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redis/src/aof.c

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/*
* Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "server.h"
#include "bio.h"
#include "rio.h"
#include <signal.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <sys/param.h>
void aofUpdateCurrentSize(void);
void aofClosePipes(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, pos;
/* Note that 'buf' must be the last field of aofrwblock struct, because
* memory allocator may give us more memory than our apply for reducing
* fragments, but we want to make full use of given memory, i.e. we may
* access the memory after 'buf'. To avoid make others fields corrupt,
* 'buf' must be the last one. */
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 rewrite buffer. */
unsigned long aofRewriteBufferSize(void) {
listNode *ln;
listIter li;
unsigned long size = 0;
listRewind(server.aof_rewrite_buf_blocks,&li);
while((ln = listNext(&li))) {
aofrwblock *block = listNodeValue(ln);
size += block->used;
}
return size;
}
/* This function is different from aofRewriteBufferSize, to get memory usage,
* we should also count all other fields(except 'buf') of aofrwblock and the
* last block's free size. */
unsigned long aofRewriteBufferMemoryUsage(void) {
unsigned long size = aofRewriteBufferSize();
listNode *ln = listLast(server.aof_rewrite_buf_blocks);
if (ln != NULL) {
aofrwblock *block = listNodeValue(ln);
size += block->free;
size += (offsetof(aofrwblock,buf) *
listLength(server.aof_rewrite_buf_blocks));
}
return size;
}
/* Event handler used to send data to the child process doing the AOF
* rewrite. We send pieces of our AOF differences buffer so that the final
* write when the child finishes the rewrite will be small. */
void aofChildWriteDiffData(aeEventLoop *el, int fd, void *privdata, int mask) {
listNode *ln;
aofrwblock *block;
ssize_t nwritten;
mstime_t latency;
UNUSED(el);
UNUSED(fd);
UNUSED(privdata);
UNUSED(mask);
latencyStartMonitor(latency);
while(1) {
ln = listFirst(server.aof_rewrite_buf_blocks);
block = ln ? ln->value : NULL;
if (server.aof_stop_sending_diff || !block) {
aeDeleteFileEvent(server.el,server.aof_pipe_write_data_to_child,
AE_WRITABLE);
break;
}
if (block->used != block->pos) {
nwritten = write(server.aof_pipe_write_data_to_child,
block->buf+block->pos,block->used-block->pos);
if (nwritten <= 0) break;
block->pos += nwritten;
}
if (block->used == block->pos) listDelNode(server.aof_rewrite_buf_blocks,ln);
}
latencyEndMonitor(latency);
latencyAddSampleIfNeeded("aof-rewrite-write-data-to-child",latency);
}
/* 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;
size_t usable_size;
block = zmalloc_usable(sizeof(*block), &usable_size);
block->free = usable_size-offsetof(aofrwblock,buf);
block->used = 0;
block->pos = 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 ? LL_WARNING :
LL_NOTICE;
serverLog(level,"Background AOF buffer size: %lu MB",
aofRewriteBufferSize()/(1024*1024));
}
}
}
/* Install a file event to send data to the rewrite child if there is
* not one already. */
if (aeGetFileEvents(server.el,server.aof_pipe_write_data_to_child) == 0) {
aeCreateFileEvent(server.el, server.aof_pipe_write_data_to_child,
AE_WRITABLE, aofChildWriteDiffData, NULL);
}
}
/* Write the buffer (possibly composed of multiple blocks) into the specified
* fd. If a 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 != block->pos) {
nwritten = write(fd,block->buf+block->pos,block->used-block->pos);
if (nwritten != (ssize_t)(block->used-block->pos)) {
if (nwritten == 0) errno = EIO;
return -1;
}
count += nwritten;
}
}
return count;
}
/* ----------------------------------------------------------------------------
* AOF file implementation
* ------------------------------------------------------------------------- */
/* Return true if an AOf fsync is currently already in progress in a
* BIO thread. */
int aofFsyncInProgress(void) {
return bioPendingJobsOfType(BIO_AOF_FSYNC) != 0;
}
/* 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) {
bioCreateFsyncJob(fd);
}
/* Kills an AOFRW child process if exists */
void killAppendOnlyChild(void) {
int statloc;
/* No AOFRW child? return. */
if (server.child_type != CHILD_TYPE_AOF) return;
/* Kill AOFRW child, wait for child exit. */
serverLog(LL_NOTICE,"Killing running AOF rewrite child: %ld",
(long) server.child_pid);
if (kill(server.child_pid,SIGUSR1) != -1) {
while(waitpid(-1, &statloc, 0) != server.child_pid);
}
/* Reset the buffer accumulating changes while the child saves. */
aofRewriteBufferReset();
aofRemoveTempFile(server.child_pid);
resetChildState();
server.aof_rewrite_time_start = -1;
/* Close pipes used for IPC between the two processes. */
aofClosePipes();
}
/* Called when the user switches from "appendonly yes" to "appendonly no"
* at runtime using the CONFIG command. */
void stopAppendOnly(void) {
serverAssert(server.aof_state != AOF_OFF);
flushAppendOnlyFile(1);
if (redis_fsync(server.aof_fd) == -1) {
serverLog(LL_WARNING,"Fail to fsync the AOF file: %s",strerror(errno));
} else {
server.aof_fsync_offset = server.aof_current_size;
server.aof_last_fsync = server.unixtime;
}
close(server.aof_fd);
server.aof_fd = -1;
server.aof_selected_db = -1;
server.aof_state = AOF_OFF;
server.aof_rewrite_scheduled = 0;
killAppendOnlyChild();
sdsfree(server.aof_buf);
server.aof_buf = sdsempty();
}
/* Called when the user switches from "appendonly no" to "appendonly yes"
* at runtime using the CONFIG command. */
int startAppendOnly(void) {
char cwd[MAXPATHLEN]; /* Current working dir path for error messages. */
int newfd;
newfd = open(server.aof_filename,O_WRONLY|O_APPEND|O_CREAT,0644);
serverAssert(server.aof_state == AOF_OFF);
if (newfd == -1) {
char *cwdp = getcwd(cwd,MAXPATHLEN);
serverLog(LL_WARNING,
"Redis needs to enable the AOF but can't open the "
"append only file %s (in server root dir %s): %s",
server.aof_filename,
cwdp ? cwdp : "unknown",
strerror(errno));
return C_ERR;
}
if (hasActiveChildProcess() && server.child_type != CHILD_TYPE_AOF) {
server.aof_rewrite_scheduled = 1;
serverLog(LL_WARNING,"AOF was enabled but there is already another background operation. An AOF background was scheduled to start when possible.");
} else {
/* If there is a pending AOF rewrite, we need to switch it off and
* start a new one: the old one cannot be reused because it is not
* accumulating the AOF buffer. */
if (server.child_type == CHILD_TYPE_AOF) {
serverLog(LL_WARNING,"AOF was enabled but there is already an AOF rewriting in background. Stopping background AOF and starting a rewrite now.");
killAppendOnlyChild();
}
if (rewriteAppendOnlyFileBackground() == C_ERR) {
close(newfd);
serverLog(LL_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 C_ERR;
}
}
/* We correctly switched on AOF, now wait for the rewrite to be complete
* in order to append data on disk. */
server.aof_state = AOF_WAIT_REWRITE;
server.aof_last_fsync = server.unixtime;
server.aof_fd = newfd;
/* If AOF fsync error in bio job, we just ignore it and log the event. */
int aof_bio_fsync_status;
atomicGet(server.aof_bio_fsync_status, aof_bio_fsync_status);
if (aof_bio_fsync_status == C_ERR) {
serverLog(LL_WARNING,
"AOF reopen, just ignore the AOF fsync error in bio job");
atomicSet(server.aof_bio_fsync_status,C_OK);
}
/* If AOF was in error state, we just ignore it and log the event. */
if (server.aof_last_write_status == C_ERR) {
serverLog(LL_WARNING,"AOF reopen, just ignore the last error.");
server.aof_last_write_status = C_OK;
}
return C_OK;
}
/* This is a wrapper to the write syscall in order to retry on short writes
* or if the syscall gets interrupted. It could look strange that we retry
* on short writes given that we are writing to a block device: normally if
* the first call is short, there is a end-of-space condition, so the next
* is likely to fail. However apparently in modern systems this is no longer
* true, and in general it looks just more resilient to retry the write. If
* there is an actual error condition we'll get it at the next try. */
ssize_t aofWrite(int fd, const char *buf, size_t len) {
ssize_t nwritten = 0, totwritten = 0;
while(len) {
nwritten = write(fd, buf, len);
if (nwritten < 0) {
if (errno == EINTR) continue;
return totwritten ? totwritten : -1;
}
len -= nwritten;
buf += nwritten;
totwritten += nwritten;
}
return totwritten;
}
/* Write the append only file buffer on disk.
