HGET

Returns the value of a field in a hash.

Browse all commands · Upstream source documentation

Reference field	Value
Canonical name	`HGET`
Catalog group	Hash commands
Upstream since	2.0.0 — upstream Redis/module version, not an ffkv release
Pinned catalog	Redis 8.10.0

Syntax

HGET key field

ffkv behavior and limits

Hash fields have independent expiration. Counted field forms use FIELDS n; HSETEX counts field/value pairs. Key TTL and field TTL are distinct.

Source: README.md:587–599; tests/bdd/features/hashes.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(1)

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

Command flags: READONLY, FAST.

ACL categories: HASH.

Argument structure

Argument	Type	Constraints / metadata
`key`	key	key_spec_index: 0
`field`	string	Required

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": "hash",
  "since": "2.0.0"
}

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

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.

Restore-asking uses the same verified value payload and collision rules — tests/bdd/features/catalog.feature:212; invocation observed.
Dynamic document deletion denials identify only the rejected document — tests/bdd/features/client_control_repair.feature:533; invocation observed.
Atomic import transfers real typed data and survives destination restart — tests/bdd/features/cluster.feature:498; invocation observed.
Existence counts repeated arguments but deletion counts each removed key once — tests/bdd/features/generic.feature:129; invocation observed.
Hash serialization preserves binary fields and absolute field expiration independently — tests/bdd/features/generic.feature:316; invocation observed.
Move respects destination collisions and transfers a hash with its deadline to another database — tests/bdd/features/generic.feature:768; invocation observed.
Migration copies into a real target database and removes the source only for a move — tests/bdd/features/generic.feature:1408; invocation observed.
Hash writes count new binary-safe fields and preserve requested read order — tests/bdd/features/hashes.feature:4; command tag and invocation observed.
Conditional creation cannot overwrite an existing field — tests/bdd/features/hashes.feature:49; invocation observed.
Legacy multiple writes retain last duplicate value — tests/bdd/features/hashes.feature:97; invocation observed.
Signed integer increments preserve existing field deadlines — tests/bdd/features/hashes.feature:197; invocation observed.
Floating increments normalize decimals and resolve durable values — tests/bdd/features/hashes.feature:242; invocation observed.
Get-with-expiry supports absolute deadlines persistence and immediate expiration — tests/bdd/features/hashes.feature:343; invocation observed.
Malformed field blocks never consume values — tests/bdd/features/hashes.feature:404; invocation observed.
HEXPIREAT exposes absolute deadlines and independent conditional outcomes — tests/bdd/features/hashes.feature:566; invocation observed.
HPEXPIREAT exposes absolute deadlines and independent conditional outcomes — tests/bdd/features/hashes.feature:614; invocation observed.
Hash operations reject incompatible key types — tests/bdd/features/hashes.feature:816; command tag and invocation observed.
Prepared layouts preserve declared field order and replace complete hashes — tests/bdd/features/hashes.feature:877; invocation observed.
Discarding session definitions never removes imported hashes — tests/bdd/features/hashes.feature:984; invocation observed.
Import layouts are isolated per connection — tests/bdd/features/hashes.feature:1117; invocation observed.
Reset forgets definitions without changing imported hashes — tests/bdd/features/hashes.feature:1146; invocation observed.
Imported values survive recovery without resurrecting session definitions — tests/bdd/features/hashes.feature:1175; invocation observed.
Transactions apply session imports in execution order — tests/bdd/features/hashes.feature:1197; invocation observed.
Discarded transactions never discard prepared definitions — tests/bdd/features/hashes.feature:1229; invocation observed.
Import names fields and values are binary safe — tests/bdd/features/hashes.feature:1287; invocation observed.
Counted field blocks permit trailing options and keyword field names — tests/bdd/features/hashes.feature:1323; invocation observed.
Extended-precision float arithmetic avoids double rounding — tests/bdd/features/hashes.feature:1402; invocation observed.
Expiry conditions may follow counted fields and mixed conditions fail atomically — tests/bdd/features/hashes.feature:1492; invocation observed.
Invalid indexed values reject the document but never roll back HSET — tests/bdd/features/search.feature:161; invocation observed.
DROPINDEX keeps documents unless DD explicitly deletes indexed sources — tests/bdd/features/search.feature:462; invocation observed.
Invalid query schema and pipeline options fail without document mutation (Scenario Outline) — tests/bdd/features/search.feature:1027; invocation observed.
Invalid vector blobs do not undo successful document writes — tests/bdd/features/search.feature:1132; invocation observed.
Swapping database zero reconciles search documents without replacing schemas or aliases — tests/bdd/features/search.feature:1381; 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.

Import names fields and values are binary safe — tests/bdd/features/hashes.feature:1313 (I execute:)

[
  "HGET",
  "h",
  ""
]

Next source assertion: the reply equals:

"empty-field"

Hash writes count new binary-safe fields and preserve requested read order — tests/bdd/features/hashes.feature:23 (I execute:)

[
  "HGET",
  "h",
  "a"
]

Next source assertion: the reply equals:

"3"

Signed integer increments preserve existing field deadlines — tests/bdd/features/hashes.feature:232 (I execute:)

[
  "HGET",
  "h",
  "n"
]

Next source assertion: the reply equals:

"9223372036854775807"