Add limit and line_returned in the query log.

[cyriltovena]

This can be useful to investigate how many wasted queries have been made by the frontend.

Signed-off-by: Cyril Tovena [email protected]

[codecov-io]

Codecov Report

Merging #3423 (845751c) into master (20ef66d) will decrease coverage by 0.01%.
The diff coverage is 91.30%.

@@            Coverage Diff             @@
##           master    #3423      +/-   ##
==========================================
- Coverage   63.01%   63.00%   -0.02%     
==========================================
  Files         205      205              
  Lines       17499    17509      +10     
==========================================
+ Hits        11027    11031       +4     
- Misses       5481     5491      +10     
+ Partials      991      987       -4     

Impacted Files	Coverage Δ
pkg/querier/queryrange/stats.go	83.01% <77.77%> (ø)
pkg/logql/engine.go	87.03% <100.00%> (+0.87%)	⬆️
pkg/logql/metrics.go	91.83% <100.00%> (+1.36%)	⬆️
pkg/promtail/positions/positions.go	46.80% <0.00%> (-11.71%)	⬇️
pkg/querier/queryrange/downstreamer.go	95.29% <0.00%> (-2.36%)	⬇️
pkg/promtail/targets/file/tailer.go	78.57% <0.00%> (+5.35%)	⬆️