client-go/kv/store_vars.go

103 lines
3.1 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/kv/store_vars.go
//
// Copyright 2019 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 kv
import (
"fmt"
"go.uber.org/atomic"
)
// StoreLimit will update from config reload and global variable set.
var StoreLimit atomic.Int64
// DefTxnCommitBatchSize is the default value of TxnCommitBatchSize.
const DefTxnCommitBatchSize uint64 = 16 * 1024
// TxnCommitBatchSize controls the batch size of transaction commit related requests sent by client to TiKV,
// TiKV recommends each RPC packet should be less than ~1MB.
var TxnCommitBatchSize atomic.Uint64
func init() {
TxnCommitBatchSize.Store(DefTxnCommitBatchSize)
}
// ReplicaReadType is the type of replica to read data from
type ReplicaReadType byte
const (
// ReplicaReadLeader stands for 'read from leader'.
ReplicaReadLeader ReplicaReadType = iota
// ReplicaReadFollower stands for 'read from follower'.
ReplicaReadFollower
// ReplicaReadMixed stands for 'read from leader and follower and learner'.
ReplicaReadMixed
// ReplicaReadLearner stands for 'read from learner'.
ReplicaReadLearner
// ReplicaReadPreferLeader stands for 'read from leader and auto-turn to followers if leader is abnormal'.
ReplicaReadPreferLeader
)
// IsFollowerRead checks if follower is going to be used to read data.
func (r ReplicaReadType) IsFollowerRead() bool {
return r != ReplicaReadLeader
}
// String implements fmt.Stringer interface.
func (r ReplicaReadType) String() string {
switch r {
case ReplicaReadLeader:
return "leader"
case ReplicaReadFollower:
return "follower"
case ReplicaReadMixed:
return "mixed"
case ReplicaReadLearner:
return "learner"
case ReplicaReadPreferLeader:
return "prefer-leader"
default:
return fmt.Sprintf("unknown-%v", byte(r))
}
}
type AccessLocationType byte
const (
AccessUnknown AccessLocationType = iota
AccessLocalZone
AccessCrossZone
)