[IGNITE-10972] MERGE INTO hangs in MVCC mode with unsorted keys

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 2.7
• Component/s: mvcc
• Assignee: Unassigned
• Reporter: Ilya Kasnacheev
• Created: 17/Jan/19 16:42
• Updated: 25/Aug/23 08:36
• Resolved: 25/Aug/23 08:36

Description

right now, if you perform repeatedly
MERGE INTO T(K, V) VALUES(k1, v1), (k2, v2), (k3, v3);
and in parallel
MERGE INTO T(K, V) VALUES(k2, v2), (k1, v1);

you will eventually see a deadlock. This is expected behavior as per old putAll behavior, but the expectation is that you should see "Cannot serialize transaction" errors instead of deadlock when using MVCC.

When doing MERGE INTO with sorted keys you will not get deadlock but will see a lot of "Cannot serialize transaction" exception with expectation that such statements to not conflict instead since they are ordered.

Please see attached test and userlist discussion.

Issue Links

• relates to: IGNITE-9322 MVCC: implement deadlock detector
• links to: Userlist thread