Skip to content

Commit

Permalink
Sharing of small integer objects: may save a lot of memory with datas…
Browse files Browse the repository at this point in the history 
…ets having many of this
  • Loading branch information
@antirez
antirez committed Apr 12, 2010
1 parent dae121d commit 05df762
Showing 1 changed file with 37 additions and 24 deletions.
61 changes: 37 additions & 24 deletions redis.c
View file
Expand Up @@ -505,6 +505,7 @@ typedef struct zset {

/* Our shared "common" objects */

#define REDIS_SHARED_INTEGERS 10000
struct sharedObjectsStruct {
robj *crlf, *ok, *err, *emptybulk, *czero, *cone, *pong, *space,
*colon, *nullbulk, *nullmultibulk, *queued,
Expand All @@ -513,7 +514,7 @@ struct sharedObjectsStruct {
*select0, *select1, *select2, *select3, *select4,
*select5, *select6, *select7, *select8, *select9,
*messagebulk, *subscribebulk, *unsubscribebulk, *mbulk3,
*psubscribebulk, *punsubscribebulk;
*psubscribebulk, *punsubscribebulk, *integers[REDIS_SHARED_INTEGERS];
} shared;

/* Global vars that are actally used as constants. The following double
Expand Down Expand Up @@ -556,7 +557,7 @@ static robj *dupStringObject(robj *o);
static void replicationFeedSlaves(list *slaves, int dictid, robj **argv, int argc);
static void feedAppendOnlyFile(struct redisCommand *cmd, int dictid, robj **argv, int argc);
static int syncWithMaster(void);
static int tryObjectEncoding(robj *o);
static robj *tryObjectEncoding(robj *o);
static robj *getDecodedObject(robj *o);
static int removeExpire(redisDb *db, robj *key);
static int expireIfNeeded(redisDb *db, robj *key);
Expand Down Expand Up @@ -1484,6 +1485,8 @@ static void beforeSleep(struct aeEventLoop *eventLoop) {
}

static void createSharedObjects(void) {
int j;

shared.crlf = createObject(REDIS_STRING,sdsnew("\r\n"));
shared.ok = createObject(REDIS_STRING,sdsnew("+OK\r\n"));
shared.err = createObject(REDIS_STRING,sdsnew("-ERR\r\n"));
Expand Down Expand Up @@ -1524,6 +1527,10 @@ static void createSharedObjects(void) {
shared.psubscribebulk = createStringObject("$10\r\npsubscribe\r\n",17);
shared.punsubscribebulk = createStringObject("$12\r\npunsubscribe\r\n",19);
shared.mbulk3 = createStringObject("*3\r\n",4);
for (j = 0; j < REDIS_SHARED_INTEGERS; j++) {
shared.integers[j] = createObject(REDIS_STRING,(void*)(long)j);
shared.integers[j]->encoding = REDIS_ENCODING_INT;
}
}

static void appendServerSaveParams(time_t seconds, int changes) {
Expand Down Expand Up @@ -2277,7 +2284,7 @@ static int processCommand(redisClient *c) {
}
/* Let's try to encode the bulk object to save space. */
if (cmd->flags & REDIS_CMD_BULK)
tryObjectEncoding(c->argv[c->argc-1]);
c->argv[c->argc-1] = tryObjectEncoding(c->argv[c->argc-1]);

/* Check if the user is authenticated */
if (server.requirepass && !c->authenticated && cmd->proc != authCommand) {
Expand Down Expand Up @@ -2963,29 +2970,35 @@ static int isStringRepresentableAsLong(sds s, long *longval) {
}

/* Try to encode a string object in order to save space */
static int tryObjectEncoding(robj *o) {
static robj *tryObjectEncoding(robj *o) {
long value;
sds s = o->ptr;

if (o->encoding != REDIS_ENCODING_RAW)
return REDIS_ERR; /* Already encoded */
return o; /* Already encoded */

/* It's not save to encode shared objects: shared objects can be shared
/* It's not safe to encode shared objects: shared objects can be shared
* everywhere in the "object space" of Redis. Encoded objects can only
* appear as "values" (and not, for instance, as keys) */
if (o->refcount > 1) return REDIS_ERR;
if (o->refcount > 1) return o;

/* Currently we try to encode only strings */
redisAssert(o->type == REDIS_STRING);

/* Check if we can represent this string as a long integer */
if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return REDIS_ERR;
if (isStringRepresentableAsLong(s,&value) == REDIS_ERR) return o;

/* Ok, this object can be encoded */
o->encoding = REDIS_ENCODING_INT;
sdsfree(o->ptr);
o->ptr = (void*) value;
return REDIS_OK;
if (value >= 0 && value < REDIS_SHARED_INTEGERS) {
decrRefCount(o);
incrRefCount(shared.integers[value]);
return shared.integers[value];
} else {
o->encoding = REDIS_ENCODING_INT;
sdsfree(o->ptr);
o->ptr = (void*) value;
return o;
}
}

