How to clear event history using in memory tracker store?

RASA: 1.6 OS: Ubuntu

I’m using an in memory tracker store. After many turns of conversation, rasa become slower and slower. Checked the log and then I find that every time rasa core extract all events and send to action server. Related logs following:

2020-08-04 10:30:21 DEBUG    rasa.core.processor  - Logged UserUtterance - tracker now has 23242 events.

2020-08-04 10:30:21 DEBUG    rasa.core.processor  - Predicted next action 'form_xx' with confidence 1.00.
2020-08-04 10:30:21 DEBUG    rasa.core.actions.action  - Calling action endpoint to run action 'form_xx'.
/usr/local/miniconda3/lib/python3.6/site-packages/aiohttp/ ResourceWarning: Sending a large body directly with raw bytes might lock the event loop. You should probably pass an io.BytesIO object instead

I checked action call data, and found that it’s very big. Waiting for your reply. Thank you very much.

Hi, the InMemoryTrackerStore always stores the whole conversation history and there is no nice way to clear it. Also, there shouldn’t be, because that would mean that in the middle of the conversation the bot suddenly “forgets” everything that was said.

What you can do is to use a custom tracker store instead for which you specify a maximum number of events to store. How to add a custom tracker store is described in our docs. Set up your custom tracker store to use a tracker with the parameter max_event_history set to some number instead of None .

E.g. your tracker store class could look similar to this:

class InMemoryTrackerStoreLimited(InMemoryTrackerStore):

    def __init__(
        self, domain: Domain, url: Text, event_broker: Optional[EventBroker] = None, max_event_history: Optional[int] = 60
    ) -> None:
        super().__init__(domain, event_broker)
        self.max_event_history = max_event_history

Another example of a custom tracker store limiting the event number (using Mongo) can be found in this blogpost.

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I’m a little unsure how max_event_history works with regards to the tracker. Does it stop storing new events in the tracker when that limit hits? Or does it do a rolling number of events that are retrieved each time?

One could use an http-api while creating a new event – restart-- with the help of a post request on RASA server: http://localhost:5605/conversations/{sender_id}/tracker/events and payload as: [


“event”: “restart”,

“timestamp”: 1559744410


] This would restart the session while deleting every event stored in In-Memory tracker store

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