X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/2767f1c0c6983c75689dc67638546196c5dddb26..f0d962c0eca870e3fd2a4529de321db217c2e9fe:/src/aof.c diff --git a/src/aof.c b/src/aof.c index a2e732d2..607bdce8 100644 --- a/src/aof.c +++ b/src/aof.c @@ -1,4 +1,6 @@ #include "redis.h" +#include "bio.h" +#include "rio.h" #include #include @@ -8,45 +10,171 @@ #include #include +void aofUpdateCurrentSize(void); + +/* ---------------------------------------------------------------------------- + * AOF rewrite buffer implementation. + * + * The following code implement a simple buffer used in order to accumulate + * changes while the background process is rewriting the AOF file. + * + * We only need to append, but can't just use realloc with a large block + * because 'huge' reallocs are not always handled as one could expect + * (via remapping of pages at OS level) but may involve copying data. + * + * For this reason we use a list of blocks, every block is + * AOF_RW_BUF_BLOCK_SIZE bytes. + * ------------------------------------------------------------------------- */ + +#define AOF_RW_BUF_BLOCK_SIZE (1024*1024*10) /* 10 MB per block */ + +typedef struct aofrwblock { + unsigned long used, free; + char buf[AOF_RW_BUF_BLOCK_SIZE]; +} aofrwblock; + +/* This function free the old AOF rewrite buffer if needed, and initialize + * a fresh new one. It tests for server.aof_rewrite_buf_blocks equal to NULL + * so can be used for the first initialization as well. */ +void aofRewriteBufferReset(void) { + if (server.aof_rewrite_buf_blocks) + listRelease(server.aof_rewrite_buf_blocks); + + server.aof_rewrite_buf_blocks = listCreate(); + listSetFreeMethod(server.aof_rewrite_buf_blocks,zfree); +} + +/* Return the current size of the AOF rerwite buffer. */ +unsigned long aofRewriteBufferSize(void) { + listNode *ln = listLast(server.aof_rewrite_buf_blocks); + aofrwblock *block = ln ? ln->value : NULL; + + if (block == NULL) return 0; + unsigned long size = + (listLength(server.aof_rewrite_buf_blocks)-1) * AOF_RW_BUF_BLOCK_SIZE; + size += block->used; + return size; +} + +/* Append data to the AOF rewrite buffer, allocating new blocks if needed. */ +void aofRewriteBufferAppend(unsigned char *s, unsigned long len) { + listNode *ln = listLast(server.aof_rewrite_buf_blocks); + aofrwblock *block = ln ? ln->value : NULL; + + while(len) { + /* If we already got at least an allocated block, try appending + * at least some piece into it. */ + if (block) { + unsigned long thislen = (block->free < len) ? block->free : len; + if (thislen) { /* The current block is not already full. */ + memcpy(block->buf+block->used, s, thislen); + block->used += thislen; + block->free -= thislen; + s += thislen; + len -= thislen; + } + } + + if (len) { /* First block to allocate, or need another block. */ + int numblocks; + + block = zmalloc(sizeof(*block)); + block->free = AOF_RW_BUF_BLOCK_SIZE; + block->used = 0; + listAddNodeTail(server.aof_rewrite_buf_blocks,block); + + /* Log every time we cross more 10 or 100 blocks, respectively + * as a notice or warning. */ + numblocks = listLength(server.aof_rewrite_buf_blocks); + if (((numblocks+1) % 10) == 0) { + int level = ((numblocks+1) % 100) == 0 ? REDIS_WARNING : + REDIS_NOTICE; + redisLog(level,"Background AOF buffer size: %lu MB", + aofRewriteBufferSize()/(1024*1024)); + } + } + } +} + +/* Write the buffer (possibly composed of multiple blocks) into the specified + * fd. If no short write or any other error happens -1 is returned, + * otherwise the number of bytes written is returned. */ +ssize_t aofRewriteBufferWrite(int fd) { + listNode *ln; + listIter li; + ssize_t count = 0; + + listRewind(server.aof_rewrite_buf_blocks,&li); + while((ln = listNext(&li))) { + aofrwblock *block = listNodeValue(ln); + ssize_t nwritten; + + if (block->used) { + nwritten = write(fd,block->buf,block->used); + if (nwritten != block->used) { + if (nwritten == 0) errno = EIO; + return -1; + } + count += nwritten; + } + } + return count; +} + +/* ---------------------------------------------------------------------------- + * AOF file implementation + * ------------------------------------------------------------------------- */ + +/* Starts a background task that performs fsync() against the specified + * file descriptor (the one of the AOF file) in another thread. */ +void aof_background_fsync(int fd) { + bioCreateBackgroundJob(REDIS_BIO_AOF_FSYNC,(void*)(long)fd,NULL,NULL); +} + /* Called when the user switches from "appendonly yes" to "appendonly no" * at runtime using the CONFIG command. */ void stopAppendOnly(void) { - flushAppendOnlyFile(); - aof_fsync(server.appendfd); - close(server.appendfd); - - server.appendfd = -1; - server.appendseldb = -1; - server.appendonly = 0; + redisAssert(server.aof_state != REDIS_AOF_OFF); + flushAppendOnlyFile(1); + aof_fsync(server.aof_fd); + close(server.aof_fd); + + server.aof_fd = -1; + server.aof_selected_db = -1; + server.aof_state = REDIS_AOF_OFF; /* rewrite operation in progress? kill it, wait child exit */ - if (server.bgsavechildpid != -1) { + if (server.aof_child_pid != -1) { int statloc; - if (kill(server.bgsavechildpid,SIGKILL) != -1) + redisLog(REDIS_NOTICE,"Killing running AOF rewrite child: %ld", + (long) server.aof_child_pid); + if (kill(server.aof_child_pid,SIGKILL) != -1) wait3(&statloc,0,NULL); /* reset the buffer accumulating changes while the child saves */ - sdsfree(server.bgrewritebuf); - server.bgrewritebuf = sdsempty(); - server.bgsavechildpid = -1; + aofRewriteBufferReset(); + aofRemoveTempFile(server.aof_child_pid); + server.aof_child_pid = -1; } } /* Called when the user switches from "appendonly no" to "appendonly yes" * at runtime using the CONFIG command. */ int startAppendOnly(void) { - server.appendonly = 1; - server.lastfsync = time(NULL); - server.appendfd = open(server.appendfilename,O_WRONLY|O_APPEND|O_CREAT,0644); - if (server.appendfd == -1) { - redisLog(REDIS_WARNING,"Used tried to switch on AOF via CONFIG, but I can't open the AOF file: %s",strerror(errno)); + server.aof_last_fsync = server.unixtime; + server.aof_fd = open(server.aof_filename,O_WRONLY|O_APPEND|O_CREAT,0644); + redisAssert(server.aof_state == REDIS_AOF_OFF); + if (server.aof_fd == -1) { + redisLog(REDIS_WARNING,"Redis needs to enable the AOF but can't open the append only file: %s",strerror(errno)); return REDIS_ERR; } if (rewriteAppendOnlyFileBackground() == REDIS_ERR) { - server.appendonly = 0; - close(server.appendfd); - redisLog(REDIS_WARNING,"Used tried to switch on AOF via CONFIG, I can't trigger a background AOF rewrite operation. Check the above logs for more info about the error.",strerror(errno)); + close(server.aof_fd); + redisLog(REDIS_WARNING,"Redis needs to enable the AOF but can't trigger a background AOF rewrite operation. Check the above logs for more info about the error."); return REDIS_ERR; } + /* We correctly switched on AOF, now wait for the rerwite to be complete + * in order to append data on disk. */ + server.aof_state = REDIS_AOF_WAIT_REWRITE; return REDIS_OK; } @@ -56,79 +184,161 @@ int startAppendOnly(void) { * and the only way the client socket can get a write is entering when the * the event loop, we accumulate all the AOF writes in a memory * buffer and write it on disk using this function just before entering - * the event loop again. */ -void flushAppendOnlyFile(void) { - time_t now; + * the event loop again. + * + * About the 'force' argument: + * + * When the fsync policy is set to 'everysec' we may delay the flush if there + * is still an fsync() going on in the background thread, since for instance + * on Linux write(2) will be blocked by the background fsync anyway. + * When this happens we remember that there is some aof buffer to be + * flushed ASAP, and will try to do that in the serverCron() function. + * + * However if force is set to 1 we'll write regardless of the background + * fsync. */ +void flushAppendOnlyFile(int force) { ssize_t nwritten; - - if (sdslen(server.aofbuf) == 0) return; + int sync_in_progress = 0; + + if (sdslen(server.aof_buf) == 0) return; + + if (server.aof_fsync == AOF_FSYNC_EVERYSEC) + sync_in_progress = bioPendingJobsOfType(REDIS_BIO_AOF_FSYNC) != 0; + + if (server.aof_fsync == AOF_FSYNC_EVERYSEC && !force) { + /* With this append fsync policy we do background fsyncing. + * If the fsync is still in progress we can try to delay + * the write for a couple of seconds. */ + if (sync_in_progress) { + if (server.aof_flush_postponed_start == 0) { + /* No previous write postponinig, remember that we are + * postponing the flush and return. */ + server.aof_flush_postponed_start = server.unixtime; + return; + } else if (server.unixtime - server.aof_flush_postponed_start < 2) { + /* We were already waiting for fsync to finish, but for less + * than two seconds this is still ok. Postpone again. */ + return; + } + /* Otherwise fall trough, and go write since we can't wait + * over two seconds. */ + server.aof_delayed_fsync++; + 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."); + } + } + /* If you are following this code path, then we are going to write so + * set reset the postponed flush sentinel to zero. */ + server.aof_flush_postponed_start = 0; /* We want to perform a single write. This should be guaranteed atomic * at least if the filesystem we are writing is a real physical one. * While this will save us against the server being killed I don't think * there is much to do about the whole server stopping for power problems * or alike */ - nwritten = write(server.appendfd,server.aofbuf,sdslen(server.aofbuf)); - if (nwritten != (signed)sdslen(server.aofbuf)) { + nwritten = write(server.aof_fd,server.aof_buf,sdslen(server.aof_buf)); + if (nwritten != (signed)sdslen(server.aof_buf)) { /* Ooops, we are in troubles. The best thing to do for now is * aborting instead of giving the illusion that everything is * working as expected. */ - if (nwritten == -1) { + if (nwritten == -1) { redisLog(REDIS_WARNING,"Exiting on error writing to the append-only file: %s",strerror(errno)); - } else { - redisLog(REDIS_WARNING,"Exiting on short write while writing to the append-only file: %s",strerror(errno)); - } - exit(1); + } else { + redisLog(REDIS_WARNING,"Exiting on short write while writing to " + "the append-only file: %s (nwritten=%ld, " + "expected=%ld)", + strerror(errno), + (long)nwritten, + (long)sdslen(server.aof_buf)); + } + exit(1); + } + server.aof_current_size += nwritten; + + /* Re-use AOF buffer when it is small enough. The maximum comes from the + * arena size of 4k minus some overhead (but is otherwise arbitrary). */ + if ((sdslen(server.aof_buf)+sdsavail(server.aof_buf)) < 4000) { + sdsclear(server.aof_buf); + } else { + sdsfree(server.aof_buf); + server.aof_buf = sdsempty(); } - sdsfree(server.aofbuf); - server.aofbuf = sdsempty(); - /* Don't Fsync if no-appendfsync-on-rewrite is set to yes and we have - * childs performing heavy I/O on disk. */ - if (server.no_appendfsync_on_rewrite && - (server.bgrewritechildpid != -1 || server.bgsavechildpid != -1)) + /* Don't fsync if no-appendfsync-on-rewrite is set to yes and there are + * children doing I/O in the background. */ + if (server.aof_no_fsync_on_rewrite && + (server.aof_child_pid != -1 || server.rdb_child_pid != -1)) return; - /* Fsync if needed */ - now = time(NULL); - if (server.appendfsync == APPENDFSYNC_ALWAYS || - (server.appendfsync == APPENDFSYNC_EVERYSEC && - now-server.lastfsync > 1)) - { + + /* Perform the fsync if needed. */ + if (server.aof_fsync == AOF_FSYNC_ALWAYS) { /* aof_fsync is defined as fdatasync() for Linux in order to avoid * flushing metadata. */ - aof_fsync(server.appendfd); /* Let's try to get this data on the disk */ - server.lastfsync = now; + aof_fsync(server.aof_fd); /* Let's try to get this data on the disk */ + server.aof_last_fsync = server.unixtime; + } else if ((server.aof_fsync == AOF_FSYNC_EVERYSEC && + server.unixtime > server.aof_last_fsync)) { + if (!sync_in_progress) aof_background_fsync(server.aof_fd); + server.aof_last_fsync = server.unixtime; } } -sds catAppendOnlyGenericCommand(sds buf, int argc, robj **argv) { - int j; - buf = sdscatprintf(buf,"*%d\r\n",argc); +sds catAppendOnlyGenericCommand(sds dst, int argc, robj **argv) { + char buf[32]; + int len, j; + robj *o; + + buf[0] = '*'; + len = 1+ll2string(buf+1,sizeof(buf)-1,argc); + buf[len++] = '\r'; + buf[len++] = '\n'; + dst = sdscatlen(dst,buf,len); + for (j = 0; j < argc; j++) { - robj *o = getDecodedObject(argv[j]); - buf = sdscatprintf(buf,"$%lu\r\n",(unsigned long)sdslen(o->ptr)); - buf = sdscatlen(buf,o->ptr,sdslen(o->ptr)); - buf = sdscatlen(buf,"\r\n",2); + o = getDecodedObject(argv[j]); + buf[0] = '$'; + len = 1+ll2string(buf+1,sizeof(buf)-1,sdslen(o->ptr)); + buf[len++] = '\r'; + buf[len++] = '\n'; + dst = sdscatlen(dst,buf,len); + dst = sdscatlen(dst,o->ptr,sdslen(o->ptr)); + dst = sdscatlen(dst,"\r\n",2); decrRefCount(o); } - return buf; + return dst; } -sds catAppendOnlyExpireAtCommand(sds buf, robj *key, robj *seconds) { - int argc = 3; - long when; +/* Create the sds representation of an PEXPIREAT command, using + * 'seconds' as time to live and 'cmd' to understand what command + * we are translating into a PEXPIREAT. + * + * This command is used in order to translate EXPIRE and PEXPIRE commands + * into PEXPIREAT command so that we retain precision in the append only + * file, and the time is always absolute and not relative. */ +sds catAppendOnlyExpireAtCommand(sds buf, struct redisCommand *cmd, robj *key, robj *seconds) { + long long when; robj *argv[3]; /* Make sure we can use strtol */ seconds = getDecodedObject(seconds); - when = time(NULL)+strtol(seconds->ptr,NULL,10); + when = strtoll(seconds->ptr,NULL,10); + /* Convert argument into milliseconds for EXPIRE, SETEX, EXPIREAT */ + if (cmd->proc == expireCommand || cmd->proc == setexCommand || + cmd->proc == expireatCommand) + { + when *= 1000; + } + /* Convert into absolute time for EXPIRE, PEXPIRE, SETEX, PSETEX */ + if (cmd->proc == expireCommand || cmd->proc == pexpireCommand || + cmd->proc == setexCommand || cmd->proc == psetexCommand) + { + when += mstime(); + } decrRefCount(seconds); - argv[0] = createStringObject("EXPIREAT",8); + argv[0] = createStringObject("PEXPIREAT",9); argv[1] = key; - argv[2] = createObject(REDIS_STRING, - sdscatprintf(sdsempty(),"%ld",when)); - buf = catAppendOnlyGenericCommand(buf, argc, argv); + argv[2] = createStringObjectFromLongLong(when); + buf = catAppendOnlyGenericCommand(buf, 3, argv); decrRefCount(argv[0]); decrRefCount(argv[2]); return buf; @@ -140,45 +350,54 @@ void feedAppendOnlyFile(struct redisCommand *cmd, int dictid, robj **argv, int a /* The DB this command was targetting is not the same as the last command * we appendend. To issue a SELECT command is needed. */ - if (dictid != server.appendseldb) { + if (dictid != server.aof_selected_db) { char seldb[64]; snprintf(seldb,sizeof(seldb),"%d",dictid); buf = sdscatprintf(buf,"*2\r\n$6\r\nSELECT\r\n$%lu\r\n%s\r\n", (unsigned long)strlen(seldb),seldb); - server.appendseldb = dictid; + server.aof_selected_db = dictid; } - if (cmd->proc == expireCommand) { - /* Translate EXPIRE into EXPIREAT */ - buf = catAppendOnlyExpireAtCommand(buf,argv[1],argv[2]); - } else if (cmd->proc == setexCommand) { - /* Translate SETEX to SET and EXPIREAT */ + if (cmd->proc == expireCommand || cmd->proc == pexpireCommand || + cmd->proc == expireatCommand) { + /* Translate EXPIRE/PEXPIRE/EXPIREAT into PEXPIREAT */ + buf = catAppendOnlyExpireAtCommand(buf,cmd,argv[1],argv[2]); + } else if (cmd->proc == setexCommand || cmd->proc == psetexCommand) { + /* Translate SETEX/PSETEX to SET and PEXPIREAT */ tmpargv[0] = createStringObject("SET",3); tmpargv[1] = argv[1]; tmpargv[2] = argv[3]; buf = catAppendOnlyGenericCommand(buf,3,tmpargv); decrRefCount(tmpargv[0]); - buf = catAppendOnlyExpireAtCommand(buf,argv[1],argv[2]); + buf = catAppendOnlyExpireAtCommand(buf,cmd,argv[1],argv[2]); } else { + /* All the other commands don't need translation or need the + * same translation already operated in the command vector + * for the replication itself. */ buf = catAppendOnlyGenericCommand(buf,argc,argv); } /* Append to the AOF buffer. This will be flushed on disk just before * of re-entering the event loop, so before the client will get a * positive reply about the operation performed. */ - server.aofbuf = sdscatlen(server.aofbuf,buf,sdslen(buf)); + if (server.aof_state == REDIS_AOF_ON) + server.aof_buf = sdscatlen(server.aof_buf,buf,sdslen(buf)); /* If a background append only file rewriting is in progress we want to * accumulate the differences between the child DB and the current one * in a buffer, so that when the child process will do its work we * can append the differences to the new append only file. */ - if (server.bgrewritechildpid != -1) - server.bgrewritebuf = sdscatlen(server.bgrewritebuf,buf,sdslen(buf)); + if (server.aof_child_pid != -1) + aofRewriteBufferAppend((unsigned char*)buf,sdslen(buf)); sdsfree(buf); } +/* ---------------------------------------------------------------------------- + * AOF loading + * ------------------------------------------------------------------------- */ + /* In Redis commands are always executed in the context of a client, so in * order to load the append only file we need to create a fake client. */ struct redisClient *createFakeClient(void) { @@ -187,13 +406,18 @@ struct redisClient *createFakeClient(void) { selectDb(c,0); c->fd = -1; c->querybuf = sdsempty(); + c->querybuf_peak = 0; c->argc = 0; c->argv = NULL; + c->bufpos = 0; c->flags = 0; /* We set the fake client as a slave waiting for the synchronization * so that Redis will not try to send replies to this client. */ c->replstate = REDIS_REPL_WAIT_BGSAVE_START; c->reply = listCreate(); + c->reply_bytes = 0; + c->obuf_soft_limit_reached_time = 0; + c->watched_keys = listCreate(); listSetFreeMethod(c->reply,decrRefCount); listSetDupMethod(c->reply,dupClientReplyValue); initClientMultiState(c); @@ -203,6 +427,7 @@ struct redisClient *createFakeClient(void) { void freeFakeClient(struct redisClient *c) { sdsfree(c->querybuf); listRelease(c->reply); + listRelease(c->watched_keys); freeClientMultiState(c); zfree(c); } @@ -214,10 +439,14 @@ int loadAppendOnlyFile(char *filename) { struct redisClient *fakeClient; FILE *fp = fopen(filename,"r"); struct redis_stat sb; - int appendonly = server.appendonly; + int old_aof_state = server.aof_state; + long loops = 0; - if (redis_fstat(fileno(fp),&sb) != -1 && sb.st_size == 0) + if (fp && redis_fstat(fileno(fp),&sb) != -1 && sb.st_size == 0) { + server.aof_current_size = 0; + fclose(fp); return REDIS_ERR; + } if (fp == NULL) { redisLog(REDIS_WARNING,"Fatal error: can't open the append log file for reading: %s",strerror(errno)); @@ -226,9 +455,11 @@ int loadAppendOnlyFile(char *filename) { /* Temporarily disable AOF, to prevent EXEC from feeding a MULTI * to the same file we're about to read. */ - server.appendonly = 0; + server.aof_state = REDIS_AOF_OFF; fakeClient = createFakeClient(); + startLoading(fp); + while(1) { int argc, j; unsigned long len; @@ -236,7 +467,12 @@ int loadAppendOnlyFile(char *filename) { char buf[128]; sds argsds; struct redisCommand *cmd; - int force_swapout; + + /* Serve the clients from time to time */ + if (!