{"record":{"id":"87e6e26456229157","repo":"vitessio/vitess","slug":"could-not-map-v-to-a-keyspace-id-got-destination","errorCode":null,"errorMessage":"could not map %v to a keyspace id, got destination %v","messagePattern":"could not map (.+?) to a keyspace id, got destination (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"go/vt/binlog/keyspace_id_resolver.go","lineNumber":114,"sourceCode":"\t}, nil\n}\n\n// keyspaceIDResolverFactoryV3 uses the Vindex to compute the value.\ntype keyspaceIDResolverFactoryV3 struct {\n\tvindex vindexes.SingleColumn\n}\n\nfunc (r *keyspaceIDResolverFactoryV3) keyspaceID(v sqltypes.Value) ([]byte, error) {\n\tdestinations, err := r.vindex.Map(context.TODO(), nil, []sqltypes.Value{v})\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\tif len(destinations) != 1 {\n\t\treturn nil, fmt.Errorf(\"mapping row to keyspace id returned an invalid array of destinations: %v\", key.DestinationsString(destinations))\n\t}\n\tksid, ok := destinations[0].(key.DestinationKeyspaceID)\n\tif !ok || len(ksid) == 0 {\n\t\treturn nil, fmt.Errorf(\"could not map %v to a keyspace id, got destination %v\", v, destinations[0])\n\t}\n\treturn ksid, nil\n}\n","sourceCodeStart":96,"sourceCodeEnd":118,"githubUrl":"https://github.com/vitessio/vitess/blob/01a25a7d176f94613b8d59d799f438380a8760e4/go/vt/binlog/keyspace_id_resolver.go#L96-L118","documentation":"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.","triggerScenarios":"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.","commonSituations":"Sharding key value absent from a lookup vindex; NULL or malformed sharding key; vindex returning symbolic destinations for unknown values.","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."],"exampleFix":"// before: NULL sharding key in row\nINSERT INTO t (uid, msg) VALUES (NULL, 'x');\n// after\nINSERT INTO t (uid, msg) VALUES (12345, 'x');","handlingStrategy":"type-guard","validationCode":"dests, err := vindex.Map(ctx, env, []sqltypes.Value{val})\nif err != nil { return err }\nif _, ok := dests[0].(key.DestinationKeyspaceID); !ok || len(dests) != 1 {\n\treturn fmt.Errorf(\"value %v does not resolve to a concrete keyspace id\", val)\n}","typeGuard":"func toKeyspaceID(d key.Destination) (key.DestinationKeyspaceID, bool) {\n\tksid, ok := d.(key.DestinationKeyspaceID)\n\tif !ok || len(ksid) == 0 { return nil, false }\n\treturn ksid, true\n}","tryCatchPattern":"if err := streamKeyRange(ctx, kr); err != nil {\n\tif strings.Contains(err.Error(), \"could not map\") {\n\t\t// inspect the printed value; fix row data or lookup vindex\n\t}\n\treturn err\n}","preventionTips":["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."],"tags":["vindex","keyspace-id","binlog","data"],"backgroundTag":"keyspace-id-map-failed","analyzedSha":"01a25a7d176f94613b8d59d799f438380a8760e4","analyzedAt":"2026-09-01T17:28:30.605Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}