vitessio/vitess · error
could not map %v to a keyspace id, got destination %v
Error message
could not map %v to a keyspace id, got destination %v
What it means
The vindex Map returned exactly one destination, but it is not a concrete DestinationKeyspaceID (or is an empty keyspace ID) — e.g. DestinationAllShards, DestinationNone, or a range — so a binary keyspace id cannot be derived.
Source
Thrown at go/vt/binlog/keyspace_id_resolver.go:114
}, nil
}
// keyspaceIDResolverFactoryV3 uses the Vindex to compute the value.
type keyspaceIDResolverFactoryV3 struct {
vindex vindexes.SingleColumn
}
func (r *keyspaceIDResolverFactoryV3) keyspaceID(v sqltypes.Value) ([]byte, error) {
destinations, err := r.vindex.Map(context.TODO(), nil, []sqltypes.Value{v})
if err != nil {
return nil, err
}
if len(destinations) != 1 {
return nil, fmt.Errorf("mapping row to keyspace id returned an invalid array of destinations: %v", key.DestinationsString(destinations))
}
ksid, ok := destinations[0].(key.DestinationKeyspaceID)
if !ok || len(ksid) == 0 {
return nil, fmt.Errorf("could not map %v to a keyspace id, got destination %v", v, destinations[0])
}
return ksid, nil
}
View on GitHub (pinned to 01a25a7d17)
Solutions
- Inspect the value %v printed in the error; fix the offending row's sharding key data.
- Repair/repopulate the lookup vindex table if entries are missing.
- Use a functional unique vindex (e.g. hash) that always yields a concrete keyspace id.
Example fix
// before: NULL sharding key in row INSERT INTO t (uid, msg) VALUES (NULL, 'x'); // after INSERT INTO t (uid, msg) VALUES (12345, 'x');
Defensive patterns
Strategy: type-guard
Validate before calling
dests, err := vindex.Map(ctx, env, []sqltypes.Value{val})
if err != nil { return err }
if _, ok := dests[0].(key.DestinationKeyspaceID); !ok || len(dests) != 1 {
return fmt.Errorf("value %v does not resolve to a concrete keyspace id", val)
} Type guard
func toKeyspaceID(d key.Destination) (key.DestinationKeyspaceID, bool) {
ksid, ok := d.(key.DestinationKeyspaceID)
if !ok || len(ksid) == 0 { return nil, false }
return ksid, true
} Try / catch
if err := streamKeyRange(ctx, kr); err != nil {
if strings.Contains(err.Error(), "could not map") {
// inspect the printed value; fix row data or lookup vindex
}
return err
} Prevention
- Enforce NOT NULL on sharding-key columns so rows always map.
- Repair lookup vindex tables when rows are missing or stale.
- Prefer functional vindexes that never return DestinationNone for valid values.
When it happens
Trigger: keyspaceID(v) sees destinations[0] not type-assertable to key.DestinationKeyspaceID, or len(ksid)==0 — typically DestinationNone/AllShards from the vindex for the given value.
Common situations: Sharding key value absent from a lookup vindex; NULL or malformed sharding key; vindex returning symbolic destinations for unknown values.
Related errors
- mapping row to keyspace id returned an invalid array of dest
- cannot find column to use to find keyspace_id for table %v
- cannot build vschema for keyspace %v: %v
- Numeric.ReverseMap: length of keyspaceId is not 8: %d
- invalid keyspace id: %v
AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01).
Data as JSON: /api/errors/87e6e26456229157.
Report an issue: GitHub.