Create record using aerospike operate command - aerospike

Question

I am trying following code. Getting "key not found" error. I want to know whether it is possible to create a record using aerospike multi ops.
public long incrementSingle(String counterName, long by){
// Create a key
Key recordKey = new Key(Constants.NAMESPACE, Constants.SINGLE_SET, counterName);
// Increment operation
Bin incrementCounter = new Bin(Constants.SINGLE_COUNTER_BIN, by);
// https://www.aerospike.com/docs/client/java/usage/kvs/multiops.html#operation-specification
Record record = asClient.operate(null, recordKey,
Operation.add(incrementCounter),
Operation.get(Constants.SINGLE_COUNTER_BIN));
return record.getLong(Constants.SINGLE_COUNTER_BIN);
}

Answer 1

I don't see any problem with this. Here's some Python code that does the same:
# -*- coding: utf-8 -*-
from __future__ import print_function
import aerospike
from aerospike import exception as e
from aerospike_helpers.operations import operations as oh
import sys
config = {"hosts": [("192.168.243.133", 3000)]}
try:
client = aerospike.client(config).connect()
except e.ClientError as e:
print("Error: {0} [{1}]".format(e.msg, e.code))
sys.exit(2)
key = ("test", "demo", "count-this")
print("Nuke the record")
try:
client.remove(key)
except:
pass
ops = [oh.increment("counter", 2), oh.read("counter")]
meta = {"ttl": aerospike.TTL_NEVER_EXPIRE}
for i in range(4):
try:
k, m, b = client.operate_ordered(key, ops, meta)
print("Iteration {0}: bin value is {1}".format(i, b))
except e.RecordError as e:
print("Error: {0} [{1}]".format(e.msg, e.code))
sys.exit(4)
client.close()
Resulting in the expected
Nuke the record
Iteration 0: bin value is [('counter', 2)]
Iteration 1: bin value is [('counter', 4)]
Iteration 2: bin value is [('counter', 6)]
Iteration 3: bin value is [('counter', 8)]

Answer 2

I think for add() to work, the record must exist before. Test with creating the record referred by recordKey with some initial value (say initialize to 0) in the counter bin and then increment it. The Operation API for add() does not specifically point this out, but I am just guessing because add() will first read existing record on disk and is perhaps not finding it. (Edit: See further definitive test/clarification per Write Policy used in the comments below.)