Which two statements are true about MySQL server multi-source replication? (Choose two.)

Question

Options

• AIt is not compatible with auto-positioning.
• BIt needs to be re-instanced after a crash to maintain consistency.
• CIt uses only time-based replication conflict resolution.
• DIt relies on relay_log_recovery for resilient operations.
• EIt does not attempt to detect or resolve replication conflicts.
• FIt must use GTID replication.

• A
  7% (3)
• B
  14% (6)
• C
  75% (33)
• D
  2% (1)
• E
  2% (1)

Explanation

C and F identify the two defining constraints of MySQL multi-source replication.

Why C is correct: When multiple sources write to the same replica, conflicts are inevitable. MySQL's multi-source replication resolves these conflicts exclusively through time-based ordering (last-writer-wins using epoch/timestamp). There is no row-level diffing or transaction-level arbitration - time is the only arbiter, making C accurate.

Why F is correct: Multi-source replication requires GTID mode because each source's transactions must carry a globally unique identifier so the replica can track, de-duplicate, and route them across independent channels. Without GTIDs, the replica cannot reliably distinguish which transaction came from which source.

Why the distractors are wrong:

• A is wrong - multi-source is compatible with GTID auto-positioning; each channel supports it independently.
• B is wrong - a full re-instance is not required after a crash; standard crash recovery procedures apply.
• D is wrong and is a trap: relay_log_recovery=ON is actually incompatible with multi-source replication, so the replica does not rely on it.
• E is wrong because multi-source does attempt conflict resolution - it's just limited to the time-based method described in C. E and C are mutually exclusive; only one can be true.

Memory tip: Think "GT" = GTID + Time - multi-source replication runs on GTID and resolves conflicts only by Time. If you remember those two anchors, you can eliminate every distractor.

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