diff options
| -rw-r--r-- | reftable/stack.c | 123 | ||||
| -rw-r--r-- | reftable/stack.h | 3 | ||||
| -rw-r--r-- | reftable/stack_test.c | 66 | ||||
| -rwxr-xr-x | t/t0610-reftable-basics.sh | 50 |
4 files changed, 111 insertions, 131 deletions
diff --git a/reftable/stack.c b/reftable/stack.c index 1a7cdad12c..80266bcbab 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -1216,75 +1216,76 @@ static int segment_size(struct segment *s) return s->end - s->start; } -int fastlog2(uint64_t sz) -{ - int l = 0; - if (sz == 0) - return 0; - for (; sz; sz /= 2) { - l++; - } - return l - 1; -} - -struct segment *sizes_to_segments(size_t *seglen, uint64_t *sizes, size_t n) -{ - struct segment *segs = reftable_calloc(n, sizeof(*segs)); - struct segment cur = { 0 }; - size_t next = 0, i; - - if (n == 0) { - *seglen = 0; - return segs; - } - for (i = 0; i < n; i++) { - int log = fastlog2(sizes[i]); - if (cur.log != log && cur.bytes > 0) { - struct segment fresh = { - .start = i, - }; - - segs[next++] = cur; - cur = fresh; - } - - cur.log = log; - cur.end = i + 1; - cur.bytes += sizes[i]; - } - segs[next++] = cur; - *seglen = next; - return segs; -} - struct segment suggest_compaction_segment(uint64_t *sizes, size_t n) { - struct segment min_seg = { - .log = 64, - }; - struct segment *segs; - size_t seglen = 0, i; - - segs = sizes_to_segments(&seglen, sizes, n); - for (i = 0; i < seglen; i++) { - if (segment_size(&segs[i]) == 1) - continue; + struct segment seg = { 0 }; + uint64_t bytes; + size_t i; - if (segs[i].log < min_seg.log) - min_seg = segs[i]; - } + /* + * If there are no tables or only a single one then we don't have to + * compact anything. The sequence is geometric by definition already. + */ + if (n <= 1) + return seg; - while (min_seg.start > 0) { - size_t prev = min_seg.start - 1; - if (fastlog2(min_seg.bytes) < fastlog2(sizes[prev])) + /* + * Find the ending table of the compaction segment needed to restore the + * geometric sequence. Note that the segment end is exclusive. + * + * To do so, we iterate backwards starting from the most recent table + * until a valid segment end is found. If the preceding table is smaller + * than the current table multiplied by the geometric factor (2), the + * compaction segment end has been identified. + * + * Tables after the ending point are not added to the byte count because + * they are already valid members of the geometric sequence. Due to the + * properties of a geometric sequence, it is not possible for the sum of + * these tables to exceed the value of the ending point table. + * + * Example table size sequence requiring no compaction: + * 64, 32, 16, 8, 4, 2, 1 + * + * Example table size sequence where compaction segment end is set to + * the last table. Since the segment end is exclusive, the last table is + * excluded during subsequent compaction and the table with size 3 is + * the final table included: + * 64, 32, 16, 8, 4, 3, 1 + */ + for (i = n - 1; i > 0; i--) { + if (sizes[i - 1] < sizes[i] * 2) { + seg.end = i + 1; + bytes = sizes[i]; break; + } + } - min_seg.start = prev; - min_seg.bytes += sizes[prev]; + /* + * Find the starting table of the compaction segment by iterating + * through the remaining tables and keeping track of the accumulated + * size of all tables seen from the segment end table. The previous + * table is compared to the accumulated size because the tables from the + * segment end are merged backwards recursively. + * + * Note that we keep iterating even after we have found the first + * starting point. This is because there may be tables in the stack + * preceding that first starting point which violate the geometric + * sequence. + * + * Example compaction segment start set to table with size 32: + * 128, 32, 16, 8, 4, 3, 1 + */ + for (; i > 0; i--) { + uint64_t curr = bytes; + bytes += sizes[i - 1]; + + if (sizes[i - 1] < curr * 2) { + seg.start = i - 1; + seg.bytes = bytes; + } } - reftable_free(segs); - return min_seg; + return seg; } static uint64_t *stack_table_sizes_for_compaction(struct reftable_stack *st) diff --git a/reftable/stack.h b/reftable/stack.h index c862053025..d43efa4760 100644 --- a/reftable/stack.h +++ b/reftable/stack.h @@ -32,12 +32,9 @@ int read_lines(const char *filename, char ***lines); struct segment { size_t start, end; - int log; uint64_t bytes; }; -int fastlog2(uint64_t sz); -struct segment *sizes_to_segments(size_t *seglen, uint64_t *sizes, size_t n); struct segment suggest_compaction_segment(uint64_t *sizes, size_t n); #endif diff --git a/reftable/stack_test.c b/reftable/stack_test.c index fc14b1d1f5..c63c2d9f86 100644 --- a/reftable/stack_test.c +++ b/reftable/stack_test.c @@ -760,59 +760,13 @@ static void test_reftable_stack_hash_id(void) clear_dir(dir); } -static void test_log2(void) -{ - EXPECT(1 == fastlog2(3)); - EXPECT(2 == fastlog2(4)); - EXPECT(2 == fastlog2(5)); -} - -static void test_sizes_to_segments(void) -{ - uint64_t sizes[] = { 2, 3, 4, 5, 7, 9 }; - /* .................0 1 2 3 4 5 */ - - size_t seglen = 0; - struct segment *segs = - sizes_to_segments(&seglen, sizes, ARRAY_SIZE(sizes)); - EXPECT(segs[2].log == 3); - EXPECT(segs[2].start == 5); - EXPECT(segs[2].end == 6); - - EXPECT(segs[1].log == 2); - EXPECT(segs[1].start == 2); - EXPECT(segs[1].end == 5); - reftable_free(segs); -} - -static void test_sizes_to_segments_empty(void) -{ - size_t seglen = 0; - struct segment *segs = sizes_to_segments(&seglen, NULL, 0); - EXPECT(seglen == 0); - reftable_free(segs); -} - -static void test_sizes_to_segments_all_equal(void) -{ - uint64_t sizes[] = { 5, 5 }; - size_t seglen = 0; - struct segment *segs = - sizes_to_segments(&seglen, sizes, ARRAY_SIZE(sizes)); - EXPECT(seglen == 1); - EXPECT(segs[0].start == 0); - EXPECT(segs[0].end == 2); - reftable_free(segs); -} - static void test_suggest_compaction_segment(void) { - uint64_t sizes[] = { 128, 64, 17, 16, 9, 9, 9, 16, 16 }; - /* .................0 1 2 3 4 5 6 */ + uint64_t sizes[] = { 512, 64, 17, 16, 9, 9, 9, 16, 2, 16 }; struct segment min = suggest_compaction_segment(sizes, ARRAY_SIZE(sizes)); - EXPECT(min.start == 2); - EXPECT(min.end == 7); + EXPECT(min.start == 1); + EXPECT(min.end == 10); } static void test_suggest_compaction_segment_nothing(void) @@ -923,6 +877,16 @@ static void test_empty_add(void) reftable_stack_destroy(st2); } +static int fastlog2(uint64_t sz) +{ + int l = 0; + if (sz == 0) + return 0; + for (; sz; sz /= 2) + l++; + return l - 1; +} + static void test_reftable_stack_auto_compaction(void) { struct reftable_write_options cfg = { @@ -1112,7 +1076,6 @@ static void test_reftable_stack_compaction_concurrent_clean(void) int stack_test_main(int argc, const char *argv[]) { RUN_TEST(test_empty_add); - RUN_TEST(test_log2); RUN_TEST(test_names_equal); RUN_TEST(test_parse_names); RUN_TEST(test_read_file); @@ -1133,9 +1096,6 @@ int stack_test_main(int argc, const char *argv[]) RUN_TEST(test_reftable_stack_update_index_check); RUN_TEST(test_reftable_stack_uptodate); RUN_TEST(test_reftable_stack_validate_refname); - RUN_TEST(test_sizes_to_segments); - RUN_TEST(test_sizes_to_segments_all_equal); - RUN_TEST(test_sizes_to_segments_empty); RUN_TEST(test_suggest_compaction_segment); RUN_TEST(test_suggest_compaction_segment_nothing); return 0; diff --git a/t/t0610-reftable-basics.sh b/t/t0610-reftable-basics.sh index c9e10b3468..8eec093788 100755 --- a/t/t0610-reftable-basics.sh +++ b/t/t0610-reftable-basics.sh @@ -293,7 +293,7 @@ test_expect_success 'ref transaction: writes cause auto-compaction' ' test_line_count = 1 repo/.git/reftable/tables.list && test_commit -C repo --no-tag A && - test_line_count = 2 repo/.git/reftable/tables.list && + test_line_count = 1 repo/.git/reftable/tables.list && test_commit -C repo --no-tag B && test_line_count = 1 repo/.git/reftable/tables.list @@ -320,6 +320,19 @@ test_expect_success 'ref transaction: env var disables compaction' ' test_line_count -lt $expected repo/.git/reftable/tables.list ' +test_expect_success 'ref transaction: alternating table sizes are compacted' ' + test_when_finished "rm -rf repo" && + + git init repo && + test_commit -C repo A && + for i in $(test_seq 5) + do + git -C repo branch -f foo && + git -C repo branch -d foo || return 1 + done && + test_line_count = 2 repo/.git/reftable/tables.list +' + check_fsync_events () { local trace="$1" && shift && @@ -345,7 +358,7 @@ test_expect_success 'ref transaction: writes are synced' ' git -C repo -c core.fsync=reference \ -c core.fsyncMethod=fsync update-ref refs/heads/branch HEAD && check_fsync_events trace2.txt <<-EOF - "name":"hardware-flush","count":2 + "name":"hardware-flush","count":4 EOF ' @@ -377,7 +390,7 @@ test_expect_success 'ref transaction: fails gracefully when auto compaction fail done || exit 1 done && - test_line_count = 13 .git/reftable/tables.list + test_line_count = 10 .git/reftable/tables.list ) ' @@ -387,8 +400,8 @@ test_expect_success 'pack-refs: compacts tables' ' test_commit -C repo A && ls -1 repo/.git/reftable >table-files && - test_line_count = 4 table-files && - test_line_count = 3 repo/.git/reftable/tables.list && + test_line_count = 3 table-files && + test_line_count = 2 repo/.git/reftable/tables.list && git -C repo pack-refs && ls -1 repo/.git/reftable >table-files && @@ -429,7 +442,7 @@ test_expect_success "$command: auto compaction" ' # The tables should have been auto-compacted, and thus auto # compaction should not have to do anything. ls -1 .git/reftable >tables-expect && - test_line_count = 4 tables-expect && + test_line_count = 3 tables-expect && git $command --auto && ls -1 .git/reftable >tables-actual && test_cmp tables-expect tables-actual && @@ -447,7 +460,7 @@ test_expect_success "$command: auto compaction" ' git branch B && git branch C && rm .git/reftable/*.lock && - test_line_count = 5 .git/reftable/tables.list && + test_line_count = 4 .git/reftable/tables.list && git $command --auto && test_line_count = 1 .git/reftable/tables.list @@ -479,7 +492,7 @@ do umask $umask && git init --shared=true repo && test_commit -C repo A && - test_line_count = 3 repo/.git/reftable/tables.list + test_line_count = 2 repo/.git/reftable/tables.list ) && git -C repo pack-refs && test_expect_perms "-rw-rw-r--" repo/.git/reftable/tables.list && @@ -847,12 +860,16 @@ test_expect_success 'worktree: pack-refs in main repo packs main refs' ' test_when_finished "rm -rf repo worktree" && git init repo && test_commit -C repo A && + + GIT_TEST_REFTABLE_AUTOCOMPACTION=false \ git -C repo worktree add ../worktree && + GIT_TEST_REFTABLE_AUTOCOMPACTION=false \ + git -C worktree update-ref refs/worktree/per-worktree HEAD && - test_line_count = 3 repo/.git/worktrees/worktree/reftable/tables.list && - test_line_count = 4 repo/.git/reftable/tables.list && + test_line_count = 4 repo/.git/worktrees/worktree/reftable/tables.list && + test_line_count = 3 repo/.git/reftable/tables.list && git -C repo pack-refs && - test_line_count = 3 repo/.git/worktrees/worktree/reftable/tables.list && + test_line_count = 4 repo/.git/worktrees/worktree/reftable/tables.list && test_line_count = 1 repo/.git/reftable/tables.list ' @@ -860,13 +877,17 @@ test_expect_success 'worktree: pack-refs in worktree packs worktree refs' ' test_when_finished "rm -rf repo worktree" && git init repo && test_commit -C repo A && + + GIT_TEST_REFTABLE_AUTOCOMPACTION=false \ git -C repo worktree add ../worktree && + GIT_TEST_REFTABLE_AUTOCOMPACTION=false \ + git -C worktree update-ref refs/worktree/per-worktree HEAD && - test_line_count = 3 repo/.git/worktrees/worktree/reftable/tables.list && - test_line_count = 4 repo/.git/reftable/tables.list && + test_line_count = 4 repo/.git/worktrees/worktree/reftable/tables.list && + test_line_count = 3 repo/.git/reftable/tables.list && git -C worktree pack-refs && test_line_count = 1 repo/.git/worktrees/worktree/reftable/tables.list && - test_line_count = 4 repo/.git/reftable/tables.list + test_line_count = 3 repo/.git/reftable/tables.list ' test_expect_success 'worktree: creating shared ref updates main stack' ' @@ -880,6 +901,7 @@ test_expect_success 'worktree: creating shared ref updates main stack' ' test_line_count = 1 repo/.git/worktrees/worktree/reftable/tables.list && test_line_count = 1 repo/.git/reftable/tables.list && + GIT_TEST_REFTABLE_AUTOCOMPACTION=false \ git -C worktree update-ref refs/heads/shared HEAD && test_line_count = 1 repo/.git/worktrees/worktree/reftable/tables.list && test_line_count = 2 repo/.git/reftable/tables.list |