Sync Issues / Tracker

[ximenabb]

Description
Standalone ticket to track general work on sync issues

Notes
Linked to : digidem/mapeo-mobile#948
digidem/mapeo-mobile#872

[achou11]

ECA

• initial context can be found in Sync issues / ECA mapeo-mobile#872
• April 6 2022
  • @gmaclennan and I did a debug session using the materials provided by ECA and programs team. We were not able to reproduce the syncing issues on our own devices, as mentioned in the original description. We then mostly looked at the data at the db level to see if there were any noticeable issues with the records. A couple of noteworthy observations:
    • The db was not missing any records. This is typically a common issue when sync issues occur, but based on our testing of their db, this was not an issue
    • There are several deletion records. Out of ~7000 records, ~3000 of them are deletions. Furthermore, it seems that there could have been a case where a deletion was deleted, which could potentially cause issues in the indexer. Requires further investigating, but could also be the case that many peers deleted data that they didn't originally author - this is only allowed on desktop but given the number of potential peers that apparently did this (~20), it seems odd
    • The UI in the desktop sync tab is a little misleading. It'll tell the user that there are X number of observations being synced, but what X really reflects is the number of records that are being synced i.e. including deletions. So when that's done and the user goes to see the synced data in the observations tab, they'll most likely expect ~X number of observations to be available, when in reality it would be X - Y number of observations (where Y is the approximate number of deletions recorded in the db). this could be contributing to any report that claims that the synced data is mismatched with what's seen in the app
    • another possible explanation for issues is due to network connectivity issues and we're not handling errors properly