[PATCH v2 10/21] read-cache: regenerate shared index if necessary
- From
Christian Couder <christian.couder@gmail.com>
- Date
- Dec 17, 2016, 14:55 UTC
- Message-ID
- <20161217145547.11748-11-chriscool@tuxfamily.org>
- In-Reply-To
- <20161217145547.11748-1-chriscool@tuxfamily.org>
When writing a new split-index and there is a big number of cache entries in the split-index compared to the shared index, it is a good idea to regenerate the shared index.
By default when the ratio reaches 20%, we will push back all the entries from the split-index into a new shared index file instead of just creating a new split-index file.
The threshold can be configured using the "splitIndex.maxPercentChange" config variable.
We need to adjust the existing tests in t1700 by setting "splitIndex.maxPercentChange" to 100 at the beginning of t1700, as the existing tests are assuming that the shared index is regenerated only when `git update-index --split-index` is used.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org> --- read-cache.c | 32 ++++++++++++++++++++++++++++++++ t/t1700-split-index.sh | 1 + 2 files changed, 33 insertions(+)
diff --git a/read-cache.c b/read-cache.c index 79aae6bd20..280b01bd6c 100644 --- a/read-cache.c +++ b/read-cache.c @@ -2223,6 +2223,36 @@ static int write_shared_index(struct index_state *istate, return ret; } +static const int default_max_percent_split_change = 20; + +static int too_many_not_shared_entries(struct index_state *istate) +{ + int i, not_shared = 0; + int max_split = git_config_get_max_percent_split_change(); + + switch (max_split) { + case -1: + /* not or badly configured: use the default value */ + max_split = default_max_percent_split_change; + break; + case 0: + return 1; /* 0% means always write a new shared index */ + case 100: + return 0; /* 100% means never write a new shared index */ + default: + ; /* do nothing: just use the configured value */ + } + + /* Count not shared entries */ + for (i = 0; i < istate->cache_nr; i++) { + struct cache_entry *ce = istate->cache[i]; + if (!ce->index) + not_shared++; + } + + return istate->cache_nr * max_split < not_shared * 100; +} + int write_locked_index(struct index_state *istate, struct lock_file *lock, unsigned flags) { @@ -2240,6 +2270,8 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock, if ((v & 15) < 6) istate->cache_changed |= SPLIT_INDEX_ORDERED; } + if (too_many_not_shared_entries(istate)) + istate->cache_changed |= SPLIT_INDEX_ORDERED; if (istate->cache_changed & SPLIT_INDEX_ORDERED) { int ret = write_shared_index(istate, lock, flags); if (ret) diff --git a/t/t1700-split-index.sh b/t/t1700-split-index.sh index db8c39f446..507a1dd1ad 100755 --- a/t/t1700-split-index.sh +++ b/t/t1700-split-index.sh @@ -8,6 +8,7 @@ test_description='split index mode tests' sane_unset GIT_TEST_SPLIT_INDEX test_expect_success 'enable split index' ' + git config splitIndex.maxPercentChange 100 && git update-index --split-index && test-dump-split-index .git/index >actual && indexversion=$(test-index-version <.git/index) &&
-- 2.11.0.49.g2414764.dirty