github.com/KinWaiYuen/client-go/v2@v2.5.4/kv/store_vars.go (about)

     1  // Copyright 2021 TiKV Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // NOTE: The code in this file is based on code from the
    16  // TiDB project, licensed under the Apache License v 2.0
    17  //
    18  // https://github.com/pingcap/tidb/tree/cc5e161ac06827589c4966674597c137cc9e809c/store/tikv/kv/store_vars.go
    19  //
    20  
    21  // Copyright 2019 PingCAP, Inc.
    22  //
    23  // Licensed under the Apache License, Version 2.0 (the "License");
    24  // you may not use this file except in compliance with the License.
    25  // You may obtain a copy of the License at
    26  //
    27  //     http://www.apache.org/licenses/LICENSE-2.0
    28  //
    29  // Unless required by applicable law or agreed to in writing, software
    30  // distributed under the License is distributed on an "AS IS" BASIS,
    31  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    32  // See the License for the specific language governing permissions and
    33  // limitations under the License.
    34  
    35  package kv
    36  
    37  import (
    38  	"go.uber.org/atomic"
    39  )
    40  
    41  // StoreLimit will update from config reload and global variable set.
    42  var StoreLimit atomic.Int64
    43  
    44  // ReplicaReadType is the type of replica to read data from
    45  type ReplicaReadType byte
    46  
    47  const (
    48  	// ReplicaReadLeader stands for 'read from leader'.
    49  	ReplicaReadLeader ReplicaReadType = iota
    50  	// ReplicaReadFollower stands for 'read from follower'.
    51  	ReplicaReadFollower
    52  	// ReplicaReadMixed stands for 'read from leader and follower and learner'.
    53  	ReplicaReadMixed
    54  )
    55  
    56  // IsFollowerRead checks if follower is going to be used to read data.
    57  func (r ReplicaReadType) IsFollowerRead() bool {
    58  	return r != ReplicaReadLeader
    59  }