[Tarantool-patches] [PATCH v6 1/3] replication: omit 0-th vclock component in replication responses
Serge Petrenko
sergepetrenko at tarantool.org
Tue Apr 7 18:49:54 MSK 2020
If an anonymous replica is promoted to a normal one and becomes
replication master later, its vclock contains a non-empty zero
component, tracking local changes on this replica from the time when it
had been anonymous. No need to pollute joining instance's vclock with
our non-empty 0 component.
When an anonymous replica reports its status to a remote instance it
should also hide its 0-th vclock component.
This is needed for backward compatibility with old instances, which
don't ignore 0th vclock component coming from a remote instance by
default.
In order to do so, introduce a new function - vclock_size_ignore0(),
which doesn't count 0th clock component, and patch xrow_encode_vclock()
to skip 0th clock component if it's present.
Also make sure that new instances ignore 0th vclock component coming
from an unpatched remote instance.
Follow-up #3186
Prerequisite #4114
---
src/box/relay.cc | 2 +-
src/box/replication.cc | 4 ++--
src/box/vclock.h | 6 ++++++
src/box/xrow.c | 10 +++++++---
test/replication/anon.result | 5 +++++
test/replication/anon.test.lua | 2 ++
6 files changed, 23 insertions(+), 6 deletions(-)
diff --git a/src/box/relay.cc b/src/box/relay.cc
index c634348a4..fec9f07d1 100644
--- a/src/box/relay.cc
+++ b/src/box/relay.cc
@@ -464,7 +464,7 @@ relay_schedule_pending_gc(struct relay *relay, const struct vclock *vclock)
* the greater signatures is due to changes pulled
* from other members of the cluster.
*/
- if (vclock_compare(&curr->vclock, vclock) > 0)
+ if (vclock_compare_ignore0(&curr->vclock, vclock) > 0)
break;
stailq_shift(&relay->pending_gc);
free(gc_msg);
diff --git a/src/box/replication.cc b/src/box/replication.cc
index 1345f189b..c833041a3 100644
--- a/src/box/replication.cc
+++ b/src/box/replication.cc
@@ -777,8 +777,8 @@ replicaset_needs_rejoin(struct replica **master)
continue;
const struct ballot *ballot = &applier->ballot;
- if (vclock_compare(&ballot->gc_vclock,
- &replicaset.vclock) <= 0) {
+ if (vclock_compare_ignore0(&ballot->gc_vclock,
+ &replicaset.vclock) <= 0) {
/*
* There's at least one master that still stores
* WALs needed by this instance. Proceed to local
diff --git a/src/box/vclock.h b/src/box/vclock.h
index 79e5a1bc0..5c0525b00 100644
--- a/src/box/vclock.h
+++ b/src/box/vclock.h
@@ -200,6 +200,12 @@ vclock_size(const struct vclock *vclock)
return bit_count_u32(vclock->map);
}
+static inline uint32_t
+vclock_size_ignore0(const struct vclock *vclock)
+{
+ return bit_count_u32(vclock->map & ~1);
+}
+
static inline int64_t
vclock_calc_sum(const struct vclock *vclock)
{
diff --git a/src/box/xrow.c b/src/box/xrow.c
index be026a43c..21a68220a 100644
--- a/src/box/xrow.c
+++ b/src/box/xrow.c
@@ -51,7 +51,7 @@ static_assert(IPROTO_DATA < 0x7f && IPROTO_METADATA < 0x7f &&
static inline uint32_t
mp_sizeof_vclock(const struct vclock *vclock)
{
- uint32_t size = vclock_size(vclock);
+ uint32_t size = vclock_size_ignore0(vclock);
return mp_sizeof_map(size) + size * (mp_sizeof_uint(UINT32_MAX) +
mp_sizeof_uint(UINT64_MAX));
}
@@ -59,10 +59,14 @@ mp_sizeof_vclock(const struct vclock *vclock)
static inline char *
mp_encode_vclock(char *data, const struct vclock *vclock)
{
- data = mp_encode_map(data, vclock_size(vclock));
+ data = mp_encode_map(data, vclock_size_ignore0(vclock));
struct vclock_iterator it;
vclock_iterator_init(&it, vclock);
- vclock_foreach(&it, replica) {
+ struct vclock_c replica;
+ replica = vclock_iterator_next(&it);
+ if (replica.id == 0)
+ replica = vclock_iterator_next(&it);
+ for ( ; replica.id < VCLOCK_MAX; replica = vclock_iterator_next(&it)) {
data = mp_encode_uint(data, replica.id);
data = mp_encode_uint(data, replica.lsn);
}
diff --git a/test/replication/anon.result b/test/replication/anon.result
index 88061569f..cbbeeef09 100644
--- a/test/replication/anon.result
+++ b/test/replication/anon.result
@@ -187,6 +187,11 @@ a > 0
| ---
| - true
| ...
+-- 0-th vclock component isn't propagated across the cluster.
+box.info.vclock[0]
+ | ---
+ | - null
+ | ...
test_run:cmd('switch default')
| ---
| - true
diff --git a/test/replication/anon.test.lua b/test/replication/anon.test.lua
index 8a8d15c18..627dc5c8e 100644
--- a/test/replication/anon.test.lua
+++ b/test/replication/anon.test.lua
@@ -66,6 +66,8 @@ test_run:cmd('switch replica_anon2')
a = box.info.vclock[1]
-- The instance did fetch a snapshot.
a > 0
+-- 0-th vclock component isn't propagated across the cluster.
+box.info.vclock[0]
test_run:cmd('switch default')
box.space.test:insert{2}
test_run:cmd("switch replica_anon2")
--
2.21.1 (Apple Git-122.3)
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