[Feature]: Purge redundant data during DB export to reduce export size

Is there an existing issue for this?

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Platform

all

App version

6.3.4

Feature

The export size of my database has increased considerably after I joined and left some chat groups on SimpleX Chat. Upon further inspection, it appears that the profiles of members from these chat groups still persist in the contact_profiles table (simplex_v1_chat.db), even though I'm no longer part of those groups. Since this table contains base64 encoded profile pictures of group members, it increases the export size significantly.

Would it be possible to detect and remove these redundant profiles (as well as anything else that isn't strictly necessary) during the export process (or preferably earlier—when leaving a chat group)? I'd like to avoid unnecessarily increasing my export size as I hop between chat groups.

Start by tracing the database export process and inspecting the contact_profiles table in simplex_v1_chat.db. Determine which profiles are no longer needed after leaving chat groups and whether cleanup belongs during export or earlier. Done means redundant profile data is removed without affecting required chat data and exports are smaller.