concurrent | ScyllaDB Docs

concurrent¶

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

Source

concurrent/index.js, line 8

Methods¶

(static) executeConcurrent(client, query, parameters, optionsopt) → {Promise<ResultSetGroup>}

Executes multiple queries concurrently at the defined concurrency level.

Parameters:

Name Type Attributes Description

client

Client

The Client instance.

query

String | Array<{query, params}>

The query to execute per each parameter item.

parameters

Array<Array<any>> | Stream | 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

Object

The execution options.

Properties

Name	Type	Attributes	Default	Description
`executionProfile`	String	<optional>		The execution profile to be used.
`concurrencyLevel`	Number	<optional>	100	The concurrency level to determine the maximum amount of in-flight operations at any given time
`raiseOnFirstError`	Boolean	<optional>	true	Determines whether execution should stop after the first failed execution and the corresponding exception will be raised.
`collectResults`	Boolean	<optional>	false	Determines whether each individual ResultSet instance should be collected in the grouped result.
`maxErrors`	Number	<optional>	100	The maximum amount of errors to be collected before ignoring the rest of the error results.

Source

concurrent/index.js, line 53

Returns:

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.

Type: Promise<ResultSetGroup>

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);

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