Files
lancedb/nodejs/lancedb/arrow.ts
Will Jones e05c0cd87e ci(node): check docs in CI (#2084)
* Make `npm run docs` fail if there are any warnings. This will catch
items missing from the API reference.
* Add a check in our CI to make sure `npm run dos` runs without warnings
and doesn't generate any new files (indicating it might be out-of-date.
* Hide constructors that aren't user facing.
* Remove unused enum `WriteMode`.

Closes #2068
2025-01-30 16:06:06 -08:00

950 lines
31 KiB
TypeScript

// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: Copyright The LanceDB Authors
import {
Table as ArrowTable,
Binary,
BufferType,
DataType,
Field,
FixedSizeBinary,
FixedSizeList,
Float,
Float32,
Int,
LargeBinary,
List,
Null,
RecordBatch,
RecordBatchFileReader,
RecordBatchFileWriter,
RecordBatchReader,
RecordBatchStreamWriter,
Schema,
Struct,
Utf8,
Vector,
makeBuilder,
makeData,
type makeTable,
vectorFromArray,
} from "apache-arrow";
import { Buffers } from "apache-arrow/data";
import { type EmbeddingFunction } from "./embedding/embedding_function";
import { EmbeddingFunctionConfig, getRegistry } from "./embedding/registry";
import {
sanitizeField,
sanitizeSchema,
sanitizeTable,
sanitizeType,
} from "./sanitize";
export * from "apache-arrow";
export type SchemaLike =
| Schema
| {
fields: FieldLike[];
metadata: Map<string, string>;
get names(): unknown[];
};
export type FieldLike =
| Field
| {
type: string;
name: string;
nullable?: boolean;
metadata?: Map<string, string>;
};
export type DataLike =
// biome-ignore lint/suspicious/noExplicitAny: <explanation>
| import("apache-arrow").Data<Struct<any>>
| {
// biome-ignore lint/suspicious/noExplicitAny: <explanation>
type: any;
length: number;
offset: number;
stride: number;
nullable: boolean;
children: DataLike[];
get nullCount(): number;
// biome-ignore lint/suspicious/noExplicitAny: <explanation>
values: Buffers<any>[BufferType.DATA];
// biome-ignore lint/suspicious/noExplicitAny: <explanation>
typeIds: Buffers<any>[BufferType.TYPE];
// biome-ignore lint/suspicious/noExplicitAny: <explanation>
nullBitmap: Buffers<any>[BufferType.VALIDITY];
// biome-ignore lint/suspicious/noExplicitAny: <explanation>
valueOffsets: Buffers<any>[BufferType.OFFSET];
};
export type RecordBatchLike =
| RecordBatch
| {
schema: SchemaLike;
data: DataLike;
};
export type TableLike =
| ArrowTable
| { schema: SchemaLike; batches: RecordBatchLike[] };
export type IntoVector =
| Float32Array
| Float64Array
| number[]
| Promise<Float32Array | Float64Array | number[]>;
export function isArrowTable(value: object): value is TableLike {
if (value instanceof ArrowTable) return true;
return "schema" in value && "batches" in value;
}
export function isNull(value: unknown): value is Null {
return value instanceof Null || DataType.isNull(value);
}
export function isInt(value: unknown): value is Int {
return value instanceof Int || DataType.isInt(value);
}
export function isFloat(value: unknown): value is Float {
return value instanceof Float || DataType.isFloat(value);
}
export function isBinary(value: unknown): value is Binary {
return value instanceof Binary || DataType.isBinary(value);
}
export function isLargeBinary(value: unknown): value is LargeBinary {
return value instanceof LargeBinary || DataType.isLargeBinary(value);
}
export function isUtf8(value: unknown): value is Utf8 {
return value instanceof Utf8 || DataType.isUtf8(value);
}
export function isLargeUtf8(value: unknown): value is Utf8 {
return value instanceof Utf8 || DataType.isLargeUtf8(value);
}
export function isBool(value: unknown): value is Utf8 {
return value instanceof Utf8 || DataType.isBool(value);
}
export function isDecimal(value: unknown): value is Utf8 {
return value instanceof Utf8 || DataType.isDecimal(value);
}
export function isDate(value: unknown): value is Utf8 {
return value instanceof Utf8 || DataType.isDate(value);
}
export function isTime(value: unknown): value is Utf8 {
return value instanceof Utf8 || DataType.isTime(value);
}
export function isTimestamp(value: unknown): value is Utf8 {
return value instanceof Utf8 || DataType.isTimestamp(value);
}
export function isInterval(value: unknown): value is Utf8 {
return value instanceof Utf8 || DataType.isInterval(value);
}
export function isDuration(value: unknown): value is Utf8 {
return value instanceof Utf8 || DataType.isDuration(value);
}
export function isList(value: unknown): value is List {
return value instanceof List || DataType.isList(value);
