Add full MetricsQL syntax support with some query improvements

[denisgolius]

Hi there!
Some times ago Grafana has ignored improvement from @hagen1778 on this pr grafana/grafana#16694 and it will be a great new future in your product to add this for support.
VictoriaMetrics has many other improvements with extended query syntax named MetricsQL - especial with using WITH templates.

[sunface]

Thanks for your suggestion.

Currently I'm updating datav to keep up with Grafana 8.1, after this, I will seriously to adopt your suggestion.

[denisgolius]

hey @sunface
Do you have any ETA for the next release date?

[sunface]

hi @denisgolius , first release will be launched at about early July

[sunface]

hey @denisgolius , I made a brief summary about the changes in next release, :

I have remove all the code came from Grafana and built a newly version from scratch, there are few reasons:

1. Grafana have many historical issues in it's codebase, like: mix React and angular, external plugins system, complex codebase, deeply integrated with redux etc. In a word: grafana's codebase is very very complex, and very hard for deeply secondary development.
2. Grafana is designed for general visualization purpose, so it's not very fitable for Observability and APM cases, as a comparison, although Datav can be also used for general purpose, but it's main purpose is Observability and APM, so many design features are different from Grafana.
3. We need more beautiful UI and LargeScreen supported

Back to this issue, we will support prometheus and jaeger natively, VM is also a great option, so here is a question:

If Datav wants to support VM natively , what's the main difference between VM and prometheus when implement the panel plugin. From my perspective, VM seems fully support PromQL grammar.

[hagen1778]

If Datav wants to support VM natively , what's the main difference between VM and prometheus when implement the panel plugin. From my perspective, VM seems fully support PromQL grammar.

It does. The main differences between Prom and VM in terms of plugin implementation are the following:

1. VM supports chars in label names which aren't supported by Prometheus. See the following issue Prometheus: label-names with dots rejected in Grafana v8.3.0 grafana/grafana#42615
2. Additionally to PromQL, VictoriaMetrics supports a wide range of extra functions in MetricsQL
3. WITH templates support brings new experience in query language by allowing to define functions or time series filters in advance. But that's optional.

[sunface]

All right, I will dig into it ,thanks :)

[denisgolius]

All right, I will dig into it ,thanks :)

Hey!
Any updates for play/etc? I see the network error on play

[sunface]

Hi @denisgolius, play.datav.io should be accessible now, and the new website and docs will release in several days later :)

[sunface]

Hi all, I'm going to add VM as a native datasource plugin to Datav.

Please feel free to leave message here if there are any problems :)

[sunface]

Hi all, I have added a basic VM plugin in datav, you can have a try now :)

And datav support datasource docs now, it can help users quickly find the query grammar they want, could you please add some docs to VM plugin in Datav :D

The image below is the Prometheus datasource docs which I copy from prometheus website: