X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/27fc5bf582b12a47e7497bc6f7a38a6d033dcb7c..73d3e8751b0954628561fef7548be06b041c2819:/src/aof.c diff --git a/src/aof.c b/src/aof.c index 59b5ab89..441ccaf1 100644 --- a/src/aof.c +++ b/src/aof.c @@ -12,6 +12,115 @@ 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 * ------------------------------------------------------------------------- */ @@ -42,10 +151,10 @@ void stopAppendOnly(void) { if (kill(server.aof_child_pid,SIGKILL) != -1) wait3(&statloc,0,NULL); /* reset the buffer accumulating changes while the child saves */ - sdsfree(server.aof_rewrite_buf); - server.aof_rewrite_buf = sdsempty(); + aofRewriteBufferReset(); aofRemoveTempFile(server.aof_child_pid); server.aof_child_pid = -1; + server.aof_rewrite_time_start = -1; } } @@ -141,6 +250,13 @@ void flushAppendOnlyFile(int force) { strerror(errno), (long)nwritten, (long)sdslen(server.aof_buf)); + + if (ftruncate(server.aof_fd, server.aof_current_size) == -1) { + redisLog(REDIS_WARNING, "Could not remove short write " + "from the append-only file. Redis may refuse " + "to load the AOF the next time it starts. " + "ftruncate: %s", strerror(errno)); + } } exit(1); } @@ -281,7 +397,7 @@ void feedAppendOnlyFile(struct redisCommand *cmd, int dictid, robj **argv, int a * 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.aof_child_pid != -1) - server.aof_rewrite_buf = sdscatlen(server.aof_rewrite_buf,buf,sdslen(buf)); + aofRewriteBufferAppend((unsigned char*)buf,sdslen(buf)); sdsfree(buf); } @@ -833,6 +949,7 @@ int rewriteAppendOnlyFileBackground(void) { redisLog(REDIS_NOTICE, "Background append only file rewriting started by pid %d",childpid); server.aof_rewrite_scheduled = 0; + server.aof_rewrite_time_start = time(NULL); server.aof_child_pid = childpid; updateDictResizePolicy(); /* We set appendseldb to -1 in order to force the next call to the @@ -885,7 +1002,6 @@ void aofUpdateCurrentSize(void) { void backgroundRewriteDoneHandler(int exitcode, int bysignal) { if (!bysignal && exitcode == 0) { int newfd, oldfd; - int nwritten; char tmpfile[256]; long long now = ustime(); @@ -903,21 +1019,15 @@ void backgroundRewriteDoneHandler(int exitcode, int bysignal) { goto cleanup; } - nwritten = write(newfd,server.aof_rewrite_buf,sdslen(server.aof_rewrite_buf)); - if (nwritten != (signed)sdslen(server.aof_rewrite_buf)) { - if (nwritten == -1) { - redisLog(REDIS_WARNING, - "Error trying to flush the parent diff to the rewritten AOF: %s", strerror(errno)); - } else { - redisLog(REDIS_WARNING, - "Short write trying to flush the parent diff to the rewritten AOF: %s", strerror(errno)); - } + 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 successfully flushed to the rewritten AOF (%lu bytes)", nwritten); + "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 @@ -990,6 +1100,8 @@ void backgroundRewriteDoneHandler(int exitcode, int bysignal) { server.aof_buf = sdsempty(); } + server.aof_lastbgrewrite_status = REDIS_OK; + 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) @@ -1001,18 +1113,23 @@ void backgroundRewriteDoneHandler(int exitcode, int bysignal) { redisLog(REDIS_VERBOSE, "Background AOF rewrite signal handler took %lldus", ustime()-now); } else if (!bysignal && exitcode != 0) { + server.aof_lastbgrewrite_status = REDIS_ERR; + redisLog(REDIS_WARNING, "Background AOF rewrite terminated with error"); } else { + server.aof_lastbgrewrite_status = REDIS_ERR; + redisLog(REDIS_WARNING, "Background AOF rewrite terminated by signal %d", bysignal); } cleanup: - sdsfree(server.aof_rewrite_buf); - server.aof_rewrite_buf = sdsempty(); + aofRewriteBufferReset(); aofRemoveTempFile(server.aof_child_pid); server.aof_child_pid = -1; + server.aof_rewrite_time_last = time(NULL)-server.aof_rewrite_time_start; + server.aof_rewrite_time_start = -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;