[Bifrost] Read stream will seal the chain if partial seal is detected #3597
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This was referenced Jul 29, 2025
tillrohrmann
approved these changes
Jul 30, 2025
There was a problem hiding this comment.
Great work @AhmedSoliman. The logic seems sound to me. LGTM. +1 for merging :-)
crates/bifrost/src/read_stream.rs
Outdated
Comment on lines
120
to
125
| Reconfiguring, | ||
| /// Waiting for the tail LSN of the substream's loglet to be determined (sealing in-progress). | ||
| /// We land on this state when we observe a "Sealed" signal from an open segment after we | ||
| /// reached the safe known tail for that loglet. We can continue reading only after the chain | ||
| /// has been sealed by a marker or with a new installed chain. | ||
| AwaitingReconfiguration { |
There was a problem hiding this comment.
Nit: Reconfiguring (compared to AwaitingReconfiguration) reads as if the read stream would reconfigure something. Could renaming Reconfiguring into Awaiting(NewSegment | Reconfiguration) and AwaitingReconfiguration into Awaiting(NewSegment | Reconfiguration)OrSealChain be an idea?
There was a problem hiding this comment.
No strong opinions here. I'll update.
The PR introduces two changes: - `Bifrost::find_tail()` will only attempt to seal the chain if FindTailOpts asks for consistent result; we don't need to cripple the fast path for find-tail. - Find tail will eagerly seal the chain without grace period. This is to avoid unnecessary startup delays for single-node setups. The fact that chain sealing is idempotent makes it lighterweight to perform as it'll coalesce nicely with other reconfigurations that might be happening concurrently.
Allows the system to capture the "source" and the "node" for chain seal markers. There is also a new `--reason` flag to `restatectl log seal` to specify the reason, and the reason + the node id will be printed in `restatectl logs describe <id>` output.
A partial seal is when the tail loglet is sealed but the chain itself is not. The read stream will detect this situation and seal the chain after a grace period (5s+50% jitter).
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
A partial seal is when the tail loglet is sealed but the chain itself is not. The read stream will detect this situation and seal the chain after a grace period (5s+50% jitter).
Stack created with Sapling. Best reviewed with ReviewStack.