A shared FIFO queue is implemented using ETS

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FWIW, this is what we came up with in a hurry: GitHub - hnc-agency/shq (no docs, no tests, no specs, just the bare implementation :sweat_smile:).

Downside: It uses a managing (per queue) gen_server process, which is what you tried to avoid. However, the gen_server overhead could be removed if necessary, implementing it as a streamlined special process, but for a quick implementation we went with gen_server.

Upsides that (should) make up for that are…

  • constant time (O(1)) access for all operations (both insertion and retrieval, both front and rear) because we avoided the ordered_set table type and used set instead
  • avoiding the (arguably expensive) erlang:unique_integer altogether while ensuring queue order
  • making it work across nodes, ie removing the local node restriction (or rather, this comes for free because we are using a process)
  • no need for a named table (but the managing process can be named if you so wish)
  • fully OTP compliant, ie it can be used in a supervision tree

Aside from the gen_server overhead, I believe this is as fast as we can get with the things we already have at our hands, ie without resorting to NIF magic or implementing new functions in ets :wink:

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