BigData / Apache Hudi Interview Questions
When would you choose Merge-on-Read over Copy-on-Write?
MoR is the right call for write-heavy or high-frequency workloads — think streaming CDC ingestion from Kafka/Debezium where updates arrive continuously and need to land with low latency.
Because updates go to cheap append-only log files rather than rewriting Parquet immediately, ingestion latency stays low even under heavy update volume. The trade-off shifts to reads: consumers wanting the freshest data pay a merge cost at query time, unless they're fine reading the slightly-stale read-optimized view. Teams choosing MoR also take on the operational responsibility of tuning and monitoring compaction so log files don't grow unbounded.
MoR is the natural fit for:
Choosing MoR adds which operational responsibility?
More Related questions...
