kv: stop encoding or decoding synthetic timestamp bit in/from mvcc keys#105523
Merged
craig[bot] merged 2 commits intocockroachdb:masterfrom Jul 11, 2023
Merged
Conversation
Informs cockroachdb#101938. This commit removes logic in mvcc key encoding routines that handle synthetic timestamps. As a result, we no longer write keys with synthetic timestamps, though we retain the ability to decode them. As described in cockroachdb#72121 (comment) and later in cockroachdb@24c56df (see "Future improvements"), the introduction of the mvcc value header and the optional, per-version local timestamp paved the way for the removal of synthetic timestamps. MVCC keys no longer need to carry the synthetic bit in order for reads from GLOBAL tables to behave properly. As a result, we no longer need to write it. Release note: None
Informs cockroachdb#101938. This commit removes logic in mvcc key decoding routines to decode synthetic timestamps. We retain the ability to decode keys with the synthetic timestamp bit set, but we simply ignore its presence. As discussed in the previous commit, the role of these synthetic timestamp markers was eliminated in cockroachdb#80706 by the local_timestamp field in the mvcc value header, which was first present in v22.2. v23.2 does not require compatibility with v22.2, so it can rely on the fact that any txn that has a synthetic timestamp (because it writes in the future) will also write local timestamps into each of its values. Release note: None
Member
|
This change is |
sumeerbhola
approved these changes
Jul 10, 2023
Collaborator
sumeerbhola
left a comment
There was a problem hiding this comment.
Reviewed 6 of 6 files at r1, 7 of 7 files at r2, all commit messages.
Reviewable status:complete! 1 of 0 LGTMs obtained (waiting on @nvanbenschoten)
Contributor
Author
|
TFTR! bors r=sumeerbhola |
Contributor
|
Build succeeded: |
This was referenced Jan 3, 2024
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
3 participants
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.
Informs #101938.
This first commit removes logic in mvcc key encoding routines that handle synthetic timestamps. As a result, we no longer write keys with synthetic timestamps, though we retain the ability to decode them.
The second commit removes logic in mvcc key decoding routines to decode synthetic timestamps. We retain the ability to decode keys with the synthetic timestamp bit set, but we simply ignore its presence.
As described in #72121 (comment) and later in 24c56df (see "Future improvements"), the introduction of the mvcc value header and the optional, per-version local timestamp paved the way for the removal of synthetic timestamps. MVCC keys no longer need to carry the synthetic bit in order for reads from GLOBAL tables to behave properly. As a result, we no longer need to write it.
Release note: None