Sort same-priced transactions by arrival time

[ghost]

Rationale

Currently, same-priced transactions are not sorted. Because of this, back-run arbitrators have to send thousands of transactions for one arbitrage opportunity. This is the main reason why there are too many spams in the Polygon network.

ETH had the same problem and it has been solved since go-ethereum v1.9.19. I think Polygon can also have this feature to reduce the spams.

@ssandeep @Uttam-Singhh

[ferranbt]

Hi! Thank you for opening the issue. Could you point me where go-ethereum implements this change? We usually upstream from the main repo so we should have the change applied too.

[ghost]

@ferranbt Please check this PR. There are similar code in Polygon code base. I'm not sure why it doesn't work like ETH.

This behavior is found by the following case:
A back-run arbitrator will monitor tx pool and then send arbTx when a profitable userTx is found.
For ETH, arbTx is usually behind userTx. Sometimes arbTx will be in front of userTx but only a very small count or zero of other txs between them.
For Polygon, there is a significantly high rate that arbTx will be in front of userTx. And there will be many other txs between them, sometimes hundreds.

[ghost]

close this issue since no one care about this.

[ajb]

The reason that the expected "first in first out" behavior doesn't work on Polygon is because of the sentry / validator architecture.