Function BenchmarkFastOrRunContainers

benchmark_test.go:1366–1420

BenchmarkFastOrRunContainers measures FastOr over inputs containing runContainer16 slots (the shape AddRange and RunOptimize produce), exercising the runContainer16 -> bitmapContainer pre-promotion in (*Bitmap).lazyOR. See issue #81. go test -bench BenchmarkFastOrRunContainers -benchmem -run - -ben

(b *testing.B)

//
// go test -bench BenchmarkFastOrRunContainers -benchmem -run - -benchtime=2s
func BenchmarkFastOrRunContainers(b *testing.B) {
	const numBitmaps = 15
	const blocksPerBitmap = 40 // each block = 1<<16 bits
	const runsPerBlock = 8

	rng := rand.New(rand.NewSource(42))
	bms := make([]*Bitmap, numBitmaps)
	for i := 0; i < numBitmaps; i++ {
		bm := NewBitmap()
		for blk := 0; blk < blocksPerBitmap; blk++ {
			base := uint64(blk) << 16
			offset := uint64(rng.Intn(1000))
			for r := 0; r < runsPerBlock; r++ {
				start := base + offset + uint64(r)*8000 + uint64(i*37)
				end := start + 6000
				blockEnd := base + (1 << 16)
				if end > blockEnd {
					end = blockEnd
				}
				if start >= blockEnd {
					break
				}
				bm.AddRange(start, end)
			}
		}
		bm.RunOptimize()
		bms[i] = bm
	}

	// Sanity-check: the workload must actually contain runContainer16,
	// otherwise the bench wouldn't exercise the patched path.
	hasRunContainer := false
	for _, bm := range bms {
		for _, c := range bm.highlowcontainer.containers {
			if _, ok := c.(*runContainer16); ok {
				hasRunContainer = true
				break
			}
		}
		if hasRunContainer {
			break
		}
	}
	if !hasRunContainer {
		b.Fatalf("workload did not produce any runContainer16; bench would not exercise the patched path")
	}

	b.ResetTimer()
	for n := 0; n < b.N; n++ {
		res := FastOr(bms...)
		if res.GetCardinality() == 0 {
			b.Fatal("unexpected empty result")
		}
	}
}