From: Derrick Stolee <stolee@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Victoria Dye via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org, Victoria Dye <vdye@github.com>
Subject: Re: [PATCH 2/2] sparse-index: update index read to consider index.sparse config
Date: Sun, 17 Oct 2021 15:33:58 -0400 [thread overview]
Message-ID: <8c148f7d-f175-7dc5-51a0-eef48aa98c3d@gmail.com> (raw)
In-Reply-To: <xmqq5ytw19ck.fsf@gitster.g>
On 10/17/2021 1:58 AM, Junio C Hamano wrote:
> Derrick Stolee <stolee@gmail.com> writes:
>
>> I think you are slightly mistaken here: If index.sparse=true, then a
>> full index will be converted to one on write, but not immediately upon
>> read. This means that subsequent commands will read a sparse index, and
>> they will either benefit from that or not depending on whether they are
>> integrated with the sparse index or not.
>>
>> The new behavior here is that if index.sparse=false, then we convert
>> a sparse index to a full one upon read, avoiding any chance that a
>> Git command is operating on a sparse index in-memory.
>
> And if index.sparse=true, then we convert a full on-disk index to a
> sparse one in-core upon reading, right? My comment was solely on
> that side of the picture, not on the "index.sparse is set to false
> so we automatically expand" case.
>
>> The simplest summary I can say is here:
>>
>> * If index.sparse=false, then a sparse index will be converted to
>> full upon read.
>>
>> * If index.sparse=true, then a full index will be converted to sparse
>> on write.
>
> Oh, I see, so yes I was very much misunderstanding what you guys are
> trying to do. I somehow thought that sparse-to-full and
> full-to-sparse conversions (1) already happen on the write codepath,
> and (2) this patch makes them both happen also on the read codepath.
>
> IOW:
>
> * If index.sparse=false, a sparse index will be written as full,
> and if it is true, a non-sparse index will be written as
> sparse, even before these patches.
This statement is true.
> * In addition, with these patches, if index.sparse=false, a
> sparse index will be expaned to full upon reading, and if it
> is true, a non-sparse index will be shrunk to sparse upon
> reading
This is only half true. If "index.sparse=false", then a sparse
index will be expanded to full upon reading. If "index.sparse=true"
then nothing special will happen to an index on reading.
> What your summary above is saying is very much different.
Yes, these are different things. It also gets around the concern that
"if we have a non-integrated command, then index.sparse=true would
convert a full index to a sparse one, only to be expanded again".
That doesn't happen if we only convert from full to sparse on write.
Thanks,
-Stolee
next prev parent reply other threads:[~2021-10-17 19:34 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-15 19:54 [PATCH 0/2] sparse-index: expand/collapse based on 'index.sparse' Victoria Dye via GitGitGadget
2021-10-15 19:54 ` [PATCH 1/2] test-read-cache.c: prepare_repo_settings after config init Victoria Dye via GitGitGadget
2021-10-15 19:54 ` [PATCH 2/2] sparse-index: update index read to consider index.sparse config Victoria Dye via GitGitGadget
2021-10-15 21:53 ` Junio C Hamano
2021-10-17 1:21 ` Derrick Stolee
2021-10-17 5:58 ` Junio C Hamano
2021-10-17 19:33 ` Derrick Stolee [this message]
2021-10-18 1:15 ` Junio C Hamano
2021-10-18 13:25 ` Derrick Stolee
2021-10-18 14:14 ` Victoria Dye
2021-10-21 13:26 ` Derrick Stolee
2021-10-18 16:09 ` Junio C Hamano
2021-10-21 20:48 ` [PATCH v2 0/3] sparse-index: expand/collapse based on 'index.sparse' Victoria Dye via GitGitGadget
2021-10-21 20:48 ` [PATCH v2 1/3] test-read-cache.c: prepare_repo_settings after config init Victoria Dye via GitGitGadget
2021-10-21 20:48 ` [PATCH v2 2/3] sparse-index: add ensure_correct_sparsity function Victoria Dye via GitGitGadget
2021-10-21 22:20 ` Junio C Hamano
2021-10-27 17:21 ` Victoria Dye
2021-10-21 20:48 ` [PATCH v2 3/3] sparse-index: update do_read_index to ensure correct sparsity Victoria Dye via GitGitGadget
2021-10-27 18:20 ` [PATCH v3 0/3] sparse-index: expand/collapse based on 'index.sparse' Victoria Dye via GitGitGadget
2021-10-27 18:20 ` [PATCH v3 1/3] test-read-cache.c: prepare_repo_settings after config init Victoria Dye via GitGitGadget
2021-10-27 18:20 ` [PATCH v3 2/3] sparse-index: add ensure_correct_sparsity function Victoria Dye via GitGitGadget
2021-10-27 20:07 ` Derrick Stolee
2021-10-27 21:32 ` Junio C Hamano
2021-10-28 1:24 ` Derrick Stolee
2021-10-29 13:43 ` Victoria Dye
2021-10-27 18:20 ` [PATCH v3 3/3] sparse-index: update do_read_index to ensure correct sparsity Victoria Dye via GitGitGadget
2021-10-27 20:08 ` [PATCH v3 0/3] sparse-index: expand/collapse based on 'index.sparse' Derrick Stolee
2021-10-29 13:51 ` [PATCH v4 0/4] " Victoria Dye via GitGitGadget
2021-10-29 13:51 ` [PATCH v4 1/4] test-read-cache.c: prepare_repo_settings after config init Victoria Dye via GitGitGadget
2021-10-29 13:51 ` [PATCH v4 2/4] sparse-index: avoid unnecessary cache tree clearing Victoria Dye via GitGitGadget
2021-10-29 18:45 ` Junio C Hamano
2021-10-29 19:00 ` Derrick Stolee
2021-10-29 20:01 ` Junio C Hamano
2021-10-29 13:51 ` [PATCH v4 3/4] sparse-index: add ensure_correct_sparsity function Victoria Dye via GitGitGadget
2021-10-29 13:51 ` [PATCH v4 4/4] sparse-index: update do_read_index to ensure correct sparsity Victoria Dye via GitGitGadget
2021-11-22 17:36 ` Elijah Newren
2021-11-22 18:59 ` Victoria Dye
2021-11-22 17:40 ` [PATCH v4 0/4] sparse-index: expand/collapse based on 'index.sparse' Elijah Newren
2021-11-23 0:20 ` [PATCH v5 " Victoria Dye via GitGitGadget
2021-11-23 0:20 ` [PATCH v5 1/4] test-read-cache.c: prepare_repo_settings after config init Victoria Dye via GitGitGadget
2021-11-23 0:20 ` [PATCH v5 2/4] sparse-index: avoid unnecessary cache tree clearing Victoria Dye via GitGitGadget
2021-11-23 0:20 ` [PATCH v5 3/4] sparse-index: add ensure_correct_sparsity function Victoria Dye via GitGitGadget
2021-11-23 0:20 ` [PATCH v5 4/4] sparse-index: update do_read_index to ensure correct sparsity Victoria Dye via GitGitGadget
2021-11-23 17:21 ` [PATCH v5 0/4] sparse-index: expand/collapse based on 'index.sparse' Elijah Newren
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