reflector.go/lite_db/db.go
2021-07-24 01:03:16 +02:00

348 lines
8.8 KiB
Go

package lite_db
import (
"database/sql"
"time"
"github.com/lbryio/lbry.go/v2/extras/errors"
qt "github.com/lbryio/lbry.go/v2/extras/query"
"github.com/go-sql-driver/mysql"
_ "github.com/go-sql-driver/mysql" // blank import for db driver ensures its imported even if its not used
log "github.com/sirupsen/logrus"
"github.com/volatiletech/null"
)
// SdBlob is a special blob that contains information on the rest of the blobs in the stream
type SdBlob struct {
StreamName string `json:"stream_name"`
Blobs []struct {
Length int `json:"length"`
BlobNum int `json:"blob_num"`
BlobHash string `json:"blob_hash,omitempty"`
IV string `json:"iv"`
} `json:"blobs"`
StreamType string `json:"stream_type"`
Key string `json:"key"`
SuggestedFileName string `json:"suggested_file_name"`
StreamHash string `json:"stream_hash"`
}
// SQL implements the DB interface
type SQL struct {
conn *sql.DB
TrackAccessTime bool
}
func logQuery(query string, args ...interface{}) {
s, err := qt.InterpolateParams(query, args...)
if err != nil {
log.Errorln(err)
} else {
log.Debugln(s)
}
}
// Connect will create a connection to the database
func (s *SQL) Connect(dsn string) error {
var err error
// interpolateParams is necessary. otherwise uploading a stream with thousands of blobs
// will hit MySQL's max_prepared_stmt_count limit because the prepared statements are all
// opened inside a transaction. closing them manually doesn't seem to help
dsn += "?parseTime=1&collation=utf8mb4_unicode_ci&interpolateParams=1"
s.conn, err = sql.Open("mysql", dsn)
if err != nil {
return errors.Err(err)
}
s.conn.SetMaxIdleConns(12)
return errors.Err(s.conn.Ping())
}
// AddBlob adds a blob to the database.
func (s *SQL) AddBlob(hash string, length int) error {
if s.conn == nil {
return errors.Err("not connected")
}
_, err := s.insertBlob(hash, length)
return err
}
func (s *SQL) insertBlob(hash string, length int) (int64, error) {
if length <= 0 {
return 0, errors.Err("length must be positive")
}
const isStored = true
now := time.Now()
args := []interface{}{hash, isStored, length, now}
blobID, err := s.exec(
"INSERT INTO blob_ (hash, is_stored, length, last_accessed_at) VALUES ("+qt.Qs(len(args))+") ON DUPLICATE KEY UPDATE is_stored = (is_stored or VALUES(is_stored)), last_accessed_at=VALUES(last_accessed_at)",
args...,
)
if err != nil {
return 0, err
}
if blobID == 0 {
err = s.conn.QueryRow("SELECT id FROM blob_ WHERE hash = ?", hash).Scan(&blobID)
if err != nil {
return 0, errors.Err(err)
}
if blobID == 0 {
return 0, errors.Err("blob ID is 0 even after INSERTing and SELECTing")
}
}
return blobID, nil
}
// HasBlob checks if the database contains the blob information.
func (s *SQL) HasBlob(hash string) (bool, error) {
exists, err := s.HasBlobs([]string{hash})
if err != nil {
return false, err
}
return exists[hash], nil
}
// HasBlobs checks if the database contains the set of blobs and returns a bool map.
func (s *SQL) HasBlobs(hashes []string) (map[string]bool, error) {
exists, streamsNeedingTouch, err := s.hasBlobs(hashes)
s.touch(streamsNeedingTouch)
return exists, err
}
func (s *SQL) touch(blobIDs []uint64) error {
if len(blobIDs) == 0 {
return nil
}
query := "UPDATE blob_ SET last_accessed_at = ? WHERE id IN (" + qt.Qs(len(blobIDs)) + ")"
args := make([]interface{}, len(blobIDs)+1)
args[0] = time.Now()
for i := range blobIDs {
args[i+1] = blobIDs[i]
}
startTime := time.Now()
_, err := s.exec(query, args...)
log.Debugf("blobs access query touched %d blobs and took %s", len(blobIDs), time.Since(startTime))
return errors.Err(err)
}
func (s *SQL) hasBlobs(hashes []string) (map[string]bool, []uint64, error) {
if s.conn == nil {
return nil, nil, errors.Err("not connected")
}
var (
hash string
blobID uint64
lastAccessedAt null.Time
)
var needsTouch []uint64
exists := make(map[string]bool)
touchDeadline := time.Now().AddDate(0, 0, -1) // touch blob if last accessed before this time
maxBatchSize := 10000
doneIndex := 0
for len(hashes) > doneIndex {
sliceEnd := doneIndex + maxBatchSize
if sliceEnd > len(hashes) {
sliceEnd = len(hashes)
}
log.Debugf("getting hashes[%d:%d] of %d", doneIndex, sliceEnd, len(hashes))
batch := hashes[doneIndex:sliceEnd]
// TODO: this query doesn't work for SD blobs, which are not in the stream_blob table
query := `SELECT hash, id, last_accessed_at
FROM blob_
WHERE is_stored = ? and hash IN (` + qt.Qs(len(batch)) + `)`
args := make([]interface{}, len(batch)+1)
args[0] = true
for i := range batch {
args[i+1] = batch[i]
}
logQuery(query, args...)
