/
local_external_timestamp.go
54 lines (46 loc) · 1.52 KB
/
local_external_timestamp.go
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// Copyright 2022 TiKV Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package oracles
import (
"context"
"github.com/pkg/errors"
"github.com/tikv/client-go/v2/oracle"
"go.uber.org/atomic"
)
type localExternalTimestamp struct {
externalTimestamp atomic.Uint64
}
func (l *localExternalTimestamp) setExternalTimestamp(ctx context.Context, o oracle.Oracle, newTimestamp uint64) error {
currentTSO, err := o.GetTimestamp(ctx, nil)
if err != nil {
return err
}
if newTimestamp > currentTSO {
return errors.New("external timestamp is greater than global tso")
}
for {
externalTimestamp := l.externalTimestamp.Load()
if externalTimestamp > newTimestamp {
return errors.New("cannot decrease the external timestamp")
} else if externalTimestamp == newTimestamp {
return nil
}
if l.externalTimestamp.CompareAndSwap(externalTimestamp, newTimestamp) {
return nil
}
}
}
func (l *localExternalTimestamp) getExternalTimestamp(ctx context.Context) (uint64, error) {
return l.externalTimestamp.Load(), nil
}