If a query vector uses a different distance metric than the one used to create the index, what is the result?

When a query vector uses a different distance metric than the one used to create the index, the result is that a warning is logged, but the query still executes. This behavior allows for flexibility in how queries can be structured in relation to the existing index.

Using different distance metrics means that while the comparison may not be perfectly aligned with how the index was constructed, the system is still capable of performing the query. The distance metric affects how similarity and proximity are calculated, but it does not prevent the operation from being performed entirely. Logging a warning helps maintain awareness of potential discrepancies in results without halting the process, offering a way to inform users that the comparison criteria may not yield optimal results.

The other options wouldn't apply in this scenario: a query doesn't fail outright, an exact match search is not automatically triggered without specific conditions, and the index does not update automatically to accommodate differing metrics as this could lead to inconsistencies.