From 1eb22c7dd803fc05513fde0bd96befeb8c725e05 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 11 Aug 2020 15:30:18 +0000 Subject: [PATCH] multi-pack-index: repack batches below --batch-size The --batch-size= option of 'git multi-pack-index repack' is intended to limit the amount of work done by the repack. In the case of a large repository, this command should repack a number of small pack-files but leave the large pack-files alone. Most often, the repository has one large pack-file from a 'git clone' operation and number of smaller pack-files from incremental 'git fetch' operations. The issue with '--batch-size' is that it also _prevents_ the repack from happening if the expected size of the resulting pack-file is too small. This was intended as a way to avoid frequent churn of small pack-files, but it has mostly caused confusion when a repository is of "medium" size. That is, not enormous like the Windows OS repository, but also not so small that this incremental repack isn't valuable. The solution presented here is to collect pack-files for repack if their expected size is smaller than the batch-size parameter until either the total expected size exceeds the batch-size or all pack-files are considered. If there are at least two pack-files, then these are combined to a new pack-file whose size should not be too much larger than the batch-size. This new strategy should succeed in keeping the number of pack-files small in these "medium" size repositories. The concern about churn is likely not interesting, as the real control over that is the frequency in which the repack command is run. Signed-off-by: Derrick Stolee Reviewed-by: Taylor Blau Signed-off-by: Junio C Hamano --- Documentation/git-multi-pack-index.txt | 11 ++++++----- midx.c | 2 +- t/t5319-multi-pack-index.sh | 18 ++++++++++++++++++ 3 files changed, 25 insertions(+), 6 deletions(-) diff --git a/Documentation/git-multi-pack-index.txt b/Documentation/git-multi-pack-index.txt index 0c6619493c..eb0caa0439 100644 --- a/Documentation/git-multi-pack-index.txt +++ b/Documentation/git-multi-pack-index.txt @@ -51,11 +51,12 @@ repack:: multi-pack-index, then divide by the total number of objects in the pack and multiply by the pack size. We select packs with expected size below the batch size until the set of packs have - total expected size at least the batch size. If the total size - does not reach the batch size, then do nothing. If a new pack- - file is created, rewrite the multi-pack-index to reference the - new pack-file. A later run of 'git multi-pack-index expire' will - delete the pack-files that were part of this batch. + total expected size at least the batch size, or all pack-files + are considered. If only one pack-file is selected, then do + nothing. If a new pack-file is created, rewrite the + multi-pack-index to reference the new pack-file. A later run of + 'git multi-pack-index expire' will delete the pack-files that + were part of this batch. + If `repack.packKeptObjects` is `false`, then any pack-files with an associated `.keep` file will not be selected for the batch to repack. diff --git a/midx.c b/midx.c index a5fb797ede..55afc8d72c 100644 --- a/midx.c +++ b/midx.c @@ -1371,7 +1371,7 @@ static int fill_included_packs_batch(struct repository *r, free(pack_info); - if (total_size < batch_size || packs_to_repack < 2) + if (packs_to_repack < 2) return 1; return 0; diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh index 7214cab36c..b05190f500 100755 --- a/t/t5319-multi-pack-index.sh +++ b/t/t5319-multi-pack-index.sh @@ -643,6 +643,7 @@ test_expect_success 'expire respects .keep files' ' ' test_expect_success 'repack --batch-size=0 repacks everything' ' + cp -r dup dup2 && ( cd dup && rm .git/objects/pack/*.keep && @@ -662,4 +663,21 @@ test_expect_success 'repack --batch-size=0 repacks everything' ' ) ' +test_expect_success 'repack --batch-size= repacks everything' ' + ( + cd dup2 && + rm .git/objects/pack/*.keep && + ls .git/objects/pack/*idx >idx-list && + test_line_count = 2 idx-list && + git multi-pack-index repack --batch-size=2000000 && + ls .git/objects/pack/*idx >idx-list && + test_line_count = 3 idx-list && + test-tool read-midx .git/objects | grep idx >midx-list && + test_line_count = 3 midx-list && + git multi-pack-index expire && + ls -al .git/objects/pack/*idx >idx-list && + test_line_count = 1 idx-list + ) +' + test_done