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SOL-C01 · Question #92

A Snowflake administrator observes slow query performance when querying data loaded from a large set of compressed CSV files stored in an external stage (AWS S3). Which of the following actions, perfo

The correct answer is A. Increase the virtual warehouse size used for querying. D. Create a file format object that specifies the compression type used in the CSV files.. Increasing warehouse size (A) directly adds parallel compute resources, allowing Snowflake to scan and process more CSV files simultaneously from the external stage - this is the most immediate performance lever available. Creating a file format object specifying the compression

Querying and Performance

Question

A Snowflake administrator observes slow query performance when querying data loaded from a large set of compressed CSV files stored in an external stage (AWS S3). Which of the following actions, performed in conjunction, would MOST likely improve query performance? (Choose TWO)

Options

  • AIncrease the virtual warehouse size used for querying.
  • BCreate a materialized view that pre-aggregates the data from the CSV files.
  • CConfigure the external stage to use the IAM role.
  • DCreate a file format object that specifies the compression type used in the CSV files.
  • EPartition the data in S3 based on a commonly used filter column and update the stage definition to

How the community answered

(28 responses)
  • A
    68% (19)
  • B
    18% (5)
  • C
    11% (3)
  • E
    4% (1)

Explanation

Increasing warehouse size (A) directly adds parallel compute resources, allowing Snowflake to scan and process more CSV files simultaneously from the external stage - this is the most immediate performance lever available. Creating a file format object specifying the compression type (D) ensures Snowflake knows exactly how to decode each file without auto-detection overhead, enabling efficient, optimized reads from S3.

Why the distractors are wrong:

  • B - Materialized views cannot be created over external stage data (raw S3 files); they require data in Snowflake tables.
  • C - Using an IAM role is a security/authentication best practice, but it has no impact on query execution speed.
  • E - S3 partitioning with partition pruning benefits external tables (which have defined partition metadata), not a plain external stage; the stage definition alone cannot enable partition elimination.

Memory tip: Think "Scale the engine, spell out the format." When querying staged files, Snowflake needs enough horsepower (warehouse size) and clear instructions (file format with compression) - both address the read bottleneck directly, while the other options touch security, views, or infrastructure that don't fix the core I/O problem.

Topics

#CSV compression handling#Query performance tuning#Virtual warehouse sizing#External stage optimization

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