Pulse Documentation

name: op-agg-distinct-count
description: Count distinct non-null values across the input set.
kind: operator
category: AGG
operator: AGG_DISTINCT_COUNT
type: reference
applies_to: process, compose, predict
examples_tags: [cardinality-analysis, streaming-friendly]

Use when

Number of different values a field takes, over all rows or per group.

Questions it answers:

• How many different customers ordered this month?
• Does the respondent ID appear once per row, or are there duplicates?

Use something else:

• AGG_COUNT when you want how many rows there are, not how many different values.
• GROUP_CATEGORY when you want how many rows hold each value: group by the field, then count.

Params

None.

Inputs

Output

Scalar int64 — number of distinct non-null values. Per-group when wired under a grouper.

Components

Universal floor {n, n_null} plus operator-specific:

• Mergeability: Partial — distinct-set merge
• Streaming: per-chunk; merge unions per-chunk seen-sets

Gotchas

• High-cardinality fields → memory growth proportional to distinct values.
• Counts non-null only; nulls collapsed.
• set_* rejected at build time with PROCESSING_CONFIG.

See

• pulse_examples_search tags=[cardinality-analysis]
• Skills: aggregation-design, response-components