Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

876 lines (781 sloc) 34.819 kb
#include "redis.h"
#include "bio.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>
void aofUpdateCurrentSize(void);
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(1);
aof_fsync(server.appendfd);
close(server.appendfd);
server.appendfd = -1;
server.appendseldb = -1;
server.appendonly = 0;
/* rewrite operation in progress? kill it, wait child exit */
if (server.bgrewritechildpid != -1) {
int statloc;
if (kill(server.bgrewritechildpid,SIGKILL) != -1)
wait3(&statloc,0,NULL);
/* reset the buffer accumulating changes while the child saves */
sdsfree(server.bgrewritebuf);
server.bgrewritebuf = sdsempty();
server.bgrewritechildpid = -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));
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));
return REDIS_ERR;
}
return REDIS_OK;
}
/* 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
* 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. */
void flushAppendOnlyFile(int force) {
ssize_t nwritten;
int sync_in_progress = 0;
if (sdslen(server.aofbuf) == 0) return;
if (server.appendfsync == APPENDFSYNC_EVERYSEC)
sync_in_progress = bioPendingJobsOfType(REDIS_BIO_AOF_FSYNC) != 0;
if (server.appendfsync == APPENDFSYNC_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. */
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)) {
/* 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) {
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);
}
server.appendonly_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.aofbuf)+sdsavail(server.aofbuf)) < 4000) {
sdsclear(server.aofbuf);
} else {
sdsfree(server.aofbuf);
server.aofbuf = sdsempty();
}
/* Don't fsync if no-appendfsync-on-rewrite is set to yes and there are
* children doing I/O in the background. */
if (server.no_appendfsync_on_rewrite &&
(server.bgrewritechildpid != -1 || server.bgsavechildpid != -1))
return;
/* Perform the fsync if needed. */
if (server.appendfsync == APPENDFSYNC_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 = server.unixtime;
} else if ((server.appendfsync == APPENDFSYNC_EVERYSEC &&
server.unixtime > server.lastfsync)) {
if (!sync_in_progress) aof_background_fsync(server.appendfd);
server.lastfsync = 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;
}
sds catAppendOnlyExpireAtCommand(sds buf, robj *key, robj *seconds) {
int argc = 3;
long when;
robj *argv[3];
/* Make sure we can use strtol */
seconds = getDecodedObject(seconds);
when = time(NULL)+strtol(seconds->ptr,NULL,10);
decrRefCount(seconds);
argv[0] = createStringObject("EXPIREAT",8);
argv[1] = key;
argv[2] = createObject(REDIS_STRING,
sdscatprintf(sdsempty(),"%ld",when));
buf = catAppendOnlyGenericCommand(buf, argc, argv);
decrRefCount(argv[0]);
decrRefCount(argv[2]);
return buf;
}
void feedAppendOnlyFile(struct redisCommand *cmd, int dictid, robj **argv, int argc) {
sds buf = sdsempty();
robj *tmpargv[3];
/* 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) {
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;
}
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 */
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]);
} else {
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 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));
sdsfree(buf);
}
/* 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) {
struct redisClient *c = zmalloc(sizeof(*c));
selectDb(c,0);
c->fd = -1;
c->querybuf = sdsempty();
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->watched_keys = listCreate();
listSetFreeMethod(c->reply,decrRefCount);
listSetDupMethod(c->reply,dupClientReplyValue);
initClientMultiState(c);
return c;
}
void freeFakeClient(struct redisClient *c) {
sdsfree(c->querybuf);
listRelease(c->reply);
listRelease(c->watched_keys);
freeClientMultiState(c);
zfree(c);
}
/* Replay the append log file. On error REDIS_OK is returned. On non fatal
* error (the append only file is zero-length) REDIS_ERR is returned. On
* fatal error an error message is logged and the program exists. */
int loadAppendOnlyFile(char *filename) {
struct redisClient *fakeClient;
FILE *fp = fopen(filename,"r");
struct redis_stat sb;
int appendonly = server.appendonly;
long loops = 0;
if (fp && redis_fstat(fileno(fp),&sb) != -1 && sb.st_size == 0) {
server.appendonly_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));