err := func() error {
startTime := time.Now()
rows, err := s.conn.Query(query, args...)
log.Debugf("hashes query took %s", time.Since(startTime))
if err != nil {
return errors.Err(err)
}
defer closeRows(rows)
for rows.Next() {
err := rows.Scan(&hash, &blobID, &lastAccessedAt)
if err != nil {
return errors.Err(err)
}
exists[hash] = true
if s.TrackAccessTime && (!lastAccessedAt.Valid || lastAccessedAt.Time.Before(touchDeadline)) {
needsTouch = append(needsTouch, blobID)
}
}
err = rows.Err()
if err != nil {
return errors.Err(err)
}
doneIndex += len(batch)
return nil
}()
if err != nil {
return nil, nil, err
}
}
return exists, needsTouch, nil
}
// Delete will remove the blob from the db
func (s *SQL) Delete(hash string) error {
_, err := s.exec("UPDATE blob_ set is_stored = ? WHERE hash = ?", 0, hash)
return errors.Err(err)
}
// AddSDBlob insert the SD blob and all the content blobs. The content blobs are marked as "not stored",
// but they are tracked so reflector knows what it is missing.
func (s *SQL) AddSDBlob(sdHash string, sdBlobLength int) error {
if s.conn == nil {
return errors.Err("not connected")
}
_, err := s.insertBlob(sdHash, sdBlobLength)
return err
}
// GetHashRange gets the smallest and biggest hashes in the db
func (s *SQL) GetLRUBlobs(maxBlobs int) ([]string, error) {
if s.conn == nil {
return nil, errors.Err("not connected")
}
query := "SELECT hash from blob_ where is_stored = ? order by last_accessed_at limit ?"
const isStored = true
logQuery(query, isStored, maxBlobs)
rows, err := s.conn.Query(query, isStored, maxBlobs)
if err != nil {
return nil, errors.Err(err)
}
defer closeRows(rows)
blobs := make([]string, 0, maxBlobs)
for rows.Next() {
var hash string
err := rows.Scan(&hash)
if err != nil {
return nil, errors.Err(err)
}
blobs = append(blobs, hash)
}
return blobs, nil
}
func (s *SQL) AllBlobs() ([]string, error) {
if s.conn == nil {
return nil, errors.Err("not connected")
}
query := "SELECT hash from blob_ where is_stored = ?" //TODO: maybe sorting them makes more sense?
const isStored = true
logQuery(query, isStored)
rows, err := s.conn.Query(query, isStored)
if err != nil {
return nil, errors.Err(err)
}
defer closeRows(rows)
totalBlobs, err := s.BlobsCount()
if err != nil {
return nil, err
}
blobs := make([]string, 0, totalBlobs)
for rows.Next() {
var hash string
err := rows.Scan(&hash)
if err != nil {
return nil, errors.Err(err)
}
blobs = append(blobs, hash)
}
return blobs, nil
}
func (s *SQL) BlobsCount() (int, error) {
if s.conn == nil {
return 0, errors.Err("not connected")
}
query := "SELECT count(id) from blob_ where is_stored = ?" //TODO: maybe sorting them makes more sense?
const isStored = true
logQuery(query, isStored)
var count int
err := s.conn.QueryRow(query, isStored).Scan(&count)
return count, errors.Err(err)
}
func closeRows(rows *sql.Rows) {
if rows != nil {
err := rows.Close()
if err != nil {
log.Error("error closing rows: ", err)
}
}
}
func (s *SQL) exec(query string, args ...interface{}) (int64, error) {
logQuery(query, args...)
attempt, maxAttempts := 0, 3
Retry:
attempt++
result, err := s.conn.Exec(query, args...)
if isLockTimeoutError(err) {
if attempt <= maxAttempts {
//Error 1205: Lock wait timeout exceeded; try restarting transaction
goto Retry
}
err = errors.Prefix("Lock timeout for query "+query, err)
}
if err != nil {
return 0, errors.Err(err)
}
lastID, err := result.LastInsertId()
return lastID, errors.Err(err)
}
func isLockTimeoutError(err error) bool {
e, ok := err.(*mysql.MySQLError)
return ok && e != nil && e.Number == 1205
}
/* SQL schema
in prod make sure you use latin1 or utf8 charset, NOT utf8mb4. that's a waste of space.
CREATE TABLE `blob_` (
`id` bigint unsigned NOT NULL AUTO_INCREMENT,
`hash` char(96) NOT NULL,
`is_stored` tinyint(1) NOT NULL DEFAULT '0',
`length` bigint unsigned DEFAULT NULL,
`last_accessed_at` datetime DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
UNIQUE KEY `id` (`id`),
UNIQUE KEY `blob_hash_idx` (`hash`),
KEY `blob_last_accessed_idx` (`last_accessed_at`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
*/