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Snowflake

COF-C02 · Question #252

What technique does Snowflake use to limit the number of micro-partitions scanned by each query?

The correct answer is D. Pruning. Snowflake uses a technique called micro-partition pruning (partition pruning) to avoid scanning irrelevant micro-partitions. Snowflake automatically stores metadata (min/max values, distinct value counts, etc.) for each micro-partition. When a query includes a WHERE clause…

Performance Concepts

Question

What technique does Snowflake use to limit the number of micro-partitions scanned by each query?

Options

  • AB-tree
  • BIndexing
  • CMap reduce
  • DPruning

How the community answered

(52 responses)
  • A
    2% (1)
  • B
    2% (1)
  • C
    8% (4)
  • D
    88% (46)

Explanation

Snowflake uses a technique called micro-partition pruning (partition pruning) to avoid scanning irrelevant micro-partitions. Snowflake automatically stores metadata (min/max values, distinct value counts, etc.) for each micro-partition. When a query includes a WHERE clause filter, the query optimizer uses this metadata to prune (skip) micro-partitions that cannot contain matching rows, dramatically reducing I/O. Snowflake does not use traditional B-tree indexes or MapReduce.

Topics

#Micro-partitions#Query optimization#Pruning#Performance tuning

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