[Tarantool-patches] [PATCH v2 4/5] vclock: ignore 0th component in comparisons.

[sergepetrenko <sergepetrenko@tarantool.org>]

From: Serge Petrenko <sergepetrenko@tarantool.org>

0th vclock component will be used to count replica-local rows of an
anonymous replica. These rows won't be replicated and different
instances will have different values in vclock[0]. So ignore 0th
component in comparisons.

Part of #3186
---
 src/box/vclock.h    | 12 ++++++++++--
 test/unit/vclock.cc |  8 ++++----
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/box/vclock.h b/src/box/vclock.h
index b5eddcf8b..35ba6284c 100644
--- a/src/box/vclock.h
+++ b/src/box/vclock.h
@@ -279,8 +279,16 @@ vclock_compare(const struct vclock *a, const struct vclock *b)
 	struct bit_iterator it;
 	bit_iterator_init(&it, &map, sizeof(map), true);
 
-	for (size_t replica_id = bit_iterator_next(&it); replica_id < VCLOCK_MAX;
-	     replica_id = bit_iterator_next(&it)) {
+	size_t replica_id = bit_iterator_next(&it);
+	/*
+	 * Ignore 0-th component in comparisons.
+	 * It is empty for normal replicas and should
+	 * be ignored for anonymous ones.
+	 */
+	if (replica_id == 0)
+		replica_id = bit_iterator_next(&it);
+
+	for (; replica_id < VCLOCK_MAX; replica_id = bit_iterator_next(&it)) {
 
 		int64_t lsn_a = vclock_get(a, replica_id);
 		int64_t lsn_b = vclock_get(b, replica_id);
diff --git a/test/unit/vclock.cc b/test/unit/vclock.cc
index 15e9f9379..d9f676a31 100644
--- a/test/unit/vclock.cc
+++ b/test/unit/vclock.cc
@@ -50,11 +50,11 @@ test_compare_one(uint32_t a_count, const int64_t *lsns_a,
 	vclock_create(&b);
 	for (uint32_t node_id = 0; node_id < a_count; node_id++) {
 		if (lsns_a[node_id] > 0)
-			vclock_follow(&a, node_id, lsns_a[node_id]);
+			vclock_follow(&a, node_id + 1, lsns_a[node_id]);
 	}
 	for (uint32_t node_id = 0; node_id < b_count; node_id++) {
 		if (lsns_b[node_id] > 0)
-			vclock_follow(&b, node_id, lsns_b[node_id]);
+			vclock_follow(&b, node_id + 1, lsns_b[node_id]);
 	}
 
 	return vclock_compare(&a, &b);
@@ -119,7 +119,7 @@ testset_create(vclockset_t *set, int64_t *files, int files_n, int node_n)
 			signature += lsn;
 
 			/* Update cluster hash */
-			vclock_follow(vclock, node_id, lsn);
+			vclock_follow(vclock, node_id + 1, lsn);
 		}
 		vclockset_insert(set, vclock);
 	}
@@ -225,7 +225,7 @@ test_isearch()
 			if (lsn <= 0)
 				continue;
 
-			vclock_follow(&vclock, node_id, lsn);
+			vclock_follow(&vclock, node_id + 1, lsn);
 		}
 
 		int64_t check = *(query + NODE_N);
-- 
2.20.1 (Apple Git-117)