int main(void) {
unsigned char *zm;
zm = zipmapNew();
zm = zipmapSet(zm,(unsigned char*) "name",4, (unsigned char*) "foo",3,NULL);
zm = zipmapSet(zm,(unsigned char*) "surname",7, (unsigned char*) "foo",3,NULL);
zm = zipmapSet(zm,(unsigned char*) "age",3, (unsigned char*) "foo",3,NULL);
zipmapRepr(zm);
zm = zipmapSet(zm,(unsigned char*) "hello",5, (unsigned char*) "world!",6,NULL);
zm = zipmapSet(zm,(unsigned char*) "foo",3, (unsigned char*) "bar",3,NULL);
zm = zipmapSet(zm,(unsigned char*) "foo",3, (unsigned char*) "!",1,NULL);
zipmapRepr(zm);
zm = zipmapSet(zm,(unsigned char*) "foo",3, (unsigned char*) "12345",5,NULL);
zipmapRepr(zm);
zm = zipmapSet(zm,(unsigned char*) "new",3, (unsigned char*) "xx",2,NULL);
zm = zipmapSet(zm,(unsigned char*) "noval",5, (unsigned char*) "",0,NULL);
zipmapRepr(zm);
zm = zipmapDel(zm,(unsigned char*) "new",3,NULL);
zipmapRepr(zm);
printf("\nLook up large key:\n");
{
unsigned char buf[512];
unsigned char *value;
unsigned int vlen, i;
for (i = 0; i < 512; i++) buf[i] = 'a';
zm = zipmapSet(zm,buf,512,(unsigned char*) "long",4,NULL);
if (zipmapGet(zm,buf,512,&value,&vlen)) {
printf(" <long key> is associated to the %d bytes value: %.*s\n",
vlen, vlen, value);
}
}
printf("\nPerform a direct lookup:\n");
{
unsigned char *value;
unsigned int vlen;
if (zipmapGet(zm,(unsigned char*) "foo",3,&value,&vlen)) {
printf(" foo is associated to the %d bytes value: %.*s\n",
vlen, vlen, value);
}
}
printf("\nIterate through elements:\n");
{
unsigned char *i = zipmapRewind(zm);
unsigned char *key, *value;
unsigned int klen, vlen;
while((i = zipmapNext(i,&key,&klen,&value,&vlen)) != NULL) {
printf(" %d:%.*s => %d:%.*s\n", klen, klen, key, vlen, vlen, value);
}
}
return 0;
}
/* Return the number of entries inside a zipmap */
unsigned int zipmapLen(unsigned char *zm) {
unsigned int len = 0;
if (zm[0] < ZIPMAP_BIGLEN) {
len = zm[0];
} else {
unsigned char *p = zipmapRewind(zm);
while((p = zipmapNext(p,NULL,NULL,NULL,NULL)) != NULL) len++;
/* Re-store length if small enough */
if (len < ZIPMAP_BIGLEN) zm[0] = len;
}
return len;
}
/* load value which hash encoding with zipmap. */
static void *loadHashZipMapObject(unsigned char* zm, unsigned int *rlen) {
unsigned char *key, *val, *p;
unsigned int klen, vlen, len, i = 0;
len = zipmapLen(zm);
*rlen = len * 2;
sds *results = (sds *) zmalloc(*rlen * sizeof(sds));
p = zipmapRewind(zm);
while((p = zipmapNext(p,&key,&klen,&val,&vlen)) != NULL) {
results[i] = sdsnewlen(key, klen);
results[i+1] = sdsnewlen(val, vlen);
i += 2;
}
return results;
}
/* Return the number of entries inside a zipmap
*
* 返回 zipmap 中包含的节点数
*
* T = O(N)
*/
unsigned int zipmapLen(unsigned char *zm) {
unsigned int len = 0;
if (zm[0] < ZIPMAP_BIGLEN) {
// 长度可以用 1 字节保存
// T = O(1)
len = zm[0];
} else {
// 长度不能用 1 字节保存，需要遍历整个 zipmap
// T = O(N)
unsigned char *p = zipmapRewind(zm);
while((p = zipmapNext(p,NULL,NULL,NULL,NULL)) != NULL) len++;
/* Re-store length if small enough */
// 如果字节数量已经少于 ZIPMAP_BIGLEN ，那么重新将值保存到 len 中
// 这种情况在节点数超过 ZIPMAP_BIGLEN 之后，有节点被删除时会出现
if (len < ZIPMAP_BIGLEN) zm[0] = len;
}
return len;
}
/* 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;
}
/* How a good candidate is this object for swapping?
