keyspace

Get keys and values based on a probability distribution and seed.
For deterministic input to benchmarks.

Usage

const keyspace = require('keyspace')
const db = mydb()
 
// To prepare the database, we'll write 1M sequential
// keys, with random values of 100 bytes
const writer = keyspace(1e6, {
  keys: 'seq',
  values: 'random',
  valueSize: 100,
 
  // Always generate the same keys and values
  seed: 'a seed'
})
 
for (let i = 0; i < 1e6; i++) {
  db.put(writer.key(i), writer.value())
}
 
// Get a random key based on a Zipfian distribution
const reader = keyspace(1e6, {
  keys: 'random',
  distribution: 'zipfian',
  seed: 'a seed',
 
  // Favor latest keys
  skew: -1
})
 
db.get(reader.key())
db.get(reader.key())

Visual Example

API

Stability: experimental. API may change or split up.

generator = keyspace(n, [options])

Create a key and value generator for a keyspace of size N (aka cardinality). Uses xorshift128+ internally to be fast and random enough. Keys are encoded with lexicographic-integer to preserve order.

Options:

• keys (string): one of:
  • random (default): generate pseudo-random numeric keys with a certain probability distribution
  • seq: non-random, sequential numeric keys (0-N)
  • seqReverse: same keys but in reverse (N-0)
• values (string): one of:
  • random (default): generate pseudo-random values
  • empty: zero-length values or zero-filled if valueSize is set
• seed (string or Buffer): if not provided one will be generated.
• distribution (string): one of zipfian, uniform (default)
• skew (floating-point number): Zipfian skew (default 0)
• offset (number): offset keys (for example to simulate timestamps)
• valueSize (number): size of values in bytes
• keyAsBuffer, valueAsBuffer, keyAsNumber (boolean): if not set, keys and values are returned as strings (hex encoded).

key = generator.key([index])

Get a key. The index argument is required for seq and seqReverse.

value = generator.value()

Get a value.

Install

With npm do:

npm install keyspace

License

MIT © 2019-present Vincent Weevers