Is it possible to search for all keys that start with a certain prefix in Aerospike?

Question

So I am looking to model our existing redis data into aerospike. One requirement that we have is to be able to get all the keys for a given user. For eg., say we have keys such as <id>:<timestamp>. Now, at some point in time, I need to get all keys for the given id, where I would require something like a prefix search across all keys in the aerospike namespace (which are indexed) to get the values for all <id>:<timestamp> keys. Would like to know if this is possible, and if yes, how.

Answer 1

You cannot do a query on key prefix directly. The server only stores the key digest, so the key value (<id>:<timestamp> in your case) doesn't get indexed.

The way to model this would be to add the <id> part of your key as a separate record bin. Then you can index that bin and run a query on it.

Here is a simple example - it's using the Aerospike Node.js client but the concept is the same no matter what client you prefer:

const Aerospike = require('aerospike')

const ns = 'test'
const set = 'demo'

// connect to cluster and create index on 'id' bin
var client = Aerospike.client()
client.connect((err) => {
  assertOk(err, 'connecting to cluster')
  createIndex('id', 'id_idx', Aerospike.indexDataType.STRING, () => {

    // create a new sample record
    var userId = 'user1'
    var ts = new Date().getTime()
    var key = new Aerospike.Key(ns, set, `${userId}:${ts}`)
    var record = { id: userId, value: Math.random() }
    client.put(key, record, (err) => {
      assertOk(err, 'write record')

      // query for records with matching 'id'
      var query = client.query(ns, set)
      query.where(Aerospike.filter.equal('id', userId))
      var stream = query.foreach()
      stream.on('error', (error) => assertOk(error, 'executing query'))
      stream.on('end', () => client.close())
      stream.on('data', (record, meta, key) => {
        console.log(record)
      })
    })
  })
})

function assertOk (err, message) {
  if (err) {
    console.error('ERROR: %s - %s', message, err)
    process.quit()
  }
}

function createIndex (bin, name, datatype, callback) {
  var index = {
    ns: ns,
    set: set,
    bin: bin,
    index: name,
    datatype: datatype
  }
  client.createIndex(index, (err, job) => {
    assertOk(err, 'creating index')
    job.waitUntilDone(100, (err) => {
      assertOk(err, 'creating index')
      callback()
    })
  })
}

Hope this helps!