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Reference zset score in zskiplistNode from dict entries

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This avoids the extra allocation of sizeof(double) for storing the score
of a zset entry in the hash table. Saves sizeof(double) + malloc
overhead = approx. 16 bytes per zset entry.
This commit is contained in:
Pieter Noordhuis 2010-08-03 20:49:53 +02:00
parent 2159782b51
commit 69ef89f2cf
3 changed files with 60 additions and 59 deletions
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2
src/redis.c
View File

@ -338,7 +338,7 @@ dictType zsetDictType = {
NULL, /* val dup */
dictEncObjKeyCompare, /* key compare */
dictRedisObjectDestructor, /* key destructor */
dictVanillaFree /* val destructor of malloc(sizeof(double)) */
NULL /* val destructor */
};
/* Db->dict, keys are sds strings, vals are Redis objects. */

2
src/redis.h
View File

@ -675,7 +675,7 @@ void backgroundRewriteDoneHandler(int statloc);
/* Sorted sets data type */
zskiplist *zslCreate(void);
void zslFree(zskiplist *zsl);
void zslInsert(zskiplist *zsl, double score, robj *obj);
zskiplistNode *zslInsert(zskiplist *zsl, double score, robj *obj);
/* Core functions */
void freeMemoryIfNeeded(void);

115
src/t_zset.c
View File

@ -71,7 +71,7 @@ int zslRandomLevel(void) {
return (level<ZSKIPLIST_MAXLEVEL) ? level : ZSKIPLIST_MAXLEVEL;
}
void zslInsert(zskiplist *zsl, double score, robj *obj) {
zskiplistNode *zslInsert(zskiplist *zsl, double score, robj *obj) {
zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x;
unsigned int rank[ZSKIPLIST_MAXLEVEL];
int i, level;
@ -123,6 +123,7 @@ void zslInsert(zskiplist *zsl, double score, robj *obj) {
else
zsl->tail = x;
zsl->length++;
return x;
}
/* Internal function used by zslDelete, zslDeleteByScore and zslDeleteByRank */
@ -299,13 +300,11 @@ zskiplistNode* zslistTypeGetElementByRank(zskiplist *zsl, unsigned long rank) {
* Sorted set commands
*----------------------------------------------------------------------------*/
/* This generic command implements both ZADD and ZINCRBY.
* scoreval is the score if the operation is a ZADD (doincrement == 0) or
* the increment if the operation is a ZINCRBY (doincrement == 1). */
void zaddGenericCommand(redisClient *c, robj *key, robj *ele, double scoreval, int doincrement) {
/* This generic command implements both ZADD and ZINCRBY. */
void zaddGenericCommand(redisClient *c, robj *key, robj *ele, double score, int incr) {
robj *zsetobj;
zset *zs;
double *score;
zskiplistNode *znode;
zsetobj = lookupKeyWrite(c->db,key);
if (zsetobj == NULL) {
@ -319,72 +318,73 @@ void zaddGenericCommand(redisClient *c, robj *key, robj *ele, double scoreval, i
}
zs = zsetobj->ptr;
/* Ok now since we implement both ZADD and ZINCRBY here the code
* needs to handle the two different conditions. It's all about setting
* '*score', that is, the new score to set, to the right value. */
score = zmalloc(sizeof(double));
if (doincrement) {
dictEntry *de;
/* Since both ZADD and ZINCRBY are implemented here, we need to increment
* the score first by the current score if ZINCRBY is called. */
if (incr) {
/* Read the old score. If the element was not present starts from 0 */
de = dictFind(zs->dict,ele);
if (de) {
double *oldscore = dictGetEntryVal(de);
*score = *oldscore + scoreval;
} else {
*score = scoreval;
}
if (isnan(*score)) {
dictEntry *de = dictFind(zs->dict,ele);
if (de != NULL)
score += *(double*)dictGetEntryVal(de);
if (isnan(score)) {
addReplySds(c,
sdsnew("-ERR resulting score is not a number (NaN)\r\n"));
zfree(score);
/* Note that we don't need to check if the zset may be empty and
* should be removed here, as we can only obtain Nan as score if
* there was already an element in the sorted set. */
return;
}
