caller should hold cfg.mu

Maximum log size across all servers

生成一个客户端

the tester calls MakeClerk. ctrlers[] is needed to call shardctrler.MakeClerk(). make_end(servername) turns a server name from a Config.Groups[gid]

create a Coordinator. main/mrcoordinator.go calls this function. nReduce is the number of reduce tasks to use.

predict effect of Append(k, val) if old value is prev.

判断能否执行客户端发来的命令

needed by shardkv tester

Shutdown a server by isolating it

servers[] contains the ports of the set of servers that will cooperate via Raft to form the fault-tolerant key/value service. me is the index of the

* 初始服务器 */ servers[] contains the ports of the servers in this group. me is the index of the current server in servers[]. the k/v server should sto

main/mrworker.go calls this function.

* 处理好input shard，请求源节点清除output shard */ 发送给shard源节点，可以删除shard数据了 一般在apply command中处理好input的shard，发送给源节点删除保存的shard数据

check that all known appends are present in a value, and are in order for each concurrent client.

warn if the value contains non-default values, as it would if one sent an RPC but the reply struct was already modified. if the RPC reply contains de

check that none of the connected servers thinks it is the leader.

做map任务

做reduce任务

开始做任务

获取指定的shard

* 定时任务，请求input shard */ 定时获取shard

获取要向指定节点发送的日志

reduce任务时获取要输出的文件名

rpc请求：请求获取任务

处理applych

应用每一条命令

应用每一条命令

处理已经迁移走的shard，即output shard

处理config命令，即更新config 主要是处理meshard、inputshard、outputshard

* applych处理代码 */

处理新的shard数据，即input shard

处理get、put、append命令

use ihash(key) % NReduce to choose the reduce task number for each KeyValue emitted by Map.

load the application Map and Reduce functions from a plugin file, e.g. ../mrapps/wc.so

load the application Map and Reduce functions from a plugin file, e.g. ../mrapps/wc.so

Partition servers into 2 groups and put current leader in minority

data layout: bits 0-63 are in data[0], the next are in data[1], etc.

repartition the servers periodically

* 定时任务 */

Randomize server handles

Randomize server handles

restore previously persisted state. 读取持久化数据

example function to show how to make an RPC call to the coordinator. the RPC argument and reply types are defined in rpc.go. func CallExample() {

a client runs the function f and then signals it is done

保存快照

定时更新状态

发送端发送数据

向指定节点发送快照

example code to send a RequestVote RPC to a server. server is the index of the target server in rf.peers[]. expects RPC arguments in args. fills in *

an example RPC handler. the RPC argument and reply types are defined in rpc.go. func (c *Coordinator) Example(args *ExampleArgs, reply *ExampleRepl

处理要应用的日志，快照的命令比较特殊，不在这里提交

The ticker go routine starts a new election if this peer hasn't received heartsbeats recently.

尝试去提交日志 会依次判断，可以提交多个，但不能有间断

接收端处理rpc 主要进行三个处理： 1. 判断任期 2. 判断是否接收数据，success：数据全部接受，或者根本就没有数据 3. 判断是否提交数据