[stateless_validation] Broadcast chunk endrosement to next 5 block producers #10449
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| // h may be skipped and block producer at height h+1 picks up the chunk. We need to ensure | ||
| // that these later block producers also receive the chunk endorsement. | ||
| // Keeping a threshold of 5 block producers should be sufficient for most scenarios. | ||
| const NUM_NEXT_BLOCK_PRODUCERS_TO_SEND_CHUNK_ENDORSEMENT: u64 = 5; |
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nit: I would consider making that configurable.
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Maybe in a future PR. Do we have a stateless validation related config like we did for resharding?
| self.epoch_manager.get_epoch_id_from_prev_block(chunk_header.prev_block_hash())?; | ||
| let block_producer = | ||
| self.epoch_manager.get_block_producer(&epoch_id, chunk_header.height_created())?; | ||
| // Verify that we are the block producer for this height. |
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Could a malicious chunk producer try to OOM us by sending chunk endorsements for the next e100 heights?
No need to fix it here but if this is a risk please leave a TODO(stateless-validation)
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That's a very valid point! I've added a todo in code. We would definitely need to discuss this to see what are possible mitigations. I've tried listing out a few.
Codecov ReportAttention:
Additional details and impacted files@@ Coverage Diff @@
## master #10449 +/- ##
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- Coverage 72.01% 71.98% -0.03%
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Files 718 718
Lines 144922 144919 -3
Branches 144922 144919 -3
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- Hits 104360 104326 -34
- Misses 35768 35804 +36
+ Partials 4794 4789 -5
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shreyan-gupta
deleted the
shreyan/stateless_validation/broadcast_chunk_endorsement
branch
In the current implementation, we only send the chunk endorsements to the next block producer. As discussed in this Zulip thread, it's possible for a chunk to be included in a block at a height different from that it was created for. This leads to the situation where this new block producer hasn't received the chunk endorsements for this chunk.
The solution here is to broadcast the chunk endorsement message to the next 5 block producers and hope that the chunk would get included in any one of them in cases of skipped blocks.
Note that this also means we are always going to use the chunk_validators as of the
chunk.height_createdand NOTchunk.height_included