}
export function isStruct(value: unknown): value is Struct {
return value instanceof Struct || DataType.isStruct(value);
}
export function isUnion(value: unknown): value is Struct {
return value instanceof Struct || DataType.isUnion(value);
}
export function isFixedSizeBinary(value: unknown): value is FixedSizeBinary {
return value instanceof FixedSizeBinary || DataType.isFixedSizeBinary(value);
}
export function isFixedSizeList(value: unknown): value is FixedSizeList {
return value instanceof FixedSizeList || DataType.isFixedSizeList(value);
}
/** Data type accepted by NodeJS SDK */
export type Data = Record<string, unknown>[] | TableLike;
/*
* Options to control how a column should be converted to a vector array
*/
export class VectorColumnOptions {
/** Vector column type. */
type: Float = new Float32();
constructor(values?: Partial<VectorColumnOptions>) {
Object.assign(this, values);
}
}
/** Options to control the makeArrowTable call. */
export class MakeArrowTableOptions {
/*
* Schema of the data.
*
* If this is not provided then the data type will be inferred from the
* JS type. Integer numbers will become int64, floating point numbers
* will become float64 and arrays will become variable sized lists with
* the data type inferred from the first element in the array.
*
* The schema must be specified if there are no records (e.g. to make
* an empty table)
*/
schema?: SchemaLike;
/*
* Mapping from vector column name to expected type
*
* Lance expects vector columns to be fixed size list arrays (i.e. tensors)
* However, `makeArrowTable` will not infer this by default (it creates
* variable size list arrays). This field can be used to indicate that a column
* should be treated as a vector column and converted to a fixed size list.
*
* The keys should be the names of the vector columns. The value specifies the
* expected data type of the vector columns.
*
* If `schema` is provided then this field is ignored.
*
* By default, the column named "vector" will be assumed to be a float32
* vector column.
*/
vectorColumns: Record<string, VectorColumnOptions> = {
vector: new VectorColumnOptions(),
};
embeddings?: EmbeddingFunction<unknown>;
embeddingFunction?: EmbeddingFunctionConfig;
/**
* If true then string columns will be encoded with dictionary encoding
*
* Set this to true if your string columns tend to repeat the same values
* often. For more precise control use the `schema` property to specify the
* data type for individual columns.
*
* If `schema` is provided then this property is ignored.
*/
dictionaryEncodeStrings: boolean = false;
constructor(values?: Partial<MakeArrowTableOptions>) {
Object.assign(this, values);
}
}
/**
* An enhanced version of the {@link makeTable} function from Apache Arrow
* that supports nested fields and embeddings columns.
*
* (typically you do not need to call this function. It will be called automatically
* when creating a table or adding data to it)
*
* This function converts an array of Record<String, any> (row-major JS objects)
* to an Arrow Table (a columnar structure)
*
* Note that it currently does not support nulls.
*
* If a schema is provided then it will be used to determine the resulting array
* types. Fields will also be reordered to fit the order defined by the schema.
*
* If a schema is not provided then the types will be inferred and the field order
* will be controlled by the order of properties in the first record. If a type
* is inferred it will always be nullable.
*
* If the input is empty then a schema must be provided to create an empty table.
*
* When a schema is not specified then data types will be inferred. The inference
* rules are as follows:
*
* - boolean => Bool
* - number => Float64
* - String => Utf8
* - Buffer => Binary
* - Record<String, any> => Struct
* - Array<any> => List
* @example
* ```ts
* import { fromTableToBuffer, makeArrowTable } from "../arrow";
* import { Field, FixedSizeList, Float16, Float32, Int32, Schema } from "apache-arrow";
*
* const schema = new Schema([
* new Field("a", new Int32()),
* new Field("b", new Float32()),
* new Field("c", new FixedSizeList(3, new Field("item", new Float16()))),
* ]);
* const table = makeArrowTable([
* { a: 1, b: 2, c: [1, 2, 3] },
* { a: 4, b: 5, c: [4, 5, 6] },
* { a: 7, b: 8, c: [7, 8, 9] },
* ], { schema });
* ```
*
* By default it assumes that the column named `vector` is a vector column
* and it will be converted into a fixed size list array of type float32.
