From: Jeff Hostetler <git@jeffhostetler.com>
To: Duy Nguyen <pclouds@gmail.com>, Derrick Stolee <stolee@gmail.com>
Cc: "Git Mailing List" <git@vger.kernel.org>,
"Junio C Hamano" <gitster@pobox.com>, "Jeff King" <peff@peff.net>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Johannes Schindelin" <Johannes.Schindelin@gmx.de>
Subject: Re: [PATCH v2 05/10] split-index.c: dump "link" extension as json
Date: Thu, 27 Jun 2019 09:24:46 -0400 [thread overview]
Message-ID: <93562f66-07a7-d074-e225-65afd7ced1d4@jeffhostetler.com> (raw)
In-Reply-To: <CACsJy8CwWvKNbYvDqWc-zCwEPc_rz-P4y-SvXV-9jL8_XCFjZQ@mail.gmail.com>
On 6/27/2019 6:48 AM, Duy Nguyen wrote:
> On Tue, Jun 25, 2019 at 7:40 PM Derrick Stolee <stolee@gmail.com> wrote:
>>
>> On 6/25/2019 6:29 AM, Duy Nguyen wrote:
>>> On Tue, Jun 25, 2019 at 3:06 AM Jeff Hostetler <git@jeffhostetler.com> wrote:
>>>> I'm curious how big these EWAHs will be in practice and
>>>> how useful an array of integers will be (especially as the
>>>> pretty format will be one integer per line). Perhaps it
>>>> would helpful to have an extended example in one of the
>>>> tests.
>>>
>>> It's one integer per updated entry. So if you have a giant index and
>>> updated every single one of them, the EWAH bitmap contains that many
>>> integers.
>>>
>>> If it was easy to just merge these bitmaps back to the entry (e.g. in
>>> this example, add "replaced": true to entry zero) I would have done
>>> it. But we dump as we stream and it's already too late to do it.
>>>
>>>> Would it be better to have the caller of ewah_each_bit()
>>>> build a hex or bit string in a strbuf and then write it
>>>> as a single string?
>>>
>>> I don't think the current EWAH representation is easy to read in the
>>> first place. You'll probably have to run through some script to update
>>> the main entries part and will have a much better view, but that's
>>> pretty quick. If it's for scripts, then it's probably best to keep as
>>> an array of integers, not a string. Less post processing.
>>
>> I don't think the intent is to dump the EWAH directly, but instead to
>> dump a string of the uncompressed bitmap. Something like:
>>
>> "delete_bitmap" : "01101101101"
>>
>> instead of
>>
>> "delete_bitmap" : [ 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1 ]
>
> I get this part. But the numbers in the array were the position of the
> set bits. It's not showing just the actual bit map.
>
> The same bitmap would be currently displayed as
>
> "delete_bitmap": [ 1, 2, 4, 5, 7, 8, 9, 11 ]
>
> And that maps back to the entry[1], entry[2], entry[4]... in the index
> being deleted from the base index. So displaying as a real bit map
> actually adds more work for both the reader and the tool because you
> have to calculate the position either way. And it gets harder if the
> bit you're intereted in is on the far right.
Thanks for the clarification. That helps.
Jeff
next prev parent reply other threads:[~2019-06-27 13:24 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 13:02 [PATCH v2 00/10] Add 'ls-files --debug-json' to dump the index in json Nguyễn Thái Ngọc Duy
2019-06-24 13:02 ` [PATCH v2 01/10] ls-files: add --json to dump the index Nguyễn Thái Ngọc Duy
2019-06-24 19:15 ` Jeff Hostetler
2019-06-24 20:04 ` Junio C Hamano
2019-06-25 9:21 ` Johannes Schindelin
2019-06-25 9:52 ` Duy Nguyen
2019-06-25 15:37 ` Jeff Hostetler
2019-06-25 9:05 ` Thomas Gummerer
2019-06-25 9:44 ` Johannes Schindelin
2019-06-25 11:31 ` Johannes Schindelin
2019-06-25 13:57 ` Johannes Schindelin
2019-06-25 22:28 ` Junio C Hamano
2019-06-26 19:51 ` Junio C Hamano
2019-06-24 13:02 ` [PATCH v2 02/10] read-cache.c: dump common extension info in json Nguyễn Thái Ngọc Duy
2019-06-24 13:02 ` [PATCH v2 03/10] cache-tree.c: dump "TREE" extension as json Nguyễn Thái Ngọc Duy
2019-06-24 13:02 ` [PATCH v2 04/10] dir.c: dump "UNTR" " Nguyễn Thái Ngọc Duy
2019-06-24 19:32 ` Jeff Hostetler
2019-06-24 13:02 ` [PATCH v2 05/10] split-index.c: dump "link" " Nguyễn Thái Ngọc Duy
2019-06-24 20:06 ` Jeff Hostetler
2019-06-25 10:29 ` Duy Nguyen
2019-06-25 12:40 ` Derrick Stolee
2019-06-27 10:48 ` Duy Nguyen
2019-06-27 13:24 ` Jeff Hostetler [this message]
2019-06-27 13:42 ` Derrick Stolee
2019-06-27 13:47 ` Duy Nguyen
2019-07-03 9:08 ` SZEDER Gábor
2019-07-04 20:01 ` SZEDER Gábor
2019-07-04 23:54 ` Duy Nguyen
2019-07-08 17:58 ` Junio C Hamano
2019-06-24 13:02 ` [PATCH v2 06/10] fsmonitor.c: dump "FSMN" " Nguyễn Thái Ngọc Duy
2019-06-24 13:02 ` [PATCH v2 07/10] resolve-undo.c: dump "REUC" " Nguyễn Thái Ngọc Duy
2019-06-24 13:02 ` [PATCH v2 08/10] read-cache.c: dump "EOIE" " Nguyễn Thái Ngọc Duy
2019-06-24 13:02 ` [PATCH v2 09/10] read-cache.c: dump "IEOT" " Nguyễn Thái Ngọc Duy
2019-06-24 13:02 ` [PATCH v2 10/10] t3008: use the new SINGLE_CPU prereq Nguyễn Thái Ngọc Duy
2019-06-24 18:00 ` [PATCH v2 00/10] Add 'ls-files --debug-json' to dump the index in json Johannes Schindelin
2019-06-24 18:39 ` Jeff Hostetler
2019-06-25 9:05 ` Duy Nguyen
2019-06-25 9:38 ` Thomas Gummerer
2019-06-25 11:27 ` Johannes Schindelin
2019-06-25 12:06 ` Duy Nguyen
2019-06-25 14:10 ` Johannes Schindelin
2019-06-25 17:08 ` Ramsay Jones
2019-06-26 15:05 ` Johannes Schindelin
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