[Tarantool-patches] [PATCH v4 05/12] box: make clear_synchro_queue() write a PROMOTE entry instead of CONFIRM + ROLLBACK
Serge Petrenko
sergepetrenko at tarantool.org
Fri Apr 16 19:25:36 MSK 2021
A successful box_clear_synchro_queue() call results in writing
CONFIRM(N) ROLLBACK(N+1) pair, where N is the confirmed lsn.
Let's write a single PROMOTE(N) entry instead. It'll have the same
meaning as CONFIRM + ROLLBACK and it will give followers some additional
information regarding leader state change later.
Part of #5445
---
src/box/box.cc | 14 +++++++-
src/box/txn_limbo.c | 78 +++++++++++++++++++++++++--------------------
src/box/txn_limbo.h | 9 ++----
3 files changed, 60 insertions(+), 41 deletions(-)
diff --git a/src/box/box.cc b/src/box/box.cc
index 2d2ae233c..e0bed74f1 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -1556,7 +1556,19 @@ box_clear_synchro_queue(bool try_wait)
"new synchronous transactions appeared");
rc = -1;
} else {
- txn_limbo_force_empty(&txn_limbo, wait_lsn);
+ /*
+ * Term parameter is unused now, We'll pass
+ * box_raft()->term there later.
+ */
+ txn_limbo_write_promote(&txn_limbo, wait_lsn, 0);
+ struct synchro_request req = {
+ .type = IPROTO_PROMOTE,
+ .replica_id = former_leader_id,
+ .origin_id = instance_id,
+ .lsn = wait_lsn,
+ .term = 0, /* unused */
+ };
+ txn_limbo_process(&txn_limbo, &req);
assert(txn_limbo_is_empty(&txn_limbo));
}
}
diff --git a/src/box/txn_limbo.c b/src/box/txn_limbo.c
index c96e497c6..2346331c7 100644
--- a/src/box/txn_limbo.c
+++ b/src/box/txn_limbo.c
@@ -317,19 +317,21 @@ txn_limbo_write_cb(struct journal_entry *entry)
}
static void
-txn_limbo_write_synchro(struct txn_limbo *limbo, uint16_t type, int64_t lsn)
+txn_limbo_write_synchro(struct txn_limbo *limbo, uint16_t type, int64_t lsn,
+ uint64_t term)
{
- assert(lsn > 0);
+ assert(lsn >= 0);
struct synchro_request req = {
.type = type,
.replica_id = limbo->owner_id,
.lsn = lsn,
+ .term = term,
};
/*
- * This is a synchronous commit so we can
- * allocate everything on a stack.
+ * This is a synchronous commit so we can allocate everything on a
+ * stack. Note, that promote body includes synchro body.
*/
char body[XROW_SYNCHRO_BODY_LEN_MAX];
struct xrow_header row;
@@ -371,14 +373,14 @@ txn_limbo_write_confirm(struct txn_limbo *limbo, int64_t lsn)
assert(lsn > limbo->confirmed_lsn);
assert(!limbo->is_in_rollback);
limbo->confirmed_lsn = lsn;
- txn_limbo_write_synchro(limbo, IPROTO_CONFIRM, lsn);
+ txn_limbo_write_synchro(limbo, IPROTO_CONFIRM, lsn, 0);
}
/** Confirm all the entries <= @a lsn. */
static void
txn_limbo_read_confirm(struct txn_limbo *limbo, int64_t lsn)
{
- assert(limbo->owner_id != REPLICA_ID_NIL);
+ assert(limbo->owner_id != REPLICA_ID_NIL || txn_limbo_is_empty(limbo));
assert(limbo == &txn_limbo);
struct txn_limbo_entry *e, *tmp;
rlist_foreach_entry_safe(e, &limbo->queue, in_queue, tmp) {
@@ -425,7 +427,7 @@ txn_limbo_write_rollback(struct txn_limbo *limbo, int64_t lsn)
assert(lsn > limbo->confirmed_lsn);
assert(!limbo->is_in_rollback);
limbo->is_in_rollback = true;
- txn_limbo_write_synchro(limbo, IPROTO_ROLLBACK, lsn);
+ txn_limbo_write_synchro(limbo, IPROTO_ROLLBACK, lsn, 0);
limbo->is_in_rollback = false;
}
@@ -433,7 +435,7 @@ txn_limbo_write_rollback(struct txn_limbo *limbo, int64_t lsn)
static void
txn_limbo_read_rollback(struct txn_limbo *limbo, int64_t lsn)
{
- assert(limbo->owner_id != REPLICA_ID_NIL);
+ assert(limbo->owner_id != REPLICA_ID_NIL || txn_limbo_is_empty(limbo));
assert(limbo == &txn_limbo);
struct txn_limbo_entry *e, *tmp;
struct txn_limbo_entry *last_rollback = NULL;
@@ -464,6 +466,37 @@ txn_limbo_read_rollback(struct txn_limbo *limbo, int64_t lsn)
box_update_ro_summary();
}
+void
+txn_limbo_write_promote(struct txn_limbo *limbo, int64_t lsn, uint64_t term)
+{
+ limbo->confirmed_lsn = lsn;
+ limbo->is_in_rollback = true;
+ /*
+ * We make sure that promote is only written once everything this
+ * instance has may be confirmed.
+ */
+ struct txn_limbo_entry *e = txn_limbo_last_synchro_entry(limbo);
+ assert(e == NULL || e->lsn <= lsn);
+ (void) e;
+ txn_limbo_write_synchro(limbo, IPROTO_PROMOTE, lsn, term);
+ limbo->is_in_rollback = false;
+}
+
+/**
+ * Process a PROMOTE request, i.e. confirm all entries <= @req.lsn and rollback all
+ * entries > @req.lsn.
+ */
+static void
+txn_limbo_read_promote(struct txn_limbo *limbo,
+ const struct synchro_request *req)
+{
+ txn_limbo_read_confirm(limbo, req->lsn);
+ txn_limbo_read_rollback(limbo, req->lsn + 1);
+ assert(txn_limbo_is_empty(&txn_limbo));
+ limbo->owner_id = req->origin_id;
+ limbo->confirmed_lsn = 0;
+}
+
void
txn_limbo_ack(struct txn_limbo *limbo, uint32_t replica_id, int64_t lsn)
{
@@ -626,38 +659,15 @@ txn_limbo_process(struct txn_limbo *limbo, const struct synchro_request *req)
case IPROTO_ROLLBACK:
txn_limbo_read_rollback(limbo, req->lsn);
break;
+ case IPROTO_PROMOTE:
+ txn_limbo_read_promote(limbo, req);
+ break;
default:
unreachable();
}
return;
}
-void
-txn_limbo_force_empty(struct txn_limbo *limbo, int64_t confirm_lsn)
-{
- struct txn_limbo_entry *e, *last_quorum = NULL;
- struct txn_limbo_entry *rollback = NULL;
- rlist_foreach_entry(e, &limbo->queue, in_queue) {
- if (txn_has_flag(e->txn, TXN_WAIT_ACK)) {
- if (e->lsn <= confirm_lsn) {
- last_quorum = e;
- } else {
- rollback = e;
- break;
- }
- }
- }
-
- if (last_quorum != NULL) {
- txn_limbo_write_confirm(limbo, last_quorum->lsn);
- txn_limbo_read_confirm(limbo, last_quorum->lsn);
- }
- if (rollback != NULL) {
- txn_limbo_write_rollback(limbo, rollback->lsn);
- txn_limbo_read_rollback(limbo, rollback->lsn);
- }
-}
-
void
txn_limbo_on_parameters_change(struct txn_limbo *limbo)
{
diff --git a/src/box/txn_limbo.h b/src/box/txn_limbo.h
index f2a98c8bb..f35771dc9 100644
--- a/src/box/txn_limbo.h
+++ b/src/box/txn_limbo.h
@@ -272,14 +272,11 @@ int
txn_limbo_wait_confirm(struct txn_limbo *limbo);
/**
- * Make txn_limbo confirm all the entries with lsn less than or
- * equal to the given one, and rollback all the following entries.
- * The function makes txn_limbo write CONFIRM and ROLLBACK
- * messages for appropriate lsns, and then process the messages
- * immediately.
+ * Write a PROMOTE request, which has the same effect as CONFIRM(@a lsn) and
+ * ROLLBACK(@a lsn + 1) combined.
*/
void
-txn_limbo_force_empty(struct txn_limbo *limbo, int64_t last_confirm);
+txn_limbo_write_promote(struct txn_limbo *limbo, int64_t lsn, uint64_t term);
/**
* Update qsync parameters dynamically.
--
2.24.3 (Apple Git-128)
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