*
* Since we are required to write the AOF before replying to the client,
* and the only way the client socket can get a write is entering when
* 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.
*
* 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. */
#define AOF_WRITE_LOG_ERROR_RATE 30 /* Seconds between errors logging. */
void flushAppendOnlyFile(int force) {
ssize_t nwritten;
int sync_in_progress = 0;
mstime_t latency;
if (sdslen(server.aof_buf) == 0) {
/* Check if we need to do fsync even the aof buffer is empty,
* because previously in AOF_FSYNC_EVERYSEC mode, fsync is
* called only when aof buffer is not empty, so if users
* stop write commands before fsync called in one second,
* the data in page cache cannot be flushed in time. */
if (server.aof_fsync == AOF_FSYNC_EVERYSEC &&
server.aof_fsync_offset != server.aof_current_size &&
server.unixtime > server.aof_last_fsync &&
!(sync_in_progress = aofFsyncInProgress())) {
goto try_fsync;
} else {
return;
}
}
if (server.aof_fsync == AOF_FSYNC_EVERYSEC)
sync_in_progress = aofFsyncInProgress();
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 postponing, 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 through, and go write since we can't wait
* over two seconds. */
server.aof_delayed_fsync++;
serverLog(LL_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.");
}
}
/* 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 */
if (server.aof_flush_sleep && sdslen(server.aof_buf)) {
usleep(server.aof_flush_sleep);
}
latencyStartMonitor(latency);
nwritten = aofWrite(server.aof_fd,server.aof_buf,sdslen(server.aof_buf));
latencyEndMonitor(latency);
/* We want to capture different events for delayed writes:
* when the delay happens with a pending fsync, or with a saving child
* active, and when the above two conditions are missing.
* We also use an additional event name to save all samples which is
* useful for graphing / monitoring purposes. */
if (sync_in_progress) {
latencyAddSampleIfNeeded("aof-write-pending-fsync",latency);
} else if (hasActiveChildProcess()) {
latencyAddSampleIfNeeded("aof-write-active-child",latency);
} else {
latencyAddSampleIfNeeded("aof-write-alone",latency);
}
latencyAddSampleIfNeeded("aof-write",latency);
/* We performed the write so reset the postponed flush sentinel to zero. */
server.aof_flush_postponed_start = 0;
if (nwritten != (ssize_t)sdslen(server.aof_buf)) {
static time_t last_write_error_log = 0;
int can_log = 0;
/* Limit logging rate to 1 line per AOF_WRITE_LOG_ERROR_RATE seconds. */
if ((server.unixtime - last_write_error_log) > AOF_WRITE_LOG_ERROR_RATE) {
can_log = 1;
last_write_error_log = server.unixtime;
}
/* Log the AOF write error and record the error code. */
if (nwritten == -1) {
if (can_log) {
serverLog(LL_WARNING,"Error writing to the AOF file: %s",
strerror(errno));
server.aof_last_write_errno = errno;
}
} else {
if (can_log) {
serverLog(LL_WARNING,"Short write while writing to "
"the AOF file: (nwritten=%lld, "
"expected=%lld)",
(long long)nwritten,
(long long)sdslen(server.aof_buf));
}
if (ftruncate(server.aof_fd, server.aof_current_size) == -1) {
if (can_log) {
serverLog(LL_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));
}
} else {
/* If the ftruncate() succeeded we can set nwritten to
* -1 since there is no longer partial data into the AOF. */
nwritten = -1;
}
server.aof_last_write_errno = ENOSPC;
}
/* Handle the AOF write error. */
if (server.aof_fsync == AOF_FSYNC_ALWAYS) {
/* We can't recover when the fsync policy is ALWAYS since the reply
* for the client is already in the output buffers (both writes and
* reads), and the changes to the db can't be rolled back. Since we
* have a contract with the user that on acknowledged or observed
* writes are is synced on disk, we must exit. */
serverLog(LL_WARNING,"Can't recover from AOF write error when the AOF fsync policy is 'always'. Exiting...");
exit(1);
} else {
/* Recover from failed write leaving data into the buffer. However
* set an error to stop accepting writes as long as the error
* condition is not cleared. */
server.aof_last_write_status = C_ERR;
/* Trim the sds buffer if there was a partial write, and there
* was no way to undo it with ftruncate(2). */
if (nwritten > 0) {
server.aof_current_size += nwritten;
sdsrange(server.aof_buf,nwritten,-1);
}
return; /* We'll try again on the next call... */
}
} else {
/* Successful write(2). If AOF was in error state, restore the
* OK state and log the event. */
if (server.aof_last_write_status == C_ERR) {
serverLog(LL_WARNING,
"AOF write error looks solved, Redis can write again.");
server.aof_last_write_status = C_OK;
}
}
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();
}
try_fsync:
/* 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 && hasActiveChildProcess())
return;
/* Perform the fsync if needed. */
if (server.aof_fsync == AOF_FSYNC_ALWAYS) {
/* redis_fsync is defined as fdatasync() for Linux in order to avoid
* flushing metadata. */
latencyStartMonitor(latency);
/* Let's try to get this data on the disk. To guarantee data safe when
* the AOF fsync policy is 'always', we should exit if failed to fsync
* AOF (see comment next to the exit(1) after write error above). */
if (redis_fsync(server.aof_fd) == -1) {
serverLog(LL_WARNING,"Can't persist AOF for fsync error when the "
"AOF fsync policy is 'always': %s. Exiting...", strerror(errno));
exit(1);
}
latencyEndMonitor(latency);
latencyAddSampleIfNeeded("aof-fsync-always",latency);
server.aof_fsync_offset = server.aof_current_size;
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_fsync_offset = server.aof_current_size;
}
server.aof_last_fsync = server.unixtime;
}
}
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++) {
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 dst;
}
void feedAppendOnlyFile(int dictid, robj **argv, int argc) {
sds buf = sdsempty();
/* The DB this command was targeting is not the same as the last command
* we appended. To issue a SELECT command is needed. */
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.aof_selected_db = dictid;
}
/* All commands should be propagated the same way in AOF as in replication.
