Add noscore option to zscan.

src/commands.def

@@ -9080,6 +9080,7 @@ struct COMMAND_ARG ZSCAN_Args[] = {
 {MAKE_ARG("cursor",ARG_TYPE_INTEGER,-1,NULL,NULL,NULL,CMD_ARG_NONE,0,NULL)},
 {MAKE_ARG("pattern",ARG_TYPE_PATTERN,-1,"MATCH",NULL,NULL,CMD_ARG_OPTIONAL,0,NULL)},
 {MAKE_ARG("count",ARG_TYPE_INTEGER,-1,"COUNT",NULL,NULL,CMD_ARG_OPTIONAL,0,NULL)},
+{MAKE_ARG("noscores",ARG_TYPE_PURE_TOKEN,-1,"NOSCORES",NULL,NULL,CMD_ARG_OPTIONAL,0,NULL)},
 };
 
 /********** ZSCORE ********************/
@@ -10864,7 +10865,7 @@ struct COMMAND_STRUCT serverCommandTable[] = {
 {MAKE_CMD("zrevrangebylex","Returns members in a sorted set within a lexicographical range in reverse order.","O(log(N)+M) with N being the number of elements in the sorted set and M the number of elements being returned. If M is constant (e.g. always asking for the first 10 elements with LIMIT), you can consider it O(log(N)).","2.8.9",CMD_DOC_DEPRECATED,"`ZRANGE` with the `REV` and `BYLEX` arguments","6.2.0","sorted_set",COMMAND_GROUP_SORTED_SET,ZREVRANGEBYLEX_History,0,ZREVRANGEBYLEX_Tips,0,zrevrangebylexCommand,-4,CMD_READONLY,ACL_CATEGORY_SORTEDSET,ZREVRANGEBYLEX_Keyspecs,1,NULL,4),.args=ZREVRANGEBYLEX_Args},
 {MAKE_CMD("zrevrangebyscore","Returns members in a sorted set within a range of scores in reverse order.","O(log(N)+M) with N being the number of elements in the sorted set and M the number of elements being returned. If M is constant (e.g. always asking for the first 10 elements with LIMIT), you can consider it O(log(N)).","2.2.0",CMD_DOC_DEPRECATED,"`ZRANGE` with the `REV` and `BYSCORE` arguments","6.2.0","sorted_set",COMMAND_GROUP_SORTED_SET,ZREVRANGEBYSCORE_History,1,ZREVRANGEBYSCORE_Tips,0,zrevrangebyscoreCommand,-4,CMD_READONLY,ACL_CATEGORY_SORTEDSET,ZREVRANGEBYSCORE_Keyspecs,1,NULL,5),.args=ZREVRANGEBYSCORE_Args},
 {MAKE_CMD("zrevrank","Returns the index of a member in a sorted set ordered by descending scores.","O(log(N))","2.0.0",CMD_DOC_NONE,NULL,NULL,"sorted_set",COMMAND_GROUP_SORTED_SET,ZREVRANK_History,1,ZREVRANK_Tips,0,zrevrankCommand,-3,CMD_READONLY|CMD_FAST,ACL_CATEGORY_SORTEDSET,ZREVRANK_Keyspecs,1,NULL,3),.args=ZREVRANK_Args},
