VISMEMBER

Check if an element exists in a vector set.

Browse all commands · Upstream source documentation

Reference field	Value
Canonical name	VISMEMBER
Catalog group	Vector set commands
Upstream since	8.0.0 — upstream Redis/module version, not an ffkv release
Pinned catalog	Redis 8.10.0

Syntax

VISMEMBER key element

ffkv behavior and limits

Limits include 65,536 dimensions, 64 KiB members, 1 MiB attributes and a 1 GiB estimated per-set allocation budget, plus bounded M/EF/search work. Normal searches traverse HNSW; TRUTH requests exhaustive search. Vector sets remain RAM-resident.

Source: README.md:368–377; tests/bdd/features/vectors.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.

Metadata availability

This command is in the canonical catalog but has no matching entry in the pinned src/command_metadata.json. Argument flags, complexity and key specifications are not invented. Use the syntax, upstream source documentation and actual scenario evidence below.

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.

• Binary insertion preserves numeric dimensions embeddings and raw float data — tests/bdd/features/vectors.feature:6; command tag and invocation observed.
• Lexical range deletion and random selection operate on actual remaining members — tests/bdd/features/vectors.feature:149; 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.

Binary insertion preserves numeric dimensions embeddings and raw float data — tests/bdd/features/vectors.feature:33 (client “v3” executes:)

[
  "VISMEMBER",
  "directions",
  "east"
]

Next source assertion: the reply equals:

true

Lexical range deletion and random selection operate on actual remaining members — tests/bdd/features/vectors.feature:212 (client “v3” executes:)

[
  "VISMEMBER",
  "directions",
  "beta"
]

Next source assertion: the reply equals:

false

Binary insertion preserves numeric dimensions embeddings and raw float data — tests/bdd/features/vectors.feature:41 (client “v3” executes:)

[
  "VISMEMBER",
  "directions",
  "absent"
]

Next source assertion: the reply equals:

false