aof\u4fdd\u5b58
aof\u662fredis\u7684\u4e00\u79cd\u6301\u4e45\u5316\u65b9\u5f0f,\u53ef\u4ee5\u6839\u636e\u914d\u7f6e\u81ea\u52a8\u89e6\u53d1\u4fdd\u5b58,\u4e5f\u53ef\u4ee5\u624b\u52a8\u6267\u884c\u4fdd\u5b58
\/\/\u5728\u914d\u7f6e\u4e2d
appendonly yes \/\/\u6253\u5f00aof\u4fdd\u5b58
appendfilename “aof111.aof” \/\/ \u8bbe\u7f6eaof\u62a5\u9519\u8def\u5f84
appendfsync always \/\/ \u6bcf\u6b21\u64cd\u4f5c\u90fdaof\u4fdd\u5b58
appendfsync everysec \/\/ \u6bcf\u79d2aof\u4fdd\u5b58
appendfsync no \/\/ \u4e0d\u4fdd\u5b58
1.\u624b\u52a8\u4fdd\u5b58,\u5f53\u5ba2\u6237\u7aef\u6267\u884cbgrewriteaof\u547d\u4ee4,redis\u670d\u52a1\u7aef\u4f1a\u6267\u884cbgrewriteaofCommand\u65b9\u6cd5\u5f00\u59cb\u76f8\u5173\u7684\u4fdd\u5b58\u903b\u8f91
2.\u81ea\u52a8\u4fdd\u5b58,\u5f53\u5ba2\u6237\u7aef\u4f20\u6765\u547d\u4ee4\u540e,redis\u5728call\u65b9\u6cd5\u6267\u884cc->cmd->proc\u547d\u4ee4\u540e,\u4f1a\u5bf9\u547d\u4ee4\u8fdb\u884c\u8bb0\u5f55,\u5c06\u547d\u4ee4\u5b58\u653e\u5230server.aof_buf\u4e2d,\u5f53\u4e0b\u4e00\u4e2a\u4e8b\u4ef6\u5230\u6765\u65f6(beforeSleep)\u6216\u8005\u670d\u52a1\u5668\u6bcf\u6beb\u79d2\u7684\u5faa\u73af(serverCron)\u4f1a\u6839\u636e\u914d\u7f6e\u770b\u662f\u5426\u89e6\u53d1\u5199\u6587\u4ef6<\/p>\n\n\n\n
\n\/\/1.beforeSleep\u624b\u52a8\u4fdd\u5b58\nvoid bgrewriteaofCommand(redisClient *c)\n{\n if (server.aof_child_pid != -1)\n {\n addReplyError(c, \"Background append only file rewriting already in progress\");\n }\n else if (server.rdb_child_pid != -1)\n {\n server.aof_rewrite_scheduled = 1;\n addReplyStatus(c, \"Background append only file rewriting scheduled\");\n }\n else if (rewriteAppendOnlyFileBackground() == REDIS_OK)\n {\n addReplyStatus(c, \"Background append only file rewriting started\");\n }\n else\n {\n addReply(c, shared.err);\n }\n}\n\/\/ \u540e\u53f0\u4fdd\u5b58\nint rewriteAppendOnlyFileBackground(void)\n{\n pid_t childpid;\n long long start;\n\n \/\/ \u5df2\u7ecf\u6709\u8fdb\u7a0b\u5728\u8fdb\u884c AOF \u91cd\u5199\u4e86\n if (server.aof_child_pid != -1)\n return REDIS_ERR;\n\n \/\/ \u8bb0\u5f55 fork \u5f00\u59cb\u524d\u7684\u65f6\u95f4\uff0c\u8ba1\u7b97 fork \u8017\u65f6\u7528\n start = ustime();\n\n if ((childpid = fork()) == 0)\n {\n char tmpfile[256];\n\n \/* Child *\/\n\n \/\/ \u5173\u95ed\u7f51\u7edc\u8fde\u63a5 fd\n closeListeningSockets(0);\n\n \/\/ \u4e3a\u8fdb\u7a0b\u8bbe\u7f6e\u540d\u5b57\uff0c\u65b9\u4fbf\u8bb0\u8ba4\n redisSetProcTitle(\"redis-aof-rewrite\");\n\n \/\/ \u521b\u5efa\u4e34\u65f6\u6587\u4ef6\uff0c\u5e76\u8fdb\u884c AOF \u91cd\u5199\n snprintf(tmpfile, 256, \"temp-rewriteaof-bg-%d.aof\", (int)getpid());\n if (rewriteAppendOnlyFile(tmpfile) == REDIS_OK)\n {\n size_t private_dirty = zmalloc_get_private_dirty();\n\n if (private_dirty)\n {\n redisLog(REDIS_NOTICE,\n \"AOF rewrite: %zu MB of memory used by copy-on-write\",\n private_dirty \/ (1024 * 1024));\n }\n \/\/ \u53d1\u9001\u91cd\u5199\u6210\u529f\u4fe1\u53f7\n exitFromChild(0);\n }\n else\n {\n \/\/ \u53d1\u9001\u91cd\u5199\u5931\u8d25\u4fe1\u53f7\n exitFromChild(1);\n }\n }\n else\n {\n \/* Parent *\/\n \/\/ \u8bb0\u5f55\u6267\u884c fork \u6240\u6d88\u8017\u7684\u65f6\u95f4\n server.stat_fork_time = ustime() - start;\n\n if (childpid == -1)\n {\n redisLog(REDIS_WARNING,\n \"Can't rewrite append only file in