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

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!