[Tarantool-patches] [PATCH 6/6] qsync: reset confirmed lsn in limbo on owner change

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Order of LSNs from different instances can be any. It means, that
if the synchronous transaction limbo changed its owner, the old
value of maximal confirmed LSN does not make sense. The new owner
means new LSNs, even less than the previously confirmed LSN of an
old owner.

The patch resets the confirmed LSN when the owner is changed. No
specific test for that, as this is a hotfix - tests start fail on
every run after a new election test was added in the previous
commit. A test for this bug will be added later.

Part of #5395
---
 src/box/txn_limbo.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/box/txn_limbo.c b/src/box/txn_limbo.c
index 3655338d8..908a17fcc 100644
--- a/src/box/txn_limbo.c
+++ b/src/box/txn_limbo.c
@@ -76,6 +76,7 @@ txn_limbo_append(struct txn_limbo *limbo, uint32_t id, struct txn *txn)
 		if (limbo->instance_id == REPLICA_ID_NIL ||
 		    rlist_empty(&limbo->queue)) {
 			limbo->instance_id = id;
+			limbo->confirmed_lsn = 0;
 		} else {
 			diag_set(ClientError, ER_UNCOMMITTED_FOREIGN_SYNC_TXNS,
 				 limbo->instance_id);
-- 
2.21.1 (Apple Git-122.3)