Christophe Pettus: All Your GUCs in a Row: file_extend_method
2026-07-21 3 min PostgreSQL All Your GUCs in a Row: file_extend_method file_extend_method is an escape hatch wearing the costume of a tuning knob. It exists for one purpose: to let you turn off a PostgreSQL 16 optimization on the filesystems where that optimization turned out to misbehave. The parameter is an enum choosing between them, it is sighup so it reloads without a restart, and its default is posix_fallocate on any system that has the function.
- ▪2026-07-21 3 min PostgreSQL All Your GUCs in a Row: file_extend_method file_extend_method is an escape hatch wearing the costume of a tuning knob.
- ▪It exists for one purpose: to let you turn off a PostgreSQL 16 optimization on the filesystems where that optimization turned out to misbehave.
- ▪The parameter is an enum choosing between them, it is sighup so it reloads without a restart, and its default is posix_fallocate on any system that has the function.
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Record
| Original publisher | Postgr |
| Canonical URL | https://postgr.es/p/9qd |
| Publication time | Wed, 22 Jul 2026 01:00:00 +0000 |
| Retrieval time | 2026-07-26T10:01:45.843Z |
| Last seen | 2026-07-26T10:01:45.843Z |
| Headline source | Publisher (no WeSearch rewrite) |
| Excerpt source | publisher body |
| Excerpt method | First ~120 words (~800 chars) of extracted publisher body, fair-use limited. |
| Summary | WeSearch · cerebras-chat (WeSearch summarizer) |
| Summary source text | contentText |
| Citation coverage | Summary is a WeSearch-generated derivative; primary citation is the original publisher URL. |
| Cluster | WLweH_33K9z3 · 5 stories |
| Cluster logic | Grouped by semantic title/content similarity across sources within a rolling window. Same-publisher template collisions are excluded from coverage comparison. |
| Ranking reason | Story pages are not engagement-ranked. Hub feeds use recency, with optional source-diversified chronological ordering (cap consecutive stories per source). No personalized ranking. |
| Publisher visit | Yes — open original |
| Substitutes article? | No — link-out required for full text |
Rights status (four layers)
WeSearch handling by dimension
| Indexing | May the item be indexed (stored, ranked, made findable)? | Allowed |
| Snippet | May a short excerpt of the publisher's text be shown? | Allowed |
| AI summary | May WeSearch generate its own short summary of the article? | Limited |
| Retrieval / RAG | May the content be exposed for third-party retrieval-augmented generation? | Not asserted |
| Model training | May the content be used to train AI models? | Not asserted |
| Commercial reuse | May the content be reused commercially? | Not permitted |
Basis: Derived from the published RSS/Atom feed. Contact: [email protected]. Reviewed: 2026-07-24.
Opening excerpt (first ~120 words) tap to expand
2026-07-21 3 min PostgreSQL All Your GUCs in a Row: file_extend_method file_extend_method is an escape hatch wearing the costume of a tuning knob. It exists for one purpose: to let you turn off a PostgreSQL 16 optimization on the filesystems where that optimization turned out to misbehave. When a table grows, PostgreSQL has to extend its data file, and there are two ways to do that. posix_fallocate asks the operating system to reserve the disk space through the standard POSIX call, without writing anything into it; write_zeros extends the file the old-fashioned way, by physically writing out blocks of zeroes. The parameter is an enum choosing between them, it is sighup so it reloads without a restart, and its default is posix_fallocate on any system that has the function.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at Postgr.
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