* No need for AOF-specific translation. */
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. */
if (server.aof_state == 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.child_type == CHILD_TYPE_AOF)
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 client *createAOFClient(void) {
struct client *c = zmalloc(sizeof(*c));
selectDb(c,0);
c->id = CLIENT_ID_AOF; /* So modules can identify it's the AOF client. */
c->conn = NULL;
c->name = NULL;
c->querybuf = sdsempty();
c->querybuf_peak = 0;
c->argc = 0;
c->argv = NULL;
c->original_argc = 0;
c->original_argv = NULL;
c->argv_len_sum = 0;
c->bufpos = 0;
c->buf_usable_size = zmalloc_usable_size(c)-offsetof(client,buf);
/*
* The AOF client should never be blocked (unlike master
* replication connection).
* This is because blocking the AOF client might cause
* deadlock (because potentially no one will unblock it).
* Also, if the AOF client will be blocked just for
* background processing there is a chance that the
* command execution order will be violated.
*/
c->flags = CLIENT_DENY_BLOCKING;
c->btype = BLOCKED_NONE;
/* 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 = SLAVE_STATE_WAIT_BGSAVE_START;
c->reply = listCreate();
c->reply_bytes = 0;
c->obuf_soft_limit_reached_time = 0;
c->watched_keys = listCreate();
c->peerid = NULL;
c->sockname = NULL;
c->resp = 2;
c->user = NULL;
listSetFreeMethod(c->reply,freeClientReplyValue);
listSetDupMethod(c->reply,dupClientReplyValue);
initClientMultiState(c);
return c;
}
void freeFakeClientArgv(struct client *c) {
int j;
for (j = 0; j < c->argc; j++)
decrRefCount(c->argv[j]);
zfree(c->argv);
c->argv_len_sum = 0;
}
void freeFakeClient(struct client *c) {
sdsfree(c->querybuf);
listRelease(c->reply);
listRelease(c->watched_keys);
freeClientMultiState(c);
freeClientOriginalArgv(c);
zfree(c);
}
/* Replay the append log file. On success C_OK is returned. On non fatal
* error (the append only file is zero-length) C_ERR is returned. On
* fatal error an error message is logged and the program exists. */
int loadAppendOnlyFile(char *filename) {
struct client *fakeClient;
FILE *fp = fopen(filename,"r");
struct redis_stat sb;
int old_aof_state = server.aof_state;
long loops = 0;
off_t valid_up_to = 0; /* Offset of latest well-formed command loaded. */
off_t valid_before_multi = 0; /* Offset before MULTI command loaded. */
if (fp == NULL) {
serverLog(LL_WARNING,"Fatal error: can't open the append log file for reading: %s",strerror(errno));
exit(1);
}
/* Handle a zero-length AOF file as a special case. An empty AOF file
* is a valid AOF because an empty server with AOF enabled will create
* a zero length file at startup, that will remain like that if no write
* operation is received. */
if (fp && redis_fstat(fileno(fp),&sb) != -1 && sb.st_size == 0) {
server.aof_current_size = 0;
server.aof_fsync_offset = server.aof_current_size;
fclose(fp);
return C_ERR;
}
/* Temporarily disable AOF, to prevent EXEC from feeding a MULTI
* to the same file we're about to read. */
server.aof_state = AOF_OFF;
fakeClient = createAOFClient();
startLoadingFile(fp, filename, RDBFLAGS_AOF_PREAMBLE);
/* Check if this AOF file has an RDB preamble. In that case we need to
* load the RDB file and later continue loading the AOF tail. */
char sig[5]; /* "REDIS" */
if (fread(sig,1,5,fp) != 5 || memcmp(sig,"REDIS",5) != 0) {
/* No RDB preamble, seek back at 0 offset. */
if (fseek(fp,0,SEEK_SET) == -1) goto readerr;
} else {
/* RDB preamble. Pass loading the RDB functions. */
rio rdb;
serverLog(LL_NOTICE,"Reading RDB preamble from AOF file...");
if (fseek(fp,0,SEEK_SET) == -1) goto readerr;
rioInitWithFile(&rdb,fp);
if (rdbLoadRio(&rdb,RDBFLAGS_AOF_PREAMBLE,NULL) != C_OK) {
serverLog(LL_WARNING,"Error reading the RDB preamble of the AOF file, AOF loading aborted");
goto readerr;
} else {
serverLog(LL_NOTICE,"Reading the remaining AOF tail...");
}
}
/* Read the actual AOF file, in REPL format, command by command. */
while(1) {
int argc, j;
unsigned long len;
robj **argv;
char buf[128];
sds argsds;
struct redisCommand *cmd;
/* Serve the clients from time to time */
if (!(loops++ % 1000)) {
loadingProgress(ftello(fp));
processEventsWhileBlocked();
processModuleLoadingProgressEvent(1);
}
if (fgets(buf,sizeof(buf),fp) == NULL) {
if (feof(fp))
break;
else
goto readerr;
}
if (buf[0] != '*') goto fmterr;
if (buf[1] == '\0') goto readerr;
argc = atoi(buf+1);
if (argc < 1) goto fmterr;
/* Load the next command in the AOF as our fake client
* argv. */
argv = zmalloc(sizeof(robj*)*argc);
fakeClient->argc = argc;
fakeClient->argv = argv;
for (j = 0; j < argc; j++) {
/* Parse the argument len. */
char *readres = fgets(buf,sizeof(buf),fp);
if (readres == NULL || buf[0] != '$') {
fakeClient->argc = j; /* Free up to j-1. */
freeFakeClientArgv(fakeClient);
if (readres == NULL)
goto readerr;
else
goto fmterr;
}
len = strtol(buf+1,NULL,10);
/* Read it into a string object. */
argsds = sdsnewlen(SDS_NOINIT,len);
if (len && fread(argsds,len,1,fp) == 0) {
sdsfree(argsds);
fakeClient->argc = j; /* Free up to j-1. */
freeFakeClientArgv(fakeClient);
goto readerr;
}
argv[j] = createObject(OBJ_STRING,argsds);
/* Discard CRLF. */
if (fread(buf,2,1,fp) == 0) {
fakeClient->argc = j+1; /* Free up to j. */
freeFakeClientArgv(fakeClient);
goto readerr;
}
}
/* Command lookup */
cmd = lookupCommand(argv[0]->ptr);
if (!cmd) {
serverLog(LL_WARNING,
"Unknown command '%s' reading the append only file",
(char*)argv[0]->ptr);
exit(1);
}
if (cmd == server.multiCommand) valid_before_multi = valid_up_to;
/* Run the command in the context of a fake client */
fakeClient->cmd = fakeClient->lastcmd = cmd;
if (fakeClient->flags & CLIENT_MULTI &&
fakeClient->cmd->proc != execCommand)
{
queueMultiCommand(fakeClient);
} else {
cmd->proc(fakeClient);
}
/* The fake client should not have a reply */
serverAssert(fakeClient->bufpos == 0 &&
listLength(fakeClient->reply) == 0);
/* The fake client should never get blocked */
serverAssert((fakeClient->flags & CLIENT_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. */
freeFakeClientArgv(fakeClient);
fakeClient->cmd = NULL;
if (server.aof_load_truncated) valid_up_to = ftello(fp);
if (server.key_load_delay)
debugDelay(server.key_load_delay);
}
/* This point can only be reached when EOF is reached without errors.
