第 11 章： AOF 持久化

Redis 服务器在进行 AOF 持久化时， 客户端、服务器与 AOF 文件之间的互动。

digraph { label = "\n图 11-1 AOF 持久化"; rankdir = LR; // client [label = "客户端", shape = circle, height = 1.3, width = 1.3]; server [label = "服务器", shape = box, width = 1.0, height = 2, width = 1.5]; aof [label = "AOF 文件", shape = note, height = 1.3]; // client -> server [label = "发送写命令"]; server -> aof [label = "保存被执行的写命令"]; }

AOF 文件的载入过程。

digraph { label = "\n 图 11-2 AOF 文件载入过程" // node [shape = box] start_loading [label = "服务器启动载入程序", width = 4] create_fake_client [label = "创建伪客户端", width = 4] load_a_command_from_aof [label = "从 AOF 文件中分析并读取出一条写命令", width = 4] exec_command_via_fake_client [label = "使用伪客户端执行写命令"] all_command_exec_or_not [shape = diamond, label = "AOF 文件中的所有写命令\n都已经被执行完毕？"] done [label = "载入完毕", width = 4] // start_loading -> create_fake_client -> load_a_command_from_aof -> exec_command_via_fake_client -> all_command_exec_or_not; all_command_exec_or_not -> done [label = "是"] all_command_exec_or_not -> load_a_command_from_aof [label = "否"] }

在进行 AOF 重写时， 服务器会同时将命令发送给 AOF 文件和 AOF 重写缓冲区。

digraph { label = "图 11-4 服务器同时将命令发送给 AOF 文件和 AOF 重写缓冲区"; rankdir = LR; client [label = "客户端", shape = circle, height = 1.5]; subgraph cluster_server { label = "服务器"; command_handler [label = "命\n令\n处\n理\n器", shape = box, height = 2.0]; aof_rewrite_buf [label = "AOF 重写缓冲区", shape = box]; aof_buf [label = "AOF 缓冲区", shape = box]; command_handler -> aof_rewrite_buf [label = "追加命令"]; command_handler -> aof_buf [label = "追加命令"]; } client -> command_handler [label = "发送命令"]; }