background: fork: %s\",\n strerror(errno));\n return REDIS_ERR;\n }\n\n redisLog(REDIS_NOTICE,\n \"Background append only file rewriting started by pid %d\", childpid);\n\n \/\/ \u8bb0\u5f55 AOF \u91cd\u5199\u7684\u4fe1\u606f\n server.aof_rewrite_scheduled = 0;\n server.aof_rewrite_time_start = time(NULL);\n server.aof_child_pid = childpid;\n\n \/\/ \u5173\u95ed\u5b57\u5178\u81ea\u52a8 rehash\n updateDictResizePolicy();\n\n \/* We set appendseldb to -1 in order to force the next call to the\n * feedAppendOnlyFile() to issue a SELECT command, so the differences\n * accumulated by the parent into server.aof_rewrite_buf will start\n * with a SELECT statement and it will be safe to merge. \n *\n * \u5c06 aof_selected_db \u8bbe\u4e3a -1 \uff0c\n * \u5f3a\u5236\u8ba9 feedAppendOnlyFile() \u4e0b\u6b21\u6267\u884c\u65f6\u5f15\u53d1\u4e00\u4e2a SELECT \u547d\u4ee4\uff0c\n * \u4ece\u800c\u786e\u4fdd\u4e4b\u540e\u65b0\u6dfb\u52a0\u7684\u547d\u4ee4\u4f1a\u8bbe\u7f6e\u5230\u6b63\u786e\u7684\u6570\u636e\u5e93\u4e2d\n *\/\n server.aof_selected_db = -1;\n replicationScriptCacheFlush();\n return REDIS_OK;\n }\n return REDIS_OK; \/* unreached *\/\n}\n\/\/\u5177\u4f53\u91cd\u5199\u903b\u8f91\nint rewriteAppendOnlyFile(char *filename)\n{\n dictIterator *di = NULL;\n dictEntry *de;\n rio aof;\n FILE *fp;\n char tmpfile[256];\n int j;\n long long now = mstime();\n\n \/* Note that we have to use a different temp name here compared to the\n * one used by rewriteAppendOnlyFileBackground() function. \n *\n * \u521b\u5efa\u4e34\u65f6\u6587\u4ef6\n *\n * \u6ce8\u610f\u8fd9\u91cc\u521b\u5efa\u7684\u6587\u4ef6\u540d\u548c rewriteAppendOnlyFileBackground() \u521b\u5efa\u7684\u6587\u4ef6\u540d\u7a0d\u6709\u4e0d\u540c\n *\/\n snprintf(tmpfile, 256, \"temp-rewriteaof-%d.aof\", (int)getpid());\n fp = fopen(tmpfile, \"w\");\n if (!fp)\n {\n redisLog(REDIS_WARNING, \"Opening the temp file for AOF rewrite in rewriteAppendOnlyFile(): %s\", strerror(errno));\n return REDIS_ERR;\n }\n\n \/\/ \u521d\u59cb\u5316\u6587\u4ef6 io\n rioInitWithFile(&aof, fp);\n\n \/\/ \u8bbe\u7f6e\u6bcf\u5199\u5165 REDIS_AOF_AUTOSYNC_BYTES \u5b57\u8282\n \/\/ \u5c31\u6267\u884c\u4e00\u6b21 FSYNC\n \/\/ \u9632\u6b62\u7f13\u5b58\u4e2d\u79ef\u7d2f\u592a\u591a\u547d\u4ee4\u5185\u5bb9\uff0c\u9020\u6210 I\/O \u963b\u585e\u65f6\u95f4\u8fc7\u957f\n if (server.aof_rewrite_incremental_fsync)\n rioSetAutoSync(&aof, REDIS_AOF_AUTOSYNC_BYTES);\n\n \/\/ \u904d\u5386\u6240\u6709\u6570\u636e\u5e93\n for (j = 0; j < server.dbnum; j++)\n {\n\n char selectcmd[] = \"*2\\r\\n6\\r\\nSELECT\\r\\n\";\n\n redisDb *db = server.db + j;\n\n \/\/ \u6307\u5411\u952e\u7a7a\u95f4\n dict *d = db->dict;\n if (dictSize(d) == 0)\n continue;\n\n \/\/ \u521b\u5efa\u952e\u7a7a\u95f4\u8fed\u4ee3\u5668\n di = dictGetSafeIterator(d);\n if (!di)\n {\n fclose(fp);\n return REDIS_ERR;\n }\n\n \/* SELECT the new DB *\n * \u9996\u5148\u5199\u5165 SELECT \u547d\u4ee4\uff0c\u786e\u4fdd\u4e4b\u540e\u7684\u6570\u636e\u4f1a\u88ab\u63d2\u5165\u5230\u6b63\u786e\u7684\u6570\u636e\u5e93\u4e0a\n *\/\n if (rioWrite(&aof, selectcmd, sizeof(selectcmd) - 1) == 0)\n goto werr;\n if (rioWriteBulkLongLong(&aof, j) == 0)\n goto werr;\n\n \/* Iterate this DB writing every entry *\n * \u904d\u5386\u6570\u636e\u5e93\u6240\u6709\u952e\uff0c\u5e76\u901a\u8fc7\u547d\u4ee4\u5c06\u5b83\u4eec\u7684\u5f53\u524d\u72b6\u6001\uff08\u503c\uff09\u8bb0\u5f55\u5230\u65b0 AOF \u6587\u4ef6\u4e2d\n *\/\n while ((de = dictNext(di)) != NULL)\n {\n sds keystr;\n robj key, *o;\n long long expiretime;\n\n \/\/ \u53d6\u51fa\u952e\n keystr = dictGetKey(de);\n\n \/\/ \u53d6\u51fa\u503c\n o = dictGetVal(de);\n initStaticStringObject(key, keystr);\n\n \/\/ \u53d6\u51fa\u8fc7\u671f\u65f6\u95f4\n expiretime = getExpire(db, &key);\n\n \/* If this key is already expired skip it *\n * \u5982\u679c\u952e\u5df2\u7ecf\u8fc7\u671f\uff0c\u90a3\u4e48\u8df3\u8fc7\u5b83\uff0c\u4e0d\u4fdd\u5b58\n *\/\n if (expiretime != -1 && expiretime3\\r\\nSET\\r\\n\";\n if (rioWrite(&aof, cmd, sizeof(cmd) - 1) == 0)\n goto werr;\n \/* Key and value *\/\n if (rioWriteBulkObject(&aof, &key) == 0)\n goto werr;\n if (rioWriteBulkObject(&aof, o) == 0)\n goto werr;\n }\n else if (o->type == REDIS_LIST)\n {\n if (rewriteListObject(&aof, &key, o) == 0)\n goto werr;\n }\n else if (o->type == REDIS_SET)\n {\n if (rewriteSetObject(&aof, &key, o) == 0)\n goto werr;\n }\n else if (o->type == REDIS_ZSET)\n {\n if (rewriteSortedSetObject(&aof, &key, o) == 0)\n goto werr;\n }\n else if (o->type == REDIS_HASH)\n {\n if (rewriteHashObject(&aof, &key, o) == 0)\n goto werr;\n }\n else\n {\n redisPanic(\"Unknown object type\");\n }\n\n \/* Save the expire time \n *\n * \u4fdd\u5b58\u952e\u7684\u8fc7\u671f\u65f6\u95f4\n *\/\n if (expiretime != -1)\n {\n char cmd[] = \"*3\\r\\n9\\r\\nPEXPIREAT\\r\\n\";\n\n \/\/ \u5199\u5165 PEXPIREAT expiretime \u547d\u4ee4\n if (rioWrite(&aof, cmd, sizeof(cmd) - 1) == 0)\n goto werr;\n if (rioWriteBulkObject(&aof, &key) == 0)\n goto werr;\n if (rioWriteBulkLongLong(&aof, expiretime) == 0)\n goto werr;\n }\n }\n\n \/\/ \u91ca\u653e\u8fed\u4ee3\u5668\n dictReleaseIterator(di);\n }\n\n \/* Make sure data will not remain on the OS's output buffers *\/\n \/\/ \u51b2\u6d17\u5e76\u5173\u95ed\u65b0 AOF \u6587\u4ef6\n if (fflush(fp) == EOF)\n goto werr;\n if (aof_fsync(fileno(fp)) == -1)\n goto werr;\n if (fclose(fp) == EOF)\n goto werr;\n\n \/* Use RENAME to make sure the DB file is changed atomically only\n * if the generate DB file is ok. *\n * \u539f\u5b50\u5730\u6539\u540d\uff0c\u7528\u91cd\u5199\u540e\u7684\u65b0 AOF \u6587\u4ef6\u8986\u76d6\u65e7 AOF \u6587\u4ef6\n *\/\n if (rename(tmpfile, filename) == -1)\n {\n redisLog(REDIS_WARNING, \"Error moving temp append only file on the final destination: %s\", strerror(errno));\n unlink(tmpfile);\n return REDIS_ERR;\n }\n\n redisLog(REDIS_NOTICE, \"SYNC append only file rewrite performed\");\n\n return REDIS_OK;\n\nwerr:\n fclose(fp);\n unlink(tmpfile);\n redisLog(REDIS_WARNING, \"Write error writing append only file on disk: %s\", strerror(errno));\n if (di)\n dictReleaseIterator(di);\n return REDIS_ERR;\n}\n\n\/\/ 2.