hyperloglog

Category: Probabilistic
Wire type: hyperloglog
Construction: CREATE

Probabilistic structures provide bounded-memory estimates and membership/frequency queries.

Create a value

Use the top-level CREATE command to initialize this structured value. The example shows its construction options.

amaquet-cli -uri amaquet://127.0.0.1:13378 CREATE '{"key":"example:hyperloglog","type":"hyperloglog","options":{"precision":12}}'

Construction options

Example CREATE options: {"precision":12}. Omitted fields use server defaults.

Supported operations

ADD, COUNT.

See the complete operation contract for exact arguments, defaults, results, and whether a listed GET is the top-level key command or a type-specific OP. It also identifies read-only operations and documents validation, lazy maintenance, and key-version behavior.

Operation payloads

The following examples use the public amaquet-cli JSON command format. Replace example:hyperloglog with the key used by your application.

Construction payloads

Use the payload below to initialize this type before issuing reads or type-specific operations.

CREATE

This payload initializes the value and must complete before its type-specific operations are used.

{
  "key": "example:hyperloglog",
  "type": "hyperloglog",
  "options": {
    "precision": 12
  }
}

Operations

Each request uses the OP envelope. The response is the type-specific value described in the complete operation contract.

OP ADD

Accepts string value and returns whether a register increased.

{
  "key": "example:hyperloglog",
  "operation": "ADD",
  "args": {
    "value": "alice"
  }
}

OP COUNT

Takes no arguments and returns rounded approximate cardinality with small-range linear counting.

{
  "key": "example:hyperloglog",
  "operation": "COUNT",
  "args": {}
}

Top-level read payload

GET reads the current value without changing it:

{
  "key": "example:hyperloglog"
}

Key lifecycle payloads

These commands apply to the key regardless of its registered type:

• TYPE: {"key":"example:hyperloglog"} — returns the wire type.
• EXISTS: {"key":"example:hyperloglog"} — reports whether the key exists.
• EXPIRE: {"key":"example:hyperloglog","ttl_ms":5000} — assigns a five-second TTL.
• TTL: {"key":"example:hyperloglog"} — returns the remaining TTL in milliseconds.
• PERSIST: {"key":"example:hyperloglog"} — removes the TTL.
• DEL: {"keys":["example:hyperloglog"]} — deletes the key.

For defaults, validation, result shapes, and persistence classification, see the complete operation contract.

Key lifecycle

The key participates in TYPE, EXISTS, TTL, EXPIRE, PERSIST, and DEL. Top-level GET returns the type’s direct public value or a synchronized snapshot.