# FlowControl

Applies light flow control to throttle senders when queues near full.

This parameter applies to imtcp: TCP Syslog Input Module.

Name:

  FlowControl

Scope:

  module, input

Type:

  boolean

Default:

  module=on, input=module parameter

Required?:

  no

Introduced:

  at least 5.x, possibly earlier

## Description

This setting specifies whether some message flow control shall be exercised on the related TCP input. If set to on, messages are handled as “light delayable”, which means the sender is throttled a bit when the queue becomes near-full. This is done in order to preserve some queue space for inputs that can not throttle (like UDP), but it may have some undesired effect in some configurations. Still, we consider this as a useful setting and thus it is the default. To turn the handling off, simply configure that explicitly.

The same-named input parameter can override this module setting.

## Module usage

    module(load="imtcp" flowControl="off")

## Input usage

    input(type="imtcp" port="514" flowControl="off")

### Legacy names (for reference)

Historic names/directives for compatibility. Do not use in new configs.

- $InputTCPFlowControl — maps to FlowControl (status: legacy)

## See also

See also imtcp: TCP Syslog Input Module.

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