Method emitRightOuterResults

packages/db-ivm/src/operators/join.ts:195–247

(
    deltaA: Index<K, V1>,
    deltaB: Index<K, V2>,
    results: MultiSet<any>,
  )

  }

  private emitRightOuterResults(
    deltaA: Index<K, V1>,
    deltaB: Index<K, V2>,
    results: MultiSet<any>,
  ): void {
    // Emit unmatched right rows from deltaB
    if (deltaB.size > 0) {
      for (const [key, valueIterator] of deltaB.entriesIterators()) {
        const currentMultiplicityA =
          this.#indexA.getConsolidatedMultiplicity(key)
        const deltaMultiplicityA = deltaA.getConsolidatedMultiplicity(key)
        const finalMultiplicityA = currentMultiplicityA + deltaMultiplicityA

        if (finalMultiplicityA === 0) {
          for (const [value, multiplicity] of valueIterator) {
            if (multiplicity !== 0) {
              results.add([key, [null, value]], multiplicity)
            }
          }
        }
      }
    }

    // Handle presence transitions from left side changes
    if (deltaA.size > 0) {
      for (const key of deltaA.getPresenceKeys()) {
        const before = this.#indexA.getConsolidatedMultiplicity(key)
        const deltaMult = deltaA.getConsolidatedMultiplicity(key)
        if (deltaMult === 0) continue
        const after = before + deltaMult

        // Skip transition handling if presence doesn't flip (both zero or both non-zero)
        // Note: Index updates happen later regardless - we're only skipping null-extension emissions here
        if ((before === 0) === (after === 0)) continue

        // Determine the type of transition:
        // - 0 → non-zero: Left becomes non-empty, right rows transition from unmatched to matched
        //   → RETRACT previously emitted null-extended rows (emit with negative multiplicity)
        // - non-zero → 0: Left becomes empty, right rows transition from matched to unmatched
        //   → EMIT new null-extended rows (emit with positive multiplicity)
        const transitioningToMatched = before === 0

        for (const [value, multiplicity] of this.#indexB.getIterator(key)) {
          if (multiplicity !== 0) {
            results.add(
              [key, [null, value]],
              transitioningToMatched ? -multiplicity : +multiplicity,
            )
          }
        }
      }
    }
  }
}

/**