backport-2.0: storage: lower the raft-log queue timer from 50ms to 0ms #23884
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Lower the raft-log queue timer from 50ms to 0ms. This timer was forcing an artificial delay between raft-log truncation operations which was in turn allowing the raft-log to grow undesirably long in cluster overload situations. When the raft-log for a range grows to large, the eventual truncation operation can then take a prohibitively long time which leads to a downward spiral of performance, oftentimes resulting in Raft snapshots (which are significantly more expensive) and even further performance degradation. There are no downsides to a zero duration between raft-log truncations as there are other mechanisms in place to avoid performing truncations unless they are necessary (e.g. tracking of the raft-log size and the number of entries). Release note (performance improvement): Improve cluster performance during overload scenarios.
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a-robinson
approved these changes
Mar 15, 2018
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Backport 1/1 commits from #23869.
/cc @cockroachdb/release
Lower the raft-log queue timer from 50ms to 0ms. This timer was forcing
an artificial delay between raft-log truncation operations which was in
turn allowing the raft-log to grow undesirably long in cluster overload
situations. When the raft-log for a range grows to large, the eventual
truncation operation can then take a prohibitively long time which leads
to a downward spiral of performance, oftentimes resulting in Raft
snapshots (which are significantly more expensive) and even further
performance degradation. There are no downsides to a zero duration
between raft-log truncations as there are other mechanisms in place to
avoid performing truncations unless they are necessary (e.g. tracking of
the raft-log size and the number of entries).
Release note (performance improvement): Improve cluster performance
during overload scenarios.