(loops++ % 1000)) { + loadingProgress(ftello(fp)); + aeProcessEvents(server.el, AE_FILE_EVENTS|AE_DONT_WAIT); + } if (fgets(buf,sizeof(buf),fp) == NULL) { if (feof(fp)) @@ -246,6 +482,8 @@ int loadAppendOnlyFile(char *filename) { } if (buf[0] != '*') goto fmterr; argc = atoi(buf+1); + if (argc < 1) goto fmterr; + argv = zmalloc(sizeof(robj*)*argc); for (j = 0; j < argc; j++) { if (fgets(buf,sizeof(buf),fp) == NULL) goto readerr; @@ -263,29 +501,21 @@ int loadAppendOnlyFile(char *filename) { redisLog(REDIS_WARNING,"Unknown command '%s' reading the append only file", argv[0]->ptr); exit(1); } - /* Try object encoding */ - if (cmd->flags & REDIS_CMD_BULK) - argv[argc-1] = tryObjectEncoding(argv[argc-1]); /* Run the command in the context of a fake client */ fakeClient->argc = argc; fakeClient->argv = argv; cmd->proc(fakeClient); - /* Discard the reply objects list from the fake client */ - while(listLength(fakeClient->reply)) - listDelNode(fakeClient->reply,listFirst(fakeClient->reply)); - /* Clean up, ready for the next command */ - for (j = 0; j < argc; j++) decrRefCount(argv[j]); - zfree(argv); - /* Handle swapping while loading big datasets when VM is on */ - force_swapout = 0; - if ((zmalloc_used_memory() - server.vm_max_memory) > 1024*1024*32) - force_swapout = 1; - - if (server.vm_enabled && force_swapout) { - while (zmalloc_used_memory() > server.vm_max_memory) { - if (vmSwapOneObjectBlocking() == REDIS_ERR) break; - } - } + + /* The fake client should not have a reply */ + redisAssert(fakeClient->bufpos == 0 && listLength(fakeClient->reply) == 0); + /* The fake client should never get blocked */ + redisAssert((fakeClient->flags & REDIS_BLOCKED) == 0); + + /* Clean up. Command code may have changed argv/argc so we use the + * argv/argc of the client instead of the local variables. */ + for (j = 0; j < fakeClient->argc; j++) + decrRefCount(fakeClient->argv[j]); + zfree(fakeClient->argv); } /* This point can only be reached when EOF is reached without errors. @@ -294,7 +524,10 @@ int loadAppendOnlyFile(char *filename) { fclose(fp); freeFakeClient(fakeClient); - server.appendonly = appendonly; + server.aof_state = old_aof_state; + stopLoading(); + aofUpdateCurrentSize(); + server.aof_rewrite_base_size = server.aof_current_size; return REDIS_OK; readerr: @@ -305,248 +538,340 @@ readerr: } exit(1); fmterr: - redisLog(REDIS_WARNING,"Bad file format reading the append only file"); + redisLog(REDIS_WARNING,"Bad file format reading the append only file: make a backup of your AOF file, then use ./redis-check-aof --fix "); exit(1); } -/* Write binary-safe string into a file in the bulkformat - * $\r\n\r\n */ -int fwriteBulkString(FILE *fp, char *s, unsigned long len) { - char cbuf[128]; - int clen; - cbuf[0] = '$'; - clen = 1+ll2string(cbuf+1,sizeof(cbuf)-1,len); - cbuf[clen++] = '\r'; - cbuf[clen++] = '\n'; - if (fwrite(cbuf,clen,1,fp) == 0) return 0; - if (len > 0 && fwrite(s,len,1,fp) == 0) return 0; - if (fwrite("\r\n",2,1,fp) == 0) return 0; +/* ---------------------------------------------------------------------------- + * AOF rewrite + * ------------------------------------------------------------------------- */ + +/* Delegate writing an object to writing a bulk string or bulk long long. + * This is not placed in rio.c since that adds the redis.h dependency. */ +int rioWriteBulkObject(rio *r, robj *obj) { + /* Avoid using getDecodedObject to help copy-on-write (we are often + * in a child process when this function is called). */ + if (obj->encoding == REDIS_ENCODING_INT) { + return rioWriteBulkLongLong(r,(long)obj->ptr); + } else if (obj->encoding == REDIS_ENCODING_RAW) { + return rioWriteBulkString(r,obj->ptr,sdslen(obj->ptr)); + } else { + redisPanic("Unknown string encoding"); + } +} + +/* Emit the commands needed to rebuild a list object. + * The function returns 0 on error, 1 on success. */ +int rewriteListObject(rio *r, robj *key, robj *o) { + long long count = 0, items = listTypeLength(o); + + if (o->encoding == REDIS_ENCODING_ZIPLIST) { + unsigned char *zl = o->ptr; + unsigned char *p = ziplistIndex(zl,0); + unsigned char *vstr; + unsigned int vlen; + long long vlong; + + while(ziplistGet(p,&vstr,&vlen,&vlong)) { + if (count == 0) { + int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ? + REDIS_AOF_REWRITE_ITEMS_PER_CMD : items; + + if (rioWriteBulkCount(r,'*',2+cmd_items) == 0) return 0; + if (rioWriteBulkString(r,"RPUSH",5) == 0) return 0; + if (rioWriteBulkObject(r,key) == 0) return 0; + } + if (vstr) { + if (rioWriteBulkString(r,(char*)vstr,vlen) == 0) return 0; + } else { + if (rioWriteBulkLongLong(r,vlong) == 0) return 0; + } + p = ziplistNext(zl,p); + if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0; + items--; + } + } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) { + list *list = o->ptr; + listNode *ln; + listIter li; + + listRewind(list,&li); + while((ln = listNext(&li))) { + robj *eleobj = listNodeValue(ln); + + if (count == 0) { + int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ? + REDIS_AOF_REWRITE_ITEMS_PER_CMD : items; + + if (rioWriteBulkCount(r,'*',2+cmd_items) == 0) return 0; + if (rioWriteBulkString(r,"RPUSH",5) == 0) return 0; + if (rioWriteBulkObject(r,key) == 0) return 0; + } + if (rioWriteBulkObject(r,eleobj) == 