Go中用于并行读/写操作的数据类型

Question

I have a scenario where I create a worker pool which has 4 workers. These workers picks up job from a channel and stores the result to the memory. So the worker execute the job and may update the result in parallel. I would like to know which data type is best to save the result as it would be accessed by multiple workers at a time. I would need to use the lock mechanism to achieve this.

The result will be key-value format. So can maps be considered in this scenario.

Answer 1

Yes, you could use a map for that and you would have to protect it by a mutex.

I would however suggest that each job contains a result channel where you can input the result of the job. Here a rough sketch of what that would look like:

playground: note that playground only has one core so the numbers will appear in sequence.

package main

import (
    "fmt"
    "time"
)

type job struct {
    a     int
    b     int
    chRes chan int
}

func main() {

    var chIn = make(chan job, 20)

    for i := 0; i < 10; i++ {
        go worker(chIn)
    }

    for i := 0; i < 100; i++ {
        go func(i int) {
            chRes := make(chan int)
            chIn <- job{
                a:     i,
                b:     i,
                chRes: chRes,
            }

            fmt.Println(<-chRes)
        }(i)
    }

    // I'm lazy, so here just a sleep so we can see something
    time.Sleep(1 * time.Second)
}

func worker(ch chan job) {
    for job := range ch {
        job.chRes <- job.a + job.b
    }
}

-- edit --

If you device to go with a store instead (which kind of goes against the go mantra share memory by communicating instead of communicate by sharing memory): there is also a sync.Map that is already concurrency safe. No mutex needed.