Which method is generally the slowest for identifying/specifying data files to load from a stage?

• A. Providing a discrete list of files
• B. Letting Snowflake auto-detect
• C. Using a wildcard pattern
• D. Pattern matching using a regular expression

Answer: (C)

The speed comes from how selective you are about which files to load. An explicit list of files is the fastest because Snowflake only touches those exact files, with no extra filtering. Auto-detect is reasonable but still requires Snowflake to read the stage contents to identify candidates, which adds some overhead. A wildcard pattern can match a broad set of file names, so Snowflake often has to enumerate many files and then filter down, which increases I/O and processing time. A regular expression offers more precise control and can be applied efficiently to prune the candidate set early, making it faster than a plain wildcard in typical scenarios. So, broad wildcard usage tends to be the slowest option.