Snowflake COF-C03 Question Answer
What will happen if multiple identical COPY INTO < table > statements, using the default settings, are executed in parallel on the same data file?
The statements will load the data only once in the table.
The statements will duplicate the data in the table.
The statements will fail with an error relating to reading the same file.
The statements will overwrite the data in the table.
The Answer Is:
AExplanation:
The correct answer is A. The statements will load the data only once in the table .
By default, Snowflake tracks metadata for files that have already been loaded into a table. This load metadata helps prevent the same staged file from being loaded again into the same table when using the default COPY INTO < table > behavior.
Why A is correct:
Snowflake’s default copy behavior prevents duplicate loading of the same file into the same table. Even if multiple identical COPY INTO statements run against the same file, Snowflake uses load metadata to avoid loading the same file multiple times.
Important default behavior:
The default value of FORCE is FALSE. This means Snowflake does not reload files that have already been loaded successfully into the table.
Why the other options are incorrect:
B. Data is not duplicated under the default settings because Snowflake tracks loaded files.
C. Running parallel copy statements does not automatically fail just because they reference the same file.
D. COPY INTO < table > does not overwrite table data by default. It appends loaded rows, but duplicate file loading is prevented by load metadata.
Official Snowflake documentation reference:
Snowflake documentation explains that Snowflake maintains load metadata for tables and prevents reloading the same files by default unless FORCE = TRUE is specified.