exit(1);
}
/* Temporarily disable AOF, to prevent EXEC from feeding a MULTI
* to the same file we're about to read. */
server.appendonly = 0;
fakeClient = createFakeClient();
startLoading(fp);
while(1) {
int argc, j;
unsigned long len;
robj **argv;
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))
break;
else
goto readerr;
}
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;
if (buf[0] != '$') goto fmterr;
len = strtol(buf+1,NULL,10);
argsds = sdsnewlen(NULL,len);
if (len && fread(argsds,len,1,fp) == 0) goto fmterr;
argv[j] = createObject(REDIS_STRING,argsds);
if (fread(buf,2,1,fp) == 0) goto fmterr; /* discard CRLF */
}
/* Command lookup */
cmd = lookupCommand(argv[0]->ptr);
if (!cmd) {
redisLog(REDIS_WARNING,"Unknown command '%s' reading the append only file", argv[0]->ptr);
exit(1);
}
/* Run the command in the context of a fake client */
fakeClient->argc = argc;
fakeClient->argv = argv;
cmd->proc(fakeClient);
/* 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);
/* 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;
}
}
}
/* This point can only be reached when EOF is reached without errors.
* If the client is in the middle of a MULTI/EXEC, log error and quit. */
if (fakeClient->flags & REDIS_MULTI) goto readerr;
fclose(fp);
freeFakeClient(fakeClient);
server.appendonly = appendonly;
stopLoading();
aofUpdateCurrentSize();
server.auto_aofrewrite_base_size = server.appendonly_current_size;
return REDIS_OK;
readerr:
if (feof(fp)) {
redisLog(REDIS_WARNING,"Unexpected end of file reading the append only file");
} else {
redisLog(REDIS_WARNING,"Unrecoverable error reading the append only file: %s", strerror(errno));
}
exit(1);
fmterr:
redisLog(REDIS_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);
}
/* Write a sequence of commands able to fully rebuild the dataset into
* "filename". Used both by REWRITEAOF and BGREWRITEAOF. */
int rewriteAppendOnlyFile(char *filename) {
dictIterator *di = NULL;
dictEntry *de;
FILE *fp;
char tmpfile[256];
int j;
time_t now = time(NULL);
/* 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));
return REDIS_ERR;
}
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);
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;
/* Iterate this DB writing every entry */
while((de = dictNext(di)) != NULL) {
sds keystr = dictGetEntryKey(de);
robj key, *o;
time_t expiretime;
int swapped;
keystr = dictGetEntryKey(de);
o = dictGetEntryVal(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;
/* Key and value */
if (fwriteBulkObject(fp,&key) == 0) goto werr;
if (fwriteBulkObject(fp,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");
}
} 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;
int64_t 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");
}
} else if (o->type == REDIS_ZSET) {
/* Emit the ZADDs needed to rebuild the sorted set */
char cmd[]="*4\r\n$4\r\nZADD\r\n";
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 (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 (vstr != NULL) {
if (fwriteBulkString(fp,(char*)vstr,vlen) == 0)
goto werr;
} else {
if (fwriteBulkLongLong(fp,vll) == 0)
goto werr;
}
zzlNext(zl,&eptr,&sptr);
}
} 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 = 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);
} else {
redisPanic("Unknown sorted set encoding");
}
} 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);
}
} else {
redisPanic("Unknown object type");
}
/* Save the expire time */
if (expiretime != -1) {
char cmd[]="*3\r\n$8\r\nEXPIREAT\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 (swapped) decrRefCount(o);
}
dictReleaseIterator(di);
}
/* Make sure data will not remain on the OS's output buffers */
fflush(fp);
aof_fsync(fileno(fp));
fclose(fp);
/* Use RENAME to make sure the DB file is changed atomically only
* if the generate DB file is ok. */
if (rename(tmpfile,filename) == -1) {
redisLog(REDIS_WARNING,"Error moving temp append only file on the final destination: %s", strerror(errno));
unlink(tmpfile);
return REDIS_ERR;
}
redisLog(REDIS_NOTICE,"SYNC append only file rewrite performed");
return REDIS_OK;
werr:
fclose(fp);
unlink(tmpfile);
redisLog(REDIS_WARNING,"Write error writing append only file on disk: %s", strerror(errno));
if (di) dictReleaseIterator(di);
return REDIS_ERR;
}
/* 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.bgrewritebuf.
