Capacity limits and usage restrictions of the Alibaba Cloud Model Studio knowledge base across workspaces, file uploads, chunking, retrieval and Q&A services, datasets, and API calls.
Workspaces and knowledge bases
A workspace is the top-level container for resource isolation. Each workspace can host multiple knowledge bases.
| Item | Limit | Notes |
|---|---|---|
| Workspaces per account | 30 | The primary account's workspace is marked as default |
| Knowledge bases per workspace | 50 | Quota increase available via support ticket |
| Knowledge base name length | 1–20 characters | Must be unique within the workspace |
| Knowledge base description length | 200 characters | — |
| Documents per knowledge base | 100,000 | Consider splitting the knowledge base if exceeding this |
File uploads
Knowledge bases support various file types—including documents, spreadsheets, images, audio, and video—each subject to distinct format and size constraints.
Documents and text
| Type | Format | Per-file limit |
|---|---|---|
| Documents | .doc / .docx / .ppt / .pptx / .pdf | 150 MB or 1,000 pages |
| Plain text | .md / .txt / .html | Recommended ≤ 10 MB |
| Spreadsheets | .xls / .xlsx | Recommended ≤ 10 MB and ≤ 100,000 rows |
PDFs undergo direct text extraction; scanned PDFs are automatically processed with OCR. Spreadsheets are chunked row by row, with the first row used as field names. Markdown files are split by heading; HTML files have script and style tags automatically stripped.
Images
| Item | Limit |
|---|---|
| Formats | .png / .jpg / .jpeg / .bmp / .gif |
| Single image size | ≤ 20 MB |
| Dimension constraints | Shortest side > 15 px; longest side < 8192 px; aspect ratio < 50 |
Audio and video
| Item | Limit |
|---|---|
| Audio formats | .aac / .amr / .flac / .flv / .m4a / .mp3 / .mpeg / .ogg / .opus / .wav / .webm / .wma |
| Video formats | .mp4 / .mkv / .avi / .mov / .wmv |
| Single file size | ≤ 512 MB |
| Files per import | 50 (combined total of audio and video files) |
General upload limits
| Item | Limit |
|---|---|
| Files per upload | 50 |
Chunking
Chunks serve as the retrieval units of a knowledge base. The chunking method and maximum segment length are configured during data import.
| Item | Range | Default |
|---|---|---|
| Maximum segment length | 10–6000 | 600 (tokens) |
| Chunk content length | 0–6000 characters | Applies when manually adding chunks |
| Chunk title length | 0–50 characters | Used for display in chunk lists |
Knowledge retrieval and Q&A services
Retrieval and Q&A services are the external invocation entry points of knowledge bases. The following limits are configured when creating a service.
| Item | Range | Default |
|---|---|---|
| Knowledge bases per service | 15 | — |
| Service name | Max 40 characters | Required |
| Service description | Max 200 characters | Optional |
| Q&A prompt | Max 500 characters | Optional |
| Initial vector retrieval TopK | 1–100 | 100 |
| Initial keyword retrieval TopK | 1–100 | 100 |
| Similarity threshold | 0.01–1.0 | — |
| Max recall count | 1–20 | 5 |
| Tag length | Max 32 characters per tag | Press Enter to confirm input |
Datasets
Datasets are used to import files from external data sources into knowledge bases.
| Item | Limit | Notes |
|---|---|---|
| File dataset storage (platform-hosted) | 100,000 files / 1 TB | Free for a limited time |
| Files per upload | 50 | — |
| Dataset name length | 20 characters | — |
| Dataset description length | 200 characters | — |
API limits
Batch operations
| Operation | Per-request limit | Documentation |
|---|---|---|
| Batch delete chunks | 10 chunks | Delete chunks |
| Batch query files | 20 file IDs | Query file details |
Request rate limits
Each API has a request rate limit (QPS). Exceeding the limit returns HTTP 429. For complete throttling rules, see Rate limits.
| API category | Max QPS |
|---|---|
| Retrieval | 2,000 |
| Task status query | 20 |
| Document / file query | 5–15 |
| Knowledge base management | 10 |
| Chunk management | 10 |
| Dataset management | 2–5 |
| Monitoring data | 1 |