Supported formats
CSV — Comma Separated Values
Section titled “CSV — Comma Separated Values”Extension: .csv
Delimiter: , (comma)
Standard CSV files following RFC 4180. Quoted fields are supported, including quoted newlines inside field values. UTF-8 BOM is stripped automatically if present.
TSV — Tab Separated Values
Section titled “TSV — Tab Separated Values”Extension: .tsv
Delimiter: \t (tab)
Delimiter is auto-detected from the file extension. No manual configuration is needed.
Encoding
Section titled “Encoding”Only UTF-8 is supported. Files encoded in other encodings (Latin-1, Windows-1252, Shift-JIS, etc.) may display garbled characters. Convert your file to UTF-8 before opening if you see unexpected symbols.
Most modern tools export CSV as UTF-8 by default. In Excel, use Save As → CSV UTF-8 (Comma delimited).
What is not supported
Section titled “What is not supported”| Format | Status |
|---|---|
.xlsx / .xls (Excel) | Not supported — export to CSV first |
.parquet | Not supported |
.json / .jsonl | Not supported |
.ods (LibreOffice) | Not supported |
| Fixed-width text files | Not supported |
| Multi-character delimiters | Not supported |
Pipe-delimited (.psv) | Not supported yet |
File size limits
Section titled “File size limits”There is no hard file size limit. Columnar has been tested with files up to 14 GB and 28 million rows. The practical limit depends on available disk space (for the memory-mapped file) and the time you are willing to wait for indexing.
Row count is capped at 4,294,967,295 (2³²−1) — an index overflow guard. No real-world CSV file reaches this limit.