discord9 74deaf2e90 feat(promql): scan every metric a nameless selector matches (#10106) ...

feat(promql): answer a selector that names no metric by scanning each it matches

A PromQL selector with no metric name used to be a planning error. It is now
answered by enumerating the schema's logical metric tables, compiling one source
per match under one union input, so the fused producer still reads what the
compiler prepared: one compiler source per selector, not per metric.

Each source names the metric it reads, in its own tag list. That is what makes
this work at all: two metrics whose ordinary labels are equal are told apart by
name alone, and nothing else in the response can carry that identity. Where the
name survives is then a property of the operator rather than of discovery, so the
same tag walk decides it for every query - the walk now drops the name where the
runtime drops it, for a range function, a math or histogram kernel, a
parameterized map, a timestamp selection and an arithmetic or `bool` binary
operation, and keeps it for a filtering comparison. `sum by (__name__)` keeps it
by grouping.

The walk already had that same divergence without discovery: no metric-engine
logical table carries `__name__` as a column, so a named selector's tags did not
include it and the walk's answer was incomplete in the same way. Discovery only
made the column real.

The metric engine checks that two logical metrics agree on their time column's
unit, not on its name, so each source's bound is built from the column that
source actually carries, and a source without one is refused rather than read
unbounded.

Two upstream contracts assumed one table per selector and are widened rather than
bypassed: the time-bound pushdown walks a union's sources, and a fused node may
declare `__name__` when its inputs each name their own metric instead of binding
one name itself.

Declining still means the query goes to the existing planner; shapes this route
cannot derive keep the plan they had.

Signed-off-by: discord9 <discord9@163.com>

2026-11-04 12:11:49 +08:00

..

src

feat(promql): scan every metric a nameless selector matches (#10106)

2026-11-04 12:11:49 +08:00

Cargo.toml

chore(deps): replace cargo-udeps with cargo-shear for unused dependency checks (#9294)

2026-09-23 04:56:44 +00:00