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From: Derrick Stolee <stolee@gmail.com>
To: Taylor Blau <me@ttaylorr.com>, git@vger.kernel.org
Cc: gitster@pobox.com, larsxschneider@gmail.com, peff@peff.net,
	tytso@mit.edu
Subject: Re: [PATCH 01/17] Documentation/technical: add cruft-packs.txt
Date: Thu, 2 Dec 2021 09:33:51 -0500	[thread overview]
Message-ID: <df8990d5-98da-a05c-31cf-d3f5ce33f498@gmail.com> (raw)
In-Reply-To: <a9f7c738e0ffbc5cdedc26768a0623446c98d239.1638224692.git.me@ttaylorr.com>

On 11/29/2021 5:25 PM, Taylor Blau wrote:
> +Notable alternatives to this design include:
> +
> +  - The location of the per-object mtime data, and
> +  - Whether cruft packs should be incremental or not.

It was not obvious from this sentence that "incremental" meant that
we could store a number of cruft packs and use the mtime of each pack
as the time for all contained objects.

> +On the location of mtime data, a new auxiliary file tied to the pack was chosen
> +to avoid complicating the `.idx` format. If the `.idx` format were ever to gain
> +support for optional chunks of data, it may make sense to consolidate the
> +`.mtimes` format into the `.idx` itself.
> +
> +Incremental cruft packs (i.e., where each time a repository is repacked a new
> +cruft pack is generated containing only the unreachable objects introduced since
> +the last time a cruft pack was written) are significantly more complicated to
> +construct, and so aren't pursued here. The obvious drawback to the current
> +implementation is that the entire cruft pack must be re-written from scratch.

But you seem to be pointing that direction here. The difference being
that you don't discuss how a list of cruft packs could avoid the .mtimes
file.

I think what is hidden underneath "significantly more complicated to
construct" are situations such as "this object was in an old cruft
pack, but then became reachable, but now is unreachable again". I'll
try to remember to come back to this after seeing the situations you
cover in your tests.

Thanks,
-Stolee

  reply	other threads:[~2021-12-02 14:33 UTC|newest]

