108 lines
4.9 KiB
Markdown
108 lines
4.9 KiB
Markdown
# TopK Processor Plugin
|
|
|
|
The TopK processor plugin is a filter designed to get the top series over a period of time. It can be tweaked to do its top k computation over a period of time, so spikes can be smoothed out.
|
|
|
|
This processor goes through these steps when processing a batch of metrics:
|
|
|
|
1. Groups metrics in buckets using their tags and name as key
|
|
2. Aggregates each of the selected fields for each bucket by the selected aggregation function (sum, mean, etc)
|
|
3. Orders the buckets by one of the generated aggregations, returns all metrics in the top `K` buckets, then reorders the buckets by the next of the generated aggregations, returns all metrics in the top `K` buckets, etc, etc, etc, until it runs out of fields.
|
|
|
|
The plugin makes sure not to duplicate metrics
|
|
|
|
Note that depending on the amount of metrics on each computed bucket, more than `K` metrics may be returned
|
|
|
|
### Configuration:
|
|
|
|
```toml
|
|
[[processors.topk]]
|
|
## How many seconds between aggregations
|
|
# period = 10
|
|
|
|
## How many top metrics to return
|
|
# k = 10
|
|
|
|
## Over which tags should the aggregation be done. Globs can be specified, in
|
|
## which case any tag matching the glob will aggregated over. If set to an
|
|
## empty list is no aggregation over tags is done
|
|
# group_by = ['*']
|
|
|
|
## Over which fields are the top k are calculated
|
|
# fields = ["value"]
|
|
|
|
## What aggregation to use. Options: sum, mean, min, max
|
|
# aggregation = "mean"
|
|
|
|
## Instead of the top k largest metrics, return the bottom k lowest metrics
|
|
# bottomk = false
|
|
|
|
## The plugin assigns each metric a GroupBy tag generated from its name and
|
|
## tags. If this setting is different than "" the plugin will add a
|
|
## tag (which name will be the value of this setting) to each metric with
|
|
## the value of the calculated GroupBy tag. Useful for debugging
|
|
# add_groupby_tag = ""
|
|
|
|
## These settings provide a way to know the position of each metric in
|
|
## the top k. The 'add_rank_field' setting allows to specify for which
|
|
## fields the position is required. If the list is non empty, then a field
|
|
## will be added to each and every metric for each string present in this
|
|
## setting. This field will contain the ranking of the group that
|
|
## the metric belonged to when aggregated over that field.
|
|
## The name of the field will be set to the name of the aggregation field,
|
|
## suffixed with the string '_topk_rank'
|
|
# add_rank_fields = []
|
|
|
|
## These settings provide a way to know what values the plugin is generating
|
|
## when aggregating metrics. The 'add_aggregate_field' setting allows to
|
|
## specify for which fields the final aggregation value is required. If the
|
|
## list is non empty, then a field will be added to each every metric for
|
|
## each field present in this setting. This field will contain
|
|
## the computed aggregation for the group that the metric belonged to when
|
|
## aggregated over that field.
|
|
## The name of the field will be set to the name of the aggregation field,
|
|
## suffixed with the string '_topk_aggregate'
|
|
# add_aggregate_fields = []
|
|
```
|
|
|
|
### Tags:
|
|
|
|
This processor does not add tags by default. But the setting `add_groupby_tag` will add a tag if set to anything other than ""
|
|
|
|
|
|
### Fields:
|
|
|
|
This processor does not add fields by default. But the settings `add_rank_fields` and `add_aggregation_fields` will add one or several fields if set to anything other than ""
|
|
|
|
|
|
### Example
|
|
**Config**
|
|
```toml
|
|
[[processors.topk]]
|
|
period = 20
|
|
k = 3
|
|
group_by = ["pid"]
|
|
fields = ["cpu_usage"]
|
|
```
|
|
|
|
**Output difference with topk**
|
|
```diff
|
|
< procstat,pid=2088,process_name=Xorg cpu_usage=7.296576662282613 1546473820000000000
|
|
< procstat,pid=2780,process_name=ibus-engine-simple cpu_usage=0 1546473820000000000
|
|
< procstat,pid=2554,process_name=gsd-sound cpu_usage=0 1546473820000000000
|
|
< procstat,pid=3484,process_name=chrome cpu_usage=4.274300361942799 1546473820000000000
|
|
< procstat,pid=2467,process_name=gnome-shell-calendar-server cpu_usage=0 1546473820000000000
|
|
< procstat,pid=2525,process_name=gvfs-goa-volume-monitor cpu_usage=0 1546473820000000000
|
|
< procstat,pid=2888,process_name=gnome-terminal-server cpu_usage=1.0224991500287577 1546473820000000000
|
|
< procstat,pid=2454,process_name=ibus-x11 cpu_usage=0 1546473820000000000
|
|
< procstat,pid=2564,process_name=gsd-xsettings cpu_usage=0 1546473820000000000
|
|
< procstat,pid=12184,process_name=docker cpu_usage=0 1546473820000000000
|
|
< procstat,pid=2432,process_name=pulseaudio cpu_usage=9.892858669796528 1546473820000000000
|
|
---
|
|
> procstat,pid=2432,process_name=pulseaudio cpu_usage=11.486933087507786 1546474120000000000
|
|
> procstat,pid=2432,process_name=pulseaudio cpu_usage=10.056503212060552 1546474130000000000
|
|
> procstat,pid=23620,process_name=chrome cpu_usage=2.098690278123081 1546474120000000000
|
|
> procstat,pid=23620,process_name=chrome cpu_usage=17.52514619948493 1546474130000000000
|
|
> procstat,pid=2088,process_name=Xorg cpu_usage=1.6016732172309973 1546474120000000000
|
|
> procstat,pid=2088,process_name=Xorg cpu_usage=8.481040931533833 1546474130000000000
|
|
```
|