From 641ea69a72efa35f2d0155c2cf17290d9675d34a Mon Sep 17 00:00:00 2001
From: Patrick O'Grady <prohb125@gmail.com>
Date: Tue, 25 Oct 2022 10:01:07 -0700
Subject: [PATCH] Don't write cache on shutdown (#317)

* don't save on shutdown

* remove test
---
 core/blockchain_test.go | 57 -----------------------------------------
 trie/database.go        | 18 -------------
 2 files changed, 75 deletions(-)

diff --git a/core/blockchain_test.go b/core/blockchain_test.go
index 116ebb8098..e7f23c8496 100644
--- a/core/blockchain_test.go
+++ b/core/blockchain_test.go
@@ -7,9 +7,7 @@ import (
 	"fmt"
 	"math/big"
 	"testing"
-	"time"
 
-	"github.com/VictoriaMetrics/fastcache"
 	"github.com/ava-labs/subnet-evm/consensus/dummy"
 	"github.com/ava-labs/subnet-evm/core/rawdb"
 	"github.com/ava-labs/subnet-evm/core/state"
@@ -18,10 +16,8 @@ import (
 	"github.com/ava-labs/subnet-evm/core/vm"
 	"github.com/ava-labs/subnet-evm/ethdb"
 	"github.com/ava-labs/subnet-evm/params"
-	"github.com/ava-labs/subnet-evm/trie"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
-	"github.com/stretchr/testify/require"
 )
 
 var (
@@ -644,56 +640,3 @@ func TestCanonicalHashMarker(t *testing.T) {
 		}
 	}
 }
-
-func TestCleanCacheJournal(t *testing.T) {
-	chainDB := rawdb.NewMemoryDatabase()
-	gspec := &Genesis{
-		Config: &params.ChainConfig{HomesteadBlock: new(big.Int)},
-		Alloc: GenesisAlloc{
-			common.Address{1}: {Balance: big.NewInt(1)}, // non-zero alloc needed to cause trie writes.
-		},
-	}
-	genesisBlock := gspec.MustCommit(chainDB)
-	require.NotNil(t, genesisBlock)
-	journal := t.TempDir()
-
-	blockchain, err := createBlockChain(
-		chainDB,
-		&CacheConfig{
-			TrieCleanLimit:        64, // Smallest possible non-zero size (for a faster test).
-			TrieDirtyLimit:        256,
-			TrieDirtyCommitTarget: 20,
-			Pruning:               true, // Enable pruning
-			CommitInterval:        4096,
-			SnapshotLimit:         256,
-			AcceptorQueueLimit:    64,
-			TrieCleanRejournal:    1 * time.Minute, // Must be non-zero to enable journaling.
-			TrieCleanJournal:      journal,
-		},
-		gspec.Config,
-		common.Hash{})
-	require.NoError(t, err)
-	blockchain.Stop() // this causes the cache to be written.
-
-	// Load cache and verify it is not empty.
-	cache, err := fastcache.LoadFromFile(journal)
-	require.NoError(t, err)
-	stats := fastcache.Stats{}
-	cache.UpdateStats(&stats)
-	require.NotZero(t, stats.EntriesCount)
-
-	// The cache should contain the full state trie (since it is small enough).
-	trieDB := trie.NewDatabase(chainDB)
-	tr, err := trie.New(common.Hash{}, genesisBlock.Root(), trieDB)
-	require.NoError(t, err)
-	it := tr.NodeIterator(nil)
-	nodeCount := 0
-	for it.Next(true) {
-		if it.Leaf() {
-			continue // leaf nodes do not have a hash
-		}
-		require.True(t, cache.Has(it.Hash().Bytes()))
-		nodeCount++
-	}
-	require.NotZero(t, nodeCount)
-}
diff --git a/trie/database.go b/trie/database.go
index 7451438bf6..2a485d4ce8 100644
--- a/trie/database.go
+++ b/trie/database.go
@@ -31,7 +31,6 @@ import (
 	"fmt"
 	"io"
 	"reflect"
-	"runtime"
 	"sync"
 	"time"
 
@@ -921,16 +920,6 @@ func (db *Database) saveCache(dir string, threads int) error {
 	return nil
 }
 
-// SaveCache atomically saves fast cache data to the given dir using half
-// available CPU cores.
-func (db *Database) SaveCache(dir string) error {
-	concurrency := runtime.GOMAXPROCS(0) / 2
-	if concurrency == 0 {
-		concurrency = 1
-	}
-	return db.saveCache(dir, concurrency)
-}
-
 // SaveCachePeriodically atomically saves fast cache data to the given dir with
 // the specified interval. All dump operation will only use a single CPU core.
 func (db *Database) SaveCachePeriodically(dir string, interval time.Duration, stopCh <-chan struct{}) {
@@ -942,13 +931,6 @@ func (db *Database) SaveCachePeriodically(dir string, interval time.Duration, st
 		case <-ticker.C:
 			db.saveCache(dir, 1)
 		case <-stopCh:
-			// Write the latest contents of the cache to disk after receiving a stop request.
-			// Note: this is different than geth, which requires an explicit
-			// call to save the cache on shutdown.
-			err := db.SaveCache(dir)
-			if err != nil {
-				log.Warn("Failed to save cache after stop requested", "err", err)
-			}
 			return
 		}
 	}