From 7f32a08b6095bb5f1ff58168be70326ee0c29266 Mon Sep 17 00:00:00 2001
From: obscuren <geffobscura@gmail.com>
Date: Tue, 7 Apr 2015 22:19:01 +0200
Subject: [PATCH] Queued level db writes and batch writes. Closes #647

---
 common/db.go           |   2 -
 ethdb/database.go      | 117 ++++++++++++++++++++++++++++++-----------
 ethdb/database_test.go |  27 ++++------
 3 files changed, 97 insertions(+), 49 deletions(-)

diff --git a/common/db.go b/common/db.go
index 6505e61c6..408b1e755 100644
--- a/common/db.go
+++ b/common/db.go
@@ -4,9 +4,7 @@ package common
 type Database interface {
 	Put(key []byte, value []byte)
 	Get(key []byte) ([]byte, error)
-	//GetKeys() []*Key
 	Delete(key []byte) error
 	LastKnownTD() []byte
 	Close()
-	Print()
 }
diff --git a/ethdb/database.go b/ethdb/database.go
index cc2df5fa0..eb562f852 100644
--- a/ethdb/database.go
+++ b/ethdb/database.go
@@ -1,17 +1,25 @@
 package ethdb
 
 import (
-	"fmt"
+	"sync"
+	"time"
 
 	"github.com/ethereum/go-ethereum/compression/rle"
-	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
 	"github.com/syndtr/goleveldb/leveldb"
 	"github.com/syndtr/goleveldb/leveldb/iterator"
 )
 
 type LDBDatabase struct {
-	db   *leveldb.DB
-	comp bool
+	fn string
+
+	mu sync.Mutex
+	db *leveldb.DB
+
+	queue map[string][]byte
+
+	quit chan struct{}
 }
 
 func NewLDBDatabase(file string) (*LDBDatabase, error) {
@@ -20,35 +28,61 @@ func NewLDBDatabase(file string) (*LDBDatabase, error) {
 	if err != nil {
 		return nil, err
 	}
-	database := &LDBDatabase{db: db, comp: true}
+	database := &LDBDatabase{
+		fn:   file,
+		db:   db,
+		quit: make(chan struct{}),
+	}
+	database.makeQueue()
+
+	go database.update()
+
 	return database, nil
 }
 
-func (self *LDBDatabase) Put(key []byte, value []byte) {
-	if self.comp {
-		value = rle.Compress(value)
-	}
+func (self *LDBDatabase) makeQueue() {
+	self.queue = make(map[string][]byte)
+}
 
-	err := self.db.Put(key, value, nil)
-	if err != nil {
-		fmt.Println("Error put", err)
-	}
+func (self *LDBDatabase) Put(key []byte, value []byte) {
+	self.mu.Lock()
+	defer self.mu.Unlock()
+
+	self.queue[string(key)] = value
+	/*
+		value = rle.Compress(value)
+
+		err := self.db.Put(key, value, nil)
+		if err != nil {
+			fmt.Println("Error put", err)
+		}
+	*/
 }
 
 func (self *LDBDatabase) Get(key []byte) ([]byte, error) {
+	self.mu.Lock()
+	defer self.mu.Unlock()
+
+	// Check queue first
+	if dat, ok := self.queue[string(key)]; ok {
+		return dat, nil
+	}
+
 	dat, err := self.db.Get(key, nil)
 	if err != nil {
 		return nil, err
 	}
 
-	if self.comp {
-		return rle.Decompress(dat)
-	}
-
-	return dat, nil
+	return rle.Decompress(dat)
 }
 
 func (self *LDBDatabase) Delete(key []byte) error {
+	self.mu.Lock()
+	defer self.mu.Unlock()
+
+	// make sure it's not in the queue
+	delete(self.queue, string(key))
+
 	return self.db.Delete(key, nil)
 }
 
@@ -66,23 +100,46 @@ func (self *LDBDatabase) NewIterator() iterator.Iterator {
 	return self.db.NewIterator(nil, nil)
 }
 
-func (self *LDBDatabase) Write(batch *leveldb.Batch) error {
+func (self *LDBDatabase) Flush() error {
+	self.mu.Lock()
+	defer self.mu.Unlock()
+
+	batch := new(leveldb.Batch)
+
+	for key, value := range self.queue {
+		batch.Put([]byte(key), rle.Compress(value))
+	}
+	self.makeQueue() // reset the queue
+
 	return self.db.Write(batch, nil)
 }
 
 func (self *LDBDatabase) Close() {
+	self.quit <- struct{}{}
+	<-self.quit
+	glog.V(logger.Info).Infoln("flushed and closed db:", self.fn)
+}
+
+func (self *LDBDatabase) update() {
+	ticker := time.NewTicker(1 * time.Minute)
+done:
+	for {
+		select {
+		case <-ticker.C:
+			if err := self.Flush(); err != nil {
+				glog.V(logger.Error).Infof("error: flush '%s': %v\n", self.fn, err)
+			}
+		case <-self.quit:
+			break done
+		}
+	}
+
+	if err := self.Flush(); err != nil {
+		glog.V(logger.Error).Infof("error: flush '%s': %v\n", self.fn, err)
+	}
+
 	// Close the leveldb database
 	self.db.Close()
-}
 
-func (self *LDBDatabase) Print() {
-	iter := self.db.NewIterator(nil, nil)
-	for iter.Next() {
-		key := iter.Key()
-		value := iter.Value()
-
-		fmt.Printf("%x(%d): ", key, len(key))
-		node := common.NewValueFromBytes(value)
-		fmt.Printf("%v\n", node)
-	}
+	self.quit <- struct{}{}
 }
diff --git a/ethdb/database_test.go b/ethdb/database_test.go
index 7de30fd81..3cead8bcd 100644
--- a/ethdb/database_test.go
+++ b/ethdb/database_test.go
@@ -1,26 +1,19 @@
 package ethdb
 
-/*
 import (
-	"bytes"
-	"testing"
+	"os"
+	"path"
+
+	"github.com/ethereum/go-ethereum/common"
 )
 
-func TestCompression(t *testing.T) {
-	db, err := NewLDBDatabase("testdb")
-	if err != nil {
-		t.Fatal(err)
+func newDb() *LDBDatabase {
+	file := path.Join("/", "tmp", "ldbtesttmpfile")
+	if common.FileExist(file) {
+		os.RemoveAll(file)
 	}
 
-	in := make([]byte, 10)
-	db.Put([]byte("test1"), in)
-	out, err := db.Get([]byte("test1"))
-	if err != nil {
-		t.Fatal(err)
-	}
+	db, _ := NewLDBDatabase(file)
 
-	if bytes.Compare(out, in) != 0 {
-		t.Error("put get", in, out)
-	}
+	return db
 }
-*/