\u81ea\u52a8\u5f00\u542f\u7684aof\n\/\/redis.c\nvoid call(redisClient *c, int flags)\n{\n \/\/ \u6267\u884c\u5b9e\u73b0\u51fd\u6570\n c->cmd->proc(c);\n \/\/ \u5c06\u547d\u4ee4\u590d\u5236\u5230 AOF \u548c slave \u8282\u70b9\n if (flags&REDIS_CALL_PROPAGATE)\n {\n int flags = REDIS_PROPAGATE_NONE;\n\n \/\/ \u5f3a\u5236 REPL \u4f20\u64ad\n if (c->flags&REDIS_FORCE_REPL)\n flags |= REDIS_PROPAGATE_REPL;\n\n \/\/ \u5f3a\u5236 AOF \u4f20\u64ad\n if (c->flags&REDIS_FORCE_AOF)\n flags |= REDIS_PROPAGATE_AOF;\n\n \/\/ \u5982\u679c\u6570\u636e\u5e93\u6709\u88ab\u4fee\u6539\uff0c\u90a3\u4e48\u542f\u7528 REPL \u548c AOF \u4f20\u64ad\n if (dirty)\n flags |= (REDIS_PROPAGATE_REPL | REDIS_PROPAGATE_AOF);\n\n if (flags != REDIS_PROPAGATE_NONE)\n propagate(c->cmd, c->db->id, c->argv, c->argc, flags);\n }\n}\nvoid propagate(struct redisCommand *cmd, int dbid, robj **argv, int argc,\n int flags)\n{\n \/\/ \u4f20\u64ad\u5230 AOF\n if (server.aof_state != REDIS_AOF_OFF && flags&REDIS_PROPAGATE_AOF)\n feedAppendOnlyFile(cmd, dbid, argv, argc);\n\n \/\/ \u4f20\u64ad\u5230 slave\n if (flags&REDIS_PROPAGATE_REPL)\n replicationFeedSlaves(server.slaves, dbid, argv, argc);\n}\n\n\/*\n * \u5c06\u547d\u4ee4\u8ffd\u52a0\u5230 AOF \u6587\u4ef6\u4e2d\uff0c\n * \u5982\u679c AOF \u91cd\u5199\u6b63\u5728\u8fdb\u884c\uff0c\u90a3\u4e48\u4e5f\u5c06\u547d\u4ee4\u8ffd\u52a0\u5230 AOF \u91cd\u5199\u7f13\u5b58\u4e2d\u3002\n *\/\nvoid feedAppendOnlyFile(struct redisCommand *cmd, int dictid, robj **argv, int argc)\n{\n sds buf = sdsempty();\n robj *tmpargv[3];\n\n \/* The DB this command was targeting is not the same as the last command\n * we appendend. To issue a SELECT command is needed. *\n * \u4f7f\u7528 SELECT \u547d\u4ee4\uff0c\u663e\u5f0f\u8bbe\u7f6e\u6570\u636e\u5e93\uff0c\u786e\u4fdd\u4e4b\u540e\u7684\u547d\u4ee4\u88ab\u8bbe\u7f6e\u5230\u6b63\u786e\u7684\u6570\u636e\u5e93\n *\/\n if (dictid != server.aof_selected_db)\n {\n char seldb[64];\n\n snprintf(seldb, sizeof(seldb), \"%d\", dictid);\n buf = sdscatprintf(buf, \"*2\\r\\n<\/span>6\\r\\nSELECT\\r\\n$%lu\\r\\n%s\\r\\n\",\n (unsigned long)strlen(seldb), seldb);\n\n server.aof_selected_db = dictid;\n }\n\n \/\/ EXPIRE \u3001 PEXPIRE \u548c EXPIREAT \u547d\u4ee4\n if (cmd->proc == expireCommand || cmd->proc == pexpireCommand ||\n cmd->proc == expireatCommand)\n {\n \/* Translate EXPIRE\/PEXPIRE\/EXPIREAT into PEXPIREAT \n *\n * \u5c06 EXPIRE \u3001 PEXPIRE \u548c EXPIREAT \u90fd\u7ffb\u8bd1\u6210 PEXPIREAT\n *\/\n buf = catAppendOnlyExpireAtCommand(buf, cmd, argv[1], argv[2]);\n\n \/\/ SETEX \u548c PSETEX \u547d\u4ee4\n }\n else if (cmd->proc == setexCommand || cmd->proc == psetexCommand)\n {\n \/* Translate SETEX\/PSETEX to SET and PEXPIREAT \n *\n * \u5c06\u4e24\u4e2a\u547d\u4ee4\u90fd\u7ffb\u8bd1\u6210 SET \u548c PEXPIREAT\n *\/\n\n \/\/ SET\n tmpargv[0] = createStringObject(\"SET\", 3);\n tmpargv[1] = argv[1];\n tmpargv[2] = argv[3];\n buf = catAppendOnlyGenericCommand(buf, 3, tmpargv);\n\n \/\/ PEXPIREAT\n decrRefCount(tmpargv[0]);\n buf = catAppendOnlyExpireAtCommand(buf, cmd, argv[1], argv[2]);\n\n \/\/ \u5176\u4ed6\u547d\u4ee4\n }\n else\n {\n \/* All the other commands don't need translation or need the\n * same translation already operated in the command vector\n * for the replication itself. *\/\n buf = catAppendOnlyGenericCommand(buf, argc, argv);\n }\n\n \/* Append to the AOF buffer. This will be flushed on disk just before\n * of re-entering the event loop, so before the client will get a\n * positive reply about the operation performed. \n *\n * \u5c06\u547d\u4ee4\u8ffd\u52a0\u5230 AOF \u7f13\u5b58\u4e2d\uff0c\n * \u5728\u91cd\u65b0\u8fdb\u5165\u4e8b\u4ef6\u5faa\u73af\u4e4b\u524d\uff0c\u8fd9\u4e9b\u547d\u4ee4\u4f1a\u88ab\u51b2\u6d17\u5230\u78c1\u76d8\u4e0a\uff0c\n * \u5e76\u5411\u5ba2\u6237\u7aef\u8fd4\u56de\u4e00\u4e2a\u56de\u590d\u3002\n *\/\n if (server.aof_state == REDIS_AOF_ON)\n server.aof_buf = sdscatlen(server.aof_buf, buf, sdslen(buf));\n\n \/* If a background append only file rewriting is in progress we want to\n * accumulate the differences between the child DB and the current one\n * in a buffer, so that when the child process will do its work we\n * can append the differences to the new append only file. \n *\n * \u5982\u679c BGREWRITEAOF \u6b63\u5728\u8fdb\u884c\uff0c\n * \u90a3\u4e48\u6211\u4eec\u8fd8\u9700\u8981\u5c06\u547d\u4ee4\u8ffd\u52a0\u5230\u91cd\u5199\u7f13\u5b58\u4e2d\uff0c\n * \u4ece\u800c\u8bb0\u5f55\u5f53\u524d\u6b63\u5728\u91cd\u5199\u7684 AOF \u6587\u4ef6\u548c\u6570\u636e\u5e93\u5f53\u524d\u72b6\u6001\u7684\u5dee\u5f02\u3002\n *\/\n if (server.aof_child_pid != -1)\n aofRewriteBufferAppend((unsigned char *)buf, sdslen(buf));\n\n \/\/ \u91ca\u653e\n sdsfree(buf);\n}\n\n\/\/ \u5c06aof_buf\u4e2d\u7684\u547d\u4ee4\u5237\u5230\u6587\u4ef6\nvoid flushAppendOnlyFile(int force)\n{\n ssize_t nwritten;\n int sync_in_progress = 0;\n\n \/\/ \u7f13\u51b2\u533a\u4e2d\u6ca1\u6709\u4efb\u4f55\u5185\u5bb9\uff0c\u76f4\u63a5\u8fd4\u56de\n if (sdslen(server.aof_buf) == 0)\n return;\n\n \/\/ \u7b56\u7565\u4e3a\u6bcf\u79d2 FSYNC\n if (server.aof_fsync == AOF_FSYNC_EVERYSEC)\n \/\/ \u662f\u5426\u6709 SYNC \u6b63\u5728\u540e\u53f0\u8fdb\u884c\uff1f\n sync_in_progress = bioPendingJobsOfType(REDIS_BIO_AOF_FSYNC) != 0;\n\n \/\/ \u6bcf\u79d2 fsync \uff0c\u5e76\u4e14\u5f3a\u5236\u5199\u5165\u4e3a\u5047\n if (server.aof_fsync == AOF_FSYNC_EVERYSEC && !force)\n {\n\n \/* With this append fsync policy we do background fsyncing.\n *\n * \u5f53 fsync \u7b56\u7565\u4e3a\u6bcf\u79d2\u949f\u4e00\u6b21\u65f6\uff0c fsync \u5728\u540e\u53f0\u6267\u884c\u3002\n *\n * If the fsync is still in progress we can try to delay\n * the write for a couple of seconds. \n *\n * \u5982\u679c\u540e\u53f0\u4ecd\u5728\u6267\u884c FSYNC \uff0c\u90a3\u4e48\u6211\u4eec\u53ef\u4ee5\u5ef6\u8fdf\u5199\u64cd\u4f5c\u4e00\u4e24\u79d2\n * \uff08\u5982\u679c\u5f3a\u5236\u6267\u884c write \u7684\u8bdd\uff0c\u670d\u52a1\u5668\u4e3b\u7ebf\u7a0b\u5c06\u963b\u585e\u5728 write \u4e0a\u9762\uff09\n *\/\n if (sync_in_progress)\n {\n\n \/\/ \u6709 fsync \u6b63\u5728\u540e\u53f0\u8fdb\u884c \u3002\u3002\u3002\n\n if (server.aof_flush_postponed_start == 0)\n {\n \/* No previous write postponinig, remember that we are\n * postponing the flush and return. \n *\n * \u524d\u9762\u6ca1\u6709\u63a8\u8fdf\u8fc7 write \u64cd\u4f5c\uff0c\u8fd9\u91cc\u5c06\u63a8\u8fdf\u5199\u64cd\u4f5c\u7684\u65f6\u95f4\u8bb0\u5f55\u4e0b\u6765\n * \u7136\u540e\u5c31\u8fd4\u56de\uff0c\u4e0d\u6267\u884c write \u6216\u8005 fsync\n *\/\n server.aof_flush_postponed_start = server.unixtime;\n return;\n }\n else if (server.unixtime - server.aof_flush_postponed_start < 2)\n {\n \/* We were already waiting for fsync to finish, but for less\n * than two seconds this is still ok. Postpone again. \n *\n * \u5982\u679c\u4e4b\u524d\u5df2\u7ecf\u56e0\u4e3a fsync \u800c\u63a8\u8fdf\u4e86 write \u64cd\u4f5c\n * \u4f46\u662f\u63a8\u8fdf\u7684\u65f6\u95f4\u4e0d\u8d85\u8fc7 2 \u79d2\uff0c\u90a3\u4e48\u76f4\u63a5\u8fd4\u56de\n * \u4e0d\u6267\u884c write \u6216\u8005 fsync\n *\/\n return;\n }\n\n \/* Otherwise fall trough, and go write since we can't wait\n * over two seconds. \n *\n * \u5982\u679c\u540e\u53f0\u8fd8\u6709 fsync \u5728\u6267\u884c\uff0c\u5e76\u4e14 write \u5df2\u7ecf\u63a8\u8fdf >= 2 \u79d2\n * \u90a3\u4e48\u6267\u884c\u5199\u64cd\u4f5c\uff08write \u5c06\u88ab\u963b\u585e\uff09\n *\/\n server.aof_delayed_fsync++;\n redisLog(REDIS_NOTICE, \"Asynchronous AOF fsync is taking too long (disk is busy?). Writing the AOF buffer without waiting for fsync to complete, this may slow down Redis.\");\n }\n }\n\n \/* If you are following this code path, then we are going to write so\n * set reset the postponed flush sentinel to zero. \n *\n * \u6267\u884c\u5230\u8fd9\u91cc\uff0c\u7a0b\u5e8f\u4f1a\u5bf9 AOF \u6587\u4ef6\u8fdb\u884c\u5199\u5165\u3002\n *\n * \u6e05\u96f6\u5ef6\u8fdf write \u7684\u65f6\u95f4\u8bb0\u5f55\n *\/\n server.aof_flush_postponed_start = 0;\n\n \/* We want to perform a single write. This should be guaranteed atomic\n * at least if the filesystem we are writing is a real physical one.\n *\n * \u6267\u884c\u5355\u4e2a write \u64cd\u4f5c\uff0c\u5982\u679c\u5199\u5165\u8bbe\u5907\u662f\u7269\u7406\u7684\u8bdd\uff0c\u90a3\u4e48\u8fd9\u4e2a\u64cd\u4f5c\u5e94\u8be5\u662f\u539f\u5b50\u7684\n *\n * While this will save us against the server being killed I don't think\n * there is much to do about the whole server stopping for power problems\n * or alike \n *\n * \u5f53\u7136\uff0c\u5982\u679c\u51fa\u73b0\u50cf\u7535\u6e90\u4e2d\u65ad\u8fd9\u6837\u7684\u4e0d\u53ef\u6297\u73b0\u8c61\uff0c\u90a3\u4e48 AOF \u6587\u4ef6\u4e5f\u662f\u53ef\u80fd\u4f1a\u51fa\u73b0\u95ee\u9898\u7684\n * \u8fd9\u65f6\u5c31\u8981\u7528 redis-check-aof \u7a0b\u5e8f\u6765\u8fdb\u884c\u4fee\u590d\u3002\n *\/\n nwritten = write(server.aof_fd, server.aof_buf, sdslen(server.aof_buf));\n if (nwritten != (signed)sdslen(server.aof_buf))\n {\n\n static time_t last_write_error_log = 0;\n int can_log = 0;\n\n \/* Limit logging rate to 1 line per AOF_WRITE_LOG_ERROR_RATE seconds. *\/\n \/\/ \u5c06\u65e5\u5fd7\u7684\u8bb0\u5f55\u9891\u7387\u9650\u5236\u5728\u6bcf\u884c AOF_WRITE_LOG_ERROR_RATE \u79d2\n if ((server.unixtime - last_write_error_log) > AOF_WRITE_LOG_ERROR_RATE)\n {\n can_log = 1;\n last_write_error_log = server.unixtime;\n }\n\n \/* Lof the AOF write error and record the error code. *\/\n \/\/ \u5982\u679c\u5199\u5165\u51fa\u9519\uff0c\u90a3\u4e48\u5c1d\u8bd5\u5c06\u8be5\u60c5\u51b5\u5199\u5165\u5230\u65e5\u5fd7\u91cc\u9762\n if (nwritten == -1)\n {\n if (can_log)\n {\n redisLog(REDIS_WARNING, \"Error writing to the AOF file: %s\",\n strerror(errno));\n server.aof_last_write_errno = errno;\n }\n }\n else\n {\n if (can_log)\n {\n redisLog(REDIS_WARNING, \"Short write while writing to \"\n \"the AOF file: (nwritten=%lld, \"\n \"expected=%lld)\",\n (long long)nwritten,\n (long long)sdslen(server.aof_buf));\n }\n\n \/\/ \u5c1d\u8bd5\u79fb\u9664\u65b0\u8ffd\u52a0\u7684\u4e0d\u5b8c\u6574\u5185\u5bb9\n if (ftruncate(server.aof_fd, server.aof_current_size) == -1)\n {\n if (can_log)\n {\n redisLog(REDIS_WARNING, \"Could not remove short write \"\n \"from the append-only file. Redis may refuse \"\n \"to load the AOF the next time it starts. \"\n \"ftruncate: %s\",\n strerror(errno));\n }\n }\n else\n {\n \/* If the ftrunacate() succeeded we can set nwritten to\n * -1 since there is no longer partial data into the AOF. *\/\n nwritten = -1;\n }\n server.aof_last_write_errno = ENOSPC;\n }\n\n \/* Handle the AOF write error. *\/\n \/\/ \u5904\u7406\u5199\u5165 AOF \u6587\u4ef6\u65f6\u51fa\u73b0\u7684\u9519\u8bef\n if (server.aof_fsync == AOF_FSYNC_ALWAYS)\n {\n \/* We can't recover when the fsync policy is ALWAYS since the\n * reply for the client is already in the output buffers, and we\n * have the contract with the user that on acknowledged write data\n * is synched on disk. *\/\n redisLog(REDIS_WARNING, \"Can't recover from AOF write error when the AOF fsync policy is 'always'. Exiting...\");\n exit(1);\n }\n else\n {\n \/* Recover from failed write leaving data into the buffer. However\n * set an error to stop accepting writes as long as the error\n * condition is not cleared. *\/\n server.aof_last_write_status = REDIS_ERR;\n\n \/* Trim the sds buffer if there was a partial write, and there\n * was no way to undo it with ftruncate(2). *\/\n if (nwritten > 0)\n {\n server.aof_current_size += nwritten;\n sdsrange(server.aof_buf, nwritten, -1);\n }\n return; \/* We'll try again on the next call... *\/\n }\n }\n else\n {\n \/* Successful write(2). If AOF was in error state, restore the\n * OK state and log the event. *\/\n \/\/ \u5199\u5165\u6210\u529f\uff0c\u66f4\u65b0\u6700\u540e\u5199\u5165\u72b6\u6001\n if (server.aof_last_write_status == REDIS_ERR)\n {\n redisLog(REDIS_WARNING,\n \"AOF write error looks solved, Redis can write again.\");\n server.aof_last_write_status = REDIS_OK;\n }\n }\n\n \/\/ \u66f4\u65b0\u5199\u5165\u540e\u7684 AOF \u6587\u4ef6\u5927\u5c0f\n server.aof_current_size += nwritten;\n\n \/* Re-use AOF buffer when it is small enough. The maximum comes from the\n * arena size of 4k minus some overhead (but is otherwise arbitrary). \n *\n * \u5982\u679c AOF \u7f13\u5b58\u7684\u5927\u5c0f\u8db3\u591f\u5c0f\u7684\u8bdd\uff0c\u90a3\u4e48\u91cd\u7528\u8fd9\u4e2a\u7f13\u5b58\uff0c\n * \u5426\u5219\u7684\u8bdd\uff0c\u91ca\u653e AOF \u7f13\u5b58\u3002\n *\/\n if ((sdslen(server.aof_buf) + sdsavail(server.aof_buf)) < 4000)\n {\n \/\/ \u6e05\u7a7a\u7f13\u5b58\u4e2d\u7684\u5185\u5bb9\uff0c\u7b49\u5f85\u91cd\u7528\n sdsclear(server.aof_buf);\n }\n else\n {\n \/\/ \u91ca\u653e\u7f13\u5b58\n sdsfree(server.aof_buf);\n server.aof_buf = sdsempty();\n }\n\n \/* Don't fsync if no-appendfsync-on-rewrite is set to yes and there are\n * children doing I\/O in the background. \n *\n * \u5982\u679c no-appendfsync-on-rewrite \u9009\u9879\u4e3a\u5f00\u542f\u72b6\u6001\uff0c\n * \u5e76\u4e14\u6709 BGSAVE \u6216\u8005 BGREWRITEAOF \u6b63\u5728\u8fdb\u884c\u7684\u8bdd\uff0c\n * \u90a3\u4e48\u4e0d\u6267\u884c fsync \n *\/\n if (server.aof_no_fsync_on_rewrite &&\n (server.aof_child_pid != -1 || server.rdb_child_pid != -1))\n return;\n\n \/* Perform the fsync if needed. *\/\n\n \/\/ \u603b\u662f\u6267\u884c fsnyc\n if (server.aof_fsync == AOF_FSYNC_ALWAYS)\n {\n \/* aof_fsync is defined as fdatasync() for Linux in order to avoid\n * flushing metadata. *\/\n aof_fsync(server.aof_fd); \/* Let's try to get this data on the disk *\/\n\n \/\/ \u66f4\u65b0\u6700\u540e\u4e00\u6b21\u6267\u884c