0) return 0; + if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0; + items--; + } + } else { + redisPanic("Unknown list encoding"); + } return 1; } -/* Write a double value in bulk format $\r\n\r\n */ -int fwriteBulkDouble(FILE *fp, double d) { - char buf[128], dbuf[128]; +/* Emit the commands needed to rebuild a set object. + * The function returns 0 on error, 1 on success. */ +int rewriteSetObject(rio *r, robj *key, robj *o) { + long long count = 0, items = setTypeSize(o); + + if (o->encoding == REDIS_ENCODING_INTSET) { + int ii = 0; + int64_t llval; + + while(intsetGet(o->ptr,ii++,&llval)) { + if (count == 0) { + int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ? + REDIS_AOF_REWRITE_ITEMS_PER_CMD : items; + + if (rioWriteBulkCount(r,'*',2+cmd_items) == 0) return 0; + if (rioWriteBulkString(r,"SADD",4) == 0) return 0; + if (rioWriteBulkObject(r,key) == 0) return 0; + } + if (rioWriteBulkLongLong(r,llval) == 0) return 0; + if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0; + items--; + } + } else if (o->encoding == REDIS_ENCODING_HT) { + dictIterator *di = dictGetIterator(o->ptr); + dictEntry *de; - snprintf(dbuf,sizeof(dbuf),"%.17g\r\n",d); - snprintf(buf,sizeof(buf),"$%lu\r\n",(unsigned long)strlen(dbuf)-2); - if (fwrite(buf,strlen(buf),1,fp) == 0) return 0; - if (fwrite(dbuf,strlen(dbuf),1,fp) == 0) return 0; + while((de = dictNext(di)) != NULL) { + robj *eleobj = dictGetKey(de); + if (count == 0) { + int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ? + REDIS_AOF_REWRITE_ITEMS_PER_CMD : items; + + if (rioWriteBulkCount(r,'*',2+cmd_items) == 0) return 0; + if (rioWriteBulkString(r,"SADD",4) == 0) return 0; + if (rioWriteBulkObject(r,key) == 0) return 0; + } + if (rioWriteBulkObject(r,eleobj) == 0) return 0; + if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0; + items--; + } + dictReleaseIterator(di); + } else { + redisPanic("Unknown set encoding"); + } return 1; } -/* Write a long value in bulk format $\r\n\r\n */ -int fwriteBulkLongLong(FILE *fp, long long l) { - char bbuf[128], lbuf[128]; - unsigned int blen, llen; - llen = ll2string(lbuf,32,l); - blen = snprintf(bbuf,sizeof(bbuf),"$%u\r\n%s\r\n",llen,lbuf); - if (fwrite(bbuf,blen,1,fp) == 0) return 0; +/* Emit the commands needed to rebuild a sorted set object. + * The function returns 0 on error, 1 on success. */ +int rewriteSortedSetObject(rio *r, robj *key, robj *o) { + long long count = 0, items = zsetLength(o); + + if (o->encoding == REDIS_ENCODING_ZIPLIST) { + unsigned char *zl = o->ptr; + unsigned char *eptr, *sptr; + unsigned char *vstr; + unsigned int vlen; + long long vll; + double score; + + eptr = ziplistIndex(zl,0); + redisAssert(eptr != NULL); + sptr = ziplistNext(zl,eptr); + redisAssert(sptr != NULL); + + while (eptr != NULL) { + redisAssert(ziplistGet(eptr,&vstr,&vlen,&vll)); + score = zzlGetScore(sptr); + + if (count == 0) { + int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ? + REDIS_AOF_REWRITE_ITEMS_PER_CMD : items; + + if (rioWriteBulkCount(r,'*',2+cmd_items*2) == 0) return 0; + if (rioWriteBulkString(r,"ZADD",4) == 0) return 0; + if (rioWriteBulkObject(r,key) == 0) return 0; + } + if (rioWriteBulkDouble(r,score) == 0) return 0; + if (vstr != NULL) { + if (rioWriteBulkString(r,(char*)vstr,vlen) == 0) return 0; + } else { + if (rioWriteBulkLongLong(r,vll) == 0) return 0; + } + zzlNext(zl,&eptr,&sptr); + if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0; + items--; + } + } else if (o->encoding == REDIS_ENCODING_SKIPLIST) { + zset *zs = o->ptr; + dictIterator *di = dictGetIterator(zs->dict); + dictEntry *de; + + while((de = dictNext(di)) != NULL) { + robj *eleobj = dictGetKey(de); + double *score = dictGetVal(de); + + if (count == 0) { + int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ? + REDIS_AOF_REWRITE_ITEMS_PER_CMD : items; + + if (rioWriteBulkCount(r,'*',2+cmd_items*2) == 0) return 0; + if (rioWriteBulkString(r,"ZADD",4) == 0) return 0; + if (rioWriteBulkObject(r,key) == 0) return 0; + } + if (rioWriteBulkDouble(r,*score) == 0) return 0; + if (rioWriteBulkObject(r,eleobj) == 0) return 0; + if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0; + items--; + } + dictReleaseIterator(di); + } else { + redisPanic("Unknown sorted zset encoding"); + } return 1; } -/* Delegate writing an object to writing a bulk string or bulk long long. */ -int fwriteBulkObject(FILE *fp, robj *obj) { - /* Avoid using getDecodedObject to help copy-on-write (we are often - * in a child process when this function is called). */ - if (obj->encoding == REDIS_ENCODING_INT) { - return fwriteBulkLongLong(fp,(long)obj->ptr); - } else if (obj->encoding == REDIS_ENCODING_RAW) { - return fwriteBulkString(fp,obj->ptr,sdslen(obj->ptr)); - } else { - redisPanic("Unknown string encoding"); +/* Write either the key or the value of the currently selected item of an hash. + * The 'hi' argument passes a valid Redis hash iterator. + * The 'what' filed specifies if to write a key or a value and can be + * either REDIS_HASH_KEY or REDIS_HASH_VALUE. + * + * The function returns 0 on error, non-zero on success. */ +static int rioWriteHashIteratorCursor(rio *r, hashTypeIterator *hi, int what) { + if (hi->encoding == REDIS_ENCODING_ZIPLIST) { + unsigned char *vstr = NULL; + unsigned int vlen = UINT_MAX; + long long vll = LLONG_MAX; + + hashTypeCurrentFromZiplist(hi, what, &vstr, &vlen, &vll); + if (vstr) { + return rioWriteBulkString(r, (char*)vstr, vlen); + } else { + return rioWriteBulkLongLong(r, vll); + } + + } else if (hi->encoding == REDIS_ENCODING_HT) { + robj *value; + + hashTypeCurrentFromHashTable(hi, what, &value); + return rioWriteBulkObject(r, value); + } + + redisPanic("Unknown hash encoding"); + return 0; +} + +/* Emit the commands needed to rebuild a hash object. + * The function returns 0 on error, 1 on success. */ +int rewriteHashObject(rio *r, robj *key, robj *o) { + hashTypeIterator *hi; + long long count = 0, items = hashTypeLength(o); + + hi = hashTypeInitIterator(o); + while (hashTypeNext(hi) != REDIS_ERR) { + if (count == 0) { + int cmd_items = (items > REDIS_AOF_REWRITE_ITEMS_PER_CMD) ? + REDIS_AOF_REWRITE_ITEMS_PER_CMD : items; + + if (rioWriteBulkCount(r,'*',2+cmd_items*2) == 0) return 0; + if (rioWriteBulkString(r,"HMSET",5) == 0) return 0; + if (rioWriteBulkObject(r,key) == 0) return 0; + } + + if (rioWriteHashIteratorCursor(r, hi, REDIS_HASH_KEY) == 0) return 0; + if (rioWriteHashIteratorCursor(r, hi, REDIS_HASH_VALUE) == 0) return 0; + if (++count == REDIS_AOF_REWRITE_ITEMS_PER_CMD) count = 0; + items--; } + + hashTypeReleaseIterator(hi); + + return 1; } /* Write a sequence of commands able to fully rebuild the dataset into - * "filename". Used both by REWRITEAOF and BGREWRITEAOF. */ + * "filename". Used both by REWRITEAOF and BGREWRITEAOF. + * + * In order to minimize the number of commands needed in the rewritten + * log Redis uses variadic commands when possible, such as RPUSH, SADD + * and ZADD. However at max REDIS_AOF_REWRITE_ITEMS_PER_CMD items per time + * are inserted using a single command. */ int rewriteAppendOnlyFile(char *filename) { dictIterator *di = NULL; dictEntry *de; + rio aof; FILE *fp; char tmpfile[256]; int j; - time_t now = time(NULL); + long long now = mstime(); /* Note that we have to use a different temp name here compared to the * one used by rewriteAppendOnlyFileBackground() function. */ snprintf(tmpfile,256,"temp-rewriteaof-%d.aof", (int) getpid()); fp = fopen(tmpfile,"w"); if (!fp) { - redisLog(REDIS_WARNING, "Failed rewriting the append only file: %s", strerror(errno)); + redisLog(REDIS_WARNING, "Opening the temp file for AOF rewrite in rewriteAppendOnlyFile(): %s", strerror(errno)); return REDIS_ERR; } + + rioInitWithFile(&aof,fp); for (j = 0; j < server.dbnum; j++) { char selectcmd[] = "*2\r\n$6\r\nSELECT\r\n"; redisDb *db = server.db+j; dict *d = db->dict; if (dictSize(d) == 0) continue; - di = dictGetIterator(d); + di = dictGetSafeIterator(d); if (!di) { fclose(fp); return REDIS_ERR; } /* SELECT the new DB */ - if (fwrite(selectcmd,sizeof(selectcmd)-1,1,fp) == 0) goto werr; - if (fwriteBulkLongLong(fp,j) == 0) goto werr; + if (rioWrite(&aof,selectcmd,sizeof(selectcmd)-1) == 0) goto werr; + if (rioWriteBulkLongLong(&aof,j) == 0) goto werr; /* Iterate this DB writing every entry */ while((de = dictNext(di)) != NULL) { - sds keystr = dictGetEntryKey(de); + sds keystr; robj key, *o; - time_t expiretime; - int swapped; + long long expiretime; - keystr = dictGetEntryKey(de); - o = dictGetEntryVal(de); + keystr = dictGetKey(de); + o = dictGetVal(de); initStaticStringObject(key,keystr); - /* If the value for this key is swapped, load a preview in memory. - * We use a "swapped" flag to remember if we need to free the - * value object instead to just increment the ref count anyway - * in order to avoid copy-on-write of pages if we are forked() */ - if (!server.vm_enabled || o->storage == REDIS_VM_MEMORY || - o->storage == REDIS_VM_SWAPPING) { - swapped = 0; - } else { - o = vmPreviewObject(o); - swapped = 1; - } + expiretime = getExpire(db,&key); /* Save the key and associated value */ if (o->type == REDIS_STRING) { /* Emit a SET command */ char cmd[]="*3\r\n$3\r\nSET\r\n"; - if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr; + if (rioWrite(&aof,cmd,sizeof(cmd)-1) == 0) goto werr; /* Key and value */ - if (fwriteBulkObject(fp,&key) == 0) goto werr; - if (fwriteBulkObject(fp,o) == 0) goto werr; + if (rioWriteBulkObject(&aof,&key) == 0) goto werr; + if (rioWriteBulkObject(&aof,o) == 0) goto werr; } else if (o->type == REDIS_LIST) { - /* Emit the RPUSHes needed to rebuild the list */ - char cmd[]="*3\r\n$5\r\nRPUSH\r\n"; - if (o->encoding == REDIS_ENCODING_ZIPLIST) { - unsigned char *zl = o->ptr; - unsigned char *p = ziplistIndex(zl,0); - unsigned char *vstr; - unsigned int vlen; - long long vlong; - - while(ziplistGet(p,&vstr,&vlen,&vlong)) { - if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr; - if (fwriteBulkObject(fp,&key) == 0) goto werr; - if (vstr) { - if (fwriteBulkString(fp,(char*)vstr,vlen) == 0) - goto werr; - } else { - if (fwriteBulkLongLong(fp,vlong) == 0) - goto werr; - } - p = ziplistNext(zl,p); - } - } else if (o->encoding == REDIS_ENCODING_LINKEDLIST) { - list *list = o->ptr; - listNode *ln; - listIter li; - - listRewind(list,&li); - while((ln = listNext(&li))) { - robj *eleobj = listNodeValue(ln); - - if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr; - if (fwriteBulkObject(fp,&key) == 0) goto werr; - if (fwriteBulkObject(fp,eleobj) == 0) goto werr; - } - } else { - redisPanic("Unknown list encoding"); - } + if (rewriteListObject(&aof,&key,o) == 0) goto werr; } else if (o->type == REDIS_SET) { - char cmd[]="*3\r\n$4\r\nSADD\r\n"; - - /* Emit the SADDs needed to rebuild the set */ - if (o->encoding == REDIS_ENCODING_INTSET) { - int ii = 0; - long long llval; - while(intsetGet(o->ptr,ii++,&llval)) { - if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr; - if (fwriteBulkObject(fp,&key) == 0) goto werr; - if (fwriteBulkLongLong(fp,llval) == 0) goto werr; - } - } else if (o->encoding == REDIS_ENCODING_HT) { - dictIterator *di = dictGetIterator(o->ptr); - dictEntry *de; - while((de = dictNext(di)) != NULL) { - robj *eleobj = dictGetEntryKey(de); - if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr; - if (fwriteBulkObject(fp,&key) == 0) goto werr; - if (fwriteBulkObject(fp,eleobj) == 0) goto werr; - } - dictReleaseIterator(di); - } else { - redisPanic("Unknown set encoding"); - } + if (rewriteSetObject(&aof,&key,o) == 0) goto werr; } else if (o->type == REDIS_ZSET) { - /* Emit the ZADDs needed to rebuild the sorted set */ - zset *zs = o->ptr; - dictIterator *di = dictGetIterator(zs->dict); - dictEntry *de; - - while((de = dictNext(di)) != NULL) { - char cmd[]="*4\r\n$4\r\nZADD\r\n"; - robj *eleobj = dictGetEntryKey(de); - double *score = dictGetEntryVal(de); - - if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr; - if (fwriteBulkObject(fp,&key) == 0) goto werr; - if (fwriteBulkDouble(fp,*score) == 0) goto werr; - if (fwriteBulkObject(fp,eleobj) == 0) goto werr; - } - dictReleaseIterator(di); + if (rewriteSortedSetObject(&aof,&key,o) == 0) goto werr; } else if (o->type == REDIS_HASH) { - char cmd[]="*4\r\n$4\r\nHSET\r\n"; - - /* Emit the HSETs needed to rebuild the