MSET

Atomically creates or modifies the string values of one or more keys.

Browse all commands · Upstream source documentation

Reference field	Value
Canonical name	MSET
Catalog group	String commands
Upstream since	1.0.1 — upstream Redis/module version, not an ffkv release
Pinned catalog	Redis 8.10.0

Syntax

MSET key value [key value ...]

ffkv behavior and limits

Keys and values are binary-safe bytes. Conditional SET and DELEX comparisons use the stored bytes; DIGEST uses XXH3, not a cryptographic digest.

Source: README.md:571–585; src/engine/strings.rs; tests/bdd/features/strings.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 keys to set.

Upstream arity: -3 (includes the command name; a negative number is a minimum).

Command flags: WRITE, DENYOOM.

ACL categories: STRING.

Command tips: REQUEST_POLICY:MULTI_SHARD, RESPONSE_POLICY:ALL_SUCCEEDED.

Argument structure

Argument	Type	Constraints / metadata
data	block	multiple
↳ key	key	key_spec_index: 0
↳ value	string	Required

Key specifications

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

[
  {
    "flags": [
      "OW",
      "UPDATE"
    ],
    "begin_search": {
      "index": {
        "pos": 1
      }
    },
    "find_keys": {
      "range": {
        "lastkey": -1,
        "step": 2,
        "limit": 0
      }
    }
  }
]

Additional pinned upstream metadata

{
  "group": "string",
  "since": "1.0.1"
}

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

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.

• Local slot key enumeration is bounded and excludes other slots — tests/bdd/features/cluster.feature:234; invocation observed.
• A mixed-present multi-key migration request returns TRYAGAIN without mutation — tests/bdd/features/cluster.feature:460; invocation observed.
• Longest subsequence is not restricted to contiguous bytes — tests/bdd/features/strings.feature:580; invocation observed.
• Multi key strings overwrite other types and MGET returns null for nonstrings — tests/bdd/features/strings.feature:625; 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.

Multi key strings overwrite other types and MGET returns null for nonstrings — tests/bdd/features/strings.feature:647 (I execute:)

[
  "MSET",
  "list",
  "string"
]

Next source assertion: the reply equals:

"OK"

Longest subsequence is not restricted to contiguous bytes — tests/bdd/features/strings.feature:582 (the following commands succeed:)

[
  "MSET",
  "a",
  "ohmytext",
  "b",
  "mynewtext"
]

Local slot key enumeration is bounded and excludes other slots — tests/bdd/features/cluster.feature:236 (node “node1” executes:)

Fixture-dependent: {{…}} tokens are replaced by the BDD runtime (for example, node ports, generated IDs or temporary paths). This is not a standalone executable command.

[
  "MSET",
  "{{node1_key}}:a",
  "A",
  "{{node1_key}}:b",
  "B"
]

Next source assertion: the reply equals:

"OK"