diff --git a/src/config.c b/src/config.c
index 8f3b81a19..6f4559e6c 100644
--- a/src/config.c
+++ b/src/config.c
@@ -688,6 +688,10 @@ void loadServerConfigFromString(char *config) {
err = sentinelHandleConfiguration(argv+1,argc-1);
if (err) goto loaderr;
}
+ } else if (!strcasecmp(argv[0],"hll-use-loglogbeta") && argc == 2) {
+ if ((server.hll_use_loglogbeta = yesnotoi(argv[1])) == -1) {
+ err = "argument must be 'yes' or 'no'"; goto loaderr;
+ }
} else {
err = "Bad directive or wrong number of arguments"; goto loaderr;
}
@@ -980,7 +984,9 @@ void configSetCommand(client *c) {
} config_set_bool_field(
"slave-lazy-flush",server.repl_slave_lazy_flush) {
} config_set_bool_field(
- "no-appendfsync-on-rewrite",server.aof_no_fsync_on_rewrite) {
+ "no-appendfsync-on-rewrite",server.aof_no_fsync_on_rewrite) {
+ } config_set_bool_field(
+ "hll-use-loglogbeta",server.hll_use_loglogbeta) {
/* Numerical fields.
* config_set_numerical_field(name,var,min,max) */
@@ -1245,6 +1251,8 @@ void configGetCommand(client *c) {
server.lazyfree_lazy_server_del);
config_get_bool_field("slave-lazy-flush",
server.repl_slave_lazy_flush);
+ config_get_bool_field("hll-use-loglogbeta",
+ server.hll_use_loglogbeta);
/* Enum values */
config_get_enum_field("maxmemory-policy",
@@ -1963,6 +1971,7 @@ int rewriteConfig(char *path) {
rewriteConfigYesNoOption(state,"lazyfree-lazy-expire",server.lazyfree_lazy_expire,CONFIG_DEFAULT_LAZYFREE_LAZY_EXPIRE);
rewriteConfigYesNoOption(state,"lazyfree-lazy-server-del",server.lazyfree_lazy_server_del,CONFIG_DEFAULT_LAZYFREE_LAZY_SERVER_DEL);
rewriteConfigYesNoOption(state,"slave-lazy-flush",server.repl_slave_lazy_flush,CONFIG_DEFAULT_SLAVE_LAZY_FLUSH);
+ rewriteConfigYesNoOption(state,"hll-use-loglogbeta",server.hll_use_loglogbeta,CONFIG_DEFAULT_HLL_USE_LOGLOGBETA);
/* Rewrite Sentinel config if in Sentinel mode. */
if (server.sentinel_mode) rewriteConfigSentinelOption(state);
diff --git a/src/hyperloglog.c b/src/hyperloglog.c
index 8ccc16be2..67a928729 100644
--- a/src/hyperloglog.c
+++ b/src/hyperloglog.c
@@ -993,33 +993,51 @@ uint64_t hllCount(struct hllhdr *hdr, int *invalid) {
} else {
serverPanic("Unknown HyperLogLog encoding in hllCount()");
}
+
+ if(server.hll_use_loglogbeta) {
+ /* For loglog-beta there is a single formula to compute
+ * cardinality for the enture range
+ */
- /* Muliply the inverse of E for alpha_m * m^2 to have the raw estimate. */
- E = (1/E)*alpha*m*m;
+ double zl = log(ez + 1);
+ double beta = -0.370393911*ez +
+ 0.070471823*zl +
+ 0.17393686*pow(zl,2) +
+ 0.16339839*pow(zl,3) +
+ -0.09237745*pow(zl,4) +
+ 0.03738027*pow(zl,5) +
+ -0.005384159*pow(zl,6) +
+ 0.00042419*pow(zl,7);
+
+ E = alpha*m*(m-ez)*(1/(E+beta));
+ } else {
+ /* Muliply the inverse of E for alpha_m * m^2 to have the raw estimate. */
+ E = (1/E)*alpha*m*m;
- /* Use the LINEARCOUNTING algorithm for small cardinalities.
