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For example, instead of using COUNT (DISTINCT x), use approx_distinct(x).

  • Join processing

    • Tables should be joined in the order of a larger table to smaller tables.

    • Using a non-equi join condition slows down the query processing.

  • Columnar storage characteristics

    • Choosing too many columns slows down query processing.

  • Query result size

    • Generating too many rows takes time. Instead, use CREATE TABLE AS … or INSERT INTO or result_redirect magic comment.