-{MAKE_CMD("zscan","Iterates over members and scores of a sorted set.","O(1) for every call. O(N) for a complete iteration, including enough command calls for the cursor to return back to 0. N is the number of elements inside the collection.","2.8.0",CMD_DOC_NONE,NULL,NULL,"sorted_set",COMMAND_GROUP_SORTED_SET,ZSCAN_History,0,ZSCAN_Tips,1,zscanCommand,-3,CMD_READONLY,ACL_CATEGORY_SORTEDSET,ZSCAN_Keyspecs,1,NULL,4),.args=ZSCAN_Args},
+{MAKE_CMD("zscan","Iterates over members and scores of a sorted set.","O(1) for every call. O(N) for a complete iteration, including enough command calls for the cursor to return back to 0. N is the number of elements inside the collection.","2.8.0",CMD_DOC_NONE,NULL,NULL,"sorted_set",COMMAND_GROUP_SORTED_SET,ZSCAN_History,0,ZSCAN_Tips,1,zscanCommand,-3,CMD_READONLY,ACL_CATEGORY_SORTEDSET,ZSCAN_Keyspecs,1,NULL,5),.args=ZSCAN_Args},
 {MAKE_CMD("zscore","Returns the score of a member in a sorted set.","O(1)","1.2.0",CMD_DOC_NONE,NULL,NULL,"sorted_set",COMMAND_GROUP_SORTED_SET,ZSCORE_History,0,ZSCORE_Tips,0,zscoreCommand,3,CMD_READONLY|CMD_FAST,ACL_CATEGORY_SORTEDSET,ZSCORE_Keyspecs,1,NULL,2),.args=ZSCORE_Args},
 {MAKE_CMD("zunion","Returns the union of multiple sorted sets.","O(N)+O(M*log(M)) with N being the sum of the sizes of the input sorted sets, and M being the number of elements in the resulting sorted set.","6.2.0",CMD_DOC_NONE,NULL,NULL,"sorted_set",COMMAND_GROUP_SORTED_SET,ZUNION_History,0,ZUNION_Tips,0,zunionCommand,-3,CMD_READONLY,ACL_CATEGORY_SORTEDSET,ZUNION_Keyspecs,1,zunionInterDiffGetKeys,5),.args=ZUNION_Args},
 {MAKE_CMD("zunionstore","Stores the union of multiple sorted sets in a key.","O(N)+O(M log(M)) with N being the sum of the sizes of the input sorted sets, and M being the number of elements in the resulting sorted set.","2.0.0",CMD_DOC_NONE,NULL,NULL,"sorted_set",COMMAND_GROUP_SORTED_SET,ZUNIONSTORE_History,0,ZUNIONSTORE_Tips,0,zunionstoreCommand,-4,CMD_WRITE|CMD_DENYOOM,ACL_CATEGORY_SORTEDSET,ZUNIONSTORE_Keyspecs,2,zunionInterDiffStoreGetKeys,5),.args=ZUNIONSTORE_Args},