- * For larger values but up to 72000 HyperLogLog raw approximation is
- * used since linear counting error starts to increase. However HyperLogLog
- * shows a strong bias in the range 2.5*16384 - 72000, so we try to
- * compensate for it. */
- if (E < m*2.5 && ez != 0) {
- E = m*log(m/ez); /* LINEARCOUNTING() */
- } else if (m == 16384 && E < 72000) {
- /* We did polynomial regression of the bias for this range, this
- * way we can compute the bias for a given cardinality and correct
- * according to it. Only apply the correction for P=14 that's what
- * we use and the value the correction was verified with. */
- double bias = 5.9119*1.0e-18*(E*E*E*E)
- -1.4253*1.0e-12*(E*E*E)+
- 1.2940*1.0e-7*(E*E)
- -5.2921*1.0e-3*E+
- 83.3216;
- E -= E*(bias/100);
+ /* Use the LINEARCOUNTING algorithm for small cardinalities.
+ * For larger values but up to 72000 HyperLogLog raw approximation is
+ * used since linear counting error starts to increase. However HyperLogLog
+ * shows a strong bias in the range 2.5*16384 - 72000, so we try to
+ * compensate for it. */
+ if (E < m*2.5 && ez != 0) {
+ E = m*log(m/ez); /* LINEARCOUNTING() */
+ } else if (m == 16384 && E < 72000) {
+ /* We did polynomial regression of the bias for this range, this
+ * way we can compute the bias for a given cardinality and correct
+ * according to it. Only apply the correction for P=14 that's what
+ * we use and the value the correction was verified with. */
+ double bias = 5.9119*1.0e-18*(E*E*E*E)
+ -1.4253*1.0e-12*(E*E*E)+
+ 1.2940*1.0e-7*(E*E)
+ -5.2921*1.0e-3*E+
+ 83.3216;
+ E -= E*(bias/100);
+ }
+ /* We don't apply the correction for E > 1/30 of 2^32 since we use
+ * a 64 bit function and 6 bit counters. To apply the correction for
+ * 1/30 of 2^64 is not needed since it would require a huge set
+ * to approach such a value. */
}
- /* We don't apply the correction for E > 1/30 of 2^32 since we use
- * a 64 bit function and 6 bit counters. To apply the correction for
- * 1/30 of 2^64 is not needed since it would require a huge set
- * to approach such a value. */
return (uint64_t) E;
}
diff --git a/src/server.c b/src/server.c
index 0dc62c2b0..f20497009 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1400,6 +1400,7 @@ void initServerConfig(void) {
server.lazyfree_lazy_eviction = CONFIG_DEFAULT_LAZYFREE_LAZY_EVICTION;
server.lazyfree_lazy_expire = CONFIG_DEFAULT_LAZYFREE_LAZY_EXPIRE;
server.lazyfree_lazy_server_del = CONFIG_DEFAULT_LAZYFREE_LAZY_SERVER_DEL;
+ server.hll_use_loglogbeta = CONFIG_DEFAULT_HLL_USE_LOGLOGBETA;
server.lruclock = getLRUClock();
resetServerSaveParams();
diff --git a/src/server.h b/src/server.h
index 7ff151de8..07df986c6 100644
--- a/src/server.h
+++ b/src/server.h
@@ -151,6 +151,7 @@ typedef long long mstime_t; /* millisecond time type. */
#define CONFIG_DEFAULT_LAZYFREE_LAZY_EVICTION 0
#define CONFIG_DEFAULT_LAZYFREE_LAZY_EXPIRE 0
#define CONFIG_DEFAULT_LAZYFREE_LAZY_SERVER_DEL 0
+#define CONFIG_DEFAULT_HLL_USE_LOGLOGBETA 0
#define ACTIVE_EXPIRE_CYCLE_LOOKUPS_PER_LOOP 20 /* Loopkups per loop. */
#define ACTIVE_EXPIRE_CYCLE_FAST_DURATION 1000 /* Microseconds */
@@ -1149,6 +1150,7 @@ struct redisServer {
int watchdog_period; /* Software watchdog period in ms. 0 = off */
/* System hardware info */
size_t system_memory_size; /* Total memory in system as reported by OS */
+ int hll_use_loglogbeta; /* Use loglog-beta algorithm for HLL */
};
typedef struct pubsubPattern {