Jorge Creixell e9e3d64b7c PromQL engine: Delay deletion of __name__ label to the end of the query evaluation (#14477) ... PromQL engine: Delay deletion of __name__ label to the end of the query evaluation - This change allows optionally preserving the `__name__` label via the `label_replace` and `label_join` functions, and helps prevent the dreaded "vector cannot contain metrics with the same labelset" error. - The implementation extends the `Series` and `Sample` structs with a boolean flag indicating whether the `__name__` label should be deleted at the end of the query evaluation. - The `label_replace` and `label_join` functions can still access the value of the `__name__` label, even if it has been previously marked for deletion. If `__name__` is used as target label, it won't be dropped at the end of the query evaluation. - Fixes https://github.com/prometheus/prometheus/issues/11397 - See https://github.com/jcreixell/prometheus/pull/2 for previous discussion, including the decision to create this PR and benchmark it before considering other alternatives (like refactoring `labels.Labels`). - See https://github.com/jcreixell/prometheus/pull/1 for an alternative implementation using a special label instead of boolean flags. - Note: a feature flag `promql-delayed-name-removal` has been added as it changes the behavior of some "weird" queries (see https://github.com/prometheus/prometheus/issues/11397#issuecomment-1451998792) Example (this always fails, as `__name__` is being dropped by `count_over_time`): ``` count_over_time({__name__!=""}[1m]) => Error executing query: vector cannot contain metrics with the same labelset ``` Before: ``` label_replace(count_over_time({__name__!=""}[1m]), "__name__", "count_$1", "__name__", "(.+)") => Error executing query: vector cannot contain metrics with the same labelset ``` After: ``` label_replace(count_over_time({__name__!=""}[1m]), "__name__", "count_$1", "__name__", "(.+)") => count_go_gc_cycles_automatic_gc_cycles_total{instance="localhost:9090", job="prometheus"} 1 count_go_gc_cycles_forced_gc_cycles_total{instance="localhost:9090", job="prometheus"} 1 ... ``` Signed-off-by: Jorge Creixell <jcreixell@gmail.com> --------- Signed-off-by: Jorge Creixell <jcreixell@gmail.com> Signed-off-by: Björn Rabenstein <github@rabenste.in>		2024-08-29 15:50:39 +02:00
..
testdata	End-to-end Query Log test (#6600)	2020-01-19 21:56:13 +00:00
main.go	PromQL engine: Delay deletion of __name__ label to the end of the query evaluation (#14477)	2024-08-29 15:50:39 +02:00
main_test.go	[PRW 2.0] Merging remote-write-2.0 feature branch to main (PRW 2.0 support + metadata in WAL) (#14395)	2024-07-04 14:29:20 -07:00
main_unix_test.go	tests: remove err from message when testify prints it already	2024-02-01 14:18:01 +00:00
query_log_test.go	Fix various linting errors	2024-06-24 16:11:53 -07:00