Misthios/grafana-zabbix
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

docs: Functions usage with Direct DB Connection

Browse Source
This commit is contained in:
Alexander Zobnin
2017-07-26 13:57:24 +03:00
parent e5ebdb2691
commit f211fdf5d4
1 changed files with 9 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
docs/sources/reference/direct-db-connection.md
View File

@@ -49,3 +49,12 @@ SELECT itemid AS metric, clock AS time_sec, {aggFunc}({valueColumn}) as value
As you can see, plugin uses aggregation by given time interval. This interval is provided by Grafana and depends on the As you can see, plugin uses aggregation by given time interval. This interval is provided by Grafana and depends on the
panel with in pixels. Thus, Grafana always gets data in necessary resolution. panel with in pixels. Thus, Grafana always gets data in necessary resolution.
## Functions usage with Direct DB Connection
There's only one function affecting backend. This function is `consolidateBy`. It changes what data comes from
the backend. Other functions still work on the client side and transform data come from the backend. So you should
clearly understand that you work with pre-aggregated data (by AVG, MAX, MIN, etc). For example, you want to group
values by 1 hour interval and `max` function. But if you just apply `groupBy(10m, max)` function, result will be wrong,
because you transform data aggregated by default `AVG` function. You should use `consolidateBy(max)` coupled with
`groupBy(10m, max)` in order to get precise result.