* The `vectorColumns` option can be used to support other vector column
* names and data types.
*
* ```ts
* const schema = new Schema([
* new Field("a", new Float64()),
* new Field("b", new Float64()),
* new Field(
* "vector",
* new FixedSizeList(3, new Field("item", new Float32()))
* ),
* ]);
* const table = makeArrowTable([
* { a: 1, b: 2, vector: [1, 2, 3] },
* { a: 4, b: 5, vector: [4, 5, 6] },
* { a: 7, b: 8, vector: [7, 8, 9] },
* ]);
* assert.deepEqual(table.schema, schema);
* ```
*
* You can specify the vector column types and names using the options as well
*
* ```ts
* const schema = new Schema([
* new Field('a', new Float64()),
* new Field('b', new Float64()),
* new Field('vec1', new FixedSizeList(3, new Field('item', new Float16()))),
* new Field('vec2', new FixedSizeList(3, new Field('item', new Float16())))
* ]);
* const table = makeArrowTable([
* { a: 1, b: 2, vec1: [1, 2, 3], vec2: [2, 4, 6] },
* { a: 4, b: 5, vec1: [4, 5, 6], vec2: [8, 10, 12] },
* { a: 7, b: 8, vec1: [7, 8, 9], vec2: [14, 16, 18] }
* ], {
* vectorColumns: {
* vec1: { type: new Float16() },
* vec2: { type: new Float16() }
* }
* }
* assert.deepEqual(table.schema, schema)
* ```
*/
export function makeArrowTable(
data: Array<Record<string, unknown>>,
options?: Partial<MakeArrowTableOptions>,
metadata?: Map<string, string>,
): ArrowTable {
if (
data.length === 0 &&
(options?.schema === undefined || options?.schema === null)
) {
throw new Error("At least one record or a schema needs to be provided");
}
const opt = new MakeArrowTableOptions(options !== undefined ? options : {});
if (opt.schema !== undefined && opt.schema !== null) {
opt.schema = sanitizeSchema(opt.schema);
opt.schema = validateSchemaEmbeddings(
opt.schema as Schema,
data,
options?.embeddingFunction,
);
}
const columns: Record<string, Vector> = {};
// TODO: sample dataset to find missing columns
// Prefer the field ordering of the schema, if present
const columnNames =
opt.schema != null ? (opt.schema.names as string[]) : Object.keys(data[0]);
for (const colName of columnNames) {
if (
data.length !== 0 &&
!Object.prototype.hasOwnProperty.call(data[0], colName)
) {
// The field is present in the schema, but not in the data, skip it
continue;
}
// Extract a single column from the records (transpose from row-major to col-major)
let values = data.map((datum) => datum[colName]);
// By default (type === undefined) arrow will infer the type from the JS type
let type;
if (opt.schema !== undefined) {
// If there is a schema provided, then use that for the type instead
type = opt.schema?.fields.filter((f) => f.name === colName)[0]?.type;
if (DataType.isInt(type) && type.bitWidth === 64) {
// wrap in BigInt to avoid bug: https://github.com/apache/arrow/issues/40051
values = values.map((v) => {
if (v === null) {
return v;
}
if (typeof v === "bigint") {
return v;
}
if (typeof v === "number") {
return BigInt(v);
}
throw new Error(
`Expected BigInt or number for column ${colName}, got ${typeof v}`,
);
});
}
} else {
// Otherwise, check to see if this column is one of the vector columns
// defined by opt.vectorColumns and, if so, use the fixed size list type
const vectorColumnOptions = opt.vectorColumns[colName];
if (vectorColumnOptions !== undefined) {
const firstNonNullValue = values.find((v) => v !== null);
if (Array.isArray(firstNonNullValue)) {
type = newVectorType(
firstNonNullValue.length,
vectorColumnOptions.type,
);
} else {
throw new Error(
`Column ${colName} is expected to be a vector column but first non-null value is not an array. Could not determine size of vector column`,
);
}
}
}
try {
// Convert an Array of JS values to an arrow vector
columns[colName] = makeVector(values, type, opt.dictionaryEncodeStrings);
} catch (error: unknown) {
// eslint-disable-next-line @typescript-eslint/restrict-template-expressions
throw Error(`Could not convert column "${colName}" to Arrow: ${error}`);
}
}
if (opt.schema != null) {
// `new ArrowTable(columns)` infers a schema which may sometimes have
// incorrect nullability (it assumes nullable=true always)
//
// `new ArrowTable(schema, columns)` will also fail because it will create a
// batch with an inferred schema and then complain that the batch schema
// does not match the provided schema.
