3 ms·

If you are a fan of Gil's work, and the entire phenomenon of coordinated omission, this is right up your alley. https://www.scylladb.com/2021/04/22/on-coordina

If you are a fan of Gil's work, and the entire phenomenon of coordinated omission, this is right up your alley. https://www.scylladb.com/2021/04/22/on-coordinated-omission/ https://www.scylladb.com/2021/04/22/on-coordinated-omission/ Also, yes, P99 CONF (https://p99conf.io https://p99conf.io) is sponsored by ScyllaDB, but we're very glad to have speakers from other NoSQL vendors like Couchbase and Redis, as well as folks from across the industry — streaming systems like Kafka (Confluent), Pulsar (Splunk), Redpanda (Vectorized). Plus storage systems like Ceph, Crimson (both Redhat) and Lightbits LightOS. For the P99 CONF I recently conducted a quick poll of what people consider "acceptable" P99s. For some people it's <100 µseconds. For others, its <1 ms. And for some it goes all the way up to 1 second. But "acceptable" is use-case specific. An in-memory database or cache will have a very different expectation than someone writing data to SSD or even today, HDD. 33.3% of respondents expected <1 ms. 37.5% were okay with 1-<10 ms 20.8% were okay with 10-<100 ms Only 8.3% were okay with 100ms - 1 second (The <100 µsec was a "write-in" comment. But I am sure if I had included it, and we had a broader sample poll, you'd see it as a prevalent and vocal minority.) https://twitter.com/P99CONF/status/1440197863875629057?s=20 https://twitter.com/P99CONF/status/1440197863875629057?s=20

throwdbaaway 5y ago
The result of your poll is exactly my fear -- p99 seems to be at the peak of the hype cycle. I am totally a fan of Gil's work, but I think he over-dramatized the impact of tail latency, with the rather extreme example of "If a typical user session involves 5 pages loads, averaging 40 resources per page" from his talk. Regarding coordinated omission, I am not totally convinced that an open-model system is what happens in production, and I am actually fine with a closed-model system when running benchmark, as long as p100 is acceptable. My goal is to achieve the maximum TPS without stalling, and I don't really care that much whether p99 is 10ms or 100ms.

throwdbaaway 5y ago

The result of your poll is exactly my fear -- p99 seems to be at the peak of the hype cycle. I am totally a fan of Gil's work, but I think he over-dramatized the impact of tail latency, with the rather extreme example of "If a typical user session involves 5 pages loads, averaging 40 resources per page" from his talk. Regarding coordinated omission, I am not totally convinced that an open-model system is what happens in production, and I am actually fine with a closed-model system when running benchmark, as long as p100 is acceptable. My goal is to achieve the maximum TPS without stalling, and I don't really care that much whether p99 is 10ms or 100ms.