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release-22.1: kvserver: gossip l0sublevels instead of read amp#78995

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craig[bot] merged 1 commit intorelease-22.1from
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Mar 31, 2022
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release-22.1: kvserver: gossip l0sublevels instead of read amp#78995
craig[bot] merged 1 commit intorelease-22.1from
blathers/backport-release-22.1-78949

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@blathers-crl blathers-crl bot commented Mar 29, 2022

Backport 1/1 commits from #78949 on behalf of @kvoli.

/cc @cockroachdb/release

Previously read amplification was gossipped among stores to enable
future allocation decisions that would avoid candidates with high read
amplification. L0 Sublevels represents the number of levels with L0 and
is a portion of read amplification. This patch change read amplification
to l0 sublevels, as it is a better indicator of store health.

Release justification: low risk, replace deprecated gossip signal.

Release note: None

Release justification:

@kvoli
kvserver: gossip l0sublevels instead of read amp
aee773a 
Previously read amplification was gossipped among stores to enable
future allocation decisions that would avoid candidates with high read
amplification. L0 sublevels represents the number of levels within the
levle 0 and is normally the significant portion of read amplification.
When read amplification is high (>15) it is normally due to a similarly
high count of L0 sublevels. This patch change read amplification to l0
sublevels, as it is a better indicator of store health.

Release justification: low risk, replace deprecated gossip signal.

Release note: None
@blathers-crl blathers-crl bot requested a review from a team as a code owner March 29, 2022 22:25
@blathers-crl blathers-crl bot force-pushed the blathers/backport-release-22.1-78949 branch from ef3feea to aee773a Compare March 29, 2022 22:25
@blathers-crl blathers-crl bot requested review from kvoli and nvb March 29, 2022 22:25
@blathers-crl blathers-crl bot added blathers-backport This is a backport that Blathers created automatically. O-robot Originated from a bot. labels Mar 29, 2022
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blathers-crl bot commented Mar 29, 2022 •
edited by kvoli
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Thanks for opening a backport.

Please check the backport criteria before merging:

  • Patches should only be created for serious issues or test-only changes.
  • Patches should not break backwards-compatibility.
  • Patches should change as little code as possible.
  • Patches should not change on-disk formats or node communication protocols.
  • Patches should not add new functionality.
  • Patches must not add, edit, or otherwise modify cluster versions; or add version gates.
If some of the basic criteria cannot be satisfied, ensure that the exceptional criteria are satisfied within.
  • There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
  • The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
  • New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters.
  • The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.

Add a brief release justification to the body of your PR to justify this backport.

Some other things to consider:

  • What did we do to ensure that a user that doesn’t know & care about this backport, has no idea that it happened?
  • Will this work in a cluster of mixed patch versions? Did we test that?
  • If a user upgrades a patch version, uses this feature, and then downgrades, what happens?

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cockroach-teamcity commented Mar 29, 2022

This change is Reviewable

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kvoli commented Mar 30, 2022

rerunning build - failed ci on docker (unrelated).

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kvoli commented Mar 30, 2022

bors r+

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craig bot commented Mar 31, 2022

Build succeeded:

@craig craig bot merged commit a88367d into release-22.1 Mar 31, 2022
@craig craig bot deleted the blathers/backport-release-22.1-78949 branch March 31, 2022 01:38
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