Benchmarks for ordered ints

[recoilme]

Hello

When i pass keys without zero terminated byte, i get this results

go test -bench=Ints
goos: darwin
goarch: amd64
pkg: github.com/arriqaaq/art
cpu: Intel(R) Core(TM) i7-8569U CPU @ 2.80GHz
BenchmarkIntsArtTreeInsert-8    15019468                92.99 ns/op           25 B/op          1 allocs/op
BenchmarkIntsArtTreeSearch-8    17869408                68.18 ns/op           15 B/op          0 allocs/op
PASS

But if i add zero byte i get much better results

BenchmarkIntsArtTreeInsert-8    20680020                60.41 ns/op           10 B/op          0 allocs/op
BenchmarkIntsArtTreeSearch-8    30512358                33.79 ns/op            0 B/op          0 allocs/op

May you please to explain your motivation for using zero terminated strings in this library? It's for simplifing redis protocol parsing in flashdb or for comatiblity with С?

I add benchmarks in PR, please take a look. More benchmarks here: https://github.com/recoilme/bench_sortedsets

[arriqaaq]

Thank you for your PR @recoilme, please give me sometime to respond back. I appreciate your time in going through the code.

[recoilme]

Speed up after removing terminate:

(base) v-kulibaba:art v.kulibaba$ go test -bench=Ints
goos: darwin
goarch: amd64
pkg: github.com/arriqaaq/art
cpu: Intel(R) Core(TM) i7-8569U CPU @ 2.80GHz
BenchmarkIntsArtTreeInsert-8    26208822                46.43 ns/op            8 B/op          0 allocs/op
BenchmarkIntsArtTreeSearch-8    45115551                32.56 ns/op            0 B/op          0 allocs/op
PASS

[arriqaaq]

This looks good, I'll have a look over the weekend, can we check the memory footprint?

[recoilme]

Your current terminate implementation doesn't check last byte on 0, but any and insert at end, its buggy

func terminate(key []byte) []byte {
	index := bytes.Index(key, []byte{0})
	if index < 0 {
		key = append(key, byte(0))
	}
	return key
}

This PR fix it, too.

FYI: I decide rewrite ART from scratch, with optimized memory usage. I will publish it soon