// Go runs the diff. If there is no error, it will drain both sides.
// If an error occurs, it will just return it and stop.
func (rd *RowSubsetDiffer) Go(log logutil.Logger) (dr DiffReport, err error) {
dr.startingTime = time.Now()
defer dr.ComputeQPS()
var superset []sqltypes.Value
var subset []sqltypes.Value
advanceSuperset := true
advanceSubset := true
for {
if advanceSuperset {
superset, err = rd.superset.Next()
if err != nil {
return
}
advanceSuperset = false
}
if advanceSubset {
subset, err = rd.subset.Next()
if err != nil {
return
}
advanceSubset = false
}
dr.processedRows++
if superset == nil {
// no more rows from the superset
if subset == nil {
// no more rows from subset either, we're done
return
}
// drain subset, update count
if count, err := rd.subset.Drain(); err != nil {
return dr, err
} else {
dr.extraRowsRight += 1 + count
}
return
}
if subset == nil {
// no more rows from the subset
// we know we have rows from superset, drain
if _, err := rd.superset.Drain(); err != nil {
return dr, err
}
return
}
// we have both superset and subset, compare
f := RowsEqual(superset, subset)
if f == -1 {
// rows are the same, next
dr.matchingRows++
advanceSuperset = true
advanceSubset = true
continue
}
if f >= rd.pkFieldCount {
// rows have the same primary key, only content is different
if dr.mismatchedRows < 10 {
log.Errorf("Different content %v in same PK: %v != %v", dr.mismatchedRows, superset, subset)
}
dr.mismatchedRows++
advanceSuperset = true
advanceSubset = true
continue
}
// have to find the 'smallest' raw and advance it
c, err := CompareRows(rd.superset.Fields(), rd.pkFieldCount, superset, subset)
if err != nil {
return dr, err
}
if c < 0 {
advanceSuperset = true
continue
} else if c > 0 {
if dr.extraRowsRight < 10 {
log.Errorf("Extra row %v on subset: %v", dr.extraRowsRight, subset)
}
dr.extraRowsRight++
advanceSubset = true
continue
}
// After looking at primary keys more carefully,
// they're the same. Logging a regular difference
// then, and advancing both.
if dr.mismatchedRows < 10 {
log.Errorf("Different content %v in same PK: %v != %v", dr.mismatchedRows, superset, subset)
}
dr.mismatchedRows++
advanceSuperset = true
advanceSubset = true
}
}
// This function runs on the machine acting as the source for the clone.
//
// Check master/slave status and determine restore needs.
// If this instance is a slave, stop replication, otherwise place in read-only mode.
// Record replication position.
// Shutdown mysql
// Check paths for storing data
//
// Depending on the serverMode flag, we do the following:
// serverMode = false:
// Compress /vt/vt_[0-9a-f]+/data/vt_.+
// Compute hash (of compressed files, as we serve .gz files here)
// Place in /vt/clone_src where they will be served by http server (not rpc)
// Restart mysql
// serverMode = true:
// Make symlinks for /vt/vt_[0-9a-f]+/data/vt_.+ to innodb files
// Compute hash (of uncompressed files, as we serve uncompressed files)
// Place symlinks in /vt/clone_src where they will be served by http server
// Leave mysql stopped, return slaveStartRequired, readOnly
func (mysqld *Mysqld) CreateSnapshot(logger logutil.Logger, dbName, sourceAddr string, allowHierarchicalReplication bool, concurrency int, serverMode bool, hookExtraEnv map[string]string) (snapshotManifestUrlPath string, slaveStartRequired, readOnly bool, err error) {
if dbName == "" {
return "", false, false, errors.New("CreateSnapshot failed: no database name provided")
}
if err = mysqld.validateCloneSource(serverMode, hookExtraEnv); err != nil {
return
}
// save initial state so we can restore on Start()
slaveStartRequired = false
sourceIsMaster := false
readOnly = true
slaveStatus, err := mysqld.SlaveStatus()
if err == nil {
slaveStartRequired = slaveStatus.SlaveRunning()
} else if err == ErrNotSlave {
sourceIsMaster = true
} else {
// If we can't get any data, just fail.
return
}
readOnly, err = mysqld.IsReadOnly()
if err != nil {
return
}
// Stop sources of writes so we can get a consistent replication position.
// If the source is a slave use the master replication position
// unless we are allowing hierarchical replicas.
masterAddr := ""
var replicationPosition proto.ReplicationPosition
if sourceIsMaster {
if err = mysqld.SetReadOnly(true); err != nil {
return
}
replicationPosition, err = mysqld.MasterPosition()
if err != nil {
return
}
masterAddr = mysqld.IpAddr()
} else {
if err = mysqld.StopSlave(hookExtraEnv); err != nil {
return
}
var slaveStatus *proto.ReplicationStatus
slaveStatus, err = mysqld.SlaveStatus()
if err != nil {
return
}
replicationPosition = slaveStatus.Position
// We are a slave, check our replication strategy before
// choosing the master address.
if allowHierarchicalReplication {
masterAddr = mysqld.IpAddr()
} else {
masterAddr, err = mysqld.GetMasterAddr()
if err != nil {
return
}
}
}
if err = mysqld.Shutdown(true, MysqlWaitTime); err != nil {
return
}
var smFile string
dataFiles, snapshotErr := mysqld.createSnapshot(logger, concurrency, serverMode)
if snapshotErr != nil {
logger.Errorf("CreateSnapshot failed: %v", snapshotErr)
} else {
var sm *SnapshotManifest
sm, snapshotErr = newSnapshotManifest(sourceAddr, mysqld.IpAddr(),
masterAddr, dbName, dataFiles, replicationPosition, proto.ReplicationPosition{})
if snapshotErr != nil {
logger.Errorf("CreateSnapshot failed: %v", snapshotErr)
} else {
smFile = path.Join(mysqld.SnapshotDir, SnapshotManifestFile)
if snapshotErr = writeJson(smFile, sm); snapshotErr != nil {
logger.Errorf("CreateSnapshot failed: %v", snapshotErr)
}
}
}
// restore our state if required
if serverMode && snapshotErr == nil {
logger.Infof("server mode snapshot worked, not restarting mysql")
} else {
if err = mysqld.SnapshotSourceEnd(slaveStartRequired, readOnly, false /*deleteSnapshot*/, hookExtraEnv); err != nil {
return
}
}
if snapshotErr != nil {
return "", slaveStartRequired, readOnly, snapshotErr
}
relative, err := filepath.Rel(mysqld.SnapshotDir, smFile)
if err != nil {
return "", slaveStartRequired, readOnly, nil
}
return path.Join(SnapshotURLPath, relative), slaveStartRequired, readOnly, nil
}