Joi Ellis

I'm seeing this behavior also. I'm running a server world that was created in 1.7.4, operated in 1.7.5, and then 1.7.10. (I skipped the releases between 1.7.5 and 1.7.10) When I load the world map in either vanilla server 1.8 or 1.8.1, it fails to convert the stats for blocks and items, as described above.

We've been running this map for over a Year and I'm not eager to make my players lose all their stats.

I have the same issue, server is 1.7.4 (world generated with 1.7.2 a few weeks ago.) It was fine with 2 active players until two days ago, when the other player started exploring great distances in search of horses. The server quickly became unplayable just from this surface exploring. It was fine for weeks with 1G allocated to the java machine, I've doubled that and reduced the server render distance to 8. Otherwise the server is running defaults.

Ubuntu 13.10, Java 1.7.0_51 launched with -d64 -Xmx2048 -Xms1024 and nogui, on a 64-bit Intel i7 with 4 dual-cores and 6G of total ram.

The host does nothing else, and 'top' shows the java process is over 1.2Gig when the lag begins. I can restart the server and it's fine for a while, until we start exploring again. The conjecture that the issue is chunks failing to unload when unoccupied strikes me as the most likely issue on my server.

If there is any instrumentation or debug logging I can enable that may help diagnose this, please feel free to contact me. I am a developer myself but java is not my current focus and I'm my last professional work with it was back in the Java 1.2 days.

With 1.5.1 SSP, I have an xp grinder that uses half-slabs. On the sides where the half-slabs are on the top half of a block, the exp orbs are able to pass beneath the half-slabs and are absorbed normally. On sides where the half-slabs are on the bottom of the block, the exp orbs travel toward me, circle around, then reappear inside the grinder and repeat this cycle in an infinite loop (or until they despawn, I suppose.) If I break any of the lower half-slabs on the side I'm facing, or if I move around to another side of the grinder where the half-slabs are on the upper half of their block, the orbs immediately travel through the lower gap and are absorbed. I believe the credit for the exp does appear on the HUD the first time the orbs exit the grinder; it is only the visual orb entity that fails to disappear. Thus it seems orbs are able to travel through the lower half of a block, but not the upper half.

If all of the half-slabs are on the bottom of their blocks, then the orbs never get absorbed and will continue to cycle in and out of the grinder until they despawn. Walking around the grinder has no effect and it does not matter where I walk or stand.