Filter events by user or other context value?

[sephii]

The HistoryMiddleware stores the user in the context, which in theory could be used to filter events by user. However the field does not appear to be indexed, which means the query would do a full table scan. Is there a way to add an index to this field? I guess the ideal solution would be to index only this specific field from the context.

(more context on this issue: my application has models that belong to an organization. The organization field is usually set on aggregate roots, so it’s not directly set on every model tracked by django-pghistory and so doesn’t end up in the event models. I thought about adding the organization id to the context, but I’m afraid the performance will be bad when showing the aggregated history if it’s not indexed)

[wesleykendall]

One method is to write a custom migration that adds an index just to the "user" key of the "metadata" in the JSON field:

create index pghistory_context_user on pghistory_context (
    (metadata->>'user') 
);

[sephii]

Good idea, thanks!