src/commands/zscan.json

@@ -56,6 +56,12 @@
                 "name": "count",
                 "type": "integer",
                 "optional": true
+            },
+            {
+                "token": "NOSCORES",
+                "name": "noscores",
+                "type": "pure-token",
+                "optional": true
             }
         ],
         "reply_schema": {
@@ -69,7 +75,7 @@
                     "type": "string"
                 },
                 {
-                    "description": "List of elements of the sorted set, where each even element is the member, and each odd value is its associated score.",
+                    "description": "List of elements of the sorted set, where each even element is the member, and each odd value is its associated score, or when noscores option is on, a list of members from the sorted set.",
                     "type": "array",
                     "items": {
                         "type": "string"

src/db.c

@@ -853,7 +853,7 @@ typedef struct {
     long long type; /* the particular type when scan the db */
     sds pattern;  /* pattern string, NULL means no pattern */
     long sampled; /* cumulative number of keys sampled */
-    int no_values; /* set to 1 means to return keys only */
+    int only_keys; /* set to 1 means to return keys only */
 } scanData;
 
 /* Helper function to compare key type in scan commands */
@@ -905,18 +905,22 @@ void scanCallback(void *privdata, const dictEntry *de) {
         key = keysds;
     } else if (o->type == OBJ_HASH) {
         key = keysds;
-        val = dictGetVal(de);
+        if (!data->only_keys) {
+            val = dictGetVal(de);
+        }
     } else if (o->type == OBJ_ZSET) {
-        char buf[MAX_LONG_DOUBLE_CHARS];
-        int len = ld2string(buf, sizeof(buf), *(double *)dictGetVal(de), LD_STR_AUTO);
         key = sdsdup(keysds);
-        val = sdsnewlen(buf, len);
+        if (!data->only_keys) {
+            char buf[MAX_LONG_DOUBLE_CHARS];
+            int len = ld2string(buf, sizeof(buf), *(double *)dictGetVal(de), LD_STR_AUTO);
+            val = sdsnewlen(buf, len);
+        }
     } else {
         serverPanic("Type not handled in SCAN callback.");
     }
 
     listAddNodeTail(keys, key);
-    if (val && !data->no_values) listAddNodeTail(keys, val);
+    if (val) listAddNodeTail(keys, val);
 }
 
 /* Try to parse a SCAN cursor stored at object 'o':
@@ -989,7 +993,7 @@ void scanGenericCommand(client *c, robj *o, unsigned long long cursor) {
     sds pat = NULL;
     sds typename = NULL;
     long long type = LLONG_MAX;
-    int patlen = 0, use_pattern = 0, no_values = 0;
+    int patlen = 0, use_pattern = 0, only_keys = 0;
     dict *ht;
 
     /* Object must be NULL (to iterate keys names), or the type of the object
@@ -1040,7 +1044,14 @@ void scanGenericCommand(client *c, robj *o, unsigned long long cursor) {
                 addReplyError(c, "NOVALUES option can only be used in HSCAN");
                 return;
             }
-            no_values = 1;
+            only_keys = 1;
+            i++;
+        } else if (!strcasecmp(c->argv[i]->ptr, "noscores")) {
+            if (!o || o->type != OBJ_ZSET) {
+                addReplyError(c, "NOSCORES option can only be used in ZSCAN");
+                return;
+            }
+            only_keys = 1;
             i++;
         } else {
             addReplyErrorObject(c,shared.syntaxerr);
@@ -1101,15 +1112,15 @@ void scanGenericCommand(client *c, robj *o, unsigned long long cursor) {
          * working on an empty dict, one with a lot of empty buckets, and
          * for the buckets are not empty, we need to limit the spampled number
          * to prevent a long hang time caused by filtering too many keys;
-         * 6. data.no_values: to control whether values will be returned or 
+         * 6. data.only_keys: to control whether values will be returned or 
          * only keys are returned. */
         scanData data = {
             .keys = keys,
             .o = o,
             .type = type,
             .pattern = use_pattern ? pat : NULL,
             .sampled = 0,
-            .no_values = no_values,
+            .only_keys = only_keys,
         };
 
         /* A pattern may restrict all matching keys to one cluster slot. */
@@ -1164,7 +1175,7 @@ void scanGenericCommand(client *c, robj *o, unsigned long long cursor) {
             /* add key object */
             listAddNodeTail(keys, sdsnewlen(str, len));
             /* add value object */
-            if (!no_values) {
+            if (!only_keys) {
                 str = lpGet(p, &len, intbuf);
                 listAddNodeTail(keys, sdsnewlen(str, len));
             }

tests/unit/scan.tcl

@@ -316,6 +316,10 @@ proc test_scan {type} {
 
             set keys2 [lsort -unique $keys2]
             assert_equal $count [llength $keys2]
+
+            # Test NOSCORES 
+            set res [r zscan zset 0 count 1000 noscores]
+            assert_equal [lsort $keys2] [lsort [lindex $res 1]]
         }
     }
 
@@ -386,6 +390,13 @@ proc test_scan {type} {
         lsort -unique [lindex $res 1]
     }
 
+    test "{$type} ZSCAN with NOSCORES" {
+        r del mykey
+        r zadd mykey 1 foo 2 fab 3 fiz 10 foobar
+        set res [r zscan mykey 0 NOSCORES]
+        lsort -unique [lindex $res 1]
+    } {fab fiz foo foobar}
+
     test "{$type} ZSCAN scores: regression test for issue #2175" {
         r del mykey
         for {set j 0} {$j < 500} {incr j} {