hash */ - if (o->encoding == REDIS_ENCODING_ZIPMAP) { - unsigned char *p = zipmapRewind(o->ptr); - unsigned char *field, *val; - unsigned int flen, vlen; - - while((p = zipmapNext(p,&field,&flen,&val,&vlen)) != NULL) { - if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr; - if (fwriteBulkObject(fp,&key) == 0) goto werr; - if (fwriteBulkString(fp,(char*)field,flen) == 0) - goto werr; - if (fwriteBulkString(fp,(char*)val,vlen) == 0) - goto werr; - } - } else { - dictIterator *di = dictGetIterator(o->ptr); - dictEntry *de; - - while((de = dictNext(di)) != NULL) { - robj *field = dictGetEntryKey(de); - robj *val = dictGetEntryVal(de); - - if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr; - if (fwriteBulkObject(fp,&key) == 0) goto werr; - if (fwriteBulkObject(fp,field) == 0) goto werr; - if (fwriteBulkObject(fp,val) == 0) goto werr; - } - dictReleaseIterator(di); - } + if (rewriteHashObject(&aof,&key,o) == 0) goto werr; } else { redisPanic("Unknown object type"); } /* Save the expire time */ if (expiretime != -1) { - char cmd[]="*3\r\n$8\r\nEXPIREAT\r\n"; + char cmd[]="*3\r\n$9\r\nPEXPIREAT\r\n"; /* If this key is already expired skip it */ if (expiretime < now) continue; - if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr; - if (fwriteBulkObject(fp,&key) == 0) goto werr; - if (fwriteBulkLongLong(fp,expiretime) == 0) goto werr; + if (rioWrite(&aof,cmd,sizeof(cmd)-1) == 0) goto werr; + if (rioWriteBulkObject(&aof,&key) == 0) goto werr; + if (rioWriteBulkLongLong(&aof,expiretime) == 0) goto werr; } - if (swapped) decrRefCount(o); } dictReleaseIterator(di); } @@ -579,32 +904,34 @@ werr: * 1) The user calls BGREWRITEAOF * 2) Redis calls this function, that forks(): * 2a) the child rewrite the append only file in a temp file. - * 2b) the parent accumulates differences in server.bgrewritebuf. + * 2b) the parent accumulates differences in server.aof_rewrite_buf. * 3) When the child finished '2a' exists. * 4) The parent will trap the exit code, if it's OK, will append the - * data accumulated into server.bgrewritebuf into the temp file, and + * data accumulated into server.aof_rewrite_buf into the temp file, and * finally will rename(2) the temp file in the actual file name. * The the new file is reopened as the new append only file. Profit! */ int rewriteAppendOnlyFileBackground(void) { pid_t childpid; + long long start; - if (server.bgrewritechildpid != -1) return REDIS_ERR; - if (server.vm_enabled) waitEmptyIOJobsQueue(); + if (server.aof_child_pid != -1) return REDIS_ERR; + start = ustime(); if ((childpid = fork()) == 0) { - /* Child */ char tmpfile[256]; - if (server.vm_enabled) vmReopenSwapFile(); - close(server.fd); + /* Child */ + if (server.ipfd > 0) close(server.ipfd); + if (server.sofd > 0) close(server.sofd); snprintf(tmpfile,256,"temp-rewriteaof-bg-%d.aof", (int) getpid()); if (rewriteAppendOnlyFile(tmpfile) == REDIS_OK) { - _exit(0); + exitFromChild(0); } else { - _exit(1); + exitFromChild(1); } } else { /* Parent */ + server.stat_fork_time = ustime()-start; if (childpid == -1) { redisLog(REDIS_WARNING, "Can't rewrite append only file in background: fork: %s", @@ -613,26 +940,27 @@ int rewriteAppendOnlyFileBackground(void) { } redisLog(REDIS_NOTICE, "Background append only file rewriting started by pid %d",childpid); - server.bgrewritechildpid = childpid; + server.aof_rewrite_scheduled = 0; + server.aof_child_pid = childpid; updateDictResizePolicy(); /* We set appendseldb to -1 in order to force the next call to the * feedAppendOnlyFile() to issue a SELECT command, so the differences - * accumulated by the parent into server.bgrewritebuf will start + * accumulated by the parent into server.aof_rewrite_buf will start * with a SELECT statement and it will be safe to merge. */ - server.appendseldb = -1; + server.aof_selected_db = -1; return REDIS_OK; } return REDIS_OK; /* unreached */ } void bgrewriteaofCommand(redisClient *c) { - if (server.bgrewritechildpid != -1) { - addReplySds(c,sdsnew("-ERR background append only file rewriting already in progress\r\n")); - return; - } - if (rewriteAppendOnlyFileBackground() == REDIS_OK) { - char *status = "+Background append only file rewriting started\r\n"; - addReplySds(c,sdsnew(status)); + if (server.aof_child_pid != -1) { + addReplyError(c,"Background append only file rewriting already in progress"); + } else if (server.rdb_child_pid != -1) { + server.aof_rewrite_scheduled = 1; + addReplyStatus(c,"Background append only file rewriting scheduled"); + } else if (rewriteAppendOnlyFileBackground() == REDIS_OK) { + addReplyStatus(c,"Background append only file rewriting started"); } else { addReply(c,shared.err); } @@ -645,64 +973,147 @@ void aofRemoveTempFile(pid_t childpid) { unlink(tmpfile); } +/* Update the server.aof_current_size filed explicitly using stat(2) + * to check the size of the file. This is useful after a rewrite or after + * a restart, normally the size is updated just adding the write length + * to the current length, that is much faster. */ +void aofUpdateCurrentSize(void) { + struct redis_stat sb; + + if (redis_fstat(server.aof_fd,&sb) == -1) { + redisLog(REDIS_WARNING,"Unable to obtain the AOF file length. stat: %s", + strerror(errno)); + } else { + server.aof_current_size = sb.st_size; + } +} + /* A background append only file rewriting (BGREWRITEAOF) terminated its work. * Handle this. */ -void backgroundRewriteDoneHandler(int statloc) { - int exitcode = WEXITSTATUS(statloc); - int bysignal = WIFSIGNALED(statloc); - +void backgroundRewriteDoneHandler(int exitcode, int bysignal) { if (!bysignal && exitcode == 0) { - int fd; + int newfd, oldfd; char tmpfile[256]; + long long now = ustime(); redisLog(REDIS_NOTICE, - "Background append only file rewriting terminated with success"); - /* Now it's time to flush the differences accumulated by the parent */ - snprintf(tmpfile,256,"temp-rewriteaof-bg-%d.aof", (int) server.bgrewritechildpid); - fd = open(tmpfile,O_WRONLY|O_APPEND); - if (fd == -1) { - redisLog(REDIS_WARNING, "Not able to open the temp append only file produced by the child: %s", strerror(errno)); + "Background AOF rewrite terminated with