Hi there,

Whilst playing, I have been trading paper with Cartographers to get emeralds. I'm regularly finding that during the trade, or immediately after, the server pauses and ultimately crashes.

As far as I can tell, when not trading with cartographers, it runs just fine.

The crash usually happens after trading a lot (like 8 stacks) of paper for Emeralds. It's not an 'every time' thing - but is reasonably regular. 

[23:37:33] [Server thread/WARN]: Can't keep up! Is the server overloaded? Running 55078ms or 1101 ticks behind
[23:38:33] [Server Watchdog/FATAL]: A single server tick took 60.03 seconds (should be max 0.05)
[23:38:33] [Server Watchdog/FATAL]: Considering it to be crashed, server will forcibly shutdown.
[23:38:33] [Server Watchdog/ERROR]: This crash report has been saved to: /data/minecraft/1.15.2/./crash-reports/crash-2020-04-01_23.38.33-server.txt

Crash log is attached.

Of note is that I'm running this on Solaris x86 as the server. It's usually rock solid...

I have also noticed that at the time the issue happens, the server starts working through a bunch of files like as if it's suddenly checking or updating everything. Of note is that the moment the game shows the server is not responding, the server is off blasting through this directory. Below is a brief truss snippit:

14738/41: fstatat(AT_FDCWD, "./Killfest/region", 0x7FFF8CBFE250, 0) = 0
14738/41: fstatat(AT_FDCWD, "./Killfest/region", 0x7FFF8CBFE130, 0) = 0
14738/41: openat(AT_FDCWD, "./Killfest/region/r.8.-52.mca", O_RDWR|O_CREAT, 0666) = 313
14738/41: pread(313, "\0\0\0\0\0\0\0\0\0\0\0\0".., 8192, 0) = 8192
14738/41: pread(313, "\0\001F102 x9CED98CD nD4".., 4096, 12288) = 4096
14738/37: lwp_mutex_timedlock(0x017DC260, 0x00000000, 0x00000000) = 0
14738/37: sysconfig(_CONFIG_NPROC_ONLN) = 6
14738/41: fstatat(314, NULL, 0x7FFF8CBFE120, 0) = 0
14738/37: getpid() = 14738 [16130]
14738/37: pset_bind(PS_QUERY, P_PID, 14738, 0x7FFF8EBFD468) = 0
14738/41: pwrite(314, "\0\0\0\0\0\0\0\0\0\0\0\0".., 8192, 0) = 8192
14738/37: pset_info(PS_NONE, 0x00000000, 0x7FFF8EBFD46C, 0x00000000) = 0
14738/41: fdsync(314, FSYNC) = 0
14738/41: close(314) = 0
14738/41: fstatat(AT_FDCWD, "./Killfest/region", 0x7FFF8CBFE250, 0) = 0
14738/41: fstatat(AT_FDCWD, "./