//
// To work around this we first create a table with the wrong schema and
// then patch the schema of the batches so we can use
// `new ArrowTable(schema, batches)` which does not do any schema inference
const firstTable = new ArrowTable(columns);
const batchesFixed = firstTable.batches.map(
(batch) => new RecordBatch(opt.schema as Schema, batch.data),
);
let schema: Schema;
if (metadata !== undefined) {
let schemaMetadata = opt.schema.metadata;
if (schemaMetadata.size === 0) {
schemaMetadata = metadata;
} else {
for (const [key, entry] of schemaMetadata.entries()) {
schemaMetadata.set(key, entry);
}
}
schema = new Schema(opt.schema.fields as Field[], schemaMetadata);
} else {
schema = opt.schema as Schema;
}
return new ArrowTable(schema, batchesFixed);
}
const tbl = new ArrowTable(columns);
if (metadata !== undefined) {
// biome-ignore lint/suspicious/noExplicitAny: <explanation>
(<any>tbl.schema).metadata = metadata;
}
return tbl;
}
/**
* Create an empty Arrow table with the provided schema
*/
export function makeEmptyTable(
schema: SchemaLike,
metadata?: Map<string, string>,
): ArrowTable {
return makeArrowTable([], { schema }, metadata);
}
/**
* Helper function to convert Array<Array<any>> to a variable sized list array
*/
// @ts-expect-error (Vector<unknown> is not assignable to Vector<any>)
function makeListVector(lists: unknown[][]): Vector<unknown> {
if (lists.length === 0 || lists[0].length === 0) {
throw Error("Cannot infer list vector from empty array or empty list");
}
const sampleList = lists[0];
// biome-ignore lint/suspicious/noExplicitAny: skip
let inferredType: any;
try {
const sampleVector = makeVector(sampleList);
inferredType = sampleVector.type;
} catch (error: unknown) {
// eslint-disable-next-line @typescript-eslint/restrict-template-expressions
throw Error(`Cannot infer list vector. Cannot infer inner type: ${error}`);
}
const listBuilder = makeBuilder({
type: new List(new Field("item", inferredType, true)),
});
for (const list of lists) {
listBuilder.append(list);
}
return listBuilder.finish().toVector();
}
/** Helper function to convert an Array of JS values to an Arrow Vector */
function makeVector(
values: unknown[],
type?: DataType,
stringAsDictionary?: boolean,
// biome-ignore lint/suspicious/noExplicitAny: skip
): Vector<any> {
if (type !== undefined) {
// No need for inference, let Arrow create it
return vectorFromArray(values, type);
}
if (values.length === 0) {
throw Error(
"makeVector requires at least one value or the type must be specfied",
);
}
const sampleValue = values.find((val) => val !== null && val !== undefined);
if (sampleValue === undefined) {
throw Error(
"makeVector cannot infer the type if all values are null or undefined",
);
}
if (Array.isArray(sampleValue)) {
// Default Arrow inference doesn't handle list types
return makeListVector(values as unknown[][]);
} else if (Buffer.isBuffer(sampleValue)) {
// Default Arrow inference doesn't handle Buffer
return vectorFromArray(values, new Binary());
} else if (
!(stringAsDictionary ?? false) &&
(typeof sampleValue === "string" || sampleValue instanceof String)
) {
// If the type is string then don't use Arrow's default inference unless dictionaries are requested
// because it will always use dictionary encoding for strings
return vectorFromArray(values, new Utf8());
} else {
// Convert a JS array of values to an arrow vector
return vectorFromArray(values);
}
}
/** Helper function to apply embeddings from metadata to an input table */
async function applyEmbeddingsFromMetadata(
table: ArrowTable,
schema: Schema,
): Promise<ArrowTable> {
const registry = getRegistry();
const functions = await registry.parseFunctions(schema.metadata);
const columns = Object.fromEntries(
table.schema.fields.map((field) => [
field.name,
table.getChild(field.name)!,
]),
);
for (const functionEntry of functions.values()) {
const sourceColumn = columns[functionEntry.sourceColumn];
const destColumn = functionEntry.vectorColumn ?? "vector";
if (sourceColumn === undefined) {
throw new Error(
`Cannot apply embedding function because the source column '${functionEntry.sourceColumn}' was not present in the data`,
);
}
if (columns[destColumn] !== undefined) {
throw new Error(
`Attempt to apply embeddings to table failed because column ${destColumn} already existed`,
);
}
if (table.batches.length > 1) {
throw new Error(
"Internal error: `makeArrowTable` unexpectedly created a table with more than one batch",
);
}
