title: Redis, XREADGROUP stream with block for a year, stupid?
body: <p>Are there any downsides to telling XREADGROUP to block until there is a message rather than the client having to poll?</p>
  <p>From:</p>
  <p><a href="https://redis.io/commands/xreadgroup" rel="nofollow noreferrer">https://redis.io/commands/xreadgroup</a></p>
  <p>It is not clear that this means:</p>
  <pre><code>&quot;On the other side when XREADGROUP blocks, XADD will pay the O(N) time in order to serve the N clients blocked on the stream getting new data.&quot;
  </code></pre>
  <p>Can someone shed some light on the <strong>blocking</strong> mechanisms of streams in Redis?</p>