Module matching_filters 

Propagation of label matchers between the operands of a PromQL binary expression.

Constants

LABEL_PRESERVING_RANGE_FUNCTIONS 🔒

Rollup functions emitting at most one output series per input series, carrying the labels of the matrix selector they wrap. absent_over_time is excluded: it synthesizes a series from the matchers when its input has none.

MATCH_ALL_REGEX 🔒

super::PromPlanner::matchers_to_expr emits no filter for this, so copying it would only force a re-plan.

Functions

has_unique_aggregate_output 🔒

Whether a partitioning aggregate proves the operand emits at most one series per combination of its output labels; ranking narrows its input, so it inherits the proof. Uniqueness per match signature additionally requires every output label to be a matching label, which the caller checks.

matches_every_value 🔒

partitions_by_grouping_labels 🔒

Aggregations partitioning their input by the grouping labels, so that dropping input series by a grouping label drops exactly the matching output series and leaves the remaining aggregated values untouched.

preserves_filter 🔒

Whether adding a matcher on label to the scan selector_matchers finds leaves the operand’s output equal to the subset of its unfiltered output that satisfies the matcher. A filter may cross an aggregate only when it removes whole groups: in particular, a label retained by topk is not necessarily one of its partitioning labels.

propagate 🔒

Copies label matchers from one operand of binary to the other, so both scans discard non-joining series instead of the join.

ranks_by_grouping_labels 🔒

Ranking operators supported by the planner; limitk and limit_ratio are not implemented.

selector_matchers 🔒

Finds the scanned selector through label-preserving operations. Aggregate partitioning is checked separately for each propagated label.

single_matrix_argument 🔒

try_propagate 🔒

Err carries why the rewrite does not apply, for propagate to log.

vector_operand_is_lhs 🔒