What the data for this category looks like
Data sources are operation declaration forms, route adjustment files, and compliance inspection files from public transit enterprises. It includes structured fields such as route number, operating mileage, driver qualification number, and vehicle passenger capacity, with units including kilometers, passenger trips, years, and others. The documents contain structured forms and scanned document attachments. Updates follow declaration batches, with the length of a single declaration material ranging from a few lines to dozens of pages. There are batch-archived compliance file updates each month.
What constraints these characteristics impose on the vector models and indexing link
The declaration data for public transit has both structured fields and unstructured attachments. This requires vector models to adapt to both short-text forms and transcribed content from long-text scanned documents. Batch-updated data requires indexing to support incremental synchronization, avoiding resource consumption from full reconstruction. The length of different files varies widely, so the chunking strategy must balance the integrity of short texts and the semantic coherence of long texts. Some associated auxiliary data, such as past driver qualification records, must be included in the index. Otherwise, cross-file associated review cannot be completed.
How to set the configurations
| Configuration Item | Recommended Setting | Rationale |
|---|---|---|
| Chunk Length | 800–1200 characters | Adapts to the common paragraph length of public transit declaration materials, and aligns with the chunking logic of FastGPT v4.17.0 |
| Overlap Length | 100–150 characters | Prevents loss of semantic association for file content across chunks, and adapts to paragraph transitions for long attachments |
defaultToken | 4096 | Adapts to the total text token limit of most single declaration files, meeting basic review requirements |
| Similarity Threshold | 0.72–0.78 | Distinguishes the semantic boundary between compliant and non-compliant materials, and meets the accuracy requirements for file review |
| Single Search Limit | Top 8 results | Controls the amount of retrieved information, avoiding exceeding the processing capacity of review staff |
maxToken | 16384 | Accommodates the total vector data of batch declaration materials, and adapts to server storage capacity |
Three common mistakes
- Issue: Fails to retrieve associated historical qualification files during search, with no corresponding vector records in logs. Cause: Auxiliary data such as past driver declaration records was not included in the vector index.
- Issue: A single declaration file generates multiple independent retrieval results, leading to duplicate matches during review. Cause: The chunk overlap parameter was not configured correctly, resulting in multiple vector groups generated from a single data entry without a unified associated identifier.
- Issue: After uploading locally vectorized file data, no matching results appear in server-side searches. Cause: Different vector models were used on the local and server sides, leading to inconsistent vector spaces due to mismatched embedding dimensions.
How to confirm the configuration is correct
- Upload a typical single route adjustment file, check the vector generation logs, and confirm that the chunk length matches the preset parameters.
- Import a piece of associated historical qualification data, perform a keyword search, and confirm that the associated files can be retrieved normally.
- Switch the preset vector model, test whether the similarity calculation results fall within the preset threshold range.
- Batch import declaration data from the past week, check the index update logs, and confirm that there are no errors and data synchronization is complete.
The values provided here are common starting points, and 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.