ZRANDMEMBER

Returns one or more random members from a sorted set.

Browse all commands · Upstream source documentation

Reference field	Value
Canonical name	ZRANDMEMBER
Catalog group	Sorted set commands
Upstream since	6.2.0 — upstream Redis/module version, not an ffkv release
Pinned catalog	Redis 8.10.0

Syntax

ZRANDMEMBER key [count [WITHSCORES]]

ffkv behavior and limits

Scores and lexicographic ranges are separate query modes. Do not rely on random-pop order; sorted-set storage remains RAM-resident in hybrid mode.

Source: README.md:275–295, 810–825; tests/bdd/features/sorted_sets.feature.

All requests share the 8 MiB framing/1,024-argument ingress limit; normal RESP replies have 64 MiB wire/logical budgets with bounded nesting/value counts. Management and Lua origins impose smaller budgets. These are not a process RSS cap. Catalog inclusion is not exhaustive option or wire-format parity. See limits and compatibility.

Upstream metadata

The following fields come from the pinned Redis metadata, not measured ffkv performance or an assertion that ffkv enforces every upstream flag. Running COMMAND INFO/COMMAND DOCS describe the current engine.

Upstream Redis complexity: O(N) where N is the number of members returned

Upstream arity: -2 (includes the command name; a negative number is a minimum).

Command flags: READONLY.

ACL categories: SORTEDSET.

Command tips: NONDETERMINISTIC_OUTPUT.

Argument structure

Argument	Type	Constraints / metadata
key	key	key_spec_index: 0
options	block	optional
↳ count	integer	Required
↳ withscores	pure-token	optional; token: WITHSCORES

Key specifications

Upstream key discovery descriptors (indexes are relative to the full command vector):

[
  {
    "flags": [
      "RO",
      "ACCESS"
    ],
    "begin_search": {
      "index": {
        "pos": 1
      }
    },
    "find_keys": {
      "range": {
        "lastkey": 0,
        "step": 1,
        "limit": 0
      }
    }
  }
]

Additional pinned upstream metadata

{
  "group": "sorted_set",
  "since": "6.2.0"
}

Metadata source · Local snapshot: src/command_metadata.json, key zrandmember.

BDD coverage and source examples

These are source observations, not a test run performed by this documentation build. A tag identifies scenario intent; an extracted vector identifies a command invocation, which may intentionally produce an error. Scenarios may require setup, multiple connections, persistence, cluster nodes or native-module fixtures.

• Random members distinguish scalar and repeated scored arrays — tests/bdd/features/sorted_sets.feature:529; command tag and invocation observed.
• RESP3 scored ranges and pop replies use nested native doubles — tests/bdd/features/sorted_sets.feature:917; command tag and invocation observed.

Extracted command vectors

The following JSON arrays are the test harness’s argument vectors, not shell commands. Numeric arguments are converted by the harness; objects of the form {"base64":"…"} represent decoded binary bytes, not a literal JSON command argument. Preserve scenario setup and connection ordering. See the CLI guide for shell quoting and binary stdin. No reply is invented or inferred.

Random members distinguish scalar and repeated scored arrays — tests/bdd/features/sorted_sets.feature:535 (I execute:)

[
  "ZRANDMEMBER",
  "single"
]

Next source assertion: the reply equals:

"only"

RESP3 scored ranges and pop replies use nested native doubles — tests/bdd/features/sorted_sets.feature:940 (client “reader” executes:)

[
  "ZRANDMEMBER",
  "ranked",
  "0",
  "WITHSCORES"
]

Next source assertion: the reply equals:

[]

Random members distinguish scalar and repeated scored arrays — tests/bdd/features/sorted_sets.feature:551 (I execute:)

[
  "ZRANDMEMBER",
  "single",
  "9"
]

Next source assertion: the reply equals:

["only"]