Add additional PromQL operators to synthetic load

[kushalShukla-web]

This PR enhances the synthetic load generation by incorporating additional PromQL operators in the 6_loadgen.yaml file:

• Added binary arithmetic operators (joins) to cover more complex query types.
• Included logical operators (and, or, unless) for better query testing coverage.
• Added topk function to test query performance with ranked results.

[kushalShukla-web]

Solves #705

[kushalShukla-web]

Hi, I commented on a few, but they are all likely problemmatic. I recommend you change tack to use metrics exposed by the fake webserver, since there are a lot of them and prombench can control them.

Actually i have tested this on one of the Pull Request where the prombench was running.

[bboreham]

Ok but my recommendation remains the same.

[bboreham]

I have replaced some of the existing metrics with new ones from PromBench, such as:

How many of those did you count?

[kushalShukla-web]

Hi @bboreham all the queries having value above 2000 , and codelabz metric is having 52000 different variations .

[bboreham]

I trimmed down the newly-added queries a bit:

• Slow down arithmetic_operation and logic_operator.
• Took out a few queries to avoid overloading the server.
• Stop querying _bucket series directly; those should be used by histogram_quantile or similar.
• Use more realistic k parameters to topk.

I also trimmed down some pre-existing queries for balance, to retain about the same overall load on the server as before.