Commit Diff

Commit:
9fcbbb3e7d5e9f5a876ee27a7bf93303321e26b2
From:
Serge Petrenko <sergepetrenko@tarantool.org>
Via:
Kirill Yukhin <kyukhin@tarantool.org>
Date:
Message:
applier: fix tx boundary check for half-applied txns In case there are 2 "new" instances, running tarantool 2.2+, master and replica, and one "old" instance, running an earlier tarantool version, in a full-mesh cluster, it may happen that the "new" replica receives part of a tx from an "old" instance, and the remaining part from a "new" instance. Since "new" instances preserve tx boundaries, "new" replica would skip the tx remains assuming it has already applied the full tx if it has applied the first tx row. This leads to gaps in "new" replica's WAL and to skipping the remaining part of the tx forever. Fix this behaviour to apply the full tx even if it's beginning is already applied in mixed clusters. Closes #5125
Actions:
Patch | Tree
commit - 4c7d8281502b1a26c59ffc9a87e082e7e8826932
commit + 9fcbbb3e7d5e9f5a876ee27a7bf93303321e26b2
blob - df48b47962d2abf98328d13178341a10d4f2e482
blob + 6ca4cca94b25ee2a129698feeb1d29567b03f6bc
--- src/box/applier.cc
+++ src/box/applier.cc
@@ -737,6 +737,7 @@ applier_apply_tx(struct stailq *rows)
 	struct xrow_header *first_row = &stailq_first_entry(rows,
 					struct applier_tx_row, next)->row;
 	struct xrow_header *last_row;
+	last_row = &stailq_last_entry(rows, struct applier_tx_row, next)->row;
 	struct replica *replica = replica_by_id(first_row->replica_id);
 	/*
 	 * In a full mesh topology, the same set of changes
@@ -748,9 +749,28 @@ applier_apply_tx(struct stailq *rows)
 			       &replicaset.applier.order_latch);
 	latch_lock(latch);
 	if (vclock_get(&replicaset.applier.vclock,
-		       first_row->replica_id) >= first_row->lsn) {
+		       last_row->replica_id) >= last_row->lsn) {
 		latch_unlock(latch);
 		return 0;
+	} else if (vclock_get(&replicaset.applier.vclock,
+			      first_row->replica_id) >= first_row->lsn) {
+		/*
+		 * We've received part of the tx from an old
+		 * instance not knowing of tx boundaries.
+		 * Skip the already applied part.
+		 */
+		struct xrow_header *tmp;
+		while (true) {
+			tmp = &stailq_first_entry(rows,
+						  struct applier_tx_row,
+						  next)->row;
+			if (tmp->lsn <= vclock_get(&replicaset.applier.vclock,
+						   tmp->replica_id)) {
+				stailq_shift(rows);
+			} else {
+				break;
+			}
+		}
 	}
 
 	/**
@@ -835,7 +855,6 @@ applier_apply_tx(struct stailq *rows)
 	 * instances, which send every single tx row as a separate
 	 * transaction.
 	 */
-	last_row = &stailq_last_entry(rows, struct applier_tx_row, next)->row;
 	vclock_follow(&replicaset.applier.vclock, last_row->replica_id,
 		      last_row->lsn);
 	latch_unlock(latch);