COF-C03 Data Loading, Unloading, and Connectivity Practice Question
A data engineer is using the COPY INTO command to load data from an external stage into a Snowflake table. The engineer wants to ensure that the load operation does not fail if some files in the stage have already been loaded previously. The engineer also wants to avoid reloading files that have already been processed. Which COPY INTO option should be used to achieve this?
⚠ Common exam trap
The trap here is assuming that an explicit option is needed to skip previously loaded files, when in fact COPY INTO does this by default.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use the default behavior of COPY INTO, which automatically skips files that have been loaded in the past 64 days.
The default behavior of COPY INTO is to skip files that have already been loaded, based on load metadata retained for 64 days. This prevents duplicate loading without requiring any special options. Using FORCE or LOAD_UNCERTAIN_FILES would override this and potentially cause duplicates. PURGE deletes files but is not intended for duplicate avoidance.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Set PURGE = TRUE to remove files from the stage after loading, ensuring they are not reloaded.
Why it's wrong here
PURGE = TRUE removes the files from the stage after a successful load, which prevents them from being loaded again because they no longer exist. However, this is not the recommended way to avoid reloading; it deletes the source files, which may be undesirable. Also, it does not help if files are added again with the same name. The default metadata-based skipping is safer.
- ✗
LOAD_UNCERTAIN_FILES = TRUE
Why it's wrong here
LOAD_UNCERTAIN_FILES = TRUE allows loading of files that have an uncertain load status, such as those that may have been partially loaded. It does not prevent reloading of successfully loaded files; instead, it can cause additional loads. This option is used for recovery scenarios, not for avoiding duplicates.
- ✓
Use the default behavior of COPY INTO, which automatically skips files that have been loaded in the past 64 days.
Why this is correct
By default, COPY INTO maintains load metadata for 64 days and skips files that have already been successfully loaded. This prevents duplicate loading without additional options. The engineer should simply rely on the default behavior, which is designed to avoid reloading files within the retention period.
- ✗
FORCE = TRUE
Why it's wrong here
FORCE = TRUE forces the load of all specified files, regardless of whether they have been loaded before. This would cause reloading of previously processed files, leading to duplicate data. It is the opposite of what the engineer wants, as it ignores load metadata and reloads everything.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Snowflake exam blueprint
This COF-C03 practice question is part of Courseiva's free Snowflake certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the COF-C03 exam.