Configure a Hudi Merge-on-Read table and understand the read path differences from Copy-on-Write

Steps

1. Create a MoR table by setting hoodie.datasource.write.table.type=MERGE_ON_READ in the write options; all other upsert options (record key, precombine) remain the same as CoW.
2. Write upsert batches; Hudi appends delta log files (Avro-encoded) alongside the base Parquet files rather than rewriting the base files on every write.
3. Query the read-optimized view (base files only) for fast reads without applying deltas: spark.read.format('hudi').option('hoodie.datasource.query.type', 'read_optimized').load('/path/to/hudi/events').
4. Query the real-time view (base + delta logs merged) for up-to-date results: spark.read.format('hudi').option('hoodie.datasource.query.type', 'snapshot').load('/path/to/hudi/events').
5. Schedule compaction to merge delta logs into base Parquet files: configure hoodie.compact.inline=true for inline compaction or trigger async compaction via HoodieCompactor.