What is a "Hook"?
A WebHook is an HTTP callback: this is the notification between Podio and Workflow Automations to inform the other, that an action or update has occurred.**
When a Workflow Automations flow is created in an App, Hooks are created within the App. These Hooks can be viewed from the Developer Settings. To access these settings, click Developer from the wrench menu on the App.
Here you will be able to view all created Hooks. When workflows are running without error, these hooks are ACTIVE. If a Hook is shown as INACTIVE, re-save the flows to force a refresh.
The Hook Event on a Workflow Automations Action is turned OFF by default. This is useful for cases where your flows could cause infinite loops (eg reverting a value back to it's previous value). In order to use an action to trigger other workflows, you want this Hook Event turned ON.
By default, any update made in Podio generates a Hook Event, which would then come through to Workflow Automations and cause further actions. If you disable the notifications in the App Settings, Workflow Automations will NOT be notified of the update and nothing else will fire.
Workflow Automations will only allow a maximum of 100 concurrently processing Podio hook events for any single app.
If more hooks are received from Podio, they are queued. A separate cron job processes the queue every minute, re-initiating up to 100 queued hook events at a time until caught up.
This is done to protect users from the bad neighbour effect - ie experiencing Workflow Automations slow downs due to someone else's Excel import, and to protect Workflow Automations from badly designed flows bringing down the whole system. With fast moving flows, this may never even kick in, but with slow moving flows that have actions like "Get View", it will delay execution for the greater good. See the Article for a Solution