const values = sourceColumn.toArray();
const vectors =
await functionEntry.function.computeSourceEmbeddings(values);
if (vectors.length !== values.length) {
throw new Error(
"Embedding function did not return an embedding for each input element",
);
}
let destType: DataType;
const dtype = schema.fields.find((f) => f.name === destColumn)!.type;
if (isFixedSizeList(dtype)) {
destType = sanitizeType(dtype);
} else {
throw new Error(
"Expected FixedSizeList as datatype for vector field, instead got: " +
dtype,
);
}
const vector = makeVector(vectors, destType);
columns[destColumn] = vector;
}
const newTable = new ArrowTable(columns);
return alignTable(newTable, schema);
}
/** Helper function to apply embeddings to an input table */
async function applyEmbeddings<T>(
table: ArrowTable,
embeddings?: EmbeddingFunctionConfig,
schema?: SchemaLike,
): Promise<ArrowTable> {
if (schema !== undefined && schema !== null) {
schema = sanitizeSchema(schema);
}
if (schema?.metadata.has("embedding_functions")) {
return applyEmbeddingsFromMetadata(table, schema! as Schema);
} else if (embeddings == null || embeddings === undefined) {
return table;
}
let schemaMetadata = schema?.metadata || new Map<string, string>();
if (!(embeddings == null || embeddings === undefined)) {
const registry = getRegistry();
const embeddingMetadata = registry.getTableMetadata([embeddings]);
schemaMetadata = new Map([...schemaMetadata, ...embeddingMetadata]);
}
// Convert from ArrowTable to Record<String, Vector>
const colEntries = [...Array(table.numCols).keys()].map((_, idx) => {
const name = table.schema.fields[idx].name;
// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
const vec = table.getChildAt(idx)!;
return [name, vec];
});
const newColumns = Object.fromEntries(colEntries);
const sourceColumn = newColumns[embeddings.sourceColumn];
const destColumn = embeddings.vectorColumn ?? "vector";
const innerDestType =
embeddings.function.embeddingDataType() ?? new Float32();
if (sourceColumn === undefined) {
throw new Error(
`Cannot apply embedding function because the source column '${embeddings.sourceColumn}' was not present in the data`,
);
}
if (table.numRows === 0) {
if (Object.prototype.hasOwnProperty.call(newColumns, destColumn)) {
// We have an empty table and it already has the embedding column so no work needs to be done
// Note: we don't return an error like we did below because this is a common occurrence. For example,
// if we call convertToTable with 0 records and a schema that includes the embedding
return table;
}
const dimensions = embeddings.function.ndims();
if (dimensions !== undefined) {
const destType = newVectorType(dimensions, innerDestType);
newColumns[destColumn] = makeVector([], destType);
} else if (schema != null) {
const destField = schema.fields.find((f) => f.name === destColumn);
if (destField != null) {
newColumns[destColumn] = makeVector([], destField.type);
} else {
throw new Error(
`Attempt to apply embeddings to an empty table failed because schema was missing embedding column '${destColumn}'`,
);
}
} else {
throw new Error(
"Attempt to apply embeddings to an empty table when the embeddings function does not specify `embeddingDimension`",
);
}
} else {
if (Object.prototype.hasOwnProperty.call(newColumns, destColumn)) {
throw new Error(
`Attempt to apply embeddings to table failed because column ${destColumn} already existed`,
);
}
if (table.batches.length > 1) {
throw new Error(
"Internal error: `makeArrowTable` unexpectedly created a table with more than one batch",
);
}
const values = sourceColumn.toArray();
const vectors = await embeddings.function.computeSourceEmbeddings(
values as T[],
);
if (vectors.length !== values.length) {
throw new Error(
"Embedding function did not return an embedding for each input element",
);
}
const destType = newVectorType(vectors[0].length, innerDestType);
newColumns[destColumn] = makeVector(vectors, destType);
}
let newTable = new ArrowTable(newColumns);
if (schema != null) {
if (schema.fields.find((f) => f.name === destColumn) === undefined) {
throw new Error(
`When using embedding functions and specifying a schema the schema should include the embedding column but the column ${destColumn} was missing`,
);
}
newTable = alignTable(newTable, schema as Schema);
}
newTable = new ArrowTable(
new Schema(newTable.schema.fields, schemaMetadata),
newTable.batches,
);
return newTable;
}
/**
* Convert an Array of records into an Arrow Table, optionally applying an
* embeddings function to it.
