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author | Peter Leitzen <pleitzen@gitlab.com> | 2019-04-04 18:38:37 +0300 |
---|---|---|
committer | James Lopez <james@gitlab.com> | 2019-04-04 18:38:37 +0300 |
commit | 552d38861ad77bf6a64b1e61a91e36fcd26d057c (patch) | |
tree | 4983f872121384e08f5d899367b1d32e84cbcec1 /lib/gitlab | |
parent | c7f918aa691b1b9c6ee6a489ae28a094eacff72c (diff) |
Automatically set Prometheus step interval
By computing the step interval passed to the query_range Prometheus API
call we improve the performance on the Prometheus server and GitLab by
reducing the amount of data points sent back and prevent Prometheus
from sending errors when requesting longer intervals.
Diffstat (limited to 'lib/gitlab')
-rw-r--r-- | lib/gitlab/prometheus_client.rb | 32 |
1 files changed, 27 insertions, 5 deletions
diff --git a/lib/gitlab/prometheus_client.rb b/lib/gitlab/prometheus_client.rb index 45828c77a33..b4de7cd2bce 100644 --- a/lib/gitlab/prometheus_client.rb +++ b/lib/gitlab/prometheus_client.rb @@ -6,6 +6,14 @@ module Gitlab Error = Class.new(StandardError) QueryError = Class.new(Gitlab::PrometheusClient::Error) + # Target number of data points for `query_range`. + # Please don't exceed the limit of 11000 data points + # See https://github.com/prometheus/prometheus/blob/91306bdf24f5395e2601773316945a478b4b263d/web/api/v1/api.go#L347 + QUERY_RANGE_DATA_POINTS = 600 + + # Minimal value of the `step` parameter for `query_range` in seconds. + QUERY_RANGE_MIN_STEP = 60 + attr_reader :rest_client, :headers def initialize(rest_client) @@ -23,12 +31,18 @@ module Gitlab end def query_range(query, start: 8.hours.ago, stop: Time.now) + start = start.to_f + stop = stop.to_f + step = self.class.compute_step(start, stop) + get_result('matrix') do - json_api_get('query_range', - query: query, - start: start.to_f, - end: stop.to_f, - step: 1.minute.to_i) + json_api_get( + 'query_range', + query: query, + start: start, + end: stop, + step: step + ) end end @@ -40,6 +54,14 @@ module Gitlab json_api_get('series', 'match': matches, start: start.to_f, end: stop.to_f) end + def self.compute_step(start, stop) + diff = stop - start + + step = (diff / QUERY_RANGE_DATA_POINTS).ceil + + [QUERY_RANGE_MIN_STEP, step].max + end + private def json_api_get(type, args = {}) |