QnA Maker knowledge base limits and boundaries
QnA Maker limits provided below are a combination of the Azure AI Search pricing tier limits and the QnA Maker pricing tier limits. You need to know both sets of limits to understand how many knowledge bases you can create per resource and how large each knowledge base can grow.
Knowledge bases
The maximum number of knowledge bases is based on Azure AI Search tier limits.
| Azure AI Search tier | Free | Basic | S1 | S2 | S3 | S3 HD |
|---|---|---|---|---|---|---|
| Maximum number of published knowledge bases allowed | 2 | 14 | 49 | 199 | 199 | 2,999 |
For example, if your tier has 15 allowed indexes, you can publish 14 knowledge bases (one index per published knowledge base). The 15th index, testkb, is used for all the knowledge bases for authoring and testing.
Extraction Limits
File naming constraints
File names may not include the following characters:
| Do not use character |
|---|
Single quote ' |
Double quote " |
Maximum file size
| Format | Max file size (MB) |
|---|---|
.docx |
10 |
.pdf |
25 |
.tsv |
10 |
.txt |
10 |
.xlsx |
3 |
Maximum number of files
The maximum number of files that can be extracted and maximum file size is based on your QnA Maker pricing tier limits.
Maximum number of deep-links from URL
The maximum number of deep-links that can be crawled for extraction of QnAs from a URL page is 20.
Metadata Limits
Metadata is presented as a text-based key: value pair, such as product:windows 10. It is stored and compared in lower case. Maximum number of metadata fields is based on your Azure AI Search tier limits.
For GA version, since the test index is shared across all the KBs, the limit is applied across all KBs in the QnA Maker service.
| Azure AI Search tier | Free | Basic | S1 | S2 | S3 | S3 HD |
|---|---|---|---|---|---|---|
| Maximum metadata fields per QnA Maker service (across all KBs) | 1,000 | 100* | 1,000 | 1,000 | 1,000 | 1,000 |
By name and value
The length and acceptable characters for metadata name and value are listed in the following table.
| Item | Allowed chars | Regex pattern match | Max chars |
|---|---|---|---|
| Name (key) | Allows Alphanumeric (letters and digits) _ (underscore)Must not contain spaces. |
^[a-zA-Z0-9_]+$ |
100 |
| Value | Allows everything except: (colon)| (vertical pipe)Only one value allowed. |
^[^:|]+$ |
500 |
Knowledge Base content limits
Overall limits on the content in the knowledge base:
- Length of answer text: 25,000 characters
- Length of question text: 1,000 characters
- Length of metadata key text: 100 characters
- Length of metadata value text: 500 characters
- Supported characters for metadata name: Alphabets, digits, and
_ - Supported characters for metadata value: All except
:and| - Length of file name: 200
- Supported file formats: ".tsv", ".pdf", ".txt", ".docx", ".xlsx".
- Maximum number of alternate questions: 300
- Maximum number of question-answer pairs: Depends on the Azure AI Search tier chosen. A question and answer pair maps to a document on Azure AI Search index.
- URL/HTML page: 1 million characters
Create Knowledge base call limits:
These represent the limits for each create knowledge base action; that is, clicking Create KB or calling the CreateKnowledgeBase API.
- Recommended maximum number of alternate questions per answer: 300
- Maximum number of URLs: 10
- Maximum number of files: 10
- Maximum number of QnAs permitted per call: 1000
Update Knowledge base call limits
These represent the limits for each update action; that is, clicking Save and train or calling the UpdateKnowledgeBase API.
- Length of each source name: 300
- Recommended maximum number of alternate questions added or deleted: 300
- Maximum number of metadata fields added or deleted: 10
- Maximum number of URLs that can be refreshed: 5
- Maximum number of QnAs permitted per call: 1000
Add unstructured file limits
Note
- If you need to use larger files than the limit allows, you can break the file into smaller files before sending them to the API.
These represent the limits when unstructured files are used to Create KB or call the CreateKnowledgeBase API:
- Length of file: We will extract first 32000 characters
- Maximum three responses per file.
Prebuilt question answering limits
Note
- If you need to use larger documents than the limit allows, you can break the text into smaller chunks of text before sending them to the API.
- A document is a single string of text characters.
These represent the limits when Prebuilt API is used to Generate response or call the GenerateAnswer API:
- Number of documents: 5
- Maximum size of a single document: 5,120 characters
- Maximum three responses per document.
Important
Support for unstructured file/content and is available only in question answering.
Alterations limits
Alterations do not allow these special characters: ',', '?', ':', ';', '"', ''', '(', ')', '{', '}', '[', ']', '-', '+', '.', '/', '!', '*', '-', '_', '@', '#'
Next steps
Learn when and how to change service pricing tiers.