storage: don't synthesize MVCC point tombstones below point keys#85708
Merged
craig[bot] merged 1 commit intocockroachdb:masterfrom Aug 8, 2022
Merged
storage: don't synthesize MVCC point tombstones below point keys#85708craig[bot] merged 1 commit intocockroachdb:masterfrom
craig[bot] merged 1 commit intocockroachdb:masterfrom
Conversation
This patch changes `pointSynthesizingIter` (and by extension MVCC scans and gets) to not synthesize MVCC point tombstones below existing point keys, only above them. Point tombstones are still synthesized at the start bound of all MVCC range tombstones regardless. This patch only focuses on the behavioral change, and is not concerned with performance. A later patch will address performance optimizations. Even so, this can significantly improve `MVCCScan` performance with many range keys: ``` MVCCScan_Pebble/rows=10000/versions=1/valueSize=64/numRangeKeys=0-24 2.76ms ± 1% 2.78ms ± 2% ~ (p=0.274 n=8+10) MVCCScan_Pebble/rows=10000/versions=1/valueSize=64/numRangeKeys=1-24 6.34ms ± 1% 5.72ms ± 1% -9.80% (p=0.000 n=10+10) MVCCScan_Pebble/rows=10000/versions=1/valueSize=64/numRangeKeys=100-24 60.1ms ± 7% 23.6ms ± 7% -60.72% (p=0.000 n=10+10) MVCCGet_Pebble/batch=true/versions=1/valueSize=8/numRangeKeys=0-24 2.73µs ± 1% 2.72µs ± 1% ~ (p=0.268 n=9+10) MVCCGet_Pebble/batch=true/versions=1/valueSize=8/numRangeKeys=1-24 5.40µs ± 1% 5.46µs ± 1% +1.18% (p=0.001 n=10+10) MVCCGet_Pebble/batch=true/versions=1/valueSize=8/numRangeKeys=100-24 171µs ± 1% 170µs ± 1% ~ (p=0.247 n=10+10) MVCCGet_Pebble/batch=true/versions=10/valueSize=8/numRangeKeys=0-24 3.87µs ± 1% 3.85µs ± 0% -0.58% (p=0.030 n=10+9) MVCCGet_Pebble/batch=true/versions=10/valueSize=8/numRangeKeys=1-24 7.11µs ± 1% 7.24µs ± 1% +1.83% (p=0.000 n=9+10) MVCCGet_Pebble/batch=true/versions=10/valueSize=8/numRangeKeys=100-24 179µs ± 1% 178µs ± 1% ~ (p=0.063 n=10+10) MVCCGet_Pebble/batch=true/versions=100/valueSize=8/numRangeKeys=0-24 10.4µs ± 5% 10.0µs ± 3% -3.96% (p=0.013 n=10+9) MVCCGet_Pebble/batch=true/versions=100/valueSize=8/numRangeKeys=1-24 15.9µs ± 3% 16.2µs ± 3% +2.11% (p=0.007 n=10+10) MVCCGet_Pebble/batch=true/versions=100/valueSize=8/numRangeKeys=100-24 222µs ± 1% 220µs ± 2% ~ (p=0.063 n=10+10) ``` Release note: None
Member
|
This change is |
jbowens
approved these changes
Aug 8, 2022
Contributor
jbowens
left a comment
There was a problem hiding this comment.
nice!
Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status:complete! 1 of 0 LGTMs obtained (waiting on @erikgrinaker)
Contributor
Author
|
TFTR! bors r=jbowens |
nicktrav
approved these changes
Aug 8, 2022
Collaborator
nicktrav
left a comment
There was a problem hiding this comment.
I picked through the test cases.
Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status:
Contributor
|
Build succeeded: |
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
4 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.
This patch changes
pointSynthesizingIter(and by extension MVCC scansand gets) to not synthesize MVCC point tombstones below existing point
keys, only above them. Point tombstones are still synthesized at the
start bound of all MVCC range tombstones regardless.
This patch only focuses on the behavioral change, and is not concerned
with performance. A later patch will address performance optimizations.
Even so, this can significantly improve
MVCCScanperformance with manyrange keys:
Resolves #83899.
Release note: None