Message delivery issues not being sent or confirmed by receiver

[tomsmith8]

As per this ticket here some messages are not going through or there is an issue with the confirmation back from the receiver.

Andrew has experienced this with two different lite users.

[uncleJim21]

One proposal I had was to use checksums on the messageIds array. That way the client and server can easily "ping" each other with a value to determine if a resync is needed with relatively low overhead. What do you think @kevkevinpal?

[uncleJim21]

Here's a very simple prototype I made. The idea is that you could quickly and easily detect a discrepancy in the checksum between the local and remote database and take error correction action if the checksums are not identical:

This technique is pretty common in communication systems due to its effectiveness: you only need that one string to determine if there's an error so you can check for errors quite frequently. One way I propose we do it is just have the client & relay compare checksums every N seconds while inside a chat and if there's a discrepancy, initiate a "self healing" routine where it resends any messages on local that are not recognized as sent by the relay.

[Evanfeenstra]

Nice idea... the bigger problem though is that messages might never make it to your relay because of lightning liquidity issues, or MQTT issues

[uncleJim21]

Just so we're clear the chain of custody looks something like

(sender client) --(1)---> (sender relay) ---(2)---> (recipient relay) ----(3)---->(recipient client)

It seems you're mostly concerned about step 2 which seems to be the problem here?

[Evanfeenstra]

Right. Latest relay master waits for step 2 before returning a success or error message to the sender, so that should help a lot with "silent" failed msgs

[uncleJim21]

So are these current failures silent because the relay isn't update to latest master?

One thought for how we can help on the client side is to detect a pattern of frequent failures and make recommendations such as adding more liquidity and alert the user?