feat: persist pxe state

[alexghr]

This PR adds a persistent database to PXE. I've created a new package in the monorepo called @aztec/kv-store which exports a set of general data structures that can be used by components to store state in consistent manner. The only implementation right now is with LMDB (both persisted on disk and in-memory/temporary file).

This higher level abstraction allowed me to easily add storage to PXE's note processors, its synchronizer and the key store too.

Fix #3364

This PR refactors how PXE is synced against a node by removing the "initial L2 block" config parameter of the PXE/note processor and always starting from last known state.

Changes to the synchronizer and note processors have been taken out and will be merged in a separate PR (as part of #3570) because it will require some changes to the benchmarking code.

Synch changes here #3673

[AztecBot]

Benchmark results

Metrics with a significant change:

• note_history_successful_decrypting_time_in_ms (10): 5,032 (+20%)
• note_history_trial_decrypting_time_in_ms (5): 79.6 (-51%)
• note_history_trial_decrypting_time_in_ms (10): 149 (-59%)
• note_trial_decrypting_time_in_ms (8): 48.3 (+74%)
• note_trial_decrypting_time_in_ms (128): 104 (-48%)

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 e749daa7 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	222,912	868,016	3,449,432
l1_rollup_execution_gas	841,999	3,595,124	22,204,801
l2_block_processing_time_in_ms	2,185 (-2%)	8,411 (-3%)	33,882 (-4%)
note_successful_decrypting_time_in_ms	338 (+6%)	1,064 (+13%)	3,888 (+12%)
note_trial_decrypting_time_in_ms	⚠️ 48.3 (+74%)	60.3 (-9%)	⚠️ 104 (-48%)
l2_block_building_time_in_ms	20,088 (-1%)	80,185	320,902 (-1%)
l2_block_rollup_simulation_time_in_ms	16,571 (-1%)	66,341	265,216 (-1%)
l2_block_public_tx_process_time_in_ms	3,484 (-1%)	13,777 (-1%)	55,453 (-1%)

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	24,135 (-2%)	47,500
note_history_successful_decrypting_time_in_ms	2,453 (+14%)	⚠️ 5,032 (+20%)
note_history_trial_decrypting_time_in_ms	⚠️ 79.6 (-51%)	⚠️ 149 (-59%)
node_database_size_in_bytes	3,622,589	3,915,301
pxe_database_size_in_bytes	29,940 (+1%)	59,499

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	199	43,109	20,441
private-kernel-ordering	114 (-1%)	25,833	9,689
base-rollup	2,955	667,692	873
root-rollup	90.5 (+1%)	4,072	881
private-kernel-inner	260	64,516	20,441
public-kernel-private-input	171	25,203	20,441
public-kernel-non-first-iteration	168	25,245	20,441
merge-rollup	10.8 (-1%)	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

[PhilWindle]

Looks great!