feat: block header block number oracle

[benesjan]

...

Checklist:

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• If the pull request requires a cryptography review (e.g. cryptographic algorithm implementations) I have added the 'crypto' tag.
• I have reviewed my diff in github, line by line and removed unexpected formatting changes, testing logs, or commented-out code.
• Every change is related to the PR description.
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[AztecBot]

Benchmark results

Metrics with a significant change:

• note_history_trial_decrypting_time_in_ms (10): 237 (-35%)

Detailed results

All benchmarks are run on txs on the Benchmarking contract on the repository. Each tx consists of a batch call to create_note and increment_balance, which guarantees that each tx has a private call, a nested private call, a public call, and a nested public call, as well as an emitted private note, an unencrypted log, and public storage read and write.

This benchmark source data is available in JSON format on S3 here.

Values are compared against data from master at commit c7f18787 and shown if the difference exceeds 1%.

L2 block published to L1

Each column represents the number of txs on an L2 block published to L1.

Metric	8 txs	32 txs	128 txs
l1_rollup_calldata_size_in_bytes	45,444	179,588	716,132
l1_rollup_calldata_gas	222,888	868,280	3,449,708
l1_rollup_execution_gas	841,975	3,595,388	22,205,077
l2_block_processing_time_in_ms	2,201	8,654 (+2%)	35,067 (-1%)
note_successful_decrypting_time_in_ms	311 (-1%)	918 (-2%)	3,327 (-2%)
note_trial_decrypting_time_in_ms	19.5 (-16%)	44.8 (-26%)	199 (-1%)
l2_block_building_time_in_ms	20,195	79,818 (-1%)	320,424 (-1%)
l2_block_rollup_simulation_time_in_ms	16,668	65,913 (-1%)	264,698 (-1%)
l2_block_public_tx_process_time_in_ms	3,493	13,836	55,362

L2 chain processing

Each column represents the number of blocks on the L2 chain where each block has 16 txs.

Metric	5 blocks	10 blocks
node_history_sync_time_in_ms	25,422 (+2%)	48,664 (+1%)
note_history_successful_decrypting_time_in_ms	2,262	4,393 (+3%)
note_history_trial_decrypting_time_in_ms	166 (+2%)	⚠️ 237 (-35%)
node_database_size_in_bytes	3,620,366	3,919,569
pxe_database_size_in_bytes	29,748	59,307

Circuits stats

Stats on running time and I/O sizes collected for every circuit run across all benchmarks.

Circuit	circuit_simulation_time_in_ms	circuit_input_size_in_bytes	circuit_output_size_in_bytes
private-kernel-init	201	43,109	20,441
private-kernel-ordering	115	25,833	9,689
base-rollup	2,980 (+1%)	667,692	873
root-rollup	90.7	4,072	881
private-kernel-inner	262	64,516	20,441
public-kernel-private-input	173	25,203	20,441
public-kernel-non-first-iteration	170	25,245	20,441
merge-rollup	10.9 (-2%)	2,592	873

Miscellaneous

Transaction sizes based on how many contracts are deployed in the tx.

Metric	0 deployed contracts	1 deployed contracts
tx_size_in_bytes	10,323	25,938

[rahul-kothari]

this function name reads weirdly given the comment in the next line.
Looking at the fn name, I assume we want to get a block header from the block number. but the next comment does the opposite. While I actually know the nuance, was wondering if there is a better name?

[LHerskind]

Not sure how we should do the wording much different. Its ok to me, but I might be stupid and have too much context.

[LHerskind]

Looks good to me, I think there are snapshots trees implemented for the nullifier ones, but it might not be actually be doing any snapshotting on it in the facade.

[LHerskind]

How come NullifierRootblockNumber, would it not be the same for all of them?

[LHerskind]

As before, not clear to me why it should be the nullifier root, but think it was just to have one?

[LHerskind]

Not sure how we should do the wording much different. Its ok to me, but I might be stupid and have too much context.