We've been running the partial loader on googlesource.com for about 10
days now. Compared to the full loader, it is between 10x and 30x faster.
Latency distribution of full reloads:
- p50: 23s
- p90: 57s
- p95: 61s
- p99.9 65s
Latency distribution of partial reloads:
- p50: 0.744s
- p90: 2.8s
- p95: 3.4s
- p99.9 4.0s
We have Gerrit instances with a large number of accounts (for example,
one particular instance has 200.000 accounts). These are included in the
fleet-wide metrics. The latency distribution for parallel reads does
include loading a previously cached state from disk into memory, which
is most likely a driver for the long tail. However, open-source
installations would see this problem only upon startup of the Gerrit
instance, so it's less of a concern. Generally, we can expect numbers on
open-source instances to be even better if all Git data is on local disk
(SSD).
Change-Id: Ia92250c32482d94643cc9aae6264b16571e65c79
c486edf897