diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c index 0bed6d2ab4..1cda48c504 100644 --- a/refs/reftable-backend.c +++ b/refs/reftable-backend.c @@ -18,6 +18,7 @@ #include "../reftable/reftable-merged.h" #include "../setup.h" #include "../strmap.h" +#include "parse.h" #include "refs-internal.h" /* @@ -247,6 +248,8 @@ static struct ref_store *reftable_be_init(struct repository *repo, refs->write_options.block_size = 4096; refs->write_options.hash_id = repo->hash_algo->format_id; refs->write_options.default_permissions = calc_shared_perm(0666 & ~mask); + refs->write_options.disable_auto_compact = + !git_env_bool("GIT_TEST_REFTABLE_AUTOCOMPACTION", 1); /* * Set up the main reftable stack that is hosted in GIT_COMMON_DIR. diff --git a/reftable/reftable-writer.h b/reftable/reftable-writer.h index 7c7cae5f99..155bf0bbe2 100644 --- a/reftable/reftable-writer.h +++ b/reftable/reftable-writer.h @@ -46,6 +46,9 @@ struct reftable_write_options { * is a single line, and add '\n' if missing. */ unsigned exact_log_message : 1; + + /* boolean: Prevent auto-compaction of tables. */ + unsigned disable_auto_compact : 1; }; /* reftable_block_stats holds statistics for a single block type */ diff --git a/reftable/stack.c b/reftable/stack.c index dde50b61d6..80266bcbab 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -680,7 +680,7 @@ int reftable_addition_commit(struct reftable_addition *add) if (err) goto done; - if (!add->stack->disable_auto_compact) { + if (!add->stack->config.disable_auto_compact) { /* * Auto-compact the stack to keep the number of tables in * control. It is possible that a concurrent writer is already @@ -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; + struct segment seg = { 0 }; + uint64_t bytes; + size_t i; - segs = sizes_to_segments(&seglen, sizes, n); - for (i = 0; i < seglen; i++) { - if (segment_size(&segs[i]) == 1) - continue; + /* + * 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; - if (segs[i].log < min_seg.log) - min_seg = segs[i]; - } - - 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]; + } } - reftable_free(segs); - return min_seg; + /* + * 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; + } + } + + 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 d919455669..d43efa4760 100644 --- a/reftable/stack.h +++ b/reftable/stack.h @@ -19,7 +19,6 @@ struct reftable_stack { int list_fd; char *reftable_dir; - int disable_auto_compact; struct reftable_write_options config; @@ -33,12 +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 351e35bd86..1df3ffce52 100644 --- a/reftable/stack_test.c +++ b/reftable/stack_test.c @@ -325,7 +325,7 @@ static void test_reftable_stack_transaction_api_performs_auto_compaction(void) * we can ensure that we indeed honor this setting and have * better control over when exactly auto compaction runs. */ - st->disable_auto_compact = i != n; + st->config.disable_auto_compact = i != n; err = reftable_stack_new_addition(&add, st); EXPECT_ERR(err); @@ -497,6 +497,7 @@ static void test_reftable_stack_add(void) struct reftable_write_options cfg = { .exact_log_message = 1, .default_permissions = 0660, + .disable_auto_compact = 1, }; struct reftable_stack *st = NULL; char *dir = get_tmp_dir(__LINE__); @@ -508,7 +509,6 @@ static void test_reftable_stack_add(void) err = reftable_new_stack(&st, dir, cfg); EXPECT_ERR(err); - st->disable_auto_compact = 1; for (i = 0; i < N; i++) { char buf[256]; @@ -770,59 +770,13 @@ 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) @@ -933,9 +887,21 @@ 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 = { 0 }; + struct reftable_write_options cfg = { + .disable_auto_compact = 1, + }; struct reftable_stack *st = NULL; char *dir = get_tmp_dir(__LINE__); @@ -945,7 +911,6 @@ static void test_reftable_stack_auto_compaction(void) err = reftable_new_stack(&st, dir, cfg); EXPECT_ERR(err); - st->disable_auto_compact = 1; /* call manually below for coverage. */ for (i = 0; i < N; i++) { char name[100]; struct reftable_ref_record ref = { @@ -994,7 +959,7 @@ static void test_reftable_stack_add_performs_auto_compaction(void) * we can ensure that we indeed honor this setting and have * better control over when exactly auto compaction runs. */ - st->disable_auto_compact = i != n; + st->config.disable_auto_compact = i != n; strbuf_reset(&refname); strbuf_addf(&refname, "branch-%04d", i); @@ -1121,7 +1086,6 @@ 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); @@ -1142,9 +1106,6 @@ 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 238d4923c4..178791e086 100755 --- a/t/t0610-reftable-basics.sh +++ b/t/t0610-reftable-basics.sh @@ -121,7 +121,7 @@ test_expect_reftable_perms () { umask $umask && git init --shared=$shared 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 "$expect" repo/.git/reftable/tables.list && @@ -324,12 +324,46 @@ test_expect_success 'ref transaction: writes cause auto-compaction' ' test_line_count = 1 repo/.git/reftable/tables.list && test_commit -C repo --no-tag A && - test_line_count = 2 repo/.git/reftable/tables.list && + test_line_count = 1 repo/.git/reftable/tables.list && test_commit -C repo --no-tag B && test_line_count = 1 repo/.git/reftable/tables.list ' +test_expect_success 'ref transaction: env var disables compaction' ' + test_when_finished "rm -rf repo" && + + git init repo && + test_commit -C repo A && + + start=$(wc -l 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 && @@ -439,7 +473,7 @@ 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 $command --auto && ls -1 .git/reftable >tables-actual && test_cmp tables-expect tables-actual && @@ -457,7 +491,7 @@ test_expect_success "$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 @@ -837,12 +871,16 @@ 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 -C repo worktree add ../worktree && - test_line_count = 3 repo/.git/worktrees/worktree/reftable/tables.list && - test_line_count = 4 repo/.git/reftable/tables.list && + 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 = 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 ' @@ -850,13 +888,17 @@ 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 -C repo worktree add ../worktree && - test_line_count = 3 repo/.git/worktrees/worktree/reftable/tables.list && - test_line_count = 4 repo/.git/reftable/tables.list && + 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 = 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' ' @@ -870,6 +912,7 @@ 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