fsnyc \u7684\u65f6\u95f4\n server.aof_last_fsync = server.unixtime;\n\n \/\/ \u7b56\u7565\u4e3a\u6bcf\u79d2 fsnyc \uff0c\u5e76\u4e14\u8ddd\u79bb\u4e0a\u6b21 fsync \u5df2\u7ecf\u8d85\u8fc7 1 \u79d2\n }\n else if ((server.aof_fsync == AOF_FSYNC_EVERYSEC &&\n server.unixtime > server.aof_last_fsync))\n {\n \/\/ \u653e\u5230\u540e\u53f0\u6267\u884c\n if (!sync_in_progress)\n aof_background_fsync(server.aof_fd);\n \/\/ \u66f4\u65b0\u6700\u540e\u4e00\u6b21\u6267\u884c fsync \u7684\u65f6\u95f4\n server.aof_last_fsync = server.unixtime;\n }\n\n \/\/ \u5176\u5b9e\u4e0a\u9762\u65e0\u8bba\u6267\u884c if \u90e8\u5206\u8fd8\u662f else \u90e8\u5206\u90fd\u8981\u66f4\u65b0 fsync \u7684\u65f6\u95f4\n \/\/ \u53ef\u4ee5\u5c06\u4ee3\u7801\u632a\u5230\u4e0b\u9762\u6765\n \/\/ server.aof_last_fsync = server.unixtime;\n}\n\n\/\/ \u6bcf\u6b21\u5904\u7406\u4e8b\u4ef6\u4e4b\u524d\u6267\u884c\nvoid beforeSleep(struct aeEventLoop *eventLoop)\n{\n \/* Write the AOF buffer on disk *\/\n \/\/ \u5c06 AOF \u7f13\u51b2\u533a\u7684\u5185\u5bb9\u5199\u5165\u5230 AOF \u6587\u4ef6\n flushAppendOnlyFile(0);\n}\n\nint serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData)\n{\n\n \/\/ \u6839\u636e AOF \u653f\u7b56\uff0c\n \/\/ \u8003\u8651\u662f\u5426\u9700\u8981\u5c06 AOF \u7f13\u51b2\u533a\u4e2d\u7684\u5185\u5bb9\u5199\u5165\u5230 AOF \u6587\u4ef6\u4e2d\n \/* AOF postponed flush: Try at every cron cycle if the slow fsync\n * completed. *\/\n if (server.aof_flush_postponed_start)\n flushAppendOnlyFile(0);\n\n \/* AOF write errors: in this case we have a buffer to flush as well and\n * clear the AOF error in case of success to make the DB writable again,\n * however to try every second is enough in case of 'hz' is set to\n * an higher frequency. *\/\n run_with_period(1000)\n {\n if (server.aof_last_write_status == REDIS_ERR)\n flushAppendOnlyFile(0);\n }\n\n\n}\n<\/code><\/pre>\n\n\n\n\u57fa\u4e8e\u7248\u672c3.0.0\u7248\u672c,<\/a>\u70b9\u51fb\u4e0b\u8f7dhttps:\/\/download.redis.io\/releases\/redis-3.0.0.tar.gz<\/p>\n\n\n\n\u672c\u6587\u5730\u5740<\/a>\uff0chttps:\/\/www.ccagml.com\/?p=437<\/p>\n","protected":false},"excerpt":{"rendered":"aof\u4fdd\u5b58aof\u662fredis\u7684\u4e00\u79cd\u6301\u4e45\u5316\u65b9\u5f0f,\u53ef\u4ee5\u6839\u636e\u914d\u7f6e\u81ea\u52a8\u89e6\u53d1\u4fdd\u5b58,\u4e5f\u53ef\u4ee5\u624b\u52a8\u6267\u884c\u4fdd\u5b58\/\/\u5728\u914d\u7f6e\u4e2dappeContinue reading redis\u6e90\u7801\u4ecemain\u5f00\u59cb18<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[31,22],"tags":[],"_links":{"self":[{"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/posts\/437"}],"collection":[{"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=437"}],"version-history":[{"count":3,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/posts\/437\/revisions"}],"predecessor-version":[{"id":441,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=\/wp\/v2\/posts\/437\/revisions\/441"}],"wp:attachment":[{"href":"https:\/\/www.ccagml.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=437"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=437"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ccagml.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=437"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}