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BLMPOP

Syntax​

BLMPOP timeout numkeys key [key ...] <LEFT | RIGHT> [COUNT count]

Time complexity: O(N+M) where N is the number of provided keys and M is the number of elements returned.

ACL categories: @write, @list, @slow, @blocking

BLMPOP is the blocking variant of LMPOP.

When any of the lists has elements, this command functions exactly like LMPOP. The same applies when it is used within a MULTI/EXEC block. If all lists are empty, Dragonfly will block the connection until another client pushes elements to one of the keys or the specified timeout (a double value representing the maximum blocking time in seconds) expires. A timeout of zero can be used to block indefinitely.

Return​

  • Null reply: when no element could be popped and the timeout is reached.
  • Array reply: a two-element array with the first element being the name of the key from which elements were popped, and the second element being an array of the popped elements.