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kv: bump kv.range_merge.queue_interval to 5s #64239

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merged 1 commit into from
Apr 30, 2021

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@nvanbenschoten nvanbenschoten commented Apr 26, 2021

Informs #62700.

This commit bumps the default value for the kv.range_merge.queue_interval cluster setting from 1s to 5s. This setting serves as a per-store rate limit on the frequency at which range merges will be initiated. We've seen in a few issues, including #62700, that excessive range merge traffic can cause instability in a cluster. There's very little reason to be aggressive about range merging, as range merges are rarely needed with any urgency. However, there are good reasons to be conservative about them.

This change can also be justified as a (late) reaction to the increased max range size from 64MB to 512MB. A range merge may need to rebalance replicas in a range, so its cost can be a function of the sizes of ranges. This means that if range merges are now more expensive, we should be running them less frequently.

Informs cockroachdb#62700.

This commit bumps the default value for the `kv.range_merge.queue_interval`
cluster setting from 1s to 5s. This setting serves as a per-store rate limit on
the number of range merges that will be initiated. We've seen in a few issues
like cockroachdb#62700 that excessive range merge traffic can cause instability in a
cluster. There's very little reason to be aggressive about range merging, as
range merges are rarely needed with any urgency. However, there are good reasons
to be conservative about them.

This change can also be justified as a (late) reaction to the increased max
range size from 64MB to 512MB. A range merge may need to rebalance replicas in a
range, so its cost can be a function of the sizes of ranges. This means that if
range merges are now more expensive, we should be running them less frequently.
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This change is Reviewable

@nvanbenschoten
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bors r+

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craig bot commented Apr 30, 2021

Build succeeded:

@craig craig bot merged commit eaeaa7f into cockroachdb:master Apr 30, 2021
@nvanbenschoten nvanbenschoten deleted the nvanbenschoten/mergeDelay branch May 1, 2021 16:00
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3 participants