Utilities for concurrent query execution with the DataStax Node.js Driver.

Classes

Functions

concurrent.executeConcurrent

(Client client, String or Array<{query, params}> query, Array<Array>, Stream or Object parameters, [Object options])

Executes multiple queries concurrently at the defined concurrency level.

Static
This function is static
Examples:
Using a fixed query and an Array of Arrays as parameters
const query = 'INSERT INTO table1 (id, value) VALUES (?, ?)';
const parameters = [[1, 'a'], [2, 'b'], [3, 'c'], ]; // ...
const result = await executeConcurrent(client, query, parameters);
Using a fixed query and a readable stream
const stream = csvStream.pipe(transformLineToArrayStream);
const result = await executeConcurrent(client, query, stream);
Using a different queries
const queryAndParameters = [
  { query: 'INSERT INTO videos (id, name, user_id) VALUES (?, ?, ?)',
    params: [ id, name, userId ] },
  { query: 'INSERT INTO user_videos (user_id, id, name) VALUES (?, ?, ?)',
    params: [ userId, id, name ] },
  { query: 'INSERT INTO latest_videos (id, name, user_id) VALUES (?, ?, ?)',
    params: [ id, name, userId ] },
];

const result = await executeConcurrent(client, queryAndParameters);
Parameters:
Name Type Description
client Client

The Client instance.

query String or Array<{query, params}>

The query to execute per each parameter item.

parameters Array<Array>, Stream or Object

An Array or a readable Stream composed of Array items representing each individual set of parameters. Per each item in the Array or Stream, an execution is going to be made.

options optional Object

The execution options.

options.executionProfile optional String

The execution profile to be used.

options.concurrencyLevel optional Number

The concurrency level to determine the maximum amount of in-flight operations at any given time

(default: 100)
options.raiseOnFirstError optional Boolean

Determines whether execution should stop after the first failed execution and the corresponding exception will be raised.

(default: true)
options.collectResults optional Boolean

Determines whether each individual ResultSet instance should be collected in the grouped result.

(default: false)
options.maxErrors optional Number

The maximum amount of errors to be collected before ignoring the rest of the error results.

(default: 100)
Returns:
Type Description
Promise<ResultSetGroup>

A Promise of ResultSetGroup that is resolved when all the executions completed and it’s rejected when raiseOnFirstError is true and there is one or more failures.