Question for block.timestamp

[KittyFu307]

Environment

Mainnet

Provide a brief description of the functionality you're trying to implement.

I am trying to figure out the timestamp update of zksync era.
Have a few question of block.timestamp.

1. Assuming that the proof has not been generated yet, but tx has not been sent to L1, how do I get this timestamp?
2. Will there be a certain delay between block.timestamp and executed time?
3. Is it possible that the transaction is confirmed on l2 but fails to be submitted to l1?
4. Is the timestamp of l1 also used when the transaction is executed on l2?
   5.How often will ZkSync get the timestamp of L1?

What is the specific issue or error you're encountering?

I am trying to log the timestamp of ZkSync Era. And I send two tx on the mainet. the two tx were log the timestamp of my tx. But there are in different block but return the same block.timestamp which comfused me.

Can you share the error messages or logs you're receiving, if any?

Have you made any recent changes to the contract before encountering this issue?

no

Are there any external libraries or contracts that your contract interacts with?

https://explorer.zksync.io/address/0xbbdF04a4c418f09Bab41a6d74AbDC39339df9772#events

Can you provide the relevant portions of your contract code where the issue is occurring?

no

Have you tried to isolate the problem, and if so, what were the results?

no

What steps have you already taken to try to resolve the issue?

no

Repo Link (Optional)

No response

Additional Details

No response

[bxpana]

Here's our docs that have more details about how block number and timestamp work on zkSync Era for now https://era.zksync.io/docs/dev/developer-guides/transactions/blocks.html#block-number-and-timestamp-considerations

In the future we will be working on implementing so it returns the L2 block timestamp

[KittyFu307]

Yeah I have already read the the doc but still have above questions. @bxpana could you give me an explanation for those questions? How often will ZkSync ERA get L1’s timestamp?

[KittyFu307]

@bxpana and have a more question
Is timestamp updated when batching transaction? How often when batching transactions and how to update the timestamps

[uF4No]

block.timestamp will return the timestamp from the latest batch produed. In your case, your transactions were included in the batch #50922 which was produced at the same timestamp that your transactions emit in the event, 1685714192 (Fri Jun 02 2023 13:56:32 GMT+0000). Hope that helps understand how it currently works.

A batch will include transactions from multiple blocks and the batch is sealed/produced based on different parameters like timeout or just space in the batch, so there's not a fixed time to produce batches. You can read about that in this page of the docs. The more usage in the network, the faster batches will be sealed/produced.

Will there be a certain delay between block.timestamp and executed time?

Yes, for the moment block.timestamp will have a delayed value as it returns the timestamp the last produced batch.

Is it possible that the transaction is confirmed on l2 but fails to be submitted to l1?

Very unlikely, only if the proof cannot be generated.

Is the timestamp of l1 also used when the transaction is executed on l2?

Not exactly of L1, but from the latest batch produced.

Finally, we're working on different methods to allow developers to access both the L2 timestamp and the L1 timestamp.

[bxpana]

@KittyFu307

[Sam-Scolari]

By "last produced batch" do you mean the latest sealed batch or validated batch? I am trying to figure out if calling block.number in the EVM will give me the latest L1 block number that is either roughly a few minutes old or a day old due to finality times.

[KittyFu307]

Thank you so much!