} else {
*score = scoreval;
}
/* What follows is a simple remove and re-insert operation that is common
* to both ZADD and ZINCRBY... */
if (dictAdd(zs->dict,ele,score) == DICT_OK) {
/* case 1: New element */
/* We need to remove and re-insert the element when it was already present
* in the dictionary, to update the skiplist. Note that we delay adding a
* pointer to the score because we want to reference the score in the
* skiplist node. */
if (dictAdd(zs->dict,ele,NULL) == DICT_OK) {
dictEntry *de;
/* New element */
incrRefCount(ele); /* added to hash */
zslInsert(zs->zsl,*score,ele);
znode = zslInsert(zs->zsl,score,ele);
incrRefCount(ele); /* added to skiplist */
/* Update the score in the dict entry */
de = dictFind(zs->dict,ele);
redisAssert(de != NULL);
dictGetEntryVal(de) = &znode->score;
touchWatchedKey(c->db,c->argv[1]);
server.dirty++;
if (doincrement)
addReplyDouble(c,*score);
if (incr)
addReplyDouble(c,score);
else
addReply(c,shared.cone);
} else {
dictEntry *de;
double *oldscore;
/* case 2: Score update operation */
de = dictFind(zs->dict,ele);
redisAssert(de != NULL);
oldscore = dictGetEntryVal(de);
if (*score != *oldscore) {
robj *curobj;
double *curscore;
int deleted;
/* Remove and insert the element in the skip list with new score */
deleted = zslDelete(zs->zsl,*oldscore,ele);
/* Update score */
de = dictFind(zs->dict,ele);
redisAssert(de != NULL);
curobj = dictGetEntryKey(de);
curscore = dictGetEntryVal(de);
/* When the score is updated, reuse the existing string object to
* prevent extra alloc/dealloc of strings on ZINCRBY. */
if (score != *curscore) {
deleted = zslDelete(zs->zsl,*curscore,curobj);
redisAssert(deleted != 0);
zslInsert(zs->zsl,*score,ele);
incrRefCount(ele);
/* Update the score in the hash table */
dictReplace(zs->dict,ele,score);
znode = zslInsert(zs->zsl,score,curobj);
incrRefCount(curobj);
/* Update the score in the current dict entry */
dictGetEntryVal(de) = &znode->score;
touchWatchedKey(c->db,c->argv[1]);
server.dirty++;
} else {
zfree(score);
}
if (doincrement)
addReplyDouble(c,*score);
if (incr)
addReplyDouble(c,score);
else
addReply(c,shared.czero);
}
@ -406,7 +406,7 @@ void zremCommand(redisClient *c) {
robj *zsetobj;
zset *zs;
dictEntry *de;
double *oldscore;
double curscore;
int deleted;
if ((zsetobj = lookupKeyWriteOrReply(c,c->argv[1],shared.czero)) == NULL ||
@ -419,8 +419,8 @@ void zremCommand(redisClient *c) {
return;
}
/* Delete from the skiplist */
oldscore = dictGetEntryVal(de);
deleted = zslDelete(zs->zsl,*oldscore,c->argv[2]);
curscore = *(double*)dictGetEntryVal(de);
deleted = zslDelete(zs->zsl,curscore,c->argv[2]);
redisAssert(deleted != 0);
/* Delete from the hash table */
@ -534,6 +534,7 @@ void zunionInterGenericCommand(redisClient *c, robj *dstkey, int op) {
zsetopsrc *src;
robj *dstobj;
zset *dstzset;
zskiplistNode *znode;
dictIterator *di;
dictEntry *de;
int touched = 0;
@ -642,10 +643,10 @@ void zunionInterGenericCommand(redisClient *c, robj *dstkey, int op) {
zfree(score);
} else {
robj *o = dictGetEntryKey(de);
dictAdd(dstzset->dict,o,score);
incrRefCount(o); /* added to dictionary */
zslInsert(dstzset->zsl,*score,o);
znode = zslInsert(dstzset->zsl,*score,o);
incrRefCount(o); /* added to skiplist */
dictAdd(dstzset->dict,o,&znode->score);
incrRefCount(o); /* added to dictionary */
}
}
dictReleaseIterator(di);
@ -673,10 +674,10 @@ void zunionInterGenericCommand(redisClient *c, robj *dstkey, int op) {
}
robj *o = dictGetEntryKey(de);
dictAdd(dstzset->dict,o,score);
incrRefCount(o); /* added to dictionary */
zslInsert(dstzset->zsl,*score,o);
znode = zslInsert(dstzset->zsl,*score,o);
incrRefCount(o); /* added to skiplist */
dictAdd(dstzset->dict,o,&znode->score);
incrRefCount(o); /* added to dictionary */
}
dictReleaseIterator(di);
}