Rerebootstrap - #4982
Open
belliottsmith wants to merge 10 commits into
Open
Conversation
…r -> ExclusiveAsyncExecutor
Fairness: tasks are grouped by kind of work, and for each group we track work arrival and service via decaying counters. If work for some group(s) begin to be served at a much lower rate than some other group (e.g. because that group has a large backlog, that by simple priority comes first), then we begin processing some fraction of the work by service-ratio rather than priority. This means that we cannot starve request processing because, e.g., a sync point has produced thousands of state save tasks. Incremental processing: tasks that process many keys may be declared INCR or ASYNC. ASYNC indicates the keys are needed (so should be loaded), but may be used in follow-up work so the task may be executed if the data is not yet loaded. An ASYNC task may be followed by an INCR task that processes keys as they are loaded, with limits to the batch sizes. This limits the latency impact of processing larger transactions such as sync points. INCR tasks may be declared to be processed in either an arbitrary order with no isolation, or “atomically” with its parent task. In the latter case, the complete unit of work appears to execute as a single execution to external observers (blocking progress on unprocessed keys). Key-level ordering: AccordCacheEntry can inflate a special Queue object that can be used to impose ordering constraints: FIFO for atomic work (once it has been part processed, or submitted as part of a parent task); prioritised for tasks that have a key-level priority to impose (i.e. PreAccept/Accept/Commit/Stable/Apply want to be ordered by TxnId); and unsequenced tasks for those that have no sequencing restrictions. Additional improvements: - AccordCacheEntry are now explicitly LOCKED for the duration of their usage, which may span multiple executions for long running INCR tasks. - ExclusiveExecutor releases its ownership lock immediately, since AccordCacheEntry locks guarantee safety (as they will not be released until the task is cleaned up) - CassandraThread tracks active and locked AccordExecutor, so that we may safely and more aggressively use executeMaybeImmediately, safe in the knowledge it will never permit cross-executor executions or multiple executor locks to be held. Also: - Rename PreLoadContext -> ExecutionContext - Break out AccordExecutor/AccordTask into separate package
- fix race conditions when updating Task.info (between running and Exclusive methods) - do not run consequences of actions that fail and do not become durable (e.g. applying to data store/post-applying a transaction that we failed to complete the PreApplied/Applying step for)
claude tests fix negative histogram values under simulation, and catch and refuse bad values in other cases
- Distinguish corrupt/incomplete cases; latter case only refuses uncertain data
- Ensures quorum durability before marking own log faulty
- Refuse unsafe operations more selectively once log marked faulty
- Simplify and merge logic with standard bootstrap
belliottsmith
force-pushed
the
rerebootstrap
branch
from
July 30, 2026 15:20
cb8960e to
ba683a0
Compare
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
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.
Thanks for sending a pull request! Here are some tips if you're new here:
Commit messages should follow the following format:
The Cassandra Jira