From 135f491f83d4763bdc61642eb0126ce2e6ada286 Mon Sep 17 00:00:00 2001 From: Karthik Nayak Date: Sat, 8 Nov 2025 22:51:53 +0100 Subject: reftable/stack: return stack segments directly The `stack_table_sizes_for_compaction()` function returns individual sizes of each reftable table. This function is only called by `reftable_stack_auto_compact()` to decide which tables need to be compacted, if any. Modify the function to directly return the segments, which avoids the extra step of receiving the sizes only to pass it to `suggest_compaction_segment()`. A future commit will also add functionality for checking whether auto-compaction is necessary without performing it. This change allows code re-usability in that context. Signed-off-by: Karthik Nayak Acked-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- reftable/stack.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) (limited to 'reftable/stack.c') diff --git a/reftable/stack.c b/reftable/stack.c index 65d89820bd..49387f9344 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -1626,7 +1626,8 @@ struct segment suggest_compaction_segment(uint64_t *sizes, size_t n, return seg; } -static uint64_t *stack_table_sizes_for_compaction(struct reftable_stack *st) +static int stack_segments_for_compaction(struct reftable_stack *st, + struct segment *seg) { int version = (st->opts.hash_id == REFTABLE_HASH_SHA1) ? 1 : 2; int overhead = header_size(version) - 1; @@ -1634,29 +1635,29 @@ static uint64_t *stack_table_sizes_for_compaction(struct reftable_stack *st) REFTABLE_CALLOC_ARRAY(sizes, st->merged->tables_len); if (!sizes) - return NULL; + return REFTABLE_OUT_OF_MEMORY_ERROR; for (size_t i = 0; i < st->merged->tables_len; i++) sizes[i] = st->tables[i]->size - overhead; - return sizes; + *seg = suggest_compaction_segment(sizes, st->merged->tables_len, + st->opts.auto_compaction_factor); + reftable_free(sizes); + + return 0; } int reftable_stack_auto_compact(struct reftable_stack *st) { struct segment seg; - uint64_t *sizes; + int err; if (st->merged->tables_len < 2) return 0; - sizes = stack_table_sizes_for_compaction(st); - if (!sizes) - return REFTABLE_OUT_OF_MEMORY_ERROR; - - seg = suggest_compaction_segment(sizes, st->merged->tables_len, - st->opts.auto_compaction_factor); - reftable_free(sizes); + err = stack_segments_for_compaction(st, &seg); + if (err) + return err; if (segment_size(&seg) > 0) return stack_compact_range(st, seg.start, seg.end - 1, -- cgit v1.2.3 From e35155588aa9f0355eb7e116ea418c189479f62d Mon Sep 17 00:00:00 2001 From: Karthik Nayak Date: Sat, 8 Nov 2025 22:51:54 +0100 Subject: reftable/stack: add function to check if optimization is required The reftable backend performs auto-compaction as part of its regular flow, which is required to keep the number of tables part of a stack at bay. This allows it to stay optimized. Compaction can also be triggered voluntarily by the user via the 'git pack-refs' or the 'git refs optimize' command. However, currently there is no way for the user to check if optimization is required without actually performing it. Extract out the heuristics logic from 'reftable_stack_auto_compact()' into an internal function 'update_segment_if_compaction_required()'. Then use this to add and expose `reftable_stack_compaction_required()` which will allow users to check if the reftable backend can be optimized. Signed-off-by: Karthik Nayak Acked-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- reftable/reftable-stack.h | 11 +++++++++++ reftable/stack.c | 42 ++++++++++++++++++++++++++++++++++++----- t/unit-tests/u-reftable-stack.c | 12 ++++++++++-- 3 files changed, 58 insertions(+), 7 deletions(-) (limited to 'reftable/stack.c') diff --git a/reftable/reftable-stack.h b/reftable/reftable-stack.h index d70fcb705d..c2415cbc6e 100644 --- a/reftable/reftable-stack.h +++ b/reftable/reftable-stack.h @@ -123,6 +123,17 @@ struct reftable_log_expiry_config { int reftable_stack_compact_all(struct reftable_stack *st, struct reftable_log_expiry_config *config); +/* + * Check if compaction is required. + * + * When `use_heuristics` is false, check if all tables can be compacted to a + * single table. If true, use heuristics to determine if the tables need to be + * compacted to maintain geometric progression. + */ +int reftable_stack_compaction_required(struct reftable_stack *st, + bool use_heuristics, + bool *required); + /* heuristically compact unbalanced table stack. */ int reftable_stack_auto_compact(struct reftable_stack *st); diff --git a/reftable/stack.c b/reftable/stack.c index 49387f9344..1c9f21dfe1 100644 --- a/reftable/stack.c +++ b/reftable/stack.c @@ -1647,19 +1647,51 @@ static int stack_segments_for_compaction(struct reftable_stack *st, return 0; } -int reftable_stack_auto_compact(struct reftable_stack *st) +static int update_segment_if_compaction_required(struct reftable_stack *st, + struct segment *seg, + bool use_geometric, + bool *required) { - struct segment seg; int err; - if (st->merged->tables_len < 2) + if (st->merged->tables_len < 2) { + *required = false; + return 0; + } + + if (!use_geometric) { + *required = true; return 0; + } + + err = stack_segments_for_compaction(st, seg); + if (err) + return err; + + *required = segment_size(seg) > 0; + return 0; +} + +int reftable_stack_compaction_required(struct reftable_stack *st, + bool use_heuristics, + bool *required) +{ + struct segment seg; + return update_segment_if_compaction_required(st, &seg, use_heuristics, + required); +} + +int reftable_stack_auto_compact(struct reftable_stack *st) +{ + struct segment seg; + bool required; + int err; - err = stack_segments_for_compaction(st, &seg); + err = update_segment_if_compaction_required(st, &seg, true, &required); if (err) return err; - if (segment_size(&seg) > 0) + if (required) return stack_compact_range(st, seg.start, seg.end - 1, NULL, STACK_COMPACT_RANGE_BEST_EFFORT); diff --git a/t/unit-tests/u-reftable-stack.c b/t/unit-tests/u-reftable-stack.c index a8b91812e8..b8110cdeee 100644 --- a/t/unit-tests/u-reftable-stack.c +++ b/t/unit-tests/u-reftable-stack.c @@ -1067,6 +1067,7 @@ void test_reftable_stack__add_performs_auto_compaction(void) .value_type = REFTABLE_REF_SYMREF, .value.symref = (char *) "master", }; + bool required = false; char buf[128]; /* @@ -1087,10 +1088,17 @@ void test_reftable_stack__add_performs_auto_compaction(void) * auto compaction is disabled. When enabled, we should merge * all tables in the stack. */ - if (i != n) + cl_assert_equal_i(reftable_stack_compaction_required(st, true, &required), 0); + if (i != n) { cl_assert_equal_i(st->merged->tables_len, i + 1); - else + if (i < 1) + cl_assert_equal_b(required, false); + else + cl_assert_equal_b(required, true); + } else { cl_assert_equal_i(st->merged->tables_len, 1); + cl_assert_equal_b(required, false); + } } reftable_stack_destroy(st); -- cgit v1.2.3