feature | weaselab | fdb |
|-|-|-|
|based on|node-copying treap|node-copying treap|
|branch-free `child` function|✅|❌|
|bytes per node (worst-case)|64 + kv len + 1\*|96 + kv len|
|cheaper iteration*|❌|✅|
|efficient bulk queries|✅|❌|
|entries per set (worst-case)|1|3|
|memory-usage (rough)|40%|100%|
|node gc|mark-and-sweep|reference-counting|
|pointer size|32-bit|64-bit|
|purge strategy|scan|search|
|read from foreign thread|✅ |❌ |
|recursion-free|✅ |❌|
|returns node memory to OS|✅ |❌|
|searches per point clear|1|5|
|searches per range clear|2|5|
|searches per set (worst-case)|1|4|

\* Part of a set of tradeoffs that enable 1 entry per set worst-case

# benchmarks

## weaselab

|               ns/op |                op/s |    err% |     total | benchmark
|--------------------:|--------------------:|--------:|----------:|:----------
|            1,225.88 |          815,738.46 |    0.7% |      0.31 | `monotonically increasing`
|                1.27 |      785,633,468.91 |    0.2% |      0.01 | `*iter`
|               29.18 |       34,265,322.00 |    0.4% |      0.01 | `++iter`
|               30.55 |       32,729,535.46 |    0.6% |      0.01 | `--iter`
|              155.38 |        6,435,768.30 |    0.4% |      0.04 | `begin`
|              181.88 |        5,498,125.78 |    0.5% |      0.04 | `begin (firstGeq)`
|               46.29 |       21,603,059.16 |    0.3% |      0.01 | `end`
|              169.68 |        5,893,481.63 |    0.1% |      0.10 | `bulkFirstGeq`
|              162.61 |        6,149,704.63 |    0.1% |      0.10 | `bulkFirstGeq (latest version)`

## fdb

|               ns/op |                op/s |    err% |     total | benchmark
|--------------------:|--------------------:|--------:|----------:|:----------
|            2,237.52 |          446,923.66 |    0.6% |      0.56 | `monotonically increasing`
|                2.07 |      484,208,685.89 |    0.6% |      0.01 | `*iter`
|                9.91 |      100,926,329.70 |    0.5% |      0.01 | `++iter`
|               11.36 |       88,023,104.91 |    0.3% |      0.01 | `--iter`
|               87.70 |       11,402,839.76 |    0.2% |      0.02 | `begin`
|              110.58 |        9,043,264.46 |    0.2% |      0.03 | `begin (firstGeq)`
|               67.30 |       14,859,247.22 |    0.3% |      0.02 | `end`
|              411.72 |        2,428,853.18 |    0.1% |      0.25 | `bulkFirstGeq`
|              350.54 |        2,852,725.55 |    0.1% |      0.21 | `bulkFirstGeq (latest version)`