-- And hence on the replica that does not have TTL in-memory (this replica),
-- it will try to apply TTL, and the column will be dropped,
-- but on another replica the column won't be dropped since it has in-memory TTL and will not apply TTL.
-- and eventually this will lead to the following error:
--
-- MergeFromLogEntryTask: Code: 40. DB::Exception: Part 20100101_0_0_3 from r2 has different columns hash. (CHECKSUM_DOESNT_MATCH) (version 22.4.1.1). Data after merge is not byte-identical to data on another replicas. There could be several reasons: 1. Using newer version of compression library after server update. 2. Using another compression method. 3. Non-deterministic compression algorithm (highly unlikely). 4. Non-deterministic merge algorithm due to logical error in code. 5. Data corruption in memory due to bug in code. 6. Data corruption in memory due to hardware issue. 7. Manual modification of source data after server startup. 8. Manual modification of checksums stored in ZooKeeper. 9. Part format related settings like 'enable_mixed_granularity_parts' are different on different replicas. We will download merged part from replica to force byte-identical result.