DEA-C02 Data Movement Practice Question
A data engineer runs a COPY INTO statement that loads 120 files from an external S3 stage into a target table. The LOAD_UNCERTAIN_FILES option was not specified, and 42 files were already loaded by an earlier run that completed successfully. The engineer expects all 120 files to be reprocessed because the target table was truncated before this run. What will Snowflake actually do, and why?
⚠ Common exam trap
The trap here is assuming that clearing or truncating the target table also clears the per-table load metadata that COPY INTO uses to filter staged files.
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
✓
It will skip the 42 previously loaded files and load only the remaining 78, because load metadata is retained independently of table data.
COPY INTO maintains a per-table record of which staged files have already been loaded, and this record survives operations that change or remove table rows. With LOAD_UNCERTAIN_FILES left at its default, only files that have not been successfully loaded into the target are read, so a truncated table does not force reprocessing of files already recorded as loaded.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
It will skip the 42 previously loaded files and load only the remaining 78, because load metadata is retained independently of table data.
Why this is correct
Snowflake records which staged files have been loaded into each table in metadata that persists across DML such as TRUNCATE. Because LOAD_UNCERTAIN_FILES was omitted, files with a LOADED status for that table are filtered out before reading. Only the 78 files with no prior successful load are processed in this run.
- ✗
It will load all 120 files and produce duplicate rows because the table was emptied after the first load.
Why it's wrong here
Duplicate rows would only occur if the previously loaded files were actually read again. The load metadata marks those files as already processed for this table, so they are excluded from the candidate set. The result is a partial load of 78 files, not a full reload with duplicated content from the first run.
- ✗
It will load all 120 files because TRUNCATE TABLE removes the table's load metadata along with the rows.
Why it's wrong here
Truncating a table deletes its data, not the per-table load history recorded in the metadata store. Snowflake consults that history before reading files, so the 42 previously loaded files are still considered loaded and are skipped. The engineer's assumption that truncation resets ingestion state is the core mistake in this scenario.
- ✗
It will load all 120 files but raise an error for each previously loaded file, marking those rows as rejected.
Why it's wrong here
Previously loaded files are not re-read and therefore cannot generate row-level rejections. Snowflake silently excludes them from the file list; no per-file error is raised and no rejected rows are produced. The engineer would see a much smaller loaded-file count rather than a flood of rejections or validation errors.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
About these practice questions
Courseiva writes every DEA-C02 question from scratch — 229 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
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 DEA-C02 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 DEA-C02 exam.