What the data for this category looks like
Reference only; verify against the target FastGPT release and deployment documentation.
Constraints on vector models and indexing workflows
The varying lengths of advanced chemical materials policy documents, their structured field characteristics, and non-fixed update cycle create multiple constraints for vector model and indexing workflows. Long policy documents contain full clauses spanning tens of thousands of characters. When splitting documents, prioritize semantic integrity to avoid losing cross-paragraph policy logic. Documents include structured fields such as document numbers and effective dates. Indexing must retain field association rules to prevent confusion between policy content with different document numbers in the same scope. Some policies include supplementary data. Split this data separately for indexing, then link it to the main document to ensure relevant attachments are returned during retrieval. The non-fixed update cycle requires support for incremental indexing to reduce resource consumption from full reindexing.
How to set configurations
| Configuration Item | Recommended Range | Rationale |
|---|---|---|
| Chunk Length | 800–1200 characters | Aligns with the semantic integrity of single paragraphs in advanced chemical materials policy documents, avoiding semantic breaks from cross-clause splitting |
| Overlap Length | 100–200 characters | Compensates for semantic gaps between chunks, ensuring contextual coherence for long policy clauses |
| Similarity Threshold | 0.75–0.85 | Filters low-match irrelevant policy content, focusing on core compliance basis |
| Single Search Limit | Top 10 results | Controls the number of returned results, avoiding context overload that impacts model inference |
maxToken | 4096 token | Adapts to the input length limit of mainstream vector models, ensuring processing stability during indexing |
defaultToken | Calibrated via actual testing | Adapts to locally deployed vector model parameters, matching hardware resource and indexing accuracy requirements |
Three common misconfigurations
- Issue: Irrelevant old policy document numbers appear in retrieval results after indexing. Cause: Policy document number fields are not bound during indexing, leading to mixed matching of policy content from different batches.
- Issue: Token limit exceeded errors occur when calling indexing tools, with status code 413 returned. Cause: The
maxTokenparameter is not set, and the token input length of individual chunks is not restricted. - Issue: Insufficient retrieval results when deploying ollama locally, with complete policy basis not matched. Cause: The single search limit is set too low, and indexing configuration for associated attachments is not enabled.
How to confirm proper configuration
- Upload a single advanced chemical materials policy document, check the chunk preview interface, confirm chunk length falls within the set range, with no excessive splitting or overly long chunks.
- Input a test query such as "What are the access standards for advanced chemical materials", check if retrieval results include policy document numbers and release dates, confirm structured field association works correctly.
- Upload an updated policy document, check the incremental update status of the indexing task, confirm synchronization completes without full reindexing.
- Test calls to the vector indexing interface, confirm returned chunk token counts do not exceed the set
maxTokenvalue, with no errors returned.
The values listed are common starting points. They should be evaluated against the reader’s own samples.
Question material comes from public community discussions. Configuration values are common starting points and should be measured against your own samples. Verified on 2026-09-28.