Thread overview: 201+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-29 22:25 [PATCH 00/17] cruft packs Taylor Blau
2021-11-29 22:25 ` [PATCH 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2021-12-02 14:33   ` Derrick Stolee [this message]
2021-12-03 21:53     ` Taylor Blau
2021-12-04 22:20   ` Elijah Newren
2021-12-04 23:32     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2021-12-02 15:06   ` Derrick Stolee
2021-12-02 22:32     ` brian m. carlson
2021-12-03 22:24     ` Taylor Blau
2022-01-07 19:41       ` Taylor Blau
2021-11-29 22:25 ` [PATCH 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2021-11-29 22:25 ` [PATCH 04/17] chunk-format.h: extract oid_version() Taylor Blau
2021-12-02 15:22   ` Derrick Stolee
2021-12-03 22:40     ` Taylor Blau
2021-12-06 17:33       ` Derrick Stolee
2021-11-29 22:25 ` [PATCH 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2021-12-02 15:36   ` Derrick Stolee
2021-12-03 23:04     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2021-12-06 21:16   ` Derrick Stolee
2022-02-23 22:24     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2021-11-29 22:25 ` [PATCH 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2021-12-06 21:44   ` Derrick Stolee
2022-03-01  2:48     ` Taylor Blau
2021-12-07 15:17   ` Derrick Stolee
2022-02-23 23:34     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2021-11-29 22:25 ` [PATCH 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2021-11-29 22:25 ` [PATCH 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2021-12-07 15:30   ` Derrick Stolee
2022-02-23 23:35     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2021-12-05 20:46   ` Junio C Hamano
2022-03-01  2:00     ` Taylor Blau
2021-12-07 15:38   ` Derrick Stolee
2022-02-23 23:37     ` Taylor Blau
2021-11-29 22:25 ` [PATCH 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2021-11-29 22:25 ` [PATCH 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2021-11-29 22:25 ` [PATCH 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2021-11-29 22:25 ` [PATCH 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2021-11-29 22:25 ` [PATCH 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2021-12-03 19:51 ` [PATCH 00/17] " Junio C Hamano
2021-12-03 20:08   ` Taylor Blau
2021-12-03 20:47     ` Taylor Blau
2022-03-02  0:57 ` [PATCH v2 " Taylor Blau
2022-03-02  0:58   ` [PATCH v2 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2022-03-02  0:58   ` [PATCH v2 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-03-02 20:22     ` Derrick Stolee
2022-03-02 21:33       ` Taylor Blau
2022-03-02  0:58   ` [PATCH v2 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2022-03-02  0:58   ` [PATCH v2 04/17] chunk-format.h: extract oid_version() Taylor Blau
2022-03-02  0:58   ` [PATCH v2 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2022-03-02  0:58   ` [PATCH v2 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2022-03-02  0:58   ` [PATCH v2 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2022-03-02  0:58   ` [PATCH v2 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2022-03-02  0:58   ` [PATCH v2 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2022-03-02 20:19     ` Derrick Stolee
2022-03-02 21:28       ` Taylor Blau
2022-03-02  0:58   ` [PATCH v2 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2022-03-02  0:58   ` [PATCH v2 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2022-03-02  7:42     ` Junio C Hamano
2022-03-02 15:54       ` Taylor Blau
2022-03-02 19:57         ` Derrick Stolee
2022-03-02  0:58   ` [PATCH v2 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2022-03-02  0:58   ` [PATCH v2 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2022-03-02  0:58   ` [PATCH v2 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2022-03-02  0:58   ` [PATCH v2 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2022-03-02  0:58   ` [PATCH v2 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2022-03-02  0:58   ` [PATCH v2 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2022-03-02 20:23   ` [PATCH v2 00/17] " Derrick Stolee
2022-03-02 21:36     ` Taylor Blau
2022-03-03  0:20 ` [PATCH v3 " Taylor Blau
2022-03-03  0:20   ` [PATCH v3 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2022-03-07 18:03     ` Jonathan Nieder
