title: AWS - SQS concurrency
body: <p>a little question about SQS message concurrency.</p>
  
  <p><strong>scenario</strong>:<br>
  i created lambda with 3 minute timeout.<br>
  this lambda triggered by SQS service (with default configuration).  </p>
  
  <p>when SQS trigger my lambda he waiting X second (under 3 minute).<br>
  after waiting, he run the same lambda again.  </p>
  
  <p>now, i have two lambdas run in the same time.  </p>
  
  <p>for this case, in the end - lambda_1 is failed and lambda_2 Succeeded.  </p>
  
  <p><strong>the question</strong>:<br>
  the SQS message is remove from the queue? </p>
  
  <p>lambda which Succeeded deletes the message from queue.<br>
  lambda which failed do retry for this message.  </p>
  
  <p><strong>and how can i control concurrency issue?</strong>  </p>
  
  <p>thank you.  </p>