success"); + + /* Flush the differences accumulated by the parent to the + * rewritten AOF. */ + snprintf(tmpfile,256,"temp-rewriteaof-bg-%d.aof", + (int)server.aof_child_pid); + newfd = open(tmpfile,O_WRONLY|O_APPEND); + if (newfd == -1) { + redisLog(REDIS_WARNING, + "Unable to open the temporary AOF produced by the child: %s", strerror(errno)); goto cleanup; } - /* Flush our data... */ - if (write(fd,server.bgrewritebuf,sdslen(server.bgrewritebuf)) != - (signed) sdslen(server.bgrewritebuf)) { - redisLog(REDIS_WARNING, "Error or short write trying to flush the parent diff of the append log file in the child temp file: %s", strerror(errno)); - close(fd); + + if (aofRewriteBufferWrite(newfd) == -1) { + redisLog(REDIS_WARNING, + "Error trying to flush the parent diff to the rewritten AOF: %s", strerror(errno)); + close(newfd); goto cleanup; } - redisLog(REDIS_NOTICE,"Parent diff flushed into the new append log file with success (%lu bytes)",sdslen(server.bgrewritebuf)); - /* Now our work is to rename the temp file into the stable file. And - * switch the file descriptor used by the server for append only. */ - if (rename(tmpfile,server.appendfilename) == -1) { - redisLog(REDIS_WARNING,"Can't rename the temp append only file into the stable one: %s", strerror(errno)); - close(fd); + + redisLog(REDIS_NOTICE, + "Parent diff successfully flushed to the rewritten AOF (%lu bytes)", aofRewriteBufferSize()); + + /* The only remaining thing to do is to rename the temporary file to + * the configured file and switch the file descriptor used to do AOF + * writes. We don't want close(2) or rename(2) calls to block the + * server on old file deletion. + * + * There are two possible scenarios: + * + * 1) AOF is DISABLED and this was a one time rewrite. The temporary + * file will be renamed to the configured file. When this file already + * exists, it will be unlinked, which may block the server. + * + * 2) AOF is ENABLED and the rewritten AOF will immediately start + * receiving writes. After the temporary file is renamed to the + * configured file, the original AOF file descriptor will be closed. + * Since this will be the last reference to that file, closing it + * causes the underlying file to be unlinked, which may block the + * server. + * + * To mitigate the blocking effect of the unlink operation (either + * caused by rename(2) in scenario 1, or by close(2) in scenario 2), we + * use a background thread to take care of this. First, we + * make scenario 1 identical to scenario 2 by opening the target file + * when it exists. The unlink operation after the rename(2) will then + * be executed upon calling close(2) for its descriptor. Everything to + * guarantee atomicity for this switch has already happened by then, so + * we don't care what the outcome or duration of that close operation + * is, as long as the file descriptor is released again. */ + if (server.aof_fd == -1) { + /* AOF disabled */ + + /* Don't care if this fails: oldfd will be -1 and we handle that. + * One notable case of -1 return is if the old file does + * not exist. */ + oldfd = open(server.aof_filename,O_RDONLY|O_NONBLOCK); + } else { + /* AOF enabled */ + oldfd = -1; /* We'll set this to the current AOF filedes later. */ + } + + /* Rename the temporary file. This will not unlink the target file if + * it exists, because we reference it with "oldfd". */ + if (rename(tmpfile,server.aof_filename) == -1) { + redisLog(REDIS_WARNING, + "Error trying to rename the temporary AOF file: %s", strerror(errno)); + close(newfd); + if (oldfd != -1) close(oldfd); goto cleanup; } - /* Mission completed... almost */ - redisLog(REDIS_NOTICE,"Append only file successfully rewritten."); - if (server.appendfd != -1) { - /* If append only is actually enabled... */ - close(server.appendfd); - server.appendfd = fd; - if (server.appendfsync != APPENDFSYNC_NO) aof_fsync(fd); - server.appendseldb = -1; /* Make sure it will issue SELECT */ - redisLog(REDIS_NOTICE,"The new append only file was selected for future appends."); + + if (server.aof_fd == -1) { + /* AOF disabled, we don't need to set the AOF file descriptor + * to this new file, so we can close it. */ + close(newfd); } else { - /* If append only is disabled we just generate a dump in this - * format. Why not? */ - close(fd); + /* AOF enabled, replace the old fd with the new one. */ + oldfd = server.aof_fd; + server.aof_fd = newfd; + if (server.aof_fsync == AOF_FSYNC_ALWAYS) + aof_fsync(newfd); + else if (server.aof_fsync == AOF_FSYNC_EVERYSEC) + aof_background_fsync(newfd); + server.aof_selected_db = -1; /* Make sure SELECT is re-issued */ + aofUpdateCurrentSize(); + server.aof_rewrite_base_size = server.aof_current_size; + + /* Clear regular AOF buffer since its contents was just written to + * the new AOF from the background rewrite buffer. */ + sdsfree(server.aof_buf); + server.aof_buf = sdsempty(); } + + redisLog(REDIS_NOTICE, "Background AOF rewrite finished successfully"); + /* Change state from WAIT_REWRITE to ON if needed */ + if (server.aof_state == REDIS_AOF_WAIT_REWRITE) + server.aof_state = REDIS_AOF_ON; + + /* Asynchronously close the overwritten AOF. */ + if (oldfd != -1) bioCreateBackgroundJob(REDIS_BIO_CLOSE_FILE,(void*)(long)oldfd,NULL,NULL); + + redisLog(REDIS_VERBOSE, + "Background AOF rewrite signal handler took %lldus", ustime()-now); } else if (!bysignal && exitcode != 0) { - redisLog(REDIS_WARNING, "Background append only file rewriting error"); + redisLog(REDIS_WARNING, + "Background AOF rewrite terminated with error"); } else { redisLog(REDIS_WARNING, - "Background append only file rewriting terminated by signal %d", - WTERMSIG(statloc)); + "Background AOF rewrite terminated by signal %d", bysignal); } + cleanup: - sdsfree(server.bgrewritebuf); - server.bgrewritebuf = sdsempty(); - aofRemoveTempFile(server.bgrewritechildpid); - server.bgrewritechildpid = -1; + aofRewriteBufferReset(); + aofRemoveTempFile(server.aof_child_pid); + server.aof_child_pid = -1; + /* Schedule a new rewrite if we are waiting for it to switch the AOF ON. */ + if (server.aof_state == REDIS_AOF_WAIT_REWRITE) + server.aof_rewrite_scheduled = 1; }