2022-03-22  1:16       ` Taylor Blau
2022-03-22 21:45         ` Jonathan Nieder
2022-03-22 22:02           ` Taylor Blau
2022-03-22 23:04             ` Jonathan Nieder
2022-03-23  1:01               ` Taylor Blau
2022-03-28 18:46                 ` Taylor Blau
2022-03-28 20:55                   ` Junio C Hamano
2022-03-28 21:21                     ` Taylor Blau
2022-03-29 15:59                       ` Junio C Hamano
2022-03-30  2:23                         ` Taylor Blau
2022-03-30 13:37                           ` Junio C Hamano
2022-03-30 17:30                             ` Taylor Blau
2022-03-03  0:20   ` [PATCH v3 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-03-03  0:20   ` [PATCH v3 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2022-03-03  0:20   ` [PATCH v3 04/17] chunk-format.h: extract oid_version() Taylor Blau
2022-03-03 16:30     ` Ævar Arnfjörð Bjarmason
2022-03-03 23:32       ` Taylor Blau
2022-03-04  0:16         ` Junio C Hamano
2022-03-03  0:20   ` [PATCH v3 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2022-03-03 16:45     ` Ævar Arnfjörð Bjarmason
2022-03-03 23:35       ` Taylor Blau
2022-03-04 10:40         ` Ævar Arnfjörð Bjarmason
2022-03-03  0:20   ` [PATCH v3 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2022-03-03  0:21   ` [PATCH v3 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2022-03-03  0:21   ` [PATCH v3 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2022-03-03  0:21   ` [PATCH v3 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2022-03-03  0:21   ` [PATCH v3 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2022-03-03  0:21   ` [PATCH v3 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2022-03-03  0:21   ` [PATCH v3 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2022-03-03  0:21   ` [PATCH v3 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2022-03-03  0:21   ` [PATCH v3 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2022-03-03  0:21   ` [PATCH v3 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2022-03-03  0:21   ` [PATCH v3 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2022-03-03  0:21   ` [PATCH v3 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2022-03-03  1:29   ` [PATCH v3 00/17] " Derrick Stolee
2022-05-18 23:10 ` [PATCH v4 " Taylor Blau
2022-05-18 23:10   ` [PATCH v4 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2022-05-19 14:04     ` Junio C Hamano
2022-05-18 23:10   ` [PATCH v4 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-05-19 10:40     ` Ævar Arnfjörð Bjarmason
2022-05-19 15:21       ` Junio C Hamano
2022-05-20  7:32         ` Ævar Arnfjörð Bjarmason
2022-05-20 22:37           ` Taylor Blau
2022-05-18 23:10   ` [PATCH v4 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2022-05-18 23:11   ` [PATCH v4 04/17] chunk-format.h: extract oid_version() Taylor Blau
2022-05-19 11:44     ` Ævar Arnfjörð Bjarmason
2022-05-18 23:11   ` [PATCH v4 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2022-05-18 23:11   ` [PATCH v4 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2022-05-18 23:11   ` [PATCH v4 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2022-05-18 23:11   ` [PATCH v4 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2022-05-19 10:04     ` Junio C Hamano
2022-05-19 15:16       ` Junio C Hamano
2022-05-20 22:52         ` Taylor Blau
2022-05-18 23:11   ` [PATCH v4 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2022-05-18 23:11   ` [PATCH v4 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2022-05-18 23:11   ` [PATCH v4 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2022-05-18 23:11   ` [PATCH v4 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2022-05-19 11:29     ` Ævar Arnfjörð Bjarmason
2022-05-20 22:39       ` Taylor Blau
2022-05-18 23:11   ` [PATCH v4 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2022-05-18 23:11   ` [PATCH v4 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2022-05-18 23:11   ` [PATCH v4 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2022-05-19 11:32     ` Ævar Arnfjörð Bjarmason
2022-05-20 22:42       ` Taylor Blau
