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Answer: Delta Lake automatically gathers statistics on the first 32 columns of each table, which are used for data skipping to optimize query performance.
Delta Lake automatically collects metadata—including minimum and maximum values—for the first 32 columns defined in a table's schema. This metadata is leveraged during **data skipping**, an optimization that allows the engine to skip reading entire files that do not contain relevant data based on query filters. Key clarifications: - **Parquet** is a columnar storage format, not row-based. - **Constraints**: While Delta Lake supports informational primary and foreign key constraints, it does not enforce them during data insertion; developers must manage deduplication via `MERGE` or other logic. - **Views**: Standard views are logical transformations and do not automatically cache source data for performance improvement.
Author: LeetQuiz Editorial Team
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Which statement accurately describes the features of Delta Lake and the Lakehouse architecture?
A
Parquet utilizes row-by-row compression, meaning that string data is only compressed when specific characters are repeated multiple times.
B
Primary and foreign key constraints are strictly enforced by the Delta engine to prevent the insertion of duplicate values into dimension tables.
C
Delta Lake automatically gathers statistics on the first 32 columns of each table, which are used for data skipping to optimize query performance.
D
Views in the Lakehouse architecture maintain a continuous, valid cache of the most recent versions of all underlying source tables.