HyperLogLog: make API use the P prefix in honor of Philippe Flajolet.

src/hyperloglog.c

@@ -435,8 +435,8 @@ uint64_t hllCount(uint8_t *registers) {
 
 /* ========================== HyperLogLog commands ========================== */
 
-/* HLLADD var ele ele ele ... ele => :0 or :1 */
-void hllAddCommand(redisClient *c) {
+/* PADD var ele ele ele ... ele => :0 or :1 */
+void paddCommand(redisClient *c) {
     robj *o = lookupKeyWrite(c->db,c->argv[1]);
     uint8_t *registers;
     int updated = 0, j;
@@ -482,8 +482,8 @@ void hllAddCommand(redisClient *c) {
     addReply(c, updated ? shared.cone : shared.czero);
 }
 
-/* HLLCOUNT var -> approximated cardinality of set. */
-void hllCountCommand(redisClient *c) {
+/* PCOUNT var -> approximated cardinality of set. */
+void pcountCommand(redisClient *c) {
     robj *o = lookupKeyRead(c->db,c->argv[1]);
     uint8_t *registers;
     uint64_t card;
@@ -540,8 +540,8 @@ void hllCountCommand(redisClient *c) {
     }
 }
 
-/* HLLMERGE dest src1 src2 src3 ... srcN => OK */
-void hllMergeCommand(redisClient *c) {
+/* PMERGE dest src1 src2 src3 ... srcN => OK */
+void pmergeCommand(redisClient *c) {
     uint8_t max[REDIS_HLL_REGISTERS];
     uint8_t *registers;
     int j, i;
@@ -614,7 +614,7 @@ void hllMergeCommand(redisClient *c) {
  * the correct value to be retained and not affect adjacent values. */
 
 #define REDIS_HLL_TEST_CYCLES 1000
-void hllSelftestCommand(redisClient *c) {
+void pselftestCommand(redisClient *c) {
     int j, i;
     sds bitcounters = sdsnewlen(NULL,REDIS_HLL_SIZE);
     uint8_t bytecounters[REDIS_HLL_REGISTERS];

src/redis.c

@@ -259,10 +259,10 @@ struct redisCommand redisCommandTable[] = {
     {"bitop",bitopCommand,-4,"wm",0,NULL,2,-1,1,0,0},
     {"bitcount",bitcountCommand,-2,"r",0,NULL,1,1,1,0,0},
     {"bitpos",bitposCommand,-3,"r",0,NULL,1,1,1,0,0},
-    {"hllselftest",hllSelftestCommand,1,"r",0,NULL,0,0,0,0,0},
-    {"hlladd",hllAddCommand,-2,"wm",0,NULL,1,1,1,0,0},
-    {"hllcount",hllCountCommand,2,"w",0,NULL,1,1,1,0,0},
-    {"hllmerge",hllMergeCommand,-2,"wm",0,NULL,1,-1,1,0,0}
+    {"pselftest",pselftestCommand,1,"r",0,NULL,0,0,0,0,0},
+    {"padd",paddCommand,-2,"wm",0,NULL,1,1,1,0,0},
+    {"pcount",pcountCommand,2,"w",0,NULL,1,1,1,0,0},
+    {"pmerge",pmergeCommand,-2,"wm",0,NULL,1,-1,1,0,0}
 };
 
 /*============================ Utility functions ============================ */

src/redis.h

@@ -1351,10 +1351,10 @@ void bitopCommand(redisClient *c);
 void bitcountCommand(redisClient *c);
 void bitposCommand(redisClient *c);
 void replconfCommand(redisClient *c);
-void hllSelftestCommand(redisClient *c);
-void hllAddCommand(redisClient *c);
-void hllCountCommand(redisClient *c);
-void hllMergeCommand(redisClient *c);
+void pselftestCommand(redisClient *c);
+void paddCommand(redisClient *c);
+void pcountCommand(redisClient *c);
+void pmergeCommand(redisClient *c);
 
 #if defined(__GNUC__)
 void *calloc(size_t count, size_t size) __attribute__ ((deprecated));

utils/hyperloglog/hll-err.rb

@@ -18,9 +18,9 @@ while true do
             elements << ele
             i += 1
         }
-        r.hlladd('hll',*elements)
+        r.padd('hll',*elements)
     }
-    approx = r.hllcount('hll')
+    approx = r.pcount('hll')
     abs_err = (approx-i).abs
     rel_err = 100.to_f*abs_err/i
     puts "#{i} vs #{approx}: #{rel_err}%"

utils/hyperloglog/hll-gnuplot-graph.rb

@@ -30,9 +30,9 @@ def run_experiment(r,seed,max,step)
                 elements << ele
                 i += 1
             }
-            r.hlladd('hll',*elements)
+            r.padd('hll',*elements)
         }
-        approx = r.hllcount('hll')
+        approx = r.pcount('hll')
         err = approx-i
         rel_err = 100.to_f*err/i
         samples << [i,rel_err]