/* Get a decoded version of an encoded object (returned as a new object).
Expand Down Expand Up @@ -3603,7 +3616,7 @@ static robj *rdbLoadObject(int type, FILE *fp) {
if (type == REDIS_STRING) {
/* Read string value */
if ((o = rdbLoadStringObject(fp)) == NULL) return NULL;
tryObjectEncoding(o);
o = tryObjectEncoding(o);
} else if (type == REDIS_LIST || type == REDIS_SET) {
/* Read list/set value */
uint32_t listlen;
Expand All @@ -3619,7 +3632,7 @@ static robj *rdbLoadObject(int type, FILE *fp) {
robj *ele;

if ((ele = rdbLoadStringObject(fp)) == NULL) return NULL;
tryObjectEncoding(ele);
ele = tryObjectEncoding(ele);
if (type == REDIS_LIST) {
listAddNodeTail((list*)o->ptr,ele);
} else {
Expand All @@ -3640,7 +3653,7 @@ static robj *rdbLoadObject(int type, FILE *fp) {
double *score = zmalloc(sizeof(double));

if ((ele = rdbLoadStringObject(fp)) == NULL) return NULL;
tryObjectEncoding(ele);
ele = tryObjectEncoding(ele);
if (rdbLoadDoubleValue(fp,score) == -1) return NULL;
dictAdd(zs->dict,ele,score);
zslInsert(zs->zsl,*score,ele);
Expand Down Expand Up @@ -3679,8 +3692,8 @@ static robj *rdbLoadObject(int type, FILE *fp) {
decrRefCount(key);
decrRefCount(val);
} else {
tryObjectEncoding(key);
tryObjectEncoding(val);
key = tryObjectEncoding(key);
val = tryObjectEncoding(val);
dictAdd((dict*)o->ptr,key,val);
}
}
Expand Down Expand Up @@ -3906,7 +3919,7 @@ static void msetGenericCommand(redisClient *c, int nx) {
for (j = 1; j < c->argc; j += 2) {
int retval;

tryObjectEncoding(c->argv[j+1]);
c->argv[j+1] = tryObjectEncoding(c->argv[j+1]);
retval = dictAdd(c->db->dict,c->argv[j],c->argv[j+1]);
if (retval == DICT_ERR) {
dictReplace(c->db->dict,c->argv[j],c->argv[j+1]);
Expand Down Expand Up @@ -3954,7 +3967,7 @@ static void incrDecrCommand(redisClient *c, long long incr) {

value += incr;
o = createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",value));
tryObjectEncoding(o);
o = tryObjectEncoding(o);
retval = dictAdd(c->db->dict,c->argv[1],o);
if (retval == DICT_ERR) {
dictReplace(c->db->dict,c->argv[1],o);
Expand Down Expand Up @@ -5977,7 +5990,7 @@ static void hsetCommand(redisClient *c) {
if (zipmapLen(zm) > server.hash_max_zipmap_entries)
convertToRealHash(o);
} else {
tryObjectEncoding(c->argv[2]);
c->argv[2] = tryObjectEncoding(c->argv[2]);
/* note that c->argv[3] is already encoded, as the latest arg
* of a bulk command is always integer encoded if possible. */
if (dictReplace(o->ptr,c->argv[2],c->argv[3])) {
Expand Down Expand Up @@ -6050,7 +6063,7 @@ static void hincrbyCommand(redisClient *c) {

value += incr;
hval = createObject(REDIS_STRING,sdscatprintf(sdsempty(),"%lld",value));
tryObjectEncoding(hval);
hval = tryObjectEncoding(hval);
if (dictReplace(o->ptr,c->argv[2],hval)) {
incrRefCount(c->argv[2]);
}
Expand Down Expand Up @@ -6235,8 +6248,8 @@ static void convertToRealHash(robj *o) {

keyobj = createStringObject((char*)key,klen);
valobj = createStringObject((char*)val,vlen);
tryObjectEncoding(keyobj);
tryObjectEncoding(valobj);
keyobj = tryObjectEncoding(keyobj);
valobj = tryObjectEncoding(valobj);
dictAdd(dict,keyobj,valobj);
}
o->encoding = REDIS_ENCODING_HT;
Expand Down Expand Up @@ -7748,7 +7761,7 @@ int loadAppendOnlyFile(char *filename) {
}
/* Try object encoding */
if (cmd->flags & REDIS_CMD_BULK)
tryObjectEncoding(argv[argc-1]);
argv[argc-1] = tryObjectEncoding(argv[argc-1]);
/* Run the command in the context of a fake client */
fakeClient->argc = argc;
fakeClient->argv = argv;
Expand Down

0 comments on commit 05df762

Please sign in to comment.