The DTM reads and processes a block of rows at a time. The number of rows in the block depend on the row size and the DTM buffer size. In the following circumstances, the DTM processes one row in a block:
Log row errors. When you log row errors, the DTM processes one row in a block.
Connect CURRVAL. When you connect the CURRVAL port in a Sequence Generator transformation, the session processes one row in a block. For optimal performance, connect only the NEXTVAL port in mappings.
Configure array-based mode for Custom transformation procedure. When you configure the data access mode for a Custom transformation procedure to be row-based, the DTM processes one row in a block. By default, the data access mode is array-based, and the DTM processes multiple rows in a block.