concurrent problem, wrong order

[diamondio]

concurrent problem, wrong order

[GonzoBe]

In file queue if we will change those line:

   ...

  // Acquire lock on process
     self._running++;
   
     if (self.concurrent - self._running > 1) {
       // Continue processing until saturated
       self._processNextIfAllowed();
     }
   self._startBatch(batch, tickets, lockId);
   });

like this:

   ...

  // Acquire lock on process
     self._running++;
       self._startBatch(batch, tickets, lockId);
     if (self.concurrent - self._running > 1) {
       // Continue processing until saturated
       self._processNextIfAllowed();
     }
   });

it will work correctly

[leanderlee]

Do you have some code to reproduce the behaviour?

[GonzoBe]

var Queue = require('better-queue');
var cc = new Queue(mainTaskQueue, {
    concurrent: 8,
    filo: false, 
    maxTimeout: 1000,
    retryDelay: 100,
    maxRetries: 3,
    afterProcessDelay: 1,
});
for(let i=0; i<10;  i++) {
    let task = {nr:i};
    cc.push(task);
}

[Output]:
Nr:  6
Nr:  5
Nr:  4
Nr:  3
Nr:  2
Nr:  1
Nr:  0
Nr:  7
Nr:  9
Nr:  8

What I would like to achive and I did by changing line order in your code like I wrote before.

[Output]:
Nr:  0
Nr:  1
Nr:  2
Nr:  3
Nr:  4
Nr:  5
Nr:  6
Nr:  7
Nr:  8
Nr:  9

Your recursive program starts task after checking that another can be started. I think you should start and than check that you can start another one. Also you should think about filo parameter here.

[LinusU]

@GonzoBe I think you need to provide some more code. What's printing the "Nr: ..." string? What's mainTaskQueue?

[GonzoBe]

sorry my mistake this is code for print/main job

function mainTaskQueue (task, callback) {
console.log("Nr: "+task.nr);
}

[leanderlee]

Fixed in 3.8.8

[GonzoBe]

thanks ! :D

[kybarg]

@leanderlee 3.8.10 seems like problem is still there

[leanderlee]

The code above works for me on node 10/11. Are you on a different node version?

You may you want to check your process fn logic. Concurrent implies running in parallel so if the tasks take different amounts of time then they would finish in a different order. better-queue can only guarantee that they start processing in the order it was given.