PostgreSQL: B-Tree Assertion Fix

A single B-tree reliability fix addresses spurious assertion failures on unsatisfiable row compares with NULLs. There is no broader pattern in today's activity beyond this targeted correction.

Duration: PT2M2S

Episode overview

This episode is a short developer briefing from PostgreSQL.

It explains recent repository work in plain language.

  • Show: PostgreSQL
  • Published: 2026-10-18T13:04:12Z
  • Audio duration: PT2M2S

Transcript excerpt

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Good morning, with your developer briefing for Sunday, October 18th, 2026.

No broad trend today — just one targeted reliability fix in B-tree index handling, and it matters for debug stability.

The change is commit 45fc51f by Peter Geoghegan, correcting a spurious assertion failure in B-tree scan key preprocessing.

The problem involved row comparisons — multi-column index conditions — that can never match. Internal preprocessing logic expects the header of a row compare and its first member key to use the same comparison strategy. That invariant is checked by an assertion in the scan key required marking routine.

But when a row compare was unsatisfiable because its first member had a null argument, that first member was never adjusted to match the header strategy. That mismatch triggered a false assertion failure, specifically in the single-key fast path.

The fix is straightforward: always adjust row members to a common strategy, even when the comparison is already known to be unsatisfiable. That keeps the header and members consistent and avoids the false failure.

Nearby episodes from PostgreSQL

  1. Replication LSN Hardening and Clearer Errors
  2. Planner Sort Fixes and Replication Correctness
  3. Output Correctness and Volatility Fixes
  4. Weekly Recap - Planner Fixes and Operational Clarity
  5. Planner Correctness and Recovery Reliability
  6. Silent-Row Fixes and Operational Hardening
  7. Visibility and Type Conversion Correctness Fixes
  8. Planner Correctness and Backup Progress Fixes