* The better candidate it is, the greater the returned value.
*
* Currently we try to perform a fast estimation of the object size in
* memory, and combine it with aging informations.
*
* Basically swappability = idle-time * log(estimated size)
*
* Bigger objects are preferred over smaller objects, but not
* proportionally, this is why we use the logarithm. This algorithm is
* just a first try and will probably be tuned later. */
double computeObjectSwappability(robj *o) {
/* actual age can be >= minage, but not < minage. As we use wrapping
* 21 bit clocks with minutes resolution for the LRU. */
time_t minage = estimateObjectIdleTime(o);
#ifdef _WIN32
ssize_t asize = 0, elesize;
#else
long asize = 0, elesize;
#endif
robj *ele;
list *l;
listNode *ln;
dict *d;
struct dictEntry *de;
if (minage <= 0) return 0;
switch(o->type) {
case REDIS_STRING:
if (o->encoding != REDIS_ENCODING_RAW) {
asize = sizeof(*o);
} else {
#ifdef _WIN32
asize = sdslen(o->ptr)+sizeof(*o)+sizeof(size_t)*2;
#else
asize = sdslen(o->ptr)+sizeof(*o)+sizeof(long)*2;
#endif
}
break;
case REDIS_LIST:
if (o->encoding == REDIS_ENCODING_ZIPLIST) {
asize = sizeof(*o)+ziplistBlobLen(o->ptr);
} else {
l = o->ptr;
ln = listFirst(l);
asize = sizeof(list);
if (ln) {
ele = ln->value;
elesize = (ele->encoding == REDIS_ENCODING_RAW) ?
(sizeof(*o)+sdslen(ele->ptr)) : sizeof(*o);
asize += (sizeof(listNode)+elesize)*listLength(l);
}
}
break;
case REDIS_SET:
if (o->encoding == REDIS_ENCODING_INTSET) {
intset *is = o->ptr;
asize = sizeof(*is)+is->encoding*is->length;
} else {
d = o->ptr;
asize = sizeof(dict)+(sizeof(struct dictEntry*)*dictSlots(d));
if (dictSize(d)) {
de = dictGetRandomKey(d);
ele = dictGetEntryKey(de);
elesize = (ele->encoding == REDIS_ENCODING_RAW) ?
(sizeof(*o)+sdslen(ele->ptr)) : sizeof(*o);
asize += (sizeof(struct dictEntry)+elesize)*dictSize(d);
}
}
break;
case REDIS_ZSET:
if (o->encoding == REDIS_ENCODING_ZIPLIST) {
asize = sizeof(*o)+(ziplistBlobLen(o->ptr) / 2);
} else {
d = ((zset*)o->ptr)->dict;
asize = sizeof(zset)+(sizeof(struct dictEntry*)*dictSlots(d));
if (dictSize(d)) {
de = dictGetRandomKey(d);
ele = dictGetEntryKey(de);
elesize = (ele->encoding == REDIS_ENCODING_RAW) ?
(sizeof(*o)+sdslen(ele->ptr)) : sizeof(*o);
asize += (sizeof(struct dictEntry)+elesize)*dictSize(d);
asize += sizeof(zskiplistNode)*dictSize(d);
}
}
break;
case REDIS_HASH:
if (o->encoding == REDIS_ENCODING_ZIPMAP) {
unsigned char *p = zipmapRewind((unsigned char*)o->ptr);
unsigned int len = zipmapLen((unsigned char*)o->ptr);
unsigned int klen, vlen;
unsigned char *key, *val;
if ((p = zipmapNext(p,&key,&klen,&val,&vlen)) == NULL) {
klen = 0;
vlen = 0;
}
asize = len*(klen+vlen+3);
} else if (o->encoding == REDIS_ENCODING_HT) {
d = o->ptr;
asize = sizeof(dict)+(sizeof(struct dictEntry*)*dictSlots(d));
if (dictSize(d)) {
de = dictGetRandomKey(d);
ele = dictGetEntryKey(de);
elesize = (ele->encoding == REDIS_ENCODING_RAW) ?
