client-go/internal/client/client_collapse.go

160 lines
5.1 KiB
Go

// Copyright 2021 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.
// NOTE: The code in this file is based on code from the
// TiDB project, licensed under the Apache License v 2.0
//
// https://github.com/pingcap/tidb/tree/cc5e161ac06827589c4966674597c137cc9e809c/store/tikv/client/client_collapse.go
//
// Copyright 2020 PingCAP, Inc.
//
// 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 client provides tcp connection to kvserver.
package client
import (
"context"
"strconv"
"time"
"github.com/pkg/errors"
"github.com/tikv/client-go/v2/tikvrpc"
"github.com/tikv/client-go/v2/util/async"
"golang.org/x/sync/singleflight"
)
var _ Client = reqCollapse{}
var resolveRegionSf singleflight.Group
type reqCollapse struct {
Client
}
// NewReqCollapse creates a reqCollapse.
func NewReqCollapse(client Client) Client {
return &reqCollapse{client}
}
func (r reqCollapse) Close() error {
if r.Client == nil {
panic("client should not be nil")
}
return r.Client.Close()
}
func (r reqCollapse) SendRequest(ctx context.Context, addr string, req *tikvrpc.Request, timeout time.Duration) (*tikvrpc.Response, error) {
if r.Client == nil {
panic("client should not be nil")
}
if canCollapse, resp, err := r.tryCollapseRequest(ctx, addr, req, timeout); canCollapse {
return resp, err
}
return r.Client.SendRequest(ctx, addr, req, timeout)
}
func (r reqCollapse) SendRequestAsync(ctx context.Context, addr string, req *tikvrpc.Request, cb async.Callback[*tikvrpc.Response]) {
if r.Client == nil {
panic("client should not be nil")
}
cli, ok := r.Client.(ClientAsync)
if !ok {
cb.Invoke(nil, errors.Errorf("%T dose not implement ClientAsync interface", r.Client))
return
}
if req.Type == tikvrpc.CmdResolveLock && len(req.ResolveLock().Keys) == 0 && len(req.ResolveLock().TxnInfos) == 0 {
// try collapse resolve lock request.
key := strconv.FormatUint(req.Context.RegionId, 10) + "-" + strconv.FormatUint(req.ResolveLock().StartVersion, 10)
copyReq := *req
rsC := resolveRegionSf.DoChan(key, func() (interface{}, error) {
// resolveRegionSf will call this function in a goroutine, thus use SendRequest directly.
return r.Client.SendRequest(context.Background(), addr, &copyReq, ReadTimeoutShort)
})
// waiting the response in another goroutine.
cb.Executor().Go(func() {
select {
case <-ctx.Done():
cb.Schedule(nil, errors.WithStack(ctx.Err()))
case rs := <-rsC:
if rs.Err != nil {
cb.Schedule(nil, errors.WithStack(rs.Err))
return
}
cb.Schedule(rs.Val.(*tikvrpc.Response), nil)
}
})
} else {
cli.SendRequestAsync(ctx, addr, req, cb)
}
}
func (r reqCollapse) tryCollapseRequest(ctx context.Context, addr string, req *tikvrpc.Request, timeout time.Duration) (canCollapse bool, resp *tikvrpc.Response, err error) {
switch req.Type {
case tikvrpc.CmdResolveLock:
resolveLock := req.ResolveLock()
if len(resolveLock.Keys) > 0 {
// can not collapse resolve lock lite
return
}
if len(resolveLock.TxnInfos) > 0 {
// can not collapse batch resolve locks which is only used by GC worker.
return
}
canCollapse = true
key := strconv.FormatUint(req.Context.RegionId, 10) + "-" + strconv.FormatUint(resolveLock.StartVersion, 10)
resp, err = r.collapse(ctx, key, &resolveRegionSf, addr, req, timeout)
return
default:
// now we only support collapse resolve lock.
return
}
}
func (r reqCollapse) collapse(ctx context.Context, key string, sf *singleflight.Group,
addr string, req *tikvrpc.Request, timeout time.Duration) (resp *tikvrpc.Response, err error) {
// because the request may be used by other goroutines, copy the request to avoid data race.
copyReq := *req
rsC := sf.DoChan(key, func() (interface{}, error) {
return r.Client.SendRequest(context.Background(), addr, &copyReq, ReadTimeoutShort) // use resolveLock timeout.
})
timer := time.NewTimer(timeout)
defer timer.Stop()
select {
case <-ctx.Done():
err = errors.WithStack(ctx.Err())
return
case <-timer.C:
err = errors.WithStack(context.DeadlineExceeded)
return
case rs := <-rsC:
if rs.Err != nil {
err = errors.WithStack(rs.Err)
return
}
resp = rs.Val.(*tikvrpc.Response)
return
}
}