* If the client is in the middle of a MULTI/EXEC, handle it as it was
* a short read, even if technically the protocol is correct: we want
* to remove the unprocessed tail and continue. */
if (fakeClient->flags & CLIENT_MULTI) {
serverLog(LL_WARNING,
"Revert incomplete MULTI/EXEC transaction in AOF file");
valid_up_to = valid_before_multi;
goto uxeof;
}
loaded_ok: /* DB loaded, cleanup and return C_OK to the caller. */
fclose(fp);
freeFakeClient(fakeClient);
server.aof_state = old_aof_state;
stopLoading(1);
aofUpdateCurrentSize();
server.aof_rewrite_base_size = server.aof_current_size;
server.aof_fsync_offset = server.aof_current_size;
return C_OK;
readerr: /* Read error. If feof(fp) is true, fall through to unexpected EOF. */
if (!feof(fp)) {
if (fakeClient) freeFakeClient(fakeClient); /* avoid valgrind warning */
fclose(fp);
serverLog(LL_WARNING,"Unrecoverable error reading the append only file: %s", strerror(errno));
exit(1);
}
uxeof: /* Unexpected AOF end of file. */
if (server.aof_load_truncated) {
serverLog(LL_WARNING,"!!! Warning: short read while loading the AOF file !!!");
serverLog(LL_WARNING,"!!! Truncating the AOF at offset %llu !!!",
(unsigned long long) valid_up_to);
if (valid_up_to == -1 || truncate(filename,valid_up_to) == -1) {
if (valid_up_to == -1) {
serverLog(LL_WARNING,"Last valid command offset is invalid");
} else {
serverLog(LL_WARNING,"Error truncating the AOF file: %s",
strerror(errno));
}
} else {
/* Make sure the AOF file descriptor points to the end of the
* file after the truncate call. */
if (server.aof_fd != -1 && lseek(server.aof_fd,0,SEEK_END) == -1) {
serverLog(LL_WARNING,"Can't seek the end of the AOF file: %s",
strerror(errno));
} else {
serverLog(LL_WARNING,
"AOF loaded anyway because aof-load-truncated is enabled");
goto loaded_ok;
}
}
}
if (fakeClient) freeFakeClient(fakeClient); /* avoid valgrind warning */
fclose(fp);
serverLog(LL_WARNING,"Unexpected end of file reading the append only file. You can: 1) Make a backup of your AOF file, then use ./redis-check-aof --fix <filename>. 2) Alternatively you can set the 'aof-load-truncated' configuration option to yes and restart the server.");
exit(1);
fmterr: /* Format error. */
if (fakeClient) freeFakeClient(fakeClient); /* avoid valgrind warning */
fclose(fp);
serverLog(LL_WARNING,"Bad file format reading the append only file: make a backup of your AOF file, then use ./redis-check-aof --fix <filename>");
exit(1);
}
/* ----------------------------------------------------------------------------
* 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 server.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 == OBJ_ENCODING_INT) {
return rioWriteBulkLongLong(r,(long)obj->ptr);
} else if (sdsEncodedObject(obj)) {
return rioWriteBulkString(r,obj->ptr,sdslen(obj->ptr));
} else {
serverPanic("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 == OBJ_ENCODING_QUICKLIST) {
quicklist *list = o->ptr;
quicklistIter *li = quicklistGetIterator(list, AL_START_HEAD);
quicklistEntry entry;
while (quicklistNext(li,&entry)) {
if (count == 0) {
int cmd_items = (items > AOF_REWRITE_ITEMS_PER_CMD) ?
AOF_REWRITE_ITEMS_PER_CMD : items;
if (!rioWriteBulkCount(r,'*',2+cmd_items) ||
!rioWriteBulkString(r,"RPUSH",5) ||
!rioWriteBulkObject(r,key))
{
quicklistReleaseIterator(li);
return 0;
}
}
if (entry.value) {
if (!rioWriteBulkString(r,(char*)entry.value,entry.sz)) {
quicklistReleaseIterator(li);
return 0;
}
} else {
if (!rioWriteBulkLongLong(r,entry.longval)) {
quicklistReleaseIterator(li);
return 0;
}
}
if (++count == AOF_REWRITE_ITEMS_PER_CMD) count = 0;
items--;
}
quicklistReleaseIterator(li);
} else {
serverPanic("Unknown list encoding");
}
return 1;
}
/* 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 == OBJ_ENCODING_INTSET) {
int ii = 0;
int64_t llval;
while(intsetGet(o->ptr,ii++,&llval)) {
if (count == 0) {
int cmd_items = (items > AOF_REWRITE_ITEMS_PER_CMD) ?
AOF_REWRITE_ITEMS_PER_CMD : items;
if (!rioWriteBulkCount(r,'*',2+cmd_items) ||
!rioWriteBulkString(r,"SADD",4) ||
!rioWriteBulkObject(r,key))
{
return 0;
}
}
if (!rioWriteBulkLongLong(r,llval)) return 0;
if (++count == AOF_REWRITE_ITEMS_PER_CMD) count = 0;
items--;
}
} else if (o->encoding == OBJ_ENCODING_HT) {
dictIterator *di = dictGetIterator(o->ptr);
dictEntry *de;
while((de = dictNext(di)) != NULL) {
sds ele = dictGetKey(de);
if (count == 0) {
int cmd_items = (items > AOF_REWRITE_ITEMS_PER_CMD) ?
AOF_REWRITE_ITEMS_PER_CMD : items;
if (!rioWriteBulkCount(r,'*',2+cmd_items) ||
!rioWriteBulkString(r,"SADD",4) ||
!rioWriteBulkObject(r,key))
{
dictReleaseIterator(di);
return 0;
}
}
if (!rioWriteBulkString(r,ele,sdslen(ele))) {
dictReleaseIterator(di);
return 0;
}
if (++count == AOF_REWRITE_ITEMS_PER_CMD) count = 0;
items--;
}
dictReleaseIterator(di);
} else {
serverPanic("Unknown set encoding");
}
return 1;
}
/* 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 == OBJ_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);
serverAssert(eptr != NULL);
sptr = ziplistNext(zl,eptr);
serverAssert(sptr != NULL);
while (eptr != NULL) {
serverAssert(ziplistGet(eptr,&vstr,&vlen,&vll));
score = zzlGetScore(sptr);
if (count == 0) {
int cmd_items = (items > AOF_REWRITE_ITEMS_PER_CMD) ?
AOF_REWRITE_ITEMS_PER_CMD : items;
if (!rioWriteBulkCount(r,'*',2+cmd_items*2) ||
!rioWriteBulkString(r,"ZADD",4) ||
!rioWriteBulkObject(r,key))
{
return 0;
}
}
if (!rioWriteBulkDouble(r,score)) return 0;
if (vstr != NULL) {
if (!rioWriteBulkString(r,(char*)vstr,vlen)) return 0;
} else {
if (!rioWriteBulkLongLong(r,vll)) return 0;
}
zzlNext(zl,&eptr,&sptr);
if (++count == AOF_REWRITE_ITEMS_PER_CMD) count = 0;
items--;
}
} else if (o->encoding == OBJ_ENCODING_SKIPLIST) {
zset *zs = o->ptr;
dictIterator *di = dictGetIterator(zs->dict);
dictEntry *de;
while((de = dictNext(di)) != NULL) {
sds ele = dictGetKey(de);
double *score = dictGetVal(de);
if (count == 0) {
int cmd_items = (items > AOF_REWRITE_ITEMS_PER_CMD) ?
