Concurrency Limiting

There are maximum limits for concurrent export requests. Tenable.io applies these limits on concurrent exports to ensure that all customers experience the same level of service. You can have a maximum of two or three active concurrent export requests per Tenable.io customer instance or container depending on which endpoint you are using.

If you submit an API request after the concurrency limit is reached, Tenable.io returns an HTTP response message with a 429 (Too Many Requests) status code. The response also includes a retry-after header element that specifies the number of seconds to wait before retrying.

Example Response Header

connection:keep-alive 
content-length:580 
content-type:text/html
date:Wed, 24 Oct 2018 17:13:43 GMT 
retry-after:30 
server:tenable.io
strict-transport-security:max-age=63072000; includeSubDomains
x-content-type-options:nosniff
x-gateway-site-id:nginx-router-b-eng-us-east-1.dcld
x-path-handler:tenable-io-plugins-plugin

Concurrency Limits

This table below outlines the concurrency limits for specific Tenable.io export endpoints.

Limit	Affected Endpoints
Two concurrent vulnerability exports per container. Tenable.io also prevents duplicate exports from running concurrently. For example, export requests with the same filters.	POST /vulns/export
Two concurrent asset exports per container. Tenable.io also prevents duplicate exports from running concurrently. For example, export requests with the same filters.	POST /assets/export
Two concurrent exports per container.	GET /workbenches/export
Three concurrent requests per Tenable.io customer instance. Note: This limit is subject to change.	GET /workbenches/vulnerabilities/{plugin_id}/outputs GET /workbenches/assets/{asset_id}/vulnerabilities/{plugin_id}/outputs GET /scans/{scan_id} GET /scans/{scan_uuid}/hosts/{host_id} GET /scans/{scan_uuid}/hosts/{host_id}/plugins/{plugin_id}