ring: add GetWithOptions method to adjust per call behavior #620
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This change adds a new method that accepts 0 or more `Option` instances that modify the behavior of the call. These options can (currently) be used to adjust the replication factor for a particular key or use buffers to avoid excessive allocation. Part of grafana/mimir#9944
ring/ring.go
Outdated
| func collectOptions(opts ...Option) *Options { | ||
| final := &Options{} | ||
| for _, opt := range opts { | ||
| opt(final) | ||
| } | ||
| return final | ||
| } |
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we had some benchmarks about not allocating on Get. The plan is not to use this GetWithOptions on the hot path, right? (but also maybe just returning an Options might do away with the allocation)
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I tried returning Options but it still (presumably) escaped to the heap. I refactored this a bit locally to avoid the allocation for Get() but it's less clean than this.
The way GetWithOptions is called in Mimir - it's called to filter blocks in the store-gateway sharding strategy: done in the background, called by queriers to find a store-gateway replication set: not sure if this is a "hot path". It's called once per block that's part of a query.
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aha, i guess it's on the hot path, but it's called much less often than "once per sample" on the write path. We can probably pay the cost without noticing it
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I'll see if I can improve this since it'd be nice to clean it up:
ring/ring.go:46:18: leaking param: bufDescs
ring/ring.go:46:43: leaking param: bufHosts
ring/ring.go:46:53: leaking param: bufZones
ring/ring.go:47:14: opts does not escape
ring/ring.go:47:9: func literal escapes to heap
ring/ring.go:55:14: opts does not escape
ring/ring.go:55:9: func literal escapes to heap
ring/ring.go:60:21: opts does not escape
ring/ring.go:61:11: &Options{} escapes to heap
What this PR does:
This change adds a new method that accepts 0 or more
Optioninstances that modify the behavior of the call. These options can (currently) be used to adjust the replication factor for a particular key or use buffers to avoid excessive allocation.Which issue(s) this PR fixes:
Part of grafana/mimir#9944
Checklist
CHANGELOG.mdupdated - the order of entries should be[CHANGE],[FEATURE],[ENHANCEMENT],[BUGFIX]