2022-05-18 23:11   ` [PATCH v4 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2022-05-18 23:11   ` [PATCH v4 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2022-05-18 23:48   ` [PATCH v4 00/17] " Derrick Stolee
2022-05-20 23:19     ` Junio C Hamano
2022-05-20 23:30       ` Taylor Blau
2022-05-19 11:42   ` [RFC PATCH 0/2] Utility functions for duplicated pack(write) code Ævar Arnfjörð Bjarmason
2022-05-19 11:42     ` [RFC PATCH 1/2] packfile API: add and use a pack_name_to_ext() utility function Ævar Arnfjörð Bjarmason
2022-05-19 15:40       ` Junio C Hamano
2022-05-19 11:42     ` [RFC PATCH 2/2] hash API: add and use a hash_short_id_by_algo() function Ævar Arnfjörð Bjarmason
2022-05-19 15:50       ` Junio C Hamano
2022-05-19 19:07         ` Ævar Arnfjörð Bjarmason
2022-05-19 15:31     ` [RFC PATCH 0/2] Utility functions for duplicated pack(write) code Junio C Hamano
2022-05-19 11:54   ` [PATCH v4 00/17] cruft packs Ævar Arnfjörð Bjarmason
2022-05-20 23:17 ` [PATCH v5 " Taylor Blau
2022-05-20 23:17   ` [PATCH v5 01/17] Documentation/technical: add cruft-packs.txt Taylor Blau
2022-05-20 23:17   ` [PATCH v5 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-05-24 19:32     ` Jonathan Nieder
2022-05-24 19:44       ` rsbecker
2022-05-24 22:25         ` Taylor Blau
2022-05-24 23:24           ` rsbecker
2022-05-25  0:07             ` Taylor Blau
2022-05-25  0:20               ` rsbecker
2022-05-25  9:11               ` adding new 32-bit on-disk (unsigned) timestamp formats (was: [PATCH v5 02/17] pack-mtimes: support reading .mtimes files) Ævar Arnfjörð Bjarmason
2022-05-25 13:30                 ` Derrick Stolee
2022-05-25 21:13                   ` Taylor Blau
2022-05-26  0:02                     ` Ævar Arnfjörð Bjarmason
2022-05-26  0:12                       ` Taylor Blau
2022-05-24 22:21       ` [PATCH v5 02/17] pack-mtimes: support reading .mtimes files Taylor Blau
2022-05-25  7:48         ` Jonathan Nieder
2022-05-25 21:36           ` Taylor Blau
2022-05-25 21:58             ` rsbecker
2022-05-25 22:59               ` Taylor Blau
2022-05-25 23:02     ` Taylor Blau
2022-05-26  0:30       ` Junio C Hamano
2023-06-01 13:01     ` Andreas Schwab
2022-05-20 23:17   ` [PATCH v5 03/17] pack-write: pass 'struct packing_data' to 'stage_tmp_packfiles' Taylor Blau
2022-05-20 23:17   ` [PATCH v5 04/17] chunk-format.h: extract oid_version() Taylor Blau
2022-05-20 23:17   ` [PATCH v5 05/17] pack-mtimes: support writing pack .mtimes files Taylor Blau
2022-05-20 23:17   ` [PATCH v5 06/17] t/helper: add 'pack-mtimes' test-tool Taylor Blau
2022-05-20 23:17   ` [PATCH v5 07/17] builtin/pack-objects.c: return from create_object_entry() Taylor Blau
2022-05-20 23:17   ` [PATCH v5 08/17] builtin/pack-objects.c: --cruft without expiration Taylor Blau
2022-05-20 23:17   ` [PATCH v5 09/17] reachable: add options to add_unseen_recent_objects_to_traversal Taylor Blau
2022-05-20 23:17   ` [PATCH v5 10/17] reachable: report precise timestamps from objects in cruft packs Taylor Blau
2022-05-20 23:18   ` [PATCH v5 11/17] builtin/pack-objects.c: --cruft with expiration Taylor Blau
2022-05-20 23:18   ` [PATCH v5 12/17] builtin/repack.c: support generating a cruft pack Taylor Blau
2022-05-20 23:18   ` [PATCH v5 13/17] builtin/repack.c: allow configuring cruft pack generation Taylor Blau
2022-05-20 23:18   ` [PATCH v5 14/17] builtin/repack.c: use named flags for existing_packs Taylor Blau
2022-05-20 23:18   ` [PATCH v5 15/17] builtin/repack.c: add cruft packs to MIDX during geometric repack Taylor Blau
2022-05-20 23:18   ` [PATCH v5 16/17] builtin/gc.c: conditionally avoid pruning objects via loose Taylor Blau
2022-06-19  5:38     ` René Scharfe
2022-06-21 15:58       ` Junio C Hamano
2022-05-20 23:18   ` [PATCH v5 17/17] sha1-file.c: don't freshen cruft packs Taylor Blau
2022-05-21 11:17   ` [PATCH v5 00/17] " Ævar Arnfjörð Bjarmason
2022-05-24 19:39     ` Jonathan Nieder
2022-05-24 21:50       ` Taylor Blau
2022-05-24 21:55         ` Ævar Arnfjörð Bjarmason
2022-05-24 22:12           ` Taylor Blau
2022-05-25  7:53             ` Jonathan Nieder
2022-05-25 19:59               ` Derrick Stolee
2022-05-25 21:09                 ` Taylor Blau
2022-05-26  0:06                   ` Ævar Arnfjörð Bjarmason

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