-13Z.parquet`
	(up to `2025-12-05-17:38:30Z`) which do not have a corresponding entry in
	`datasets/buildstepoutputs-2025-12-05-17:38:30Z.csv.zst`.

	It was compiled using `./duckdb/inventory-not-in-buildstepoutputs.sql`;

	Subsequently, graphs were generated using `bin/graph-inventory-not-in-buildstepoutputs.py` and placed in `./graphs`:

	![Inventory not in Buildstepoutputs Daily](./graphs/inventory-not-in-buildstepoutputs-daily.png)
	![Inventory not in Buildstepoutputs Monthly](./graphs/inventory-not-in-buildstepoutputs-monthly.png)
	![Inventory not in Buildstepoutputs Daily](./graphs/inventory-not-in-buildstepoutputs-yearly-comparison.png)

	[Nix]: https://nixos.org/
	[Direnv]: https://direnv.net/
	[S3 Bucket]: https://aws.amazon.com/s3/
	[S3 Inventory Service]: https://docs.aws.amazon.com/AmazonS3/latest/dev/storage-inventory.html
	[Narwal]: https://github.com/numtide/narwal
	[Hydra]: https://hydra.nixos.org/