Paging Through a Parquet File in DuckDB: File_row_number or Offset?
HomeBlogPaging Through a Parquet File in DuckDB: file_row_number or OFFSET?DuckDB · July 30, 2026Paging Through a Parquet File in DuckDB: file_row_number or OFFSET?You have a large Parquet file and an API that has to return its contents, but responses have a size ceiling, so the caller pages through it. LIMIT/OFFSET is the obvious way to write that and it is the wrong one. I measured file_row_number against it: 2.53x faster on a file with 163 row groups.
- ▪HomeBlogPaging Through a Parquet File in DuckDB: file_row_number or OFFSET?DuckDB · July 30, 2026Paging Through a Parquet File in DuckDB: file_row_number or OFFSET?You have a large Parquet file and an API that has to return its contents, bu
- ▪LIMIT/OFFSET is the obvious way to write that and it is the wrong one.
- ▪I measured file_row_number against it: 2.53x faster on a file with 163 row groups.
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Record
| Original publisher | rusty.today |
| Canonical URL | https://rusty.today/blog/paging-parquet-duckdb-file-row-number-vs-offset/ |
| Publication time | Thu, 30 Jul 2026 14:58:07 +0000 |
| Retrieval time | 2026-07-30T15:27:02.121Z |
| Last seen | 2026-07-30T15:27:02.121Z |
| 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 | NQmUySJMxB0D · 1 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
HomeBlogPaging Through a Parquet File in DuckDB: file_row_number or OFFSET?DuckDB · July 30, 2026Paging Through a Parquet File in DuckDB: file_row_number or OFFSET?You have a large Parquet file and an API that has to return its contents, but responses have a size ceiling, so the caller pages through it. LIMIT/OFFSET is the obvious way to write that and it is the wrong one. I measured file_row_number against it: 2.53x faster on a file with 163 row groups. Speed is the boring half of the answer. OFFSET will also hand back the wrong rows without telling you.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at rusty.today.
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