storage: use exchange-based sequencing to broadcast internal commands #31147
Conversation
This file contains 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
The Timely `Sequencer` doesn't behave well when different workers instantiate their parts at points in time that are sufficiently spread apart. It delays commands by that creation time difference and is prone to spinning the CPU at 100%. To work around these issues, this commit replaces the `Sequencer` used in storage for broadcasting internal commands with a dataflow that sequences by sending all commands through a single worker.
teskje
force-pushed
the
storage-exchange-sequencer
branch
2 times, most recently
from
b53175b to
234a272
Compare
The previous command sequencer dataflow relied on the assumption that updates passing through Timely channels are not reordered. That isn't an assumption we should make, so this commit adds code to explicitly track and restore the correct ordering by assigning indexes to transmitted commands and then making sure that no indexes are skipped downstream.
teskje
force-pushed
the
storage-exchange-sequencer
branch
from
234a272 to
508f73d
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
The Timely
Sequencerdoesn't behave well when different workers instantiate their parts at points in time that are sufficiently spread apart. It delays commands by that creation time difference and is prone to spinning the CPU at 100%.To work around these issues, this PR replaces the
Sequencerused in storage for broadcasting internal commands with a dataflow that sequences by sending all commands through a single worker.Motivation
Fixes https://github.com/MaterializeInc/database-issues/issues/8893
Tips for reviewer
Checklist
$T ⇔ Proto$Tmapping (possibly in a backwards-incompatible way), then it is tagged with aT-protolabel.