AOF_REWRITE_ITEMS_PER_CMD : items;
if (!rioWriteBulkCount(r,'*',2+cmd_items*2) ||
!rioWriteBulkString(r,"ZADD",4) ||
!rioWriteBulkObject(r,key))
{
dictReleaseIterator(di);
return 0;
}
}
if (!rioWriteBulkDouble(r,*score) ||
!rioWriteBulkString(r,ele,sdslen(ele)))
{
dictReleaseIterator(di);
return 0;
}
if (++count == AOF_REWRITE_ITEMS_PER_CMD) count = 0;
items--;
}
dictReleaseIterator(di);
} else {
serverPanic("Unknown sorted zset encoding");
}
return 1;
}
/* Write either the key or the value of the currently selected item of a 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 OBJ_HASH_KEY or OBJ_HASH_VALUE.
*
* The function returns 0 on error, non-zero on success. */
static int rioWriteHashIteratorCursor(rio *r, hashTypeIterator *hi, int what) {
if (hi->encoding == OBJ_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 == OBJ_ENCODING_HT) {
sds value = hashTypeCurrentFromHashTable(hi, what);
return rioWriteBulkString(r, value, sdslen(value));
}
serverPanic("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) != C_ERR) {
if (count == 0) {
int cmd_items = (items > AOF_REWRITE_ITEMS_PER_CMD) ?
AOF_REWRITE_ITEMS_PER_CMD : items;
if (!rioWriteBulkCount(r,'*',2+cmd_items*2) ||
!rioWriteBulkString(r,"HMSET",5) ||
!rioWriteBulkObject(r,key))
{
hashTypeReleaseIterator(hi);
return 0;
}
}
if (!rioWriteHashIteratorCursor(r, hi, OBJ_HASH_KEY) ||
!rioWriteHashIteratorCursor(r, hi, OBJ_HASH_VALUE))
{
hashTypeReleaseIterator(hi);
return 0;
}
if (++count == AOF_REWRITE_ITEMS_PER_CMD) count = 0;
items--;
}
hashTypeReleaseIterator(hi);
return 1;
}
/* Helper for rewriteStreamObject() that generates a bulk string into the
* AOF representing the ID 'id'. */
int rioWriteBulkStreamID(rio *r,streamID *id) {
int retval;
sds replyid = sdscatfmt(sdsempty(),"%U-%U",id->ms,id->seq);
retval = rioWriteBulkString(r,replyid,sdslen(replyid));
sdsfree(replyid);
return retval;
}
/* Helper for rewriteStreamObject(): emit the XCLAIM needed in order to
* add the message described by 'nack' having the id 'rawid', into the pending
* list of the specified consumer. All this in the context of the specified
* key and group. */
int rioWriteStreamPendingEntry(rio *r, robj *key, const char *groupname, size_t groupname_len, streamConsumer *consumer, unsigned char *rawid, streamNACK *nack) {
/* XCLAIM <key> <group> <consumer> 0 <id> TIME <milliseconds-unix-time>
RETRYCOUNT <count> JUSTID FORCE. */
streamID id;
streamDecodeID(rawid,&id);
if (rioWriteBulkCount(r,'*',12) == 0) return 0;
if (rioWriteBulkString(r,"XCLAIM",6) == 0) return 0;
if (rioWriteBulkObject(r,key) == 0) return 0;
if (rioWriteBulkString(r,groupname,groupname_len) == 0) return 0;
if (rioWriteBulkString(r,consumer->name,sdslen(consumer->name)) == 0) return 0;
if (rioWriteBulkString(r,"0",1) == 0) return 0;
if (rioWriteBulkStreamID(r,&id) == 0) return 0;
if (rioWriteBulkString(r,"TIME",4) == 0) return 0;
if (rioWriteBulkLongLong(r,nack->delivery_time) == 0) return 0;
if (rioWriteBulkString(r,"RETRYCOUNT",10) == 0) return 0;
if (rioWriteBulkLongLong(r,nack->delivery_count) == 0) return 0;
if (rioWriteBulkString(r,"JUSTID",6) == 0) return 0;
if (rioWriteBulkString(r,"FORCE",5) == 0) return 0;
return 1;
}
/* Helper for rewriteStreamObject(): emit the XGROUP CREATECONSUMER is
* needed in order to create consumers that do not have any pending entries.
* All this in the context of the specified key and group. */
int rioWriteStreamEmptyConsumer(rio *r, robj *key, const char *groupname, size_t groupname_len, streamConsumer *consumer) {
/* XGROUP CREATECONSUMER <key> <group> <consumer> */
if (rioWriteBulkCount(r,'*',5) == 0) return 0;
if (rioWriteBulkString(r,"XGROUP",6) == 0) return 0;
if (rioWriteBulkString(r,"CREATECONSUMER",14) == 0) return 0;
if (rioWriteBulkObject(r,key) == 0) return 0;
if (rioWriteBulkString(r,groupname,groupname_len) == 0) return 0;
if (rioWriteBulkString(r,consumer->name,sdslen(consumer->name)) == 0) return 0;
return 1;
}
/* Emit the commands needed to rebuild a stream object.
