Add a lookaside cache in distributed.go for small CAS values #6203
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jdhollen
reviewed
Mar 21, 2024
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| const ( | ||
| // Each hinted handoff is a digest (~64 bytes), prefix, and peer | ||
| // (40 bytes). So keeping around 100000 of these means an extra 10MB | ||
| // per peer. | ||
| maxHintedHandoffsPerPeer = 100000 | ||
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| // Max size of an entry that can be cached in the lookaside cache. | ||
| maxLookasideEntrySize = 100_000 |
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might be worth adding a flag for this for if we're flushing it way too fast
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Done. (and defaulted to 10K)
| for _, r := range stillMissing { | ||
| buf, ok := results[r.GetDigest()] | ||
| if ok { | ||
| c.addLookasideEntry(r, buf) |
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missing a max size check here, i think?
bduffany
reviewed
Mar 21, 2024
Comment on lines
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| c.lookasideMu.RLock() | ||
| entry, ok := c.lookaside.Get(k) | ||
| c.lookasideMu.RUnlock() |
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Get does a mutate of the LRU so this might need to be an exclusive lock? (maybe worth also adding a concurrency test since the race detector didn't trigger)
vadimberezniker
approved these changes
Mar 21, 2024
jdhollen
approved these changes
Mar 21, 2024
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<<<All credit to @vadimberezniker for originally suggesting this and @jdhollen for instrumenting things to the point where we think it's a good idea>>>
This CL introduces a configurable size LRU in distributed.go to cache response data at read time when it's read from any remote node. If that same data is re-requested, it can be served directly from the read-through cache and skip the work of hitting a remote peer.
Doesn't cache values over 100K, and doesn't hold on to any value longer than 15 minutes (configurable).