What moves before the query
A dual encoder maps queries and passages into comparable vectors in separate encoding steps. Passage vectors can be prepared beforehand; each new query still needs encoding and an index search. The tempting assumption is that stored embeddings leave almost no retrieval work to do. In practice, preparation shifts computation in time without eliminating maintenance. A bookkeeper’s ledger offers a useful analogy: yesterday’s recorded balance needs reconciliation after today’s transactions.
A fast result can be stale
Consider an illustrative handbook whose refund deadline changes from thirty days to fourteen. If retrieval serves an old passage snapshot, a question about today’s deadline can receive an obsolete rule quickly. The query encoder cannot repair stored content. Updating the text, recomputing affected embeddings and replacing stale index entries remain necessary work. Fetching current text separately may prevent stale wording, but an outdated vector can still influence which passage is selected.
Run a controlled freshness check
Make a controlled correction and repeat the same deadline questions. Track document versions, embedding versions and when each index update becomes searchable. Inspect which passages appear and whether their text reflects the correction. Measure query latency, update delay and total encoding work over the same interval. Compare with lexical search over the current handbook. These examples are illustrative reasoning, not reported test results. ABOLTUS is in development.
Hypothetical boundary: frequent updates
Hypothetical case: a handbook changes every minute but receives only two searches daily. Encoding every revision could waste work on versions nobody queries. Decision rule: keep eager precomputation only when measured relevance, freshness and latency satisfy the task’s requirements and combined update and query cost beats the baseline. Otherwise test batching within an acceptable freshness window, or lexical search over current text. Choose using the workload you can verify; preprocessing alone does not settle the decision.