* The function returns 0 on error, 1 on success. */
int rewriteStreamObject(rio *r, robj *key, robj *o) {
stream *s = o->ptr;
streamIterator si;
streamIteratorStart(&si,s,NULL,NULL,0);
streamID id;
int64_t numfields;
if (s->length) {
/* Reconstruct the stream data using XADD commands. */
while(streamIteratorGetID(&si,&id,&numfields)) {
/* Emit a two elements array for each item. The first is
* the ID, the second is an array of field-value pairs. */
/* Emit the XADD <key> <id> ...fields... command. */
if (!rioWriteBulkCount(r,'*',3+numfields*2) ||
!rioWriteBulkString(r,"XADD",4) ||
!rioWriteBulkObject(r,key) ||
!rioWriteBulkStreamID(r,&id))
{
streamIteratorStop(&si);
return 0;
}
while(numfields--) {
unsigned char *field, *value;
int64_t field_len, value_len;
streamIteratorGetField(&si,&field,&value,&field_len,&value_len);
if (!rioWriteBulkString(r,(char*)field,field_len) ||
!rioWriteBulkString(r,(char*)value,value_len))
{
streamIteratorStop(&si);
return 0;
}
}
}
} else {
/* Use the XADD MAXLEN 0 trick to generate an empty stream if
* the key we are serializing is an empty string, which is possible
* for the Stream type. */
id.ms = 0; id.seq = 1;
if (!rioWriteBulkCount(r,'*',7) ||
!rioWriteBulkString(r,"XADD",4) ||
!rioWriteBulkObject(r,key) ||
!rioWriteBulkString(r,"MAXLEN",6) ||
!rioWriteBulkString(r,"0",1) ||
!rioWriteBulkStreamID(r,&id) ||
!rioWriteBulkString(r,"x",1) ||
!rioWriteBulkString(r,"y",1))
{
streamIteratorStop(&si);
return 0;
}
}
/* Append XSETID after XADD, make sure lastid is correct,
* in case of XDEL lastid. */
if (!rioWriteBulkCount(r,'*',3) ||
!rioWriteBulkString(r,"XSETID",6) ||
!rioWriteBulkObject(r,key) ||
!rioWriteBulkStreamID(r,&s->last_id))
{
streamIteratorStop(&si);
return 0;
}
/* Create all the stream consumer groups. */
if (s->cgroups) {
raxIterator ri;
raxStart(&ri,s->cgroups);
raxSeek(&ri,"^",NULL,0);
while(raxNext(&ri)) {
streamCG *group = ri.data;
/* Emit the XGROUP CREATE in order to create the group. */
if (!rioWriteBulkCount(r,'*',5) ||
!rioWriteBulkString(r,"XGROUP",6) ||
!rioWriteBulkString(r,"CREATE",6) ||
!rioWriteBulkObject(r,key) ||
!rioWriteBulkString(r,(char*)ri.key,ri.key_len) ||
!rioWriteBulkStreamID(r,&group->last_id))
{
raxStop(&ri);
streamIteratorStop(&si);
return 0;
}
/* Generate XCLAIMs for each consumer that happens to
* have pending entries. Empty consumers would be generated with
* XGROUP CREATECONSUMER. */
raxIterator ri_cons;
raxStart(&ri_cons,group->consumers);
raxSeek(&ri_cons,"^",NULL,0);
while(raxNext(&ri_cons)) {
streamConsumer *consumer = ri_cons.data;
/* If there are no pending entries, just emit XGROUP CREATECONSUMER */
if (raxSize(consumer->pel) == 0) {
if (rioWriteStreamEmptyConsumer(r,key,(char*)ri.key,
ri.key_len,consumer) == 0)
{
raxStop(&ri_cons);
raxStop(&ri);
streamIteratorStop(&si);
return 0;
}
continue;
}
/* For the current consumer, iterate all the PEL entries
* to emit the XCLAIM protocol. */
raxIterator ri_pel;
raxStart(&ri_pel,consumer->pel);
raxSeek(&ri_pel,"^",NULL,0);
while(raxNext(&ri_pel)) {
streamNACK *nack = ri_pel.data;
if (rioWriteStreamPendingEntry(r,key,(char*)ri.key,
ri.key_len,consumer,
ri_pel.key,nack) == 0)
{
raxStop(&ri_pel);
raxStop(&ri_cons);
raxStop(&ri);
streamIteratorStop(&si);
return 0;
}
}
raxStop(&ri_pel);
}
raxStop(&ri_cons);
}
raxStop(&ri);
}
streamIteratorStop(&si);
return 1;
}
/* Call the module type callback in order to rewrite a data type
* that is exported by a module and is not handled by Redis itself.
* The function returns 0 on error, 1 on success. */
int rewriteModuleObject(rio *r, robj *key, robj *o) {
RedisModuleIO io;
moduleValue *mv = o->ptr;
moduleType *mt = mv->type;
moduleInitIOContext(io,mt,r,key);
mt->aof_rewrite(&io,key,mv->value);
if (io.ctx) {
moduleFreeContext(io.ctx);
zfree(io.ctx);
}
return io.error ? 0 : 1;
}
/* This function is called by the child rewriting the AOF file to read
* the difference accumulated from the parent into a buffer, that is
* concatenated at the end of the rewrite. */
ssize_t aofReadDiffFromParent(void) {
char buf[65536]; /* Default pipe buffer size on most Linux systems. */
ssize_t nread, total = 0;
while ((nread =
read(server.aof_pipe_read_data_from_parent,buf,sizeof(buf))) > 0) {
server.aof_child_diff = sdscatlen(server.aof_child_diff,buf,nread);
total += nread;
}
return total;
}
int rewriteAppendOnlyFileRio(rio *aof) {
dictIterator *di = NULL;
dictEntry *de;
size_t processed = 0;
int j;
long key_count = 0;
long long updated_time = 0;
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 = dictGetSafeIterator(d);
/* SELECT the new DB */
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;
robj key, *o;
long long expiretime;
keystr = dictGetKey(de);
o = dictGetVal(de);
initStaticStringObject(key,keystr);
expiretime = getExpire(db,&key);
/* Save the key and associated value */
if (o->type == OBJ_STRING) {
/* Emit a SET command */
char cmd[]="*3\r\n$3\r\nSET\r\n";
if (rioWrite(aof,cmd,sizeof(cmd)-1) == 0) goto werr;
/* Key and value */
if (rioWriteBulkObject(aof,&key) == 0) goto werr;
if (rioWriteBulkObject(aof,o) == 0) goto werr;
} else if (o->type == OBJ_LIST) {
if (rewriteListObject(aof,&key,o) == 0) goto werr;
} else if (o->type == OBJ_SET) {
if (rewriteSetObject(aof,&key,o) == 0) goto werr;
} else if (o->type == OBJ_ZSET) {
if (rewriteSortedSetObject(aof,&key,o) == 0) goto werr;
} else if (o->type == OBJ_HASH) {
if (rewriteHashObject(aof,&key,o) == 0) goto werr;
} else if (o->type == OBJ_STREAM) {
if (rewriteStreamObject(aof,&key,o) == 0) goto werr;
} else if (o->type == OBJ_MODULE) {
if (rewriteModuleObject(aof,&key,o) == 0) goto werr;
} else {
serverPanic("Unknown object type");
}
/* Save the expire time */
if (expiretime != -1) {
char cmd[]="*3\r\n$9\r\nPEXPIREAT\r\n";
if (rioWrite(aof,cmd,sizeof(cmd)-1) == 0) goto werr;
if (rioWriteBulkObject(aof,&key) == 0) goto werr;
if (rioWriteBulkLongLong(aof,expiretime) == 0) goto werr;
}
/* Read some diff from the parent process from time to time. */
if (aof->processed_bytes > processed+AOF_READ_DIFF_INTERVAL_BYTES) {
processed = aof->processed_bytes;
aofReadDiffFromParent();
}
/* Update info every 1 second (approximately).
* in order to avoid calling mstime() on each iteration, we will
* check the diff every 1024 keys */
if ((key_count++ & 1023) == 0) {
long long now = mstime();
if (now - updated_time >= 1000) {
sendChildInfo(CHILD_INFO_TYPE_CURRENT_INFO, key_count, "AOF rewrite");
updated_time = now;
}
}
}
dictReleaseIterator(di);
di = NULL;
}
return C_OK;
werr:
if (di) dictReleaseIterator(di);
return C_ERR;
}
/* Write a sequence of commands able to fully rebuild the dataset into
* "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 AOF_REWRITE_ITEMS_PER_CMD items per time
* are inserted using a single command. */
int rewriteAppendOnlyFile(char *filename) {
rio aof;
FILE *fp = NULL;
char tmpfile[256];
char byte;
/* 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) {
serverLog(LL_WARNING, "Opening the temp file for AOF rewrite in rewriteAppendOnlyFile(): %s", strerror(errno));
return C_ERR;
}
server.aof_child_diff = sdsempty();
rioInitWithFile(&aof,fp);
if (server.aof_rewrite_incremental_fsync)
rioSetAutoSync(&aof,REDIS_AUTOSYNC_BYTES);
startSaving(RDBFLAGS_AOF_PREAMBLE);
if (server.aof_use_rdb_preamble) {
int error;
if (rdbSaveRio(&aof,&error,RDBFLAGS_AOF_PREAMBLE,NULL) == C_ERR) {
errno = error;
goto werr;
}
} else {
if (rewriteAppendOnlyFileRio(&aof) == C_ERR) goto werr;
}
/* Do an initial slow fsync here while the parent is still sending
* data, in order to make the next final fsync faster. */
if (fflush(fp) == EOF) goto werr;
if (fsync(fileno(fp)) == -1) goto werr;
/* Read again a few times to get more data from the parent.
