persist: run the heartbeat_read task on two tokio runtimes #21873
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
In response to a production incident, this runs the heartbeat task on both the in-context tokio runtime and persist's isolated runtime. We think we were seeing tasks (including this one) get stuck indefinitely in tokio while waiting for a runtime worker. This could happen if some other task in that runtime never yields. It's possible that one of the two runtimes is healthy while the other isn't (this was inconclusive in the incident debugging), and the heartbeat task is fairly lightweight, so run a copy in each in case that helps. The real fix here is to find the misbehaving task and fix it. Remove this duplication when that happens.
|
Hmm, cargo test has failed (flaked?) twice now. Neither error seems directly related to this change, but they both have to do with postgres, which is maybe suspicious |
bkirwi
approved these changes
Sep 21, 2023
|
There's two tests left still running in nightlies, but everything else has passed so far (mod some "invalid syntax" failures in the checks stuff that are also present on main) |
|
Yeah - the completed tests include the most interesting ones for this particular change, so IMO this is good to go! |
|
TFTRs! |
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Outdated suggestions cannot be applied.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.
In response to a production incident, this runs the heartbeat task on both the in-context tokio runtime and persist's isolated runtime. We think we were seeing tasks (including this one) get stuck indefinitely in tokio while waiting for a runtime worker. This could happen if some other task in that runtime never yields. It's possible that one of the two runtimes is healthy while the other isn't (this was inconclusive in the incident debugging), and the heartbeat task is fairly lightweight, so run a copy in each in case that helps.
The real fix here is to find the misbehaving task and fix it. Remove this duplication when that happens.
Motivation
Tips for reviewer
Checklist
$T ⇔ Proto$Tmapping (possibly in a backwards-incompatible way), then it is tagged with aT-protolabel.