Number of input and output link

Number of input link	:	One or more
Number of output link	:	One

Merge Assembly () is used to combine two or more data streams that have the same structure into a single unified data stream.

All input streams must have:

• The same number of fields
• The same field order
• Compatible data types

Purpose of Merge Assembly

The Merge Assembly is commonly used to:

• Combine data from multiple sources with identical schemas
• Union datasets without performing joins
• Simplify downstream processing by using a single stream
• Consolidate partitioned or parallel data outputs

How It Works

• Two or more input streams are provided to the Merge Assembly.
• Each incoming record is passed through without modification.
• Records from all input streams are emitted into one output stream.
• The order of records depends on the execution engine and partitioning.

Key Characteristics

• Performs a union operation, not a join
• Does not modify records
• Requires identical schema across all input streams
• Emits one output record for each input record
• Suitable for large-scale distributed processing

Supported Engines

Map Reduce	Spark 1.x RDD	Spark 2.x RDD	Spark 2.x Dataset	Apache Beam 2.29.0 Batch	Apache Beam 2.29.0 Streaming	Apache Flink 1.12.0 Batch	Apache Flink 1.12.0 Streaming	Apache Tez 0.9.1	PySpark