* We can't read forever (the server may receive data from clients
* faster than it is able to send data to the child), so we try to read
* some more data in a loop as soon as there is a good chance more data
* will come. If it looks like we are wasting time, we abort (this
* happens after 20 ms without new data). */
int nodata = 0;
mstime_t start = mstime();
while(mstime()-start < 1000 && nodata < 20) {
if (aeWait(server.aof_pipe_read_data_from_parent, AE_READABLE, 1) <= 0)
{
nodata++;
continue;
}
nodata = 0; /* Start counting from zero, we stop on N *contiguous*
timeouts. */
aofReadDiffFromParent();
}
/* Ask the master to stop sending diffs. */
if (write(server.aof_pipe_write_ack_to_parent,"!",1) != 1) goto werr;
if (anetNonBlock(NULL,server.aof_pipe_read_ack_from_parent) != ANET_OK)
goto werr;
/* We read the ACK from the server using a 5 seconds timeout. Normally
* it should reply ASAP, but just in case we lose its reply, we are sure
* the child will eventually get terminated. */
if (syncRead(server.aof_pipe_read_ack_from_parent,&byte,1,5000) != 1 ||
byte != '!') goto werr;
serverLog(LL_NOTICE,"Parent agreed to stop sending diffs. Finalizing AOF...");
/* Read the final diff if any. */
aofReadDiffFromParent();
/* Write the received diff to the file. */
serverLog(LL_NOTICE,
"Concatenating %.2f MB of AOF diff received from parent.",
(double) sdslen(server.aof_child_diff) / (1024*1024));
/* Now we write the entire AOF buffer we received from the parent
* via the pipe during the life of this fork child.
* once a second, we'll take a break and send updated COW info to the parent */
size_t bytes_to_write = sdslen(server.aof_child_diff);
const char *buf = server.aof_child_diff;
long long cow_updated_time = mstime();
long long key_count = dbTotalServerKeyCount();
while (bytes_to_write) {
/* We write the AOF buffer in chunk of 8MB so that we can check the time in between them */
size_t chunk_size = bytes_to_write < (8<<20) ? bytes_to_write : (8<<20);
if (rioWrite(&aof,buf,chunk_size) == 0)
goto werr;
bytes_to_write -= chunk_size;
buf += chunk_size;
/* Update COW info */
long long now = mstime();
if (now - cow_updated_time >= 1000) {
sendChildInfo(CHILD_INFO_TYPE_CURRENT_INFO, key_count, "AOF rewrite");
cow_updated_time = now;
}
}
/* Make sure data will not remain on the OS's output buffers */
if (fflush(fp)) goto werr;
if (fsync(fileno(fp))) goto werr;
if (fclose(fp)) { fp = NULL; goto werr; }
fp = NULL;
/* Use RENAME to make sure the DB file is changed atomically only
* if the generate DB file is ok. */
if (rename(tmpfile,filename) == -1) {
serverLog(LL_WARNING,"Error moving temp append only file on the final destination: %s", strerror(errno));
unlink(tmpfile);
stopSaving(0);
return C_ERR;
}
serverLog(LL_NOTICE,"SYNC append only file rewrite performed");
stopSaving(1);
return C_OK;
werr:
serverLog(LL_WARNING,"Write error writing append only file on disk: %s", strerror(errno));
if (fp) fclose(fp);
unlink(tmpfile);
stopSaving(0);
return C_ERR;
}
/* ----------------------------------------------------------------------------
* AOF rewrite pipes for IPC
* -------------------------------------------------------------------------- */
/* This event handler is called when the AOF rewriting child sends us a
* single '!' char to signal we should stop sending buffer diffs. The
* parent sends a '!' as well to acknowledge. */
void aofChildPipeReadable(aeEventLoop *el, int fd, void *privdata, int mask) {
char byte;
UNUSED(el);
UNUSED(privdata);
UNUSED(mask);
if (read(fd,&byte,1) == 1 && byte == '!') {
serverLog(LL_NOTICE,"AOF rewrite child asks to stop sending diffs.");
server.aof_stop_sending_diff = 1;
if (write(server.aof_pipe_write_ack_to_child,"!",1) != 1) {
/* If we can't send the ack, inform the user, but don't try again
* since in the other side the children will use a timeout if the
* kernel can't buffer our write, or, the children was
* terminated. */
serverLog(LL_WARNING,"Can't send ACK to AOF child: %s",
strerror(errno));
}
}
/* Remove the handler since this can be called only one time during a
* rewrite. */
aeDeleteFileEvent(server.el,server.aof_pipe_read_ack_from_child,AE_READABLE);
}
/* Create the pipes used for parent - child process IPC during rewrite.
