sroar: Serialized Roaring Bitmaps
sroar is a re-written version of Roaring Bitmaps in Go, with the aim to have equality between in-memory representation and on-disk representation. An sroar.Bitmap does not need to be marshalled or unmarshalled, as the underlying represetation is a byte slice. Therefore, it can be written to disk, brought to memory, or shipped over the network immediately. This is needed in Dgraph, where we need to deal with lots of bitmaps.
sroar only implements array and bitmap containers. It does NOT implement run containers, which is an optimization that RoaringBitmaps has. Despite that, it outperforms RoaringBitmaps as shown in the Benchmarks section.
The code borrows concepts and code from RoaringBitmaps.
Benchmarks
The benchmarks were run:
- Using real data set as described in RoaringBitmaps.
- Only on the 64-bit version of roaring bitmaps (roaring64).
- Only on
FastOr, which is the more expensive operation thanAndor equivalent. - On AMD Ryzen Threadripper 2950X 16-Core Processor.
- Using Go benchmarks serially.
Based on the benchmarks, sroar is:
- 6.5x faster (-85% p50) for benchmarks >1ms, uses
- 15x (-93.5% p50) less memory for allocations >1MB.
- 25x fewer allocations.
The benchmark command and the results are:
$ go test -bench BenchmarkRealDataFastOr --run=XXX --count=5 --benchmem
name CPU old time/op new time/op delta
RealDataFastOr/census1881-32 302ms ± 2% 2ms ± 3% -99.29% (p=0.008 n=5+5)
RealDataFastOr/wikileaks-noquotes-32 76.5ms ± 1% 0.9ms ± 1% -98.83% (p=0.008 n=5+5)
RealDataFastOr/wikileaks-noquotes_srt-32 34.8ms ± 5% 1.0ms ± 2% -97.07% (p=0.008 n=5+5)
RealDataFastOr/dimension_033-32 55.0ms ± 3% 2.7ms ± 0% -95.16% (p=0.016 n=5+4)
RealDataFastOr/census1881_srt-32 36.8ms ± 3% 2.9ms ± 1% -92.13% (p=0.008 n=5+5)
RealDataFastOr/dimension_003-32 50.4ms ± 1% 11.6ms ± 4% -77.06% (p=0.008 n=5+5)
RealDataFastOr/dimension_008-32 10.0ms ± 2% 3.7ms ± 2% -62.69% (p=0.008 n=5+5)
RealDataFastOr/weather_sept_85_srt-32 6.13ms ± 3% 2.72ms ± 2% -55.66% (p=0.008 n=5+5)
RealDataFastOr/census-income-32 1.70ms ± 3% 1.05ms ± 1% -38.53% (p=0.008 n=5+5)
RealDataFastOr/weather_sept_85-32 2.28ms ± 2% 4.07ms ± 2% +78.52% (p=0.008 n=5+5)
RealDataFastOr/uscensus2000-32 556µs ± 2% 791µs ± 1% +42.17% (p=0.008 n=5+5)
RealDataFastOr/census-income_srt-32 260µs ± 4% 986µs ± 2% +279.09% (p=0.008 n=5+5)
name MEM_BYTES old alloc/op new alloc/op delta
RealDataFastOr/census1881-32 585MB ± 0% 1MB ± 0% -99.75% (p=0.008 n=5+5)
RealDataFastOr/wikileaks-noquotes-32 76.3MB ± 0% 0.6MB ± 0% -99.24% (p=0.008 n=5+5)
RealDataFastOr/wikileaks-noquotes_srt-32 22.8MB ± 0% 0.6MB ± 0% -97.46% (p=0.008 n=5+5)
RealDataFastOr/census1881_srt-32 15.3MB ± 0% 1.4MB ± 0% -90.58% (p=0.008 n=5+5)
RealDataFastOr/dimension_003-32 7.78MB ± 0% 1.44MB ± 0% -81.49% (p=0.008 n=5+5)
RealDataFastOr/dimension_033-32 1.10MB ± 0% 1.44MB ± 0% +30.92% (p=0.008 n=5+5)
RealDataFastOr/dimension_008-32 537kB ± 0% 97kB ± 0% -81.94% (p=0.008 n=5+5)
RealDataFastOr/census-income-32 187kB ± 0% 70kB ± 0% -62.86% (p=0.008 n=5+5)
RealDataFastOr/census-income_srt-32 99.1kB ± 0% 69.6kB ± 0% -29.81% (p=0.008 n=5+5)
RealDataFastOr/weather_sept_85_srt-32 375kB ± 0% 292kB ± 0% -21.95% (p=0.008 n=5+5)
RealDataFastOr/uscensus2000-32 169kB ± 0% 231kB ± 0% +36.97% (p=0.008 n=5+5)
RealDataFastOr/weather_sept_85-32 169kB ± 0% 292kB ± 0% +72.93% (p=0.008 n=5+5)
name MEM_ALLOCS old allocs/op new allocs/op delta
RealDataFastOr/census1881_srt-32 29.7k ± 0% 0.0k ± 0% -99.91% (p=0.008 n=5+5)
RealDataFastOr/wikileaks-noquotes_srt-32 6.06k ± 0% 0.02k ± 0% -99.74% (p=0.008 n=5+5)
RealDataFastOr/dimension_003-32 4.57k ± 0% 0.03k ± 2% -99.42% (p=0.008 n=5+5)
RealDataFastOr/dimension_033-32 4.33k ± 0% 0.03k ± 0% -99.38% (p=0.000 n=5+4)
RealDataFastOr/uscensus2000-32 1.75k ± 0% 0.06k ± 0% -96.85% (p=0.008 n=5+5)
RealDataFastOr/dimension_008-32 704 ± 0% 23 ± 3% -96.79% (p=0.008 n=5+5)
RealDataFastOr/census-income-32 271 ± 0% 9 ± 0% -96.68% (p=0.008 n=5+5)
RealDataFastOr/weather_sept_85_srt-32 248 ± 0% 14 ± 0% -94.35% (p=0.008 n=5+5)
RealDataFastOr/weather_sept_85-32 81.0 ± 0% 14.0 ± 0% -82.72% (p=0.008 n=5+5)
RealDataFastOr/census-income_srt-32 40.0 ± 0% 9.0 ± 0% -77.50% (p=0.008 n=5+5)
RealDataFastOr/census1881-32 54.5k ± 0% 0.0k ± 0% ~ (p=0.079 n=4+5)
RealDataFastOr/wikileaks-noquotes-32 39.2k ± 0% 0.0k ± 0% ~ (p=0.079 n=4+5)