package ethdb
import (
"strconv"
"strings"
"time"
"github.com/ethereum/go-ethereum/compression/rle"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/rcrowley/go-metrics"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/errors"
"github.com/syndtr/goleveldb/leveldb/iterator"
"github.com/syndtr/goleveldb/leveldb/opt"
)
var OpenFileLimit = 64
type LDBDatabase struct {
fn string // filename for reporting
db *leveldb.DB // LevelDB instance
GetTimer metrics.Timer // Timer for measuring the database get request counts and latencies
PutTimer metrics.Timer // Timer for measuring the database put request counts and latencies
DelTimer metrics.Timer // Timer for measuring the database delete request counts and latencies
MissMeter metrics.Meter // Meter for measuring the missed database get requests
ReadMeter metrics.Meter // Meter for measuring the database get request data usage
WriteMeter metrics.Meter // Meter for measuring the database put request data usage
CompTimeMeter metrics.Meter // Meter for measuring the total time spent in database compaction
CompReadMeter metrics.Meter // Meter for measuring the data read during compaction
CompWriteMeter metrics.Meter // Meter for measuring the data written during compaction
}
// NewLDBDatabase returns a LevelDB wrapped object. LDBDatabase does not persist data by
// it self but requires a background poller which syncs every X. `Flush` should be called
// when data needs to be stored and written to disk.
func NewLDBDatabase(file string) (*LDBDatabase, error) {
// Open the db
db, err := leveldb.OpenFile(file, &opt.Options{OpenFilesCacheCapacity: OpenFileLimit})
// check for curruption and attempt to recover
if _, iscorrupted := err.(*errors.ErrCorrupted); iscorrupted {
db, err = leveldb.RecoverFile(file, nil)
}
// (re) check for errors and abort if opening of the db failed
if err != nil {
return nil, err
}
database := &LDBDatabase{
fn: file,
db: db,
}
go database.meter(3 * time.Second)
return database, nil
}
// Put puts the given key / value to the queue
func (self *LDBDatabase) Put(key []byte, value []byte) error {
// Measure the database put latency, if requested
if self.PutTimer != nil {
defer self.PutTimer.UpdateSince(time.Now())
}
// Generate the data to write to disk, update the meter and write
dat := rle.Compress(value)
if self.WriteMeter != nil {
self.WriteMeter.Mark(int64(len(dat)))
}
return self.db.Put(key, dat, nil)
}
// Get returns the given key if it's present.
func (self *LDBDatabase) Get(key []byte) ([]byte, error) {
// Measure the database get latency, if requested
if self.GetTimer != nil {
defer self.GetTimer.UpdateSince(time.Now())
}
// Retrieve the key and increment the miss counter if not found
dat, err := self.db.Get(key, nil)
if err != nil {
if self.MissMeter != nil {
self.MissMeter.Mark(1)
}
return nil, err
}
// Otherwise update the actually retrieved amount of data
if self.ReadMeter != nil {
self.ReadMeter.Mark(int64(len(dat)))
}
return rle.Decompress(dat)
}
// Delete deletes the key from the queue and database
func (self *LDBDatabase) Delete(key []byte) error {
// Measure the database delete latency, if requested
if self.DelTimer != nil {
defer self.DelTimer.UpdateSince(time.Now())
}
// Execute the actual operation
return self.db.Delete(key, nil)
}
func (self *LDBDatabase) NewIterator() iterator.Iterator {
return self.db.NewIterator(nil, nil)
}
// Flush flushes out the queue to leveldb
func (self *LDBDatabase) Flush() error {
return nil
}
func (self *LDBDatabase) Close() {
if err := self.Flush(); err != nil {
glog.V(logger.Error).Infof("error: flush '%s': %v\n", self.fn, err)
}
self.db.Close()
glog.V(logger.Error).Infoln("flushed and closed db:", self.fn)
}
func (self *LDBDatabase) LDB() *leveldb.DB {
return self.db
}
// meter periodically retrieves internal leveldb counters and reports them to
// the metrics subsystem.
//
// This is how a stats table look like (currently):
// Compactions
// Level | Tables | Size(MB) | Time(sec) | Read(MB) | Write(MB)
// -------+------------+---------------+---------------+---------------+---------------
// 0 | 0 | 0.00000 | 1.27969 | 0.00000 | 12.31098
// 1 | 85 | 109.27913 | 28.09293 | 213.92493 | 214.26294
// 2 | 523 | 1000.37159 | 7.26059 | 66.86342 | 66.77884
// 3 | 570 | 1113.18458 | 0.00000 | 0.00000 | 0.00000
func (self *LDBDatabase) meter(refresh time.Duration) {
// Create the counters to store current and previous values
counters := make([][]float64, 2)
for i := 0; i < 2; i++ {
counters[i] = make([]float64, 3)
}
// Iterate ad infinitum and collect the stats
for i := 1; ; i++ {
// Retrieve the database stats
stats, err := self.db.GetProperty("leveldb.stats")
if err != nil {
glog.V(logger.Error).Infof("failed to read database stats: %v", err)
return
}
// Find the compaction table, skip the header
lines := strings.Split(stats, "\n")
for len(lines) > 0 && strings.TrimSpace(lines[0]) != "Compactions" {
lines = lines[1:]
}
if len(lines) <= 3 {
glog.V(logger.Error).Infof("compaction table not found")
return
}
lines = lines[3:]
// Iterate over all the table rows, and accumulate the entries
for j := 0; j < len(counters[i%2]); j++ {
counters[i%2][j] = 0
}
for _, line := range lines {
parts := strings.Split(line, "|")
if len(parts) != 6 {
break
}
for idx, counter := range parts[3:] {
if value, err := strconv.ParseFloat(strings.TrimSpace(counter), 64); err != nil {
glog.V(logger.Error).Infof("compaction entry parsing failed: %v", err)
return
} else {
counters[i%2][idx] += value
}
}
}
// Update all the requested meters
if self.CompTimeMeter != nil {
self.CompTimeMeter.Mark(int64((counters[i%2][0] - counters[(i-1)%2][0]) * 1000 * 1000 * 1000))
}
if self.CompReadMeter != nil {
self.CompReadMeter.Mark(int64((counters[i%2][1] - counters[(i-1)%2][1]) * 1024 * 1024))
}
if self.CompWriteMeter != nil {
self.CompWriteMeter.Mark(int64((counters[i%2][2] - counters[(i-1)%2][2]) * 1024 * 1024))
}
// Sleep a bit, then repeat the stats collection
time.Sleep(refresh)
}
}
