perf: Amortize clearing unsorted cache entries (Juno genesis fix) (ba…

…ckport cosmos#12885) (cosmos#12960)

CHANGELOG.md

@@ -39,6 +39,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* [#12886](https://github.com/cosmos/cosmos-sdk/pull/12886) Amortize cost of processing cache KV store.
 * (events) [#12850](https://github.com/cosmos/cosmos-sdk/pull/12850) Add a new `fee_payer` attribute to the `tx` event that is emitted from the `DeductFeeDecorator` AnteHandler decorator.
 * (x/params) [#12615](https://github.com/cosmos/cosmos-sdk/pull/12615) Add `GetParamSetIfExists` function to params `Subspace` to prevent panics on breaking changes.
 * (x/bank) [#12674](https://github.com/cosmos/cosmos-sdk/pull/12674) Add convenience function `CreatePrefixedAccountStoreKey()` to construct key to access account's balance for a given denom.

store/cachekv/search_benchmark_test.go

@@ -0,0 +1,43 @@
+package cachekv
+
+import (
+ db "github.com/tendermint/tm-db"
+ "strconv"
+ "testing"
+)
+
+func BenchmarkLargeUnsortedMisses(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ b.StopTimer()
+ store := generateStore()
+ b.StartTimer()
+
+ for k := 0; k < 10000; k++ {
+ // cache has A + Z values
+ // these are within range, but match nothing
+ store.dirtyItems([]byte("B1"), []byte("B2"))
+ }
+ }
+}
+
+func generateStore() *Store {
+ cache := map[string]*cValue{}
+ unsorted := map[string]struct{}{}
+ for i := 0; i < 5000; i++ {
+ key := "A" + strconv.Itoa(i)
+ unsorted[key] = struct{}{}
+ cache[key] = &cValue{}
+ }
+
+ for i := 0; i < 5000; i++ {
+ key := "Z" + strconv.Itoa(i)
+ unsorted[key] = struct{}{}
+ cache[key] = &cValue{}
+ }
+
+ return &Store{
+ cache: cache,
+ unsortedCache: unsorted,
+ sortedCache: db.NewMemDB(),
+ }
+}

store/cachekv/store.go

@@ -13,6 +13,7 @@ import (
  "github.com/cosmos/cosmos-sdk/store/tracekv"
  "github.com/cosmos/cosmos-sdk/store/types"
  "github.com/cosmos/cosmos-sdk/types/kv"
+ "github.com/tendermint/tendermint/libs/math"
 )
 
 // cValue represents a cached value.
@@ -273,6 +274,8 @@ const (
  stateAlreadySorted
 )
 
+const minSortSize = 1024
+
 // Constructs a slice of dirty items, to use w/ memIterator.
 func (store *Store) dirtyItems(start, end []byte) {
  startStr, endStr := conv.UnsafeBytesToStr(start), conv.UnsafeBytesToStr(end)
@@ -289,7 +292,7 @@ func (store *Store) dirtyItems(start, end []byte) {
  // O(N^2) overhead.
  // Even without that, too many range checks eventually becomes more expensive
  // than just not having the cache.
- if n < 1024 {
+ if n < minSortSize {
  for key := range store.unsortedCache {
  if dbm.IsKeyInDomain(conv.UnsafeStrToBytes(key), start, end) {
  cacheValue := store.cache[key]
@@ -320,6 +323,17 @@ func (store *Store) dirtyItems(start, end []byte) {
  startIndex = 0
  }
 
+ // Since we spent cycles to sort the values, we should process and remove a reasonable amount
+ // ensure start to end is at least minSortSize in size
+ // if below minSortSize, expand it to cover additional values
+ // this amortizes the cost of processing elements across multiple calls
+ if endIndex-startIndex < minSortSize {
+ endIndex = math.MinInt(startIndex+minSortSize, len(strL)-1)
+ if endIndex-startIndex < minSortSize {
+ startIndex = math.MaxInt(endIndex-minSortSize, 0)
+ }
+ }
+
  kvL := make([]*kv.Pair, 0)
  for i := startIndex; i <= endIndex; i++ {
  key := strL[i]