Incremental commits off-chain

[noonio]

❄️ This PR implements most of the off-chain changes we need for the incremental commits to work. Since there are many changes we decided to have a series of follow up PRs to finally conclude the wanted feature.

Included:

Relevant code to be able to do full end-to-end test for depositing (and recovering) a user UTxO into a running Head.
This means:
❄️ everything needed to accept user requests at the API level
❄️ build off-chain transactions (deposit, recover, increment)
❄️ observe new transactions (deposit, recover and increment)
❄️ changes in the Snapshot type and all other relevant types and functions to accommodate this new feature
❄️ minimal needed changes in the on-chain code (validators just return True so once this is merged we will not be able to release until this gap is implemented)

Outstanding:

❄️ documentation - Write up some documentation to explain how incremental commits are working
❄️ Various tests described in the original issue and which are relevant to the off-chain code
❄️ Make the increment/recover use the observed UTxO instead of keeping those around
❄️ Remove Commit client input since it is not used
❄️ Revisit the observation/transaction posting types and make sure the field names make sense
❄️ Determine what should be good enough deadline for a deposit transaction (should we make it configurable or rely on the contestation deadline)

---

• CHANGELOG updated or not needed
• Documentation updated or not needed
• Haddocks updated or not needed
• No new TODOs introduced or explained herafter

[github-actions]

Transaction costs

Sizes and execution budgets for Hydra protocol transactions. Note that unlisted parameters are currently using arbitrary values and results are not fully deterministic and comparable to previous runs.

Metadata
Generated at	2024-10-04 14:53:13.624567009 UTC
Max. memory units	14000000
Max. CPU units	10000000000
Max. tx size (kB)	16384

Script summary

Name	Hash	Size (Bytes)
νInitial	2fac819a1f4f14e29639d1414220d2a18b6abd6b8e444d88d0dda8ff	3799
νCommit	2043a9f1a685bcf491413a5f139ee42e335157c8c6bc8d9e4018669d	1743
νHead	04fa9fa7d6f2dac870291a1f2274a268b64401d91d92b4bf1423843b	10176
μHead	41936d9458823cb5b4e47aa843a2f438ff3697d10ef4227a33cbe15b*	4508
νDeposit	e0091235d453844ca593223db7d93b67b27afff4aac13bda443e0e16	2791

• The minting policy hash is only usable for comparison. As the script is parameterized, the actual script is unique per head.

Init transaction costs

Parties	Tx size	% max Mem	% max CPU	Min fee ₳
1	5096	5.61	2.21	0.44
2	5298	7.18	2.84	0.46
3	5498	8.37	3.30	0.48
5	5902	11.39	4.51	0.53
10	6906	18.02	7.12	0.65
57	16355	83.00	32.84	1.78

Commit transaction costs

This uses ada-only outputs for better comparability.

UTxO	Tx size	% max Mem	% max CPU	Min fee ₳
1	569	10.52	4.15	0.29
2	759	13.86	5.65	0.34
3	947	17.33	7.20	0.38
5	1314	24.65	10.44	0.48
10	2256	45.22	19.36	0.75
20	4119	95.99	40.76	1.40

CollectCom transaction costs

Parties	UTxO (bytes)	Tx size	% max Mem	% max CPU	Min fee ₳
1	57	560	21.46	8.41	0.41
2	114	671	32.17	12.77	0.53
3	170	782	44.16	17.72	0.67
4	227	893	62.79	25.25	0.88
5	282	1004	77.71	31.50	1.05
6	338	1116	93.56	38.24	1.23

Cost of Decrement Transaction

Parties	Tx size	% max Mem	% max CPU	Min fee ₳
1	646	17.73	7.85	0.38
2	779	19.31	9.24	0.41
3	898	20.67	10.54	0.43
5	1254	24.89	13.71	0.51
10	2052	32.66	20.52	0.65
50	8080	98.06	76.82	1.85

Close transaction costs

Parties	Tx size	% max Mem	% max CPU	Min fee ₳
1	653	20.15	9.09	0.41
2	788	21.54	10.52	0.43
3	1034	23.92	12.68	0.48
5	1234	26.44	15.22	0.53
10	2004	34.35	23.04	0.68
49	7659	95.52	82.85	1.86

Contest transaction costs

Parties	Tx size	% max Mem	% max CPU	Min fee ₳
1	671	25.93	11.19	0.47
2	815	27.77	12.77	0.50
3	947	29.50	14.31	0.53
5	1428	34.69	18.80	0.63
10	2032	43.14	26.22	0.78
39	6464	98.62	75.05	1.77

Abort transaction costs

There is some variation due to the random mixture of initial and already committed outputs.

Parties	Tx size	% max Mem	% max CPU	Min fee ₳
1	4972	17.52	7.62	0.57
2	5157	29.28	12.91	0.71
3	5207	41.39	18.25	0.85
4	5331	57.16	25.26	1.03
5	5615	78.89	35.17	1.29
6	5650	97.11	43.26	1.50

FanOut transaction costs

Involves spending head output and burning head tokens. Uses ada-only UTxO for better comparability.

Parties	UTxO	UTxO (bytes)	Tx size	% max Mem	% max CPU	Min fee ₳
5	0	0	4935	7.71	3.26	0.45
5	1	57	4968	8.64	3.89	0.47
5	5	285	5104	13.76	6.99	0.54
5	10	569	5273	19.22	10.46	0.61
5	20	1140	5614	30.34	17.49	0.77
5	30	1709	5955	41.66	24.61	0.93
5	40	2277	6293	53.47	31.94	1.09
5	50	2846	6633	64.12	38.78	1.24
5	81	4605	7679	99.09	60.82	1.73

End-to-end benchmark results

This page is intended to collect the latest end-to-end benchmark results produced by Hydra's continuous integration (CI) system from the latest master code.

Please note that these results are approximate as they are currently produced from limited cloud VMs and not controlled hardware. Rather than focusing on the absolute results, the emphasis should be on relative results, such as how the timings for a scenario evolve as the code changes.

Generated at 2024-10-04 14:55:54.466747739 UTC

Baseline Scenario

Number of nodes	1
Number of txs	3000
Avg. Confirmation Time (ms)	4.946512714
P99	8.004050609999991ms
P95	6.122482349999996ms
P50	4.6671890000000005ms
Number of Invalid txs	0

Three local nodes

Number of nodes	3
Number of txs	9000
Avg. Confirmation Time (ms)	22.970043740
P99	115.73477167ms
P95	29.303824249999998ms
P50	20.578107ms
Number of Invalid txs	0

[ch1bo]

@noonio When we continue work here, we should take a step back again given the new overall design of #199 with details from #1571. The overall off-chain story has not changed much, but is basically separated in two parts:

• Part 1: hydra-node API for deposit/cancel analogous to Implement deposit validators and off-chain code #1574
• Part 2: hydra-node detects deposits, triggers ReqSn with approval and incrementTx construction & observation (as before)

[ch1bo]

❤️