(sizeof(*o)+sdslen(ele->ptr)) : sizeof(*o);
ele = dictGetEntryVal(de);
elesize = (ele->encoding == REDIS_ENCODING_RAW) ?
(sizeof(*o)+sdslen(ele->ptr)) : sizeof(*o);
asize += (sizeof(struct dictEntry)+elesize)*dictSize(d);
}
}
break;
}
return (double)minage*log(1+(double)asize);
}
/* Write a sequence of commands able to fully rebuild the dataset into
* "filename". Used both by REWRITEAOF and BGREWRITEAOF. */
static 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");
for (j = 0; j < server.dbnum; j++) {
char selectcmd[] = "*2\r\n$6\r\nSELECT\r\n";
redisDb *db = server.db+j;
dict *d = db->dict;
if (dictSize(d) == 0) continue;
di = dictGetIterator(d);
/* SELECT the new DB */
fwrite(selectcmd,sizeof(selectcmd)-1,1,fp);
fwriteBulkLong(fp,j);
/* Iterate this DB writing every entry */
while((de = dictNext(di)) != NULL) {
robj *key, *o;
time_t expiretime;
int swapped;
key = dictGetEntryKey(de);
/* 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 || key->storage == REDIS_VM_MEMORY ||
key->storage == REDIS_VM_SWAPPING) {
o = dictGetEntryVal(de);
swapped = 0;
} else {
o = vmPreviewObject(key);
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";
fwrite(cmd, sizeof(cmd)-1,1,fp);
/* Key and value */
fwriteBulkObject(fp,key);
fwriteBulkObject(fp,o);
}
else if (o->type == REDIS_LIST) {
/* Emit the RPUSHes needed to rebuild the list */
list *list = o->ptr;
listNode *ln;
listIter li;
listRewind(list,&li);
while((ln = listNext(&li))) {
char cmd[]="*3\r\n$5\r\nRPUSH\r\n";
robj *eleobj = listNodeValue(ln);
fwrite(cmd, sizeof(cmd)-1, 1, fp);
fwriteBulkObject(fp,key);
fwriteBulkObject(fp,eleobj);
}
}
else if (o->type == REDIS_SET) {
/* Emit the SADDs needed to rebuild the set */
dict *set = o->ptr;
dictIterator *di = dictGetIterator(set);
dictEntry *de;
while((de = dictNext(di)) != NULL) {
char cmd[]="*3\r\n$4\r\nSADD\r\n";
robj *eleobj = dictGetEntryKey(de);
fwrite(cmd,sizeof(cmd)-1,1,fp) ;
fwriteBulkObject(fp,key) ;
fwriteBulkObject(fp,eleobj);
}
dictReleaseIterator(di);
}
else if (o->type == REDIS_ZSET) {
/* Emit the ZADDs needed to rebuild the sorted set */
zset *zs = o->ptr;
dictIterator *di = dictGetIterator(zs->dict);
dictEntry *de;
while((de = dictNext(di)) != NULL) {
char cmd[]="*4\r\n$4\r\nZADD\r\n";
robj *eleobj = dictGetEntryKey(de);
double *score = dictGetEntryVal(de);
if (fwrite(cmd,sizeof(cmd)-1,1,fp) == 0) goto werr;
if (fwriteBulkObject(fp,key) == 0) goto werr;
if (fwriteBulkDouble(fp,*score) == 0) goto werr;
if (fwriteBulkObject(fp,eleobj) == 0) goto werr;
}
dictReleaseIterator(di);
} 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) == -1)
return -1;
if (fwriteBulkString(fp,(char*)val,vlen) == -1)
return -1;
}
} 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) == -1) return -1;
if (fwriteBulkObject(fp,val) == -1) return -1;
}
dictReleaseIterator(di);
}
} else {
redisAssert(0);
}
/* 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;
fwrite(cmd,sizeof(cmd)-1,1,fp) ;
fwriteBulkObject(fp,key) ;
fwriteBulkLong(fp,expiretime) ;
}
if (swapped) decrRefCount(o);
}
dictReleaseIterator(di);
}
/* Make sure data will not remain on the OS's output buffers */
fflush(fp);
fsync(fileno(fp));
fclose(fp);
/* Use RENAME to make sure the DB file is changed atomically only
* if the generate DB file is ok. */
rename(tmpfile,filename) ;
redisLog(REDIS_NOTICE,"SYNC append only file rewrite performed");
return REDIS_OK;
}