node js / javascript performance: buffer vs string

11251850.md

performance comparison:

section1 :

push string to array, generate string by join all data with comma.

section2 :

write int(16bit) to buffer, generate string by buffer.toString('base64').

background :

batch collect data, and send them to another server or process, with high speed and large quantity.

node version : v4.1.2 platform: Intel I7, 16G DDR3, Ubuntu x64

console.time('section 1');
var ary1 = [];
for(let i = 0 ; i < N; i++) {
    ary1.push('123');
}
var str = ary1.join(',');
console.timeEnd('section 1');


console.time('section 2');
var buf = new Buffer(10000000);
for(let i = 0 ; i < N; i++) {
    buf.writeInt16LE(123, i * 2);
}
var encode = buf.slice(0, buf.length).toString('base64');
console.timeEnd('section 2');

result:

# N : 10K
section 1: 3ms
section 2: 4ms


# N : 100K
section 1: 7ms
section 2: 5ms


# N : 1M
section 1: 101ms
section 2: 20ms


# N : 10M
section 1: 1282ms
section 2: 159ms

conclusion:

buffer solution is more effiency than array solution when data scale large enough.
for common usage, array is convenience and efficiency.