*
* This function calls `makeArrowTable` first to create the Arrow Table.
* Any provided `makeTableOptions` (e.g. a schema) will be passed on to
* that call.
*
* The embedding function will be passed a column of values (based on the
* `sourceColumn` of the embedding function) and expects to receive back
* number[][] which will be converted into a fixed size list column. By
* default this will be a fixed size list of Float32 but that can be
* customized by the `embeddingDataType` property of the embedding function.
*
* If a schema is provided in `makeTableOptions` then it should include the
* embedding columns. If no schema is provded then embedding columns will
* be placed at the end of the table, after all of the input columns.
*/
export async function convertToTable(
data: Array<Record<string, unknown>>,
embeddings?: EmbeddingFunctionConfig,
makeTableOptions?: Partial<MakeArrowTableOptions>,
): Promise<ArrowTable> {
const table = makeArrowTable(data, makeTableOptions);
return await applyEmbeddings(table, embeddings, makeTableOptions?.schema);
}
/** Creates the Arrow Type for a Vector column with dimension `dim` */
export function newVectorType<T extends Float>(
dim: number,
innerType: unknown,
): FixedSizeList<T> {
// in Lance we always default to have the elements nullable, so we need to set it to true
// otherwise we often get schema mismatches because the stored data always has schema with nullable elements
const children = new Field("item", <T>sanitizeType(innerType), true);
return new FixedSizeList(dim, children);
}
/**
* Serialize an Array of records into a buffer using the Arrow IPC File serialization
*
* This function will call `convertToTable` and pass on `embeddings` and `schema`
*
* `schema` is required if data is empty
*/
export async function fromRecordsToBuffer(
data: Array<Record<string, unknown>>,
embeddings?: EmbeddingFunctionConfig,
schema?: Schema,
): Promise<Buffer> {
if (schema !== undefined && schema !== null) {
schema = sanitizeSchema(schema);
}
const table = await convertToTable(data, embeddings, { schema });
const writer = RecordBatchFileWriter.writeAll(table);
return Buffer.from(await writer.toUint8Array());
}
/**
* Serialize an Array of records into a buffer using the Arrow IPC Stream serialization
*
* This function will call `convertToTable` and pass on `embeddings` and `schema`
*
* `schema` is required if data is empty
*/
export async function fromRecordsToStreamBuffer(
data: Array<Record<string, unknown>>,
embeddings?: EmbeddingFunctionConfig,
schema?: Schema,
): Promise<Buffer> {
if (schema !== undefined && schema !== null) {
schema = sanitizeSchema(schema);
}
const table = await convertToTable(data, embeddings, { schema });
const writer = RecordBatchStreamWriter.writeAll(table);
return Buffer.from(await writer.toUint8Array());
}
/**
* Serialize an Arrow Table into a buffer using the Arrow IPC File serialization
*
* This function will apply `embeddings` to the table in a manner similar to
* `convertToTable`.
*
* `schema` is required if the table is empty
*/
export async function fromTableToBuffer(
table: ArrowTable,
embeddings?: EmbeddingFunctionConfig,
schema?: SchemaLike,
): Promise<Buffer> {
if (schema !== undefined && schema !== null) {
schema = sanitizeSchema(schema);
}
const tableWithEmbeddings = await applyEmbeddings(table, embeddings, schema);
const writer = RecordBatchFileWriter.writeAll(tableWithEmbeddings);
return Buffer.from(await writer.toUint8Array());
}
/**
* Serialize an Arrow Table into a buffer using the Arrow IPC File serialization
*
* This function will apply `embeddings` to the table in a manner similar to
* `convertToTable`.