* We have a data pipe used to send AOF incremental diffs to the child,
* and two other pipes used by the children to signal it finished with
* the rewrite so no more data should be written, and another for the
* parent to acknowledge it understood this new condition. */
int aofCreatePipes(void) {
int fds[6] = {-1, -1, -1, -1, -1, -1};
int j;
if (pipe(fds) == -1) goto error; /* parent -> children data. */
if (pipe(fds+2) == -1) goto error; /* children -> parent ack. */
if (pipe(fds+4) == -1) goto error; /* parent -> children ack. */
/* Parent -> children data is non blocking. */
if (anetNonBlock(NULL,fds[0]) != ANET_OK) goto error;
if (anetNonBlock(NULL,fds[1]) != ANET_OK) goto error;
if (aeCreateFileEvent(server.el, fds[2], AE_READABLE, aofChildPipeReadable, NULL) == AE_ERR) goto error;
server.aof_pipe_write_data_to_child = fds[1];
server.aof_pipe_read_data_from_parent = fds[0];
server.aof_pipe_write_ack_to_parent = fds[3];
server.aof_pipe_read_ack_from_child = fds[2];
server.aof_pipe_write_ack_to_child = fds[5];
server.aof_pipe_read_ack_from_parent = fds[4];
server.aof_stop_sending_diff = 0;
return C_OK;
error:
serverLog(LL_WARNING,"Error opening /setting AOF rewrite IPC pipes: %s",
strerror(errno));
for (j = 0; j < 6; j++) if(fds[j] != -1) close(fds[j]);
return C_ERR;
}
void aofClosePipes(void) {
aeDeleteFileEvent(server.el,server.aof_pipe_read_ack_from_child,AE_READABLE);
aeDeleteFileEvent(server.el,server.aof_pipe_write_data_to_child,AE_WRITABLE);
close(server.aof_pipe_write_data_to_child);
close(server.aof_pipe_read_data_from_parent);
close(server.aof_pipe_write_ack_to_parent);
close(server.aof_pipe_read_ack_from_child);
close(server.aof_pipe_write_ack_to_child);
close(server.aof_pipe_read_ack_from_parent);
}
/* ----------------------------------------------------------------------------
* AOF background rewrite
* ------------------------------------------------------------------------- */
/* This is how rewriting of the append only file in background works:
*
* 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.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.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;
if (hasActiveChildProcess()) return C_ERR;
if (aofCreatePipes() != C_OK) return C_ERR;
if ((childpid = redisFork(CHILD_TYPE_AOF)) == 0) {
char tmpfile[256];
/* Child */
redisSetProcTitle("redis-aof-rewrite");
redisSetCpuAffinity(server.aof_rewrite_cpulist);
snprintf(tmpfile,256,"temp-rewriteaof-bg-%d.aof", (int) getpid());
if (rewriteAppendOnlyFile(tmpfile) == C_OK) {
sendChildCowInfo(CHILD_INFO_TYPE_AOF_COW_SIZE, "AOF rewrite");
exitFromChild(0);
} else {
exitFromChild(1);
}
} else {
/* Parent */
if (childpid == -1) {
serverLog(LL_WARNING,
"Can't rewrite append only file in background: fork: %s",
strerror(errno));
aofClosePipes();
return C_ERR;
}
serverLog(LL_NOTICE,
"Background append only file rewriting started by pid %ld",(long) childpid);
server.aof_rewrite_scheduled = 0;
server.aof_rewrite_time_start = time(NULL);
/* We set aof_selected_db 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.aof_rewrite_buf will start
* with a SELECT statement and it will be safe to merge. */
server.aof_selected_db = -1;
replicationScriptCacheFlush();
return C_OK;
}
return C_OK; /* unreached */
}
void bgrewriteaofCommand(client *c) {
if (server.child_type == CHILD_TYPE_AOF) {
addReplyError(c,"Background append only file rewriting already in progress");
} else if (hasActiveChildProcess()) {
server.aof_rewrite_scheduled = 1;
addReplyStatus(c,"Background append only file rewriting scheduled");
} else if (rewriteAppendOnlyFileBackground() == C_OK) {
addReplyStatus(c,"Background append only file rewriting started");
} else {
addReplyError(c,"Can't execute an AOF background rewriting. "
"Please check the server logs for more information.");
}
}
void aofRemoveTempFile(pid_t childpid) {
char tmpfile[256];
snprintf(tmpfile,256,"temp-rewriteaof-bg-%d.aof", (int) childpid);
bg_unlink(tmpfile);
snprintf(tmpfile,256,"temp-rewriteaof-%d.aof", (int) childpid);
bg_unlink(tmpfile);
}
/* Update the server.aof_current_size field 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;
mstime_t latency;
latencyStartMonitor(latency);
if (redis_fstat(server.aof_fd,&sb) == -1) {
serverLog(LL_WARNING,"Unable to obtain the AOF file length. stat: %s",
strerror(errno));
} else {
server.aof_current_size = sb.st_size;
}
latencyEndMonitor(latency);
latencyAddSampleIfNeeded("aof-fstat",latency);
}
/* A background append only file rewriting (BGREWRITEAOF) terminated its work.
* Handle this. */
void backgroundRewriteDoneHandler(int exitcode, int bysignal) {
if (!bysignal && exitcode == 0) {
int newfd, oldfd;
char tmpfile[256];
long long now = ustime();
mstime_t latency;
serverLog(LL_NOTICE,
"Background AOF rewrite terminated with success");
/* Flush the differences accumulated by the parent to the
* rewritten AOF. */
latencyStartMonitor(latency);
snprintf(tmpfile,256,"temp-rewriteaof-bg-%d.aof",
(int)server.child_pid);
newfd = open(tmpfile,O_WRONLY|O_APPEND);
if (newfd == -1) {
serverLog(LL_WARNING,
"Unable to open the temporary AOF produced by the child: %s", strerror(errno));
goto cleanup;
}
if (aofRewriteBufferWrite(newfd) == -1) {
serverLog(LL_WARNING,
"Error trying to flush the parent diff to the rewritten AOF: %s", strerror(errno));
close(newfd);
goto cleanup;
}
latencyEndMonitor(latency);
latencyAddSampleIfNeeded("aof-rewrite-diff-write",latency);
if (server.aof_fsync == AOF_FSYNC_EVERYSEC) {
aof_background_fsync(newfd);
} else if (server.aof_fsync == AOF_FSYNC_ALWAYS) {
latencyStartMonitor(latency);
if (redis_fsync(newfd) == -1) {
serverLog(LL_WARNING,
"Error trying to fsync the parent diff to the rewritten AOF: %s", strerror(errno));
close(newfd);
goto cleanup;
}
latencyEndMonitor(latency);
latencyAddSampleIfNeeded("aof-rewrite-done-fsync",latency);
}
serverLog(LL_NOTICE,
"Residual parent diff successfully flushed to the rewritten AOF (%.2f MB)", (double) aofRewriteBufferSize() / (1024*1024));
/* 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 file descriptor later. */
}
/* Rename the temporary file. This will not unlink the target file if
* it exists, because we reference it with "oldfd". */
latencyStartMonitor(latency);
if (rename(tmpfile,server.aof_filename) == -1) {
serverLog(LL_WARNING,
"Error trying to rename the temporary AOF file %s into %s: %s",
tmpfile,
server.aof_filename,
strerror(errno));
close(newfd);
if (oldfd != -1) close(oldfd);
goto cleanup;
}
latencyEndMonitor(latency);
latencyAddSampleIfNeeded("aof-rename",latency);
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 {
/* AOF enabled, replace the old fd with the new one. */
oldfd = server.aof_fd;
server.aof_fd = newfd;
server.aof_selected_db = -1; /* Make sure SELECT is re-issued */
aofUpdateCurrentSize();
server.aof_rewrite_base_size = server.aof_current_size;
server.aof_fsync_offset = server.aof_current_size;
server.aof_last_fsync = server.unixtime;
/* 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();
}
server.aof_lastbgrewrite_status = C_OK;
serverLog(LL_NOTICE, "Background AOF rewrite finished successfully");
/* Change state from WAIT_REWRITE to ON if needed */
if (server.aof_state == AOF_WAIT_REWRITE)
server.aof_state = AOF_ON;
/* Asynchronously close the overwritten AOF. */
if (oldfd != -1) bioCreateCloseJob(oldfd);
serverLog(LL_VERBOSE,
"Background AOF rewrite signal handler took %lldus", ustime()-now);
} else if (!bysignal && exitcode != 0) {
server.aof_lastbgrewrite_status = C_ERR;
serverLog(LL_WARNING,
"Background AOF rewrite terminated with error");
} else {
/* SIGUSR1 is whitelisted, so we have a way to kill a child without
* triggering an error condition. */
if (bysignal != SIGUSR1)
server.aof_lastbgrewrite_status = C_ERR;
serverLog(LL_WARNING,
"Background AOF rewrite terminated by signal %d", bysignal);
}
cleanup:
aofClosePipes();
aofRewriteBufferReset();
aofRemoveTempFile(server.child_pid);
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 == AOF_WAIT_REWRITE)
server.aof_rewrite_scheduled = 1;
}
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