What does the query time predicate METADATA$ACTION='INSERT' do in a Snowflake query?

• A. It selects rows with the primary key
• B. It filters to return only rows where METADATA$ACTION='INSERT'
• C. It marks inserted rows
• D. It updates the inserted rows

Answer: (B)

Metdata$ACTION is a change-data-capture indicator that accompanies rows produced by a Snowflake stream. It tells you what kind of DML operation affected each row: INSERT, UPDATE, or DELETE. Filtering with METADATA$ACTION = 'INSERT' narrows the stream results to only the rows that were newly inserted, ignoring updates and deletions. This is useful for incremental loads or applying only new data from a stream. It’s not about selecting by a primary key or marking/updating rows in the base table; it’s filtering the stream’s output by the type of change.