From: "SZEDER Gábor" <szeder.dev@gmail.com>
To: Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, peff@peff.net, me@ttaylorr.com,
garimasigit@gmail.com, jnareb@gmail.com,
Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH v2 06/12] bloom: use num_changes not nr for limit detection
Date: Tue, 4 Aug 2020 16:51:44 +0200 [thread overview]
Message-ID: <20200804145144.GQ2898@szeder.dev> (raw)
In-Reply-To: <8278b5c0918c6b357e1f1ab3ee65ed2091ec3f61.1589198180.git.gitgitgadget@gmail.com>
On Mon, May 11, 2020 at 11:56:13AM +0000, Derrick Stolee via GitGitGadget wrote:
> From: Derrick Stolee <dstolee@microsoft.com>
>
> As diff_tree_oid() computes a diff, it will terminate early if the
> total number of changed paths is strictly larger than max_changes.
> This includes the directories that changed, not just the file paths.
> However, only the file paths are reflected in the resulting diff
> queue's "nr" value.
>
> Use the "num_changes" from diffopt to check if the diff terminated
> early. This is incredibly important, as it can result in incorrect
> filters! For example, the first commit in the Linux kernel repo
> reports only 471 changes, but since these are nested inside several
> directories they expand to 513 "real" changes, and in fact the
> total list of changes is not reported. Thus, the computed filter
> for this commit is incorrect.
>
> Demonstrate the subtle difference by using one fewer file change
> in the 'get bloom filter for commit with 513 changes' test. Before,
> this edited 513 files inside "bigDir" which hit this inequality.
> However, dropping the file count by one demonstrates how the
> previous inequality was incorrect but the new one is correct.
>
> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
> ---
> bloom.c | 2 +-
> t/t0095-bloom.sh | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/bloom.c b/bloom.c
> index 196cda0a1bd..e2ede44126c 100644
> --- a/bloom.c
> +++ b/bloom.c
> @@ -215,7 +215,7 @@ struct bloom_filter *get_bloom_filter(struct repository *r,
> diff_tree_oid(NULL, &c->object.oid, "", &diffopt);
> diffcore_std(&diffopt);
>
> - if (diff_queued_diff.nr <= max_changes) {
> + if (diffopt.num_changes <= max_changes) {
The field 'diffopt.num_changes' is marked with:
/* For internal use only. */
> struct hashmap pathmap;
> struct pathmap_hash_entry *e;
> struct hashmap_iter iter;
> diff --git a/t/t0095-bloom.sh b/t/t0095-bloom.sh
> index 6defeb544f1..48a90625596 100755
> --- a/t/t0095-bloom.sh
> +++ b/t/t0095-bloom.sh
> @@ -100,7 +100,7 @@ test_expect_success EXPENSIVE 'get bloom filter for commit with 513 changes' '
> rm actual &&
> rm expect &&
> mkdir bigDir &&
> - for i in $(test_seq 0 512)
> + for i in $(test_seq 0 511)
> do
> echo $i >bigDir/$i
> done &&
> --
> gitgitgadget
>
next prev parent reply other threads:[~2020-08-04 14:51 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 15:30 [PATCH 00/12] Integrating line-log and changed-path Bloom filters Derrick Stolee via GitGitGadget
2020-05-01 15:30 ` [PATCH 01/12] bloom: fix whitespace around tab length Derrick Stolee via GitGitGadget
2020-05-01 22:51 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 02/12] test-bloom: fix usage typo Derrick Stolee via GitGitGadget
2020-05-01 22:51 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 03/12] Documentation: changed-path Bloom filters use byte words Derrick Stolee via GitGitGadget
2020-05-01 22:55 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 04/12] bloom: de-duplicate directory entries Derrick Stolee via GitGitGadget
2020-05-01 23:06 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 05/12] bloom: parse commit before computing filters Derrick Stolee via GitGitGadget
2020-05-01 23:10 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 06/12] bloom: use num_changes not nr for limit detection Derrick Stolee via GitGitGadget
2020-05-01 23:12 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 07/12] completion: offer '--(no-)patch' among 'git log' options SZEDER Gábor via GitGitGadget
2020-05-01 23:44 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 08/12] line-log: remove unused fields from 'struct line_log_data' SZEDER Gábor via GitGitGadget
2020-05-01 23:46 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 09/12] t4211-line-log: add tests for parent oids SZEDER Gábor via GitGitGadget
2020-05-04 17:31 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 10/12] line-log: more responsive, incremental 'git log -L' SZEDER Gábor via GitGitGadget
2020-05-04 17:52 ` Taylor Blau
2020-05-04 17:55 ` Derrick Stolee
2020-05-01 15:30 ` [PATCH 11/12] line-log: try to use generation number-based topo-ordering SZEDER Gábor via GitGitGadget
2020-05-04 21:25 ` Taylor Blau
2020-05-01 15:30 ` [PATCH 12/12] line-log: integrate with changed-path Bloom filters Derrick Stolee via GitGitGadget
2020-05-04 21:50 ` Taylor Blau
2020-05-01 17:34 ` [PATCH 00/12] Integrating line-log and " Junio C Hamano
2020-05-11 11:56 ` [PATCH v2 " Derrick Stolee via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 01/12] bloom: fix whitespace around tab length Derrick Stolee via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 02/12] test-bloom: fix usage typo Derrick Stolee via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 03/12] bloom: parse commit before computing filters Derrick Stolee via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 04/12] Documentation: changed-path Bloom filters use byte words Derrick Stolee via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 05/12] bloom: de-duplicate directory entries Derrick Stolee via GitGitGadget
2020-06-07 21:45 ` SZEDER Gábor
2020-05-11 11:56 ` [PATCH v2 06/12] bloom: use num_changes not nr for limit detection Derrick Stolee via GitGitGadget
2020-08-04 14:51 ` SZEDER Gábor [this message]
2020-05-11 11:56 ` [PATCH v2 07/12] completion: offer '--(no-)patch' among 'git log' options SZEDER Gábor via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 08/12] line-log: remove unused fields from 'struct line_log_data' SZEDER Gábor via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 09/12] t4211-line-log: add tests for parent oids SZEDER Gábor via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 10/12] line-log: more responsive, incremental 'git log -L' SZEDER Gábor via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 11/12] line-log: try to use generation number-based topo-ordering SZEDER Gábor via GitGitGadget
2020-05-11 11:56 ` [PATCH v2 12/12] line-log: integrate with changed-path Bloom filters Derrick Stolee via GitGitGadget
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