Document.source names the configured database, as SearchResult and
Citation already do. A listing spanning databases is unreadable
without it, and `--database NAME list` could not name the one it
opened.
`get_document_by_id`, `get_document_by_uri` and `get_chunk_by_id` read
through repositories a client covering a set does not have, so a lookup by
identifier raised AttributeError and `resolve_document` with it. An
identifier says nothing about which database holds it, so every database is
asked at once and the first that has it, in configured order, answers.
On the evaluation side, `--db` overrides the configured set as the CLI
documents, and population refuses a set rather than ingesting into a
database the run would not read. A case filter matching nothing raises
instead of reporting 0.0000 as though it were a score.
The modal listed every document and mounted a checkbox per document, so a
corpus of tens of thousands never finished rendering: 67k sequential
mounts across two databases, and the same for one database that size.
Titles repeat at that scale too, and the ids were derived from the title,
so they collided.
It shows a page of 200 now, mounted in one call and identified by
position, and the search box asks the database for the rest on enter,
matching titles and URIs. Typing still narrows the page on screen, for
feedback while typing. `search_filter` escapes the term, which is
whatever was typed.
A federated listing takes its window across the databases rather than
filling it from the first one: concatenating hid every database after
whichever was listed first, which for a set of a thousand papers and
sixty thousand articles meant a page of papers alone. Sorting would not
have helped, since document ids and article titles sort into separate
runs, so the page is picked by interleaving and the modal sorts it for
display.
Chat answers with the same capabilities `ask` does, so it federates as
naturally as `ask` and `analyze` — but it went through the one-database
guard and refused a configured set outright, which left no way to chat
across several databases.
The guard was the visible half. `run_chat` also defaulted `db_path` to the
single default path whenever it was None, so lifting the refusal alone
would still have opened one database. It now leaves the path unresolved
when `lancedb.databases` names the set, and the client resolves it.
Listing and counting documents fan out over the set, which is what the
document filter reads, and visual grounding resolves the database holding
the cited chunk through the citation's source: chunks, pages and bounding
boxes all come from that one database. A limit on a listing means that
many documents in total, not that many per database.
The info modal reports every database it covers, each under its
configured name and without its location, since names are the only
identity that leaves the configuration. `database_lines` is what one
database reports about itself, shared by both paths, and it reports a
failure as a line so one unreachable database does not cost the report on
the others.
`inspect` stays a one-database command. It browses one database's
documents and chunks, so a set has nothing to show it.
Chunk 2 gave search a configured set to fan out over. ask and analyze
covered one database still: the RAG capability had no way to be told which
databases a question spanned, and the analysis sandbox mounted one
document tree.
The selection travels as sources on EvidenceState, beside the filter it
scopes with, so both capabilities read it the same way. clients_covering
is the one rule that turns a selection into clients, used by search, the
sandbox mount and the cite fallback, so a question scoped to some
databases cannot search, mount or cite another. Citations carry the
database they came from, and format_for_agent names it, so the model can
attribute evidence while it answers rather than only afterwards.
The sandbox keeps one flat /documents/{id}/ namespace and resolves each id
to the client holding it, which rests on ids being UUID4. A database
copied from another breaks that, so an id held twice is refused rather
than resolved to whichever arrived last.
On the CLI, search, ask and analyze cover the configured set and label
each result with its database. Every other command works on one, named
with --database NAME (a name reaches a database behind a URI, which --db
cannot) or --db PATH, and refuses a set it cannot choose from instead of
silently reading the default database. Cold databases open together, so a
first query costs the slowest open rather than their sum.
`lancedb.databases` maps a name to a location, mutually exclusive with `uri`.
`search(sources=[…])` selects which to search, `sources=None` searches all of them
and `sources=[]` searches none; `SearchResult.source` carries the configured name,
so a path or URI never leaves the configuration. A database named in config keeps
its name even when it is the only one configured; only a legacy single `uri`
leaves `source` unset.
Databases open on first use, not at entry. Which are searched is a per-query
choice, so a set of 25 queried a few at a time opens a few, and a database nobody
asked for can neither fail a query nor be opened for nothing.
A named database that fails to open raises `SourceUnavailableError` naming it,
raised outside the handler so the original is not attached at all. A local failure
spells out the absolute path and an object-store failure can carry the bucket;
`from None` would only stop that being printed, leaving it on `__context__` for
anything that walks the chain. A legacy `uri` client has no name to report
instead, so its error passes through unchanged.
Candidates are fetched concurrently, then fused before anything is ranked. A
configured reranker scores the union, which is what makes ranking across
databases tractable: it compares query against document and does not care where a
candidate came from. Without one, reciprocal rank fusion over the per-database
rankings, since scores from separate indexes are not comparable. Enrichment then
runs on the survivors through the database each came from, concurrently, so it
costs what a single-database search costs.
The over-fetch decision and the reranker belong to the federating client alone.
Deciding per database would have each consult its own, and a local reranker loads
model weights per instance. It is built only for a text query, and closed once by
the client that owns it.
A location without a scheme is opened as a local path rather than through
`lancedb.uri`. Routing it through `uri` had `ConnectionMode` classify it as object
storage, which opens a missing database instead of reporting it.
With several databases configured, `store` and the repositories are left unset:
they have no unambiguous meaning across a set, and picking one silently would be
worse than the error.
