release-19.2: libroach: bump up rocksdb backpressure limits #41767
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System-critical writes in Cockroach, like node-liveness, just can not be slow or they will fail, meaning that if theese rocksdb back-pressure slowdowns ever kick in, they usually do not gradually slow traffic until the system reaches some stable throughput equilibrium as intended, but rather cause liveness to fail and result in sudden unavailability -- the opposite of what they were intended to do. Thus we are probably better off just letting the metrics they were intended to protect -- like read-amplification or compaction debt -- stray further into unhealthy territory, than we are back-pressuring and hastening our demise: slower reads due to elevated read-amp are still better than no reads due to node-liveness failures (and indeed slower reads may serve as their own backpressure as we usually need to read to write). Release note: None
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Backport 1/1 commits from #41719.
/cc @cockroachdb/release
System-critical writes in Cockroach, like node-liveness, just can not be
slow or they will fail, meaning that if theese rocksdb back-pressure
slowdowns ever kick in, they usually do not gradually slow traffic
until the system reaches some stable throughput equilibrium as intended,
but rather cause liveness to fail and result in sudden unavailability
-- the opposite of what they were intended to do.
Thus we are probably better off just letting the metrics they were
intended to protect -- like read-amplification or compaction debt --
stray further into unhealthy territory, than we are back-pressuring and
hastening our demise: slower reads due to elevated read-amp are still
better than no reads due to node-liveness failures (and indeed slower
reads may serve as their own backpressure as we usually need to read to
write).
Release note: None