Add a greedy join search algorithm to handle large join problems

First seen: 2025-12-02 03:48:26+00:00 · Messages: 40 · Participants: 7

Latest Update

2026-05-18 · claude-opus-4-6

Incremental Analysis: Round 8 (2026-05-14)

Summary

A single brief message from Tomas Vondra referencing an external thread about updating join_collapse_limit / geqo_threshold defaults. No new patch, no new benchmark data, no substantive technical argument beyond what was already covered.

What's New

Tomas references a separate thread [1] where Tom Lane asked whether it's time to update the join_collapse_limit/geqo_threshold defaults, and Andrei Lepikhov reported that join_collapse_limit=40 / geqo_threshold=14 worked acceptably for his case. Tomas observes:

  1. Default updates may reduce GEQO trigger frequency: If join_collapse_limit is raised (from current default 8) and/or geqo_threshold is adjusted (from current default 12), fewer queries would fall into the GEQO/GOO regime in practice.

  2. Implication for GOO's relevance: If DP becomes feasible for more queries via raised defaults, the population of queries that need a heuristic shrinks — though it doesn't disappear for truly large joins (20+ tables).

This is a contextual observation rather than a new technical argument. The message ends with "Agreed" — acknowledging a prior point without elaboration.