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  1. Minecraft: Java Edition
  2. MC-185363

sync-chunk-writes often takes over a minute to close a world


    • Icon: Bug Bug
    • Resolution: Fixed
    • 1.16 Pre-release 3
    • 20w21a, 20w22a, 1.16 Pre-release 1
    • None
    • Ubuntu 18.04
      openjdk version "1.8.0_252"
      OpenJDK Runtime Environment (build 1.8.0_252-8u252-b09-1~18.04-b09)
      OpenJDK 64-Bit Server VM (build 25.252-b09, mixed mode)
    • Plausible
    • Chunk loading
    • Important

      Apologies if this has been reported before, I searched for "save" and "saving" and could not find anything relevant.

      This issue has occurred since 20w14a. There is a workaround on a server, to disable sync-chunk-writes, but there is no workaround in singleplayer.

      To reproduce in singleplayer, start a world and close it again, observe that the world can take tens of seconds to close. To reproduce on a dedicated server, start the server and type stop in the console, and observe that the server hangs for a bit after printing the "saving chunks for level" message.

      Given that this hasn't been reported yet, I'm assuming it may be operating system dependent, although I haven't tested this on other operating systems. My OS is Ubuntu 18.04 (see the environment section).

      I ran the server through VisualVM. I have attached a screenshot of part of the profile results, as well as a CSV containing the entire snapshot.

            boq [Mojang] Bartosz Bok
            Earthcomputer Earthcomputer
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