Streaming

The @spiceai/spice SDK supports streaming partial results as they become available.

This can be used to enable more efficient pipelining scenarios where processing each row of the result set can happen independently.

The SpiceClient.sql method takes an optional onData callback that will be passed partial results as they become available.

public async sql(
    queryText: string,
    optionsOrCallback?: SqlQueryOptions | ((data: Table) => void),
    onData?: (data: Table) => void,
    headers?: { [key: string]: string }
  ): Promise<Table>

A callback may be passed either as the second argument or as onData.

In this example, we retrieve all 10,000 suppliers from the TPCH Suppliers table. This query retrieves all suppliers in a single call:

import { SpiceClient } from "@spiceai/spice";

const spiceClient = new SpiceClient({ apiKey: process.env.API_KEY! });
const query = `
SELECT s_suppkey, s_name
FROM tpch.supplier
`;
const allSuppliers = await spiceClient.sql(query);
allSuppliers.toArray().forEach((row) => {
    processSupplier(row);
});

This call will wait for the promise returned by sql() to complete, returning all 10,000 suppliers.

Alternatively, data can be processed as it is streamed to the SDK. Provide a callback function to the onData parameter, which will be called with every partial set of data streamed to the SDK:

import { SpiceClient } from "@spiceai/spice";

const spiceClient = new SpiceClient({ apiKey: process.env.API_KEY! });
const query = `
SELECT s_suppkey, s_name
FROM tpch.supplier
`;
await spiceClient.sql(query, undefined, (partialData) => {
    partialData.toArray().forEach((row) => {
        processSupplier(row);
    });
});

On the Arrow Flight transport the first message carries the schema and is not passed to onData; each subsequent message is delivered as its own Table. The promise still resolves with the complete result assembled from every chunk.