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HyperLogLog low level merge extracted from PFMERGE.

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This commit is contained in:
antirez 2014-04-17 17:08:43 +02:00
parent 0ab40d14df
commit e70c3b6c9b
1 changed files with 54 additions and 39 deletions
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93
src/hyperloglog.c
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@ -991,6 +991,55 @@ int hllAdd(robj *o, unsigned char *ele, size_t elesize) {
}
}
/* Merge by computing MAX(registers[i],hll[i]) the HyperLogLog 'hll'
* with an array of uint8_t HLL_REGISTERS registers pointed by 'max'.
*
* The hll object must be already validated via isHLLObjectOrReply()
* or in some other way.
*
* If the HyperLogLog is sparse and is found to be invalid, REDIS_ERR
* is returned, otherwise the function always succeeds. */
int hllMerge(uint8_t *max, robj *hll) {
struct hllhdr *hdr = hll->ptr;
int i;
if (hdr->encoding == HLL_DENSE) {
uint8_t val;
for (i = 0; i < HLL_REGISTERS; i++) {
HLL_DENSE_GET_REGISTER(val,hdr->registers,i);
if (val > max[i]) max[i] = val;
}
} else {
uint8_t *p = hll->ptr, *end = p + sdslen(hll->ptr);
long runlen, regval;
p += HLL_HDR_SIZE;
i = 0;
while(p < end) {
if (HLL_SPARSE_IS_ZERO(p)) {
runlen = HLL_SPARSE_ZERO_LEN(p);
i += runlen;
p++;
} else if (HLL_SPARSE_IS_XZERO(p)) {
runlen = HLL_SPARSE_XZERO_LEN(p);
i += runlen;
p += 2;
} else {
runlen = HLL_SPARSE_VAL_LEN(p);
regval = HLL_SPARSE_VAL_VALUE(p);
while(runlen--) {
if (regval > max[i]) max[i] = regval;
i++;
}
p++;
}
}
if (i != HLL_REGISTERS) return REDIS_ERR;
}
return REDIS_OK;
}
/* ========================== HyperLogLog commands ========================== */
/* Create an HLL object. We always create the HLL using sparse encoding.
@ -1157,7 +1206,7 @@ void pfcountCommand(redisClient *c) {
void pfmergeCommand(redisClient *c) {
uint8_t max[HLL_REGISTERS];
struct hllhdr *hdr;
int j, i;
int j;
/* Compute an HLL with M[i] = MAX(M[i]_j).
* We we the maximum into the max array of registers. We'll write
@ -1171,43 +1220,9 @@ void pfmergeCommand(redisClient *c) {
/* Merge with this HLL with our 'max' HHL by setting max[i]
* to MAX(max[i],hll[i]). */
hdr = o->ptr;
if (hdr->encoding == HLL_DENSE) {
uint8_t val;
for (i = 0; i < HLL_REGISTERS; i++) {
HLL_DENSE_GET_REGISTER(val,hdr->registers,i);
if (val > max[i]) max[i] = val;
}
} else {
uint8_t *p = o->ptr, *end = p + sdslen(o->ptr);
long runlen, regval;
p += HLL_HDR_SIZE;
i = 0;
while(p < end) {
if (HLL_SPARSE_IS_ZERO(p)) {
runlen = HLL_SPARSE_ZERO_LEN(p);
i += runlen;
p++;
} else if (HLL_SPARSE_IS_XZERO(p)) {
runlen = HLL_SPARSE_XZERO_LEN(p);
i += runlen;
p += 2;
} else {
runlen = HLL_SPARSE_VAL_LEN(p);
regval = HLL_SPARSE_VAL_VALUE(p);
while(runlen--) {
if (regval > max[i]) max[i] = regval;
i++;
}
p++;
}
}
if (i != HLL_REGISTERS) {
addReplySds(c,sdsnew(invalid_hll_err));
return;
}
if (hllMerge(max,o) == REDIS_ERR) {
addReplySds(c,sdsnew(invalid_hll_err));
return;
}
}
@ -1241,7 +1256,7 @@ void pfmergeCommand(redisClient *c) {
HLL_INVALIDATE_CACHE(hdr);
signalModifiedKey(c->db,c->argv[1]);
/* We generate an HLLADD event for HLLMERGE for semantical simplicity
/* We generate an PFADD event for PFMERGE for semantical simplicity
* since in theory this is a mass-add of elements. */
notifyKeyspaceEvent(REDIS_NOTIFY_STRING,"pfadd",c->argv[1],c->db->id);
server.dirty++;