cosmos-sdk/store/cache
Emmanuel T Odeke d36c6be529
store/cache: speed up + conserve memory by using map clearing idiom in Reset (#6700)
Noticed during my audit, the code for cache.CommitKVStoreCacheManager.Reset()
discarded the prior on every invocation i.e.

    m = make(map[T(key)]T(value))

However, this can be made fast and conserve memory by using the map clearing idiom
that the Go compiler recognizes i.e.

    for key := range m {
        delete(m, key)
    }

and turns into very fast code, instead of the extraneous map discarding.

The speed up generated is:

```shell
$ benchstat before after
name     old time/op    new time/op    delta
Reset-8     204ns ± 2%      66ns ± 9%   -67.86%  (p=0.000 n=20+20)

name     old alloc/op   new alloc/op   delta
Reset-8      384B ± 0%        0B       -100.00%  (p=0.000 n=20+20)

name     old allocs/op  new allocs/op  delta
Reset-8      3.00 ± 0%      0.00       -100.00%  (p=0.000 n=20+20)
```

Fixes #6681
2020-07-13 12:49:09 +02:00
..
benchmark_test.go store/cache: speed up + conserve memory by using map clearing idiom in Reset (#6700) 2020-07-13 12:49:09 +02:00
cache.go store/cache: speed up + conserve memory by using map clearing idiom in Reset (#6700) 2020-07-13 12:49:09 +02:00
cache_test.go Merge PR #6475: Pruning Refactor 2020-06-22 16:31:33 -04:00