* 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
* 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();
start = ustime();
if ((childpid = fork()) == 0) {
char tmpfile[256];
/* Child */
if (server.vm_enabled) vmReopenSwapFile();
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);
} else {
_exit(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",
strerror(errno));
return REDIS_ERR;
}
redisLog(REDIS_NOTICE,
"Background append only file rewriting started by pid %d",childpid);
server.bgrewritechildpid = 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
* with a SELECT statement and it will be safe to merge. */
server.appendseldb = -1;
return REDIS_OK;
}
return REDIS_OK; /* unreached */
}
void bgrewriteaofCommand(redisClient *c) {
if (server.bgrewritechildpid != -1) {
addReplyError(c,"Background append only file rewriting already in progress");
} else if (server.bgsavechildpid != -1) {
server.aofrewrite_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);
}
}
void aofRemoveTempFile(pid_t childpid) {
char tmpfile[256];
snprintf(tmpfile,256,"temp-rewriteaof-bg-%d.aof", (int) childpid);
unlink(tmpfile);
}
/* Update the server.appendonly_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 lenght, that is much faster. */
void aofUpdateCurrentSize(void) {
struct redis_stat sb;
if (redis_fstat(server.appendfd,&sb) == -1) {
redisLog(REDIS_WARNING,"Unable to check the AOF length: %s",
strerror(errno));
} else {
server.appendonly_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);
if (!bysignal && exitcode == 0) {
int newfd, oldfd;
int nwritten;
char tmpfile[256];
long long now = ustime();
redisLog(REDIS_NOTICE,
"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.bgrewritechildpid);
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;
}
nwritten = write(newfd,server.bgrewritebuf,sdslen(server.bgrewritebuf));
if (nwritten != (signed)sdslen(server.bgrewritebuf)) {
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));
}
close(newfd);
goto cleanup;
}
redisLog(REDIS_NOTICE,
"Parent diff successfully flushed to the rewritten AOF (%lu bytes)", nwritten);
/* 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.appendfd == -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.appendfilename,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.appendfilename) == -1) {
redisLog(REDIS_WARNING,
"Error trying to rename the temporary AOF: %s", strerror(errno));
close(newfd);
if (oldfd != -1) close(oldfd);
goto cleanup;
}
if (server.appendfd == -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.appendfd;
server.appendfd = newfd;
if (server.appendfsync == APPENDFSYNC_ALWAYS)
aof_fsync(newfd);
else if (server.appendfsync == APPENDFSYNC_EVERYSEC)
aof_background_fsync(newfd);
server.appendseldb = -1; /* Make sure SELECT is re-issued */
aofUpdateCurrentSize();
server.auto_aofrewrite_base_size = server.appendonly_current_size;
/* Clear regular AOF buffer since its contents was just written to
* the new AOF from the background rewrite buffer. */
sdsfree(server.aofbuf);
server.aofbuf = sdsempty();
}
redisLog(REDIS_NOTICE, "Background AOF rewrite successful");
/* 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 AOF rewrite terminated with error");
} else {
redisLog(REDIS_WARNING,
"Background AOF rewrite terminated by signal %d",
WTERMSIG(statloc));
}
cleanup:
sdsfree(server.bgrewritebuf);
server.bgrewritebuf = sdsempty();
aofRemoveTempFile(server.bgrewritechildpid);
server.bgrewritechildpid = -1;
}
Jump to Line
Something went wrong with that request. Please try again.