Hello Will Berkeley, Mike Percy, I'd like you to do a code review. Please visit
http://gerrit.cloudera.org:8080/9179 to review the following change. Change subject: metrics: fast-path PB/JSON dump for empty histograms ...................................................................... metrics: fast-path PB/JSON dump for empty histograms It turns out that a decent percentage of our histograms are empty in real life use cases. For example, some tablets might be cold enough that they have never had any action since the tserver started. Other histograms might correspond to features which aren't being used in a particular workload (eg commit-wait counters). For example, in a test cluster running a cycling YCSB workload, about 20% of histograms are empty. In another test cluster running more of an analytic workload with a lot of very cold tablets, 81% of histograms were empty. We can fast-path various calculations on these histograms to just return 0 for a simple speedup on the /metricsjson endpoint. Change-Id: I0732e8299e2f27c7c6021ec70740984ab46a69c0 --- M src/kudu/util/metrics.cc M src/kudu/util/metrics.h 2 files changed, 37 insertions(+), 21 deletions(-) git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/79/9179/1 -- To view, visit http://gerrit.cloudera.org:8080/9179 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: newchange Gerrit-Change-Id: I0732e8299e2f27c7c6021ec70740984ab46a69c0 Gerrit-Change-Number: 9179 Gerrit-PatchSet: 1 Gerrit-Owner: Todd Lipcon <t...@apache.org> Gerrit-Reviewer: Mike Percy <mpe...@apache.org> Gerrit-Reviewer: Will Berkeley <wdberke...@gmail.com>