*
* `schema` is required if the table is empty
*/
export async function fromDataToBuffer(
data: Data,
embeddings?: EmbeddingFunctionConfig,
schema?: Schema,
): Promise<Buffer> {
if (schema !== undefined && schema !== null) {
schema = sanitizeSchema(schema);
}
if (isArrowTable(data)) {
return fromTableToBuffer(sanitizeTable(data), embeddings, schema);
} else {
const table = await convertToTable(data, embeddings, { schema });
return fromTableToBuffer(table);
}
}
/**
* Read a single record batch from a buffer.
*
* Returns null if the buffer does not contain a record batch
*/
export async function fromBufferToRecordBatch(
data: Buffer,
): Promise<RecordBatch | null> {
const iter = await RecordBatchFileReader.readAll(Buffer.from(data)).next()
.value;
const recordBatch = iter?.next().value;
return recordBatch || null;
}
/**
* Create a buffer containing a single record batch
*/
export async function fromRecordBatchToBuffer(
batch: RecordBatch,
): Promise<Buffer> {
const writer = new RecordBatchFileWriter().writeAll([batch]);
return Buffer.from(await writer.toUint8Array());
}
/**
* Serialize an Arrow Table into a buffer using the Arrow IPC Stream serialization
*
* This function will apply `embeddings` to the table in a manner similar to
* `convertToTable`.
*
* `schema` is required if the table is empty
*/
export async function fromTableToStreamBuffer(
table: ArrowTable,
embeddings?: EmbeddingFunctionConfig,
schema?: SchemaLike,
): Promise<Buffer> {
const tableWithEmbeddings = await applyEmbeddings(table, embeddings, schema);
const writer = RecordBatchStreamWriter.writeAll(tableWithEmbeddings);
return Buffer.from(await writer.toUint8Array());
}
/**
* Reorder the columns in `batch` so that they agree with the field order in `schema`
*/
function alignBatch(batch: RecordBatch, schema: Schema): RecordBatch {
const alignedChildren = [];
for (const field of schema.fields) {
const indexInBatch = batch.schema.fields?.findIndex(
(f) => f.name === field.name,
);
if (indexInBatch < 0) {
throw new Error(
`The column ${field.name} was not found in the Arrow Table`,
);
}
alignedChildren.push(batch.data.children[indexInBatch]);
}
const newData = makeData({
type: new Struct(schema.fields),
length: batch.numRows,
nullCount: batch.nullCount,
children: alignedChildren,
});
return new RecordBatch(schema, newData);
}
/**
* Reorder the columns in `table` so that they agree with the field order in `schema`
*/
function alignTable(table: ArrowTable, schema: Schema): ArrowTable {
const alignedBatches = table.batches.map((batch) =>
alignBatch(batch, schema),
);
return new ArrowTable(schema, alignedBatches);
}
/**
* Create an empty table with the given schema
*/
export function createEmptyTable(schema: Schema): ArrowTable {
return new ArrowTable(sanitizeSchema(schema));
}
function validateSchemaEmbeddings(
schema: Schema,
data: Array<Record<string, unknown>>,
embeddings: EmbeddingFunctionConfig | undefined,
) {
const fields = [];
const missingEmbeddingFields = [];
// First we check if the field is a `FixedSizeList`
// Then we check if the data contains the field
// if it does not, we add it to the list of missing embedding fields
// Finally, we check if those missing embedding fields are `this._embeddings`
// if they are not, we throw an error
for (let field of schema.fields) {
if (isFixedSizeList(field.type)) {
field = sanitizeField(field);
if (data.length !== 0 && data?.[0]?.[field.name] === undefined) {
if (schema.metadata.has("embedding_functions")) {
const embeddings = JSON.parse(
schema.metadata.get("embedding_functions")!,
);
if (
// biome-ignore lint/suspicious/noExplicitAny: we don't know the type of `f`
embeddings.find((f: any) => f["vectorColumn"] === field.name) ===
undefined
) {
missingEmbeddingFields.push(field);
}
} else {
missingEmbeddingFields.push(field);
}
} else {
fields.push(field);
}
} else {
fields.push(field);
}
}
if (missingEmbeddingFields.length > 0 && embeddings === undefined) {
throw new Error(
`Table has embeddings: "${missingEmbeddingFields
.map((f) => f.name)
.join(",")}", but no embedding function was provided`,
);
}
return new Schema(fields, schema.metadata);
}