PostgreSQL: Join Alias Planner Fixes
Two related planner fixes address join alias expansion failures that could reject or crash valid queries. Two smaller tooling fixes improve Windows static analysis and coverage reporting.
Duration: PT2M5S
Episode overview
This episode is a short developer briefing from PostgreSQL.
It explains recent repository work in plain language.
- Show: PostgreSQL
- Published: 2026-10-04T13:03:10Z
- Audio duration: PT2M5S
Transcript excerpt
This excerpt keeps the crawler page concise. Listen to the episode or use the RSS feed for the full update.
Hello, it's October 4th, 2026, with your PostgreSQL developer briefing.
The takeaway today is planner correctness: two fixes close holes in how join aliases are expanded after query flattening.
First, a fix for lateral table sampling, in commit 852fd5b. Normally the planner skips alias expansion for sampling clauses, assuming they can't reference the current query level. That breaks when a lateral subquery containing a sampled table is pulled up into its parent — the sampling clause becomes lateral, a join…
A second fix, in commit bfa1a69, covers whole-row references to join aliases. After flattening, expanding such a reference can inject a sub-select into a lower query, but the planner only marked that condition on the single-column path. The whole-row path left the flag unset, so sub-select processing was skipped,…
Outside the planner, two maintenance fixes landed. One maps the counted-by buffer annotation to the Microsoft compiler's field-size annotation, so the static analyzer on Windows can use the sizing information. The other corrects coverage reporting for in-tree builds, where a duplicated directory option caused double…
What's next: watch for these planner fixes to arrive…
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