The Row Constructor algorithm is a specialized operator that creates a virtual row for use as the input to other algorithms. The Row Constructor algorithm is used in the following two ways:
With an INSERT ... VALUES statement, the expressions referenced in the VALUES clause (typically literal constants and/or host variables) form a virtual row to be inserted. In this case, a row constructor appears in the graphical plan underneath an INSERT.
Direct or indirect references to the system table SYS.DUMMY are transformed automatically into a Row Constructor algorithm, replacing a scan algorithm over SYS.DUMMY and eliminating the need to latch the (single) page of the DUMMY table.
In the case of short or long text plans, the plan string continues to contain a reference to the table SYS.DUMMY, even though a Row Constructor algorithm has replaced the table scan.