Carry a Fast CTE Boundary Deck Into Code Review
Recall the boundary questions that determine whether a CTE helps or hurts the final plan.
RPC What quick mnemonic helps you review a CTE boundary? Three questions before you bless the shape. Inline subquery or CTE? Choose by optimizer freedom versus controlled reuse. Readability alone is not enough; match the boundary to the workload. Making it a CTE is always safer because the logic is clearer. Response Clearer logic is good, but the plan still needs the right boundary. Some single-use CTEs block useful pushdown and make PostgreSQL compute far more rows than the final answer needs. The mistake is treating readability and optimizer freedom as unrelated. Good SQL usually preserves both on purpose. This…
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