kvserver: gossip l0sublevels instead of read amp #78949
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Reviewed 5 of 5 files at r1, all commit messages.
Reviewable status:complete! 1 of 0 LGTMs obtained (waiting on @aayushshah15 and @kvoli)
pkg/roachpb/metadata.proto, line 342 at r1 (raw file):
// This information can be used for rebalancing decisions. optional Percentiles bytes_per_replica = 6 [(gogoproto.nullable) = false]; optional Percentiles writes_per_replica = 7 [(gogoproto.nullable) = false];
Let's mark field number 11 as reserved. reserved 11; at the end.
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
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pkg/roachpb/metadata.proto, line 342 at r1 (raw file):
Previously, nvanbenschoten (Nathan VanBenschoten) wrote…
Let's mark field number 11 as reserved.
reserved 11;at the end.
Done.
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TYFTR Nathan 🤠
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Just for my (and I suspect not only my) education, what is the read amp metric actually measuring? Now that I have learned what L0Sublevels is I'm confused about that, because I thought that was read amp. |
78995: release-22.1: kvserver: gossip l0sublevels instead of read amp r=kvoli a=blathers-crl[bot] 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: Co-authored-by: Austen McClernon <[email protected]>
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