services/horizon/internal: Add limit on number of horizon requests in flight #5244
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services/horizon/internal/flags.go
Outdated
| @@ -68,7 +68,8 @@ const ( | |||
| // StellarTestnet is a constant representing the Stellar test network | |||
| StellarTestnet = "testnet" | |||
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| defaultMaxHTTPRequestSize = uint(200 * 1024) | |||
| defaultMaxConcurrentRequests = 1000 | |||
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Do you know what the number was at when we OOMed?
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it was a little over 3000 when the instance OOMed as can be observed in this graph
mollykarcher
approved these changes
Mar 13, 2024
sreuland
reviewed
Mar 13, 2024
| ConfigKey: &config.MaxConcurrentRequests, | ||
| OptType: types.Uint, | ||
| FlagDefault: defaultMaxConcurrentRequests, | ||
| Usage: "sets the limit on the maximum number of concurrent http requests, default is 1000, to disable the limit set to 0. " + |
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just for non-breaking backwards compatibility, should the default be 0 ?
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I think the default limit is really high that it should never be observed during normal usage. so, although it is technically a breaking change, I think it would be better to have this default so we can protect against OOMs by default
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looks like we get ~2k/rps on the whole cluster, so yeah 1k/machine should be way more than plenty
sreuland
approved these changes
Mar 13, 2024
Shaptic
approved these changes
Mar 13, 2024
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PR Checklist
PR Structure
otherwise).
services/friendbot, orallordocif the changes are broad or impact manypackages.
Thoroughness
.mdfiles, etc... affected by this change). Take a look in the
docsfolder for a given service,like this one.
Release planning
needed with deprecations, added features, breaking changes, and DB schema changes.
semver, or if it's mainly a patch change. The PR is targeted at the next
release branch if it's not a patch change.
What
Add limit on number of horizon requests in flight.
Why
We observed a case where a staging horizon node received too many requests which caused it to OOM. See https://stellarfoundation.slack.com/archives/C02B04RMK/p1710326856362359?thread_ts=1710235095.516249&cid=C02B04RMK for more details.
Known limitations
[N/A]