Watch and Sync events unconfirmed/confirmed behaviour

Moralis General
#1

I would like to clarify the expected behaviour for unconfirmed and confirmed transactions in Moralis that are synced using the sync contract events.
If I understand correctly, as soon as the transaction is mined, it is written to the table with confirmed = false. After a while, once the transaction is confirmed, the confirmed is updated to true. For 99% of all transactions this will probably work this way, now I want to clarify 2 edge cases:

  1. Original transaction is uncled and gets placed into another block
    what happens here? Is a second entry written to the table which will be confirmed later, leaving me with a confirmed and unconfirmed entry? Or when the transaction is confirmed will the information (e.g., block timestmap, tx index, etc) be overwritten by the confirmed values and I will have one confirmed entry?

  2. Original (successful) transaction is uncled and confirmed transaction failed (for example I make a buy on uniswap, the buy goes through initially, tx gets uncled, another transaction is placed before mine making my transaction fail due to slippage)
    Will I be left with an unconfirmed entry in the database (because with the failed transaction, no events will be emitted) or will the entry be deleted from the database?

I know that these are exceptionally rare edge cases but still, I feel like this is quite important to keep in mind and the documentation doesn’t go to deep into this topic

#2

The second case seems easier, my assumption is that the transaction will remain as unconfirmed

I’m not too sure on the first case.
There is also another more rare case when a transaction gets confirmed and then a reorg happens and the transaction is moved to another block or it fails.

#3

The case you mention should be exceptionally rare as 12 confirmations achieve 99.99% confirmation. So nothing I would worry about too much. Also proof of stake networks have a 100% confirmation so after the merge (or for other pos networks like polygon) this shouldn’t be a real issue as well.

1 Like