Which statement best reflects how production systems typically handle cross-shard transactions?

Which statement best reflects how production systems typically handle cross-shard transactions?

• A. Design your shard key to keep related data on one shard
• B. Use the Saga pattern with compensating actions
• C. Adopt 2PC for cross-shard operations
• D. Most production systems avoid 2PC and design shard keys to avoid cross-shard transactions entirely

Answer: (D)

Distributing data so that related pieces live on the same shard minimizes the need for cross-shard coordination, and when cross-shard work does occur, many systems prefer patterns that don’t rely on locking across shards. Two-phase commit across multiple shards is powerful for atomicity but introduces blocking, failure risk, and performance penalties, making it unattractive for everyday production use. In practice, teams design shard keys to keep related data together and use alternative approaches (like Saga-like compensating actions) for complex multi-step operations rather than relying on a distributed transaction protocol. That’s why the statement describing production practice as avoiding cross-shard transactions by careful shard-key design—and steering clear of 2PC—is the best fit.

Distributing data so that related pieces live on the same shard minimizes the need for cross-shard coordination, and when cross-shard work does occur, many systems prefer patterns that don’t rely on locking across shards. Two-phase commit across multiple shards is powerful for atomicity but introduces blocking, failure risk, and performance penalties, making it unattractive for everyday production use. In practice, teams design shard keys to keep related data together and use alternative approaches (like Saga-like compensating actions) for complex multi-step operations rather than relying on a distributed transaction protocol.

That’s why the statement describing production practice as avoiding cross-shard transactions by careful shard-key design—and steering clear of 2PC—is the best fit.