第 14 章： 服务器 ==================== 用户通过客户端向服务器发送命令请求的过程。 .. graphviz:: digraph { label = "\n\n 图 14-1 客户端接收并发送命令请求的过程"; rankdir = LR; node [shape = plaintext]; user [label = "用户"]; client [label = "客户端"]; server [label = "服务器"]; // user -> client [label = "键入命令请求"]; client -> server [label = "将命令请求转换成协议格式\n然后发送"]; } ---- 服务器向用户返回命令回复的过程。 .. graphviz:: digraph { label = "\n\n 图 14-8 客户端接收并打印命令回复的过程"; rankdir = LR; node [shape = plaintext]; user [label = "用户"]; client [label = "客户端"]; server [label = "服务器"]; // server -> client [label = "回复处理器将协议格式的\n命令回复返回给客户端"]; client -> user [label = "将回复格式化成人类可读格式 \n 然后打印显示"]; } ---- Redis 的命令表示例。 .. graphviz:: digraph { label = "\n 图 14-4 命令表"; rankdir = LR; node [shape = record]; commands [label = " 命令表 | ... | \"set\" | \"get\" | ... | \"sadd\" | ... | \"rpush\" | ... | \"publish\" | ... ", width = 2.0]; set [label = " redisCommand | name \n \"set\" | proc | arity \n -3 | sflags \n \"wm\" | ... "]; get [label = " redisCommand | name \n \"get\" | proc | arity \n 2 | sflags \n \"r\" | ... "]; //sadd [label = " redisCommand | name \n \"sadd\" | proc | arity \n -3 | sflags \n \"wm\" | ... "]; //rpush [label = " redisCommand | name \n \"rpush\" | proc | arity \n -3 | sflags \n \"wm\" | ... "]; //publish [label = " redisCommand | name \n \"publish\" | proc | arity \n 3 | sflags \n \"pltr\" | ... "]; node [shape = plaintext]; setCommand [label = "void setCommand(redisClient *c);"]; getCommand [label = "void getCommand(redisClient *c);"]; //saddCommand; //rpushCommand; //publishCommand; // commands:set -> set:head; set:proc -> setCommand; commands:get -> get:head; get:proc -> getCommand; //commands:sadd -> sadd:head; sadd:proc -> saddCommand; //commands:rpush -> rpush:head; rpush:proc -> rpushCommand; //commands:publish -> publish:head; publish:proc -> publishCommand; //* fix editor highlight } ---- 服务器判断是否需要执行持久化操作的流程。 .. graphviz:: digraph { label = "\n 图 14-9 判断是否需要执行持久化操作"; // node [shape = box] start [label = "服务器没有在执行任何持久化操作"] delay_bgrewriteaof_exists_or_not [shape = diamond, label = "有 BGREWRITEAOF 被延迟？"] go_bgrewriteaof [label = "执行 BGREWRITEAOF"] bgsave_satisfied_or_not [shape = diamond, label = "自动保存的条件已经满足？"] go_bgsave [label = "执行 BGSAVE"] bgrewriteaof_satisfied_or_not [shape = diamond, label = "AOF 重写的条件已经满足？"] go_do_nothing [label = "不做动作"] // start -> delay_bgrewriteaof_exists_or_not delay_bgrewriteaof_exists_or_not -> go_bgrewriteaof [label = "是"] delay_bgrewriteaof_exists_or_not -> bgsave_satisfied_or_not [label = "否"] bgsave_satisfied_or_not -> go_bgsave [label = "是"] bgsave_satisfied_or_not -> bgrewriteaof_satisfied_or_not [label = "否"] bgrewriteaof_satisfied_or_not -> go_bgrewriteaof [label = "是"] bgrewriteaof_satisfied_or_not -> go_do_nothing [label = "否"] }