count(count by (a) (hello_info))
First you want an aggregator with a result per value of a, and then you can count them.
count(count by (a) (hello_info))
First you want an aggregator with a result per value of a, and then you can count them.
Other example: If you want to count the number of apps deployed in a kubernetes cluster based on different values of a label( ex:app):
count(count(kube_pod_labels{app=~".*"}) by (app))
promql - Prometheus count specific value occurrences - Stack Overflow
How to calculate the number of requests in a time period using PromQL
count - PromQL: Counting samples of a time series - Stack Overflow
Calculating the Avg with Gaps in Data
If the metric can have either 0 or 1 values, then the sum_over_time(metric[d]) calculates the number of 1 values on the specified lookbehind window d. For example, sum_over_time(up[1h]) returns the number of up samples with 1 value during the last hour. The number of 0 values then can be calculates as count_over_time(up[1h]) - sum_over_time(up[1h]).
If the metric can have other values than 0 and 1, then Prometheus doesn't provide functions for counting the number of samples with a particular value yet :(
There is another Prometheus-like system, which allows counting the number of raw samples with the given value on the specified lookback window - VictoriaMetrics (I'm the core developer of this system). It provides count_eq_over_time function for this task. For example, the following MetricsQL query returns the number of samples for some_metric time series with the value 42 over the last hour:
count_eq_over_time(some_metric[1h], 42)
It looks like you are using Grafana as a visualisation tool. There is the possibility to add an expression to a panel. This would result in a second Metric (in my example below B). This is located in the Query Tab on Edit. You ma need a newer Grafana version (AFAIK it was introduced with v6.x)
I came up with two solutions to this, choose whichever suits you best. For the purpose of simplifying things, let's assume your Prometheus scrape at 15 seconds interval and the error state lasted for 1 minute. Then, the gathered data would look like this:
state_metric 0 @t
state_metric 1 @t+15s
state_metric 1 @t+30s
state_metric 1 @t+45s
state_metric 1 @t+60s
state_metric 0 @t+75s
With changes()
This shows how many state changes were there. It would return 1 for the exemplary data above and it only gives adequate results if the gauge in question can hold exactly two possible values (for example 1 and 0).
changes(state_metric[1d])/2
changes() shows how many times the metric value has changed during the interval, while division by 2 is to compensate the state change back to normal. This is the downside of this method, which makes it only usable for detecting quick changes of state. But you probably have an alert when the error state hangs for some time, so I think this shouldn't be really a problem.
With a subquery
This is more precisely what you asked:
the number of times when metrics were 1
But there is a catch: with the exemplary data above, the query below will return you 4:
sum_over_time(count(state_metric == 1)[1d:])
[1d:] means repeat that instant query (count(state_metric == 1)) for each data point during last 1d. This is precisely the number of times when state_metric was 1 and it can be useful, for example, to calculate the downtime (just multiply by the scrape interval). Unlike the first method, this can work with any number of possible states, since you can define what you need in the condition.
I need to calculate the number of times when metrics were 1 by range variable provided in Grafana.
The following query should return the number of times the time series matching aqa_device_health_checker{env="dev", device="FOO"} series selector had value 1 on the selected time range in Grafana (aka $__range):
last_over_time(
sum_over_time(
aqa_device_health_checker{env="dev", device="FOO"}[$__range] offset -$__range
)[$__range:$__range]
)
The query returns individual results per each matching time series. If you need summary result over all the matching time series, then just wrap the query above into sum():
sum(
last_over_time(
sum_over_time(
aqa_device_health_checker{env="dev", device="FOO"}[$__range] offset -$__range
)[$__range:$__range]
)
)
Note that both queries above allow calculating the number of times the metric had 1 value if the metric could have either 0 or 1 values. If the metric can have other values, then these queries won't work as expected. Unfortunately, Prometheus doesn't provide easy to use functionality for counting the number of raw samples with some pre-defined value N. If you know beforehand the interval between samples (aka scrape_interval), then the following hack based on Prometheus subquery can be used:
count_over_time(
(
last_over_time(m[scrape_interval]) == N
)[$__range:scrape_interval]
)
This query counts the number of raw samples with values equal to N on the time range $__range selected in Grafana.
If the interval between samples isn't known beforehand, then it is impossible to calculate the number of samples with a particular value in Prometheus. If you still need this functionality, then take a look at count_eq_over_time() function provided by VictoriaMetrics - this is Prometheus-like monitoring solution I work on. For example, the following query returns the exact number of samples with the value 10 over the last hour for time series m:
count_eq_over_time(m[1h], 10)