File size: 26,552 Bytes
7def8ff
 
 
 
 
 
 
2a41341
 
 
7def8ff
 
 
 
6a41dd6
95f34fa
6a41dd6
7d3293b
8224dee
 
6a41dd6
 
 
 
 
7def8ff
 
 
 
2ba20d7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8224dee
 
 
 
 
 
 
2ba20d7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
---
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/