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

…ckport cosmos#12885) (cosmos#12960)

CHANGELOG.md

@@ -40,6 +40,7 @@ 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

@@ -1,10 +1,9 @@
 package cachekv
 
 import (
+	db "github.com/tendermint/tm-db"
 	"strconv"
 	"testing"
-
-	"github.com/cosmos/cosmos-sdk/store/cachekv/internal"
 )
 
 func BenchmarkLargeUnsortedMisses(b *testing.B) {
@@ -39,6 +38,6 @@ func generateStore() *Store {
 	return &Store{
 		cache:         cache,
 		unsortedCache: unsorted,
-		sortedCache:   internal.NewBTree(),
+		sortedCache:   db.NewMemDB(),
 	}
 }

store/cachekv/store.go

@@ -373,6 +373,17 @@ func (store *Store) dirtyItems(start, end []byte) {
 		}
 	}
 
+	// 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]