---
title: "All Your GUCs in a Row: cpu_index_tuple_cost, cpu_operator_cost, and cpu_tuple_cost"
url: https://daily.dev/posts/all-your-gucs-in-a-row-cpu-index-tuple-cost-cpu-operator-cost-and-cpu-tuple-cost-mrzxarzqd
source_url: https://postgr.es/p/9k_
type: article
source: "Planet PostgreSQL"
published: 2026-06-02T01:03:46.112Z
updated: 2026-06-07T17:50:32.042Z
tags: ["postgresql"]
reading_time: 4
upvotes: 3
comments: 0
language: en
---

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# All Your GUCs in a Row: cpu_index_tuple_cost, cpu_operator_cost, and cpu_tuple_cost

**[Planet PostgreSQL](https://daily.dev/sources/planet-postgresql)** · 4 min read · 3 upvotes · 0 comments

## Summary

PostgreSQL's planner uses three CPU cost constants — cpu_tuple_cost (0.01), cpu_index_tuple_cost (0.005), and cpu_operator_cost (0.0025) — as relative weights anchored to seq_page_cost. These defaults encode stable CPU-to-storage ratios that have held for 25 years and should almost never be changed. When a query plan is wrong, the real culprits are almost always random_page_cost (especially on SSDs, where lowering it toward 1.1 is appropriate) or inaccurate row-count estimates (fixable via ANALYZE and statistics tuning). Changing the CPU constants is a global operation that silently re-prices every plan on the system, likely fixing one query while breaking others.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://postgr.es/p/9k_>

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Tags: [#postgresql](https://daily.dev/tags/postgresql)

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