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
|--------------------:|--------------------:|--------:|----------:|:----------
|            1,538.88 |          649,824.01 |    2.7% |      0.22 | `monotonically increasing`
|                1.25 |      798,888,023.37 |    0.0% |      0.01 | `*iter`
|               32.10 |       31,153,434.23 |    0.7% |      0.01 | `++iter`
|               31.08 |       32,178,831.30 |    0.3% |      0.01 | `--iter`
|              139.19 |        7,184,433.93 |    2.2% |      0.02 | `begin`
|              176.43 |        5,667,847.59 |    0.3% |      0.02 | `begin (firstGeq)`
|               54.56 |       18,329,336.92 |    0.4% |      0.01 | `end`
|              159.37 |        6,274,892.80 |    0.1% |      0.10 | `bulkFirstGeq`
|              153.55 |        6,512,408.74 |    0.1% |      0.09 | `bulkFirstGeq (latest version)`

## fdb

|               ns/op |                op/s |    err% |     total | benchmark
|--------------------:|--------------------:|--------:|----------:|:----------
|            2,236.83 |          447,061.26 |    1.0% |      0.29 | `monotonically increasing`
|                2.11 |      473,370,596.42 |    0.9% |      0.01 | `*iter`
|               12.07 |       82,858,977.78 |    1.2% |      0.01 | `++iter`
|                8.54 |      117,158,071.80 |    0.9% |      0.01 | `--iter`
|               94.26 |       10,608,588.66 |    1.1% |      0.01 | `begin`
|              159.01 |        6,288,940.61 |    0.4% |      0.02 | `begin (firstGeq)`
|               73.47 |       13,610,276.41 |    0.9% |      0.01 | `end`
|              422.53 |        2,366,723.10 |    0.1% |      0.25 | `bulkFirstGeq`
|              365.13 |        2,738,758.86 |    0.1% |      0.22 | `bulkFirstGeq (latest version)`