Partition columns optimize query performance by pruning out the data files that do not need to be scanned (i.e. partitioning the external table).

Partition columns optimize query performance by pruning out the data files that do not need to be scanned (i.e. partitioning the external table).

Which pseudocolumn of External table evaluate as an expression that parses the path and/or filename information.
A . METADATA$ROW_NUMBER
B . METADATA$COLUMNNAME
C . METADATA$FILEPATH
D . METADATA$FILENAME

View Answer

Answer: D

Explanation:

METADATA$FILENAME

A pseudocolumn that identifies the name of each staged data file included in the external table, including its path in the stage.

An external table creator defines partition columns in a new external table as expressions that parse the path and/or filename information stored in the METADATA$FILENAME pseudo column. A partition consists of all data files that match the path and/or filename in the expression for the partition column.