Fix memory leak due to emitting infinite events during snapshot

store/cachekv/mergeiterator.go

@@ -16,27 +16,24 @@ import (
 //
 // TODO: Optimize by memoizing.
 type cacheMergeIterator struct {
-	parent       types.Iterator
-	cache        types.Iterator
-	ascending    bool
-	eventManager *sdktypes.EventManager
-	storeKey     sdktypes.StoreKey
+	parent    types.Iterator
+	cache     types.Iterator
+	ascending bool
+	storeKey  sdktypes.StoreKey
 }
 
 var _ types.Iterator = (*cacheMergeIterator)(nil)
 
 func NewCacheMergeIterator(
 	parent, cache types.Iterator,
 	ascending bool,
-	eventManager *sdktypes.EventManager,
 	storeKey sdktypes.StoreKey,
 ) *cacheMergeIterator {
 	iter := &cacheMergeIterator{
-		parent:       parent,
-		cache:        cache,
-		ascending:    ascending,
-		eventManager: eventManager,
-		storeKey:     storeKey,
+		parent:    parent,
+		cache:     cache,
+		ascending: ascending,
+		storeKey:  storeKey,
 	}
 
 	return iter
@@ -138,14 +135,12 @@ func (iter *cacheMergeIterator) Value() []byte {
 	// If parent is invalid, get the cache value.
 	if !iter.parent.Valid() {
 		value := iter.cache.Value()
-		iter.eventManager.EmitResourceAccessReadEvent("iterator", iter.storeKey, iter.cache.Key(), value)
 		return value
 	}
 
 	// If cache is invalid, get the parent value.
 	if !iter.cache.Valid() {
 		value := iter.parent.Value()
-		iter.eventManager.EmitResourceAccessReadEvent("iterator", iter.storeKey, iter.parent.Key(), value)
 		return value
 	}
 
@@ -156,11 +151,9 @@ func (iter *cacheMergeIterator) Value() []byte {
 	switch cmp {
 	case -1: // parent < cache
 		value := iter.parent.Value()
-		iter.eventManager.EmitResourceAccessReadEvent("iterator", iter.storeKey, keyP, value)
 		return value
 	case 0, 1: // parent >= cache
 		value := iter.cache.Value()
-		iter.eventManager.EmitResourceAccessReadEvent("iterator", iter.storeKey, keyC, value)
 		return value
 	default:
 		panic("invalid comparison result")

store/cachekv/mergeiterator_test.go

@@ -4,15 +4,13 @@ import (
 	"testing"
 
 	"github.com/cosmos/cosmos-sdk/store/cachekv"
+	"github.com/cosmos/cosmos-sdk/store/dbadapter"
 	"github.com/cosmos/cosmos-sdk/store/types"
-	sdktypes "github.com/cosmos/cosmos-sdk/types"
 	"github.com/stretchr/testify/require"
 	dbm "github.com/tendermint/tm-db"
-
-	"github.com/cosmos/cosmos-sdk/store/dbadapter"
 )
 
-func TestEmitEventMangerInIterator(t *testing.T) {
+func TestMangerIterator(t *testing.T) {
 	// initiate mock kvstore
 	mem := dbadapter.Store{DB: dbm.NewMemDB()}
 	kvstore := cachekv.NewStore(mem, types.NewKVStoreKey("CacheKvTest"), types.DefaultCacheSizeLimit)
@@ -25,32 +23,17 @@ func TestEmitEventMangerInIterator(t *testing.T) {
 	}
 
 	// initialize mock mergeIterator
-	eventManager := sdktypes.NewEventManager()
 	parent := kvstore.Iterator(keys[0], keys[2])
 	cache := kvstore.Iterator(nil, nil)
 	for ; cache.Valid(); cache.Next() {
 	}
-	iter := cachekv.NewCacheMergeIterator(parent, cache, true, eventManager, types.NewKVStoreKey("CacheKvTest"))
-
-	// get the next value
-	iter.Value()
+	iter := cachekv.NewCacheMergeIterator(parent, cache, true, types.NewKVStoreKey("CacheKvTest"))
 
-	// assert the resource access is still emitted correctly when the cache store is unavailable
-	require.Equal(t, "access_type", string(eventManager.Events()[0].Attributes[0].Key))
-	require.Equal(t, "read", string(eventManager.Events()[0].Attributes[0].Value))
-	require.Equal(t, "store_key", string(eventManager.Events()[0].Attributes[1].Key))
-	require.Equal(t, "CacheKvTest", string(eventManager.Events()[0].Attributes[1].Value))
+	// get the next value and it should not be nil
+	nextValue := iter.Value()
+	require.NotNil(t, nextValue)
 
-	// assert event emission when cache is available
-	cache = kvstore.Iterator(keys[1], keys[2])
-	iter = cachekv.NewCacheMergeIterator(parent, cache, true, eventManager, types.NewKVStoreKey("CacheKvTest"))
-
 	// get the next value
-	iter.Value()
-
-	// assert the resource access is still emitted correctly when the cache store is available
-	require.Equal(t, "access_type", string(eventManager.Events()[0].Attributes[0].Key))
-	require.Equal(t, "read", string(eventManager.Events()[0].Attributes[0].Value))
-	require.Equal(t, "store_key", string(eventManager.Events()[0].Attributes[1].Key))
-	require.Equal(t, "CacheKvTest", string(eventManager.Events()[0].Attributes[1].Value))
+	nextValue = iter.Value()
+	require.NotNil(t, nextValue)
 }

store/cachekv/store.go

@@ -189,7 +189,7 @@ func (store *Store) iterator(start, end []byte, ascending bool) types.Iterator {
 	}()
 	store.dirtyItems(start, end)
 	cache = newMemIterator(start, end, store.sortedCache, store.deleted, ascending, store.eventManager, store.storeKey)
-	return NewCacheMergeIterator(parent, cache, ascending, store.eventManager, store.storeKey)
+	return NewCacheMergeIterator(parent, cache, ascending, store.storeKey)
 }
 
 func findStartIndex(strL []string, startQ string) int {