XTRIM

Deletes messages from the beginning of a stream.

Browse all commands · Upstream source documentation

Reference field	Value
Canonical name	XTRIM
Catalog group	Stream commands
Upstream since	5.0.0 — upstream Redis/module version, not an ffkv release
Pinned catalog	Redis 8.10.0

Syntax

XTRIM key <MAXLEN | MINID> [= | ~] threshold [LIMIT count] [KEEPREF | DELREF | ACKED]

ffkv behavior and limits

Stream waits are bounded to 65,536 clients and 64 MiB of retained logical requests (also limited by the connection cap). Approximate MAXLEN trimming uses 100-entry granularity. EXEC/Lua reads never block. Physical index statistics describe ffkv, not Redis allocator internals.

Source: README.md:351–374; tests/bdd/features/streams.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), with N being the number of evicted entries. Constant times are very small however, since entries are organized in macro nodes containing multiple entries that can be released with a single deallocation.

Upstream arity: -4 (includes the command name; a negative number is a minimum).

Command flags: WRITE.

ACL categories: STREAM.

Command tips: NONDETERMINISTIC_OUTPUT.

Argument structure

Argument	Type	Constraints / metadata
key	key	key_spec_index: 0
trim	block	Required
↳ strategy	oneof	Required
↳ ↳ maxlen	pure-token	token: MAXLEN
↳ ↳ minid	pure-token	token: MINID; since: 6.2.0
↳ operator	oneof	optional
↳ ↳ equal	pure-token	token: =
↳ ↳ approximately	pure-token	token: ~
↳ threshold	string	Required
↳ count	integer	optional; token: LIMIT; since: 6.2.0
↳ condition	oneof	optional
↳ ↳ keepref	pure-token	token: KEEPREF
↳ ↳ delref	pure-token	token: DELREF
↳ ↳ acked	pure-token	token: ACKED

Key specifications

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

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

Additional pinned upstream metadata

{
  "group": "stream",
  "since": "5.0.0",
  "history": [
    [
      "6.2.0",
      "Added the `MINID` trimming strategy and the `LIMIT` option."
    ],
    [
      "8.2.0",
      "Added the `KEEPREF`, `DELREF` and `ACKED` options."
    ]
  ]
}

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

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.

• Explicit IDs preserve duplicate field ordering and range direction — tests/bdd/features/streams.feature:5; command tag and invocation observed.
• ACKED trimming skips pending entries rather than stopping at them (Scenario Outline) — tests/bdd/features/streams.feature:620; command tag and invocation observed.
• Repeated reference policies reject the whole command without deleting entries or pending ownership (Scenario Outline) — tests/bdd/features/streams.feature:674; 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.

Explicit IDs preserve duplicate field ordering and range direction — tests/bdd/features/streams.feature:68 (I execute:)

[
  "XTRIM",
  "events",
  "MINID",
  "=",
  "1002-0"
]

Next source assertion: the reply equals:

1

ACKED trimming skips pending entries rather than stopping at them — tests/bdd/features/streams.feature:626 (I execute:)

Expanded from an actual Examples row: strategy=MAXLEN, threshold=0.

[
  "XTRIM",
  "events",
  "MAXLEN",
  "=",
  0,
  "ACKED"
]

Next source assertion: the reply equals:

1

Repeated reference policies reject the whole command without deleting entries or pending ownership — tests/bdd/features/streams.feature:680 (I execute:)

Expanded from an actual Examples row: command=["XTRIM","events","DELREF","MAXLEN",0,"DELREF"].

[
  "XTRIM",
  "events",
  "DELREF",
  "MAXLEN",
  0,
  "DELREF"
]

Next source assertion: the reply is an error with code “ERR”