mirror of
https://source.quilibrium.com/quilibrium/ceremonyclient.git
synced 2024-11-10 18:25:17 +00:00
57 lines
1.6 KiB
Markdown
57 lines
1.6 KiB
Markdown
|
# batchskl
|
||
|
|
|
||
|
|
Fast, non-concurrent skiplist implementation in Go that supports
|
||
|
|
forward and backward iteration.
|
||
|
|
|
||
|
|
## Limitations
|
||
|
|
|
||
|
|
* The interface is tailored for use in indexing pebble batches. Keys
|
||
|
|
and values are stored outside of the skiplist making the skiplist
|
||
|
|
awkward for general purpose use.
|
||
|
|
* Deletion is not supported. Instead, higher-level code is expected to
|
||
|
|
add deletion tombstones and needs to process those tombstones
|
||
|
|
appropriately.
|
||
|
|
|
||
|
|
## Pedigree
|
||
|
|
|
||
|
|
This code is based on Andy Kimball's arenaskl code.
|
||
|
|
|
||
|
|
The arenaskl code is based on the skiplist found in Badger, a Go-based
|
||
|
|
KV store:
|
||
|
|
|
||
|
|
https://github.com/dgraph-io/badger/tree/master/skl
|
||
|
|
|
||
|
|
The skiplist in Badger is itself based on a C++ skiplist built for
|
||
|
|
Facebook's RocksDB:
|
||
|
|
|
||
|
|
https://github.com/facebook/rocksdb/tree/master/memtable
|
||
|
|
|
||
|
|
## Benchmarks
|
||
|
|
|
||
|
|
The benchmarks consist of a mix of reads and writes executed in parallel. The
|
||
|
|
fraction of reads is indicated in the run name: "frac_X" indicates a run where
|
||
|
|
X percent of the operations are reads.
|
||
|
|
|
||
|
|
```
|
||
|
|
name time/op
|
||
|
|
ReadWrite/frac_0 1.03µs ± 2%
|
||
|
|
ReadWrite/frac_10 1.32µs ± 1%
|
||
|
|
ReadWrite/frac_20 1.26µs ± 1%
|
||
|
|
ReadWrite/frac_30 1.18µs ± 1%
|
||
|
|
ReadWrite/frac_40 1.09µs ± 1%
|
||
|
|
ReadWrite/frac_50 987ns ± 2%
|
||
|
|
ReadWrite/frac_60 1.07µs ± 1%
|
||
|
|
ReadWrite/frac_70 909ns ± 1%
|
||
|
|
ReadWrite/frac_80 693ns ± 2%
|
||
|
|
ReadWrite/frac_90 599ns ± 2%
|
||
|
|
ReadWrite/frac_100 45.3ns ± 3%
|
||
|
|
```
|
||
|
|
|
||
|
|
Forward and backward iteration are also fast:
|
||
|
|
|
||
|
|
```
|
||
|
|
name time/op
|
||
|
|
IterNext 4.49ns ± 3%
|
||
|
|
IterPrev 4.48ns ± 3%
|
||
|
|
```
|