[IGNITE-8371] MVCC TX: Force key request during rebalance may cause error on backups.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.7
• Component/s: mvcc, sql
• Assignee: Roman Kondakov
• Reporter: Roman Kondakov
• Created: 24/Apr/18 08:52
• Updated: 30/Aug/18 14:39
• Resolved: 16/Jul/18 09:02

Description

When backup is updating during rebalance and the key to be updated in TX is not supplied yet from the previous partition owner, backup makes force key request in order to obtain this key and all its versions. But later this key can be send to this backup from the previous owner once again as a part of standard rebalance process. And this causes write conflict: we have to write this key on the backup once again.

Solution: do not update key when it has already been written before (during rebalance or force key request process).

Issue Links

• is blocked by: IGNITE-8031 MVCC TX: TxLog does not support partitions rebalance at the moment. We need to implement it.
• Is contained by: IGNITE-4191 SQL: support transactions
• is related to: IGNITE-7306 Incorrect force key request processing when MVCC is enabled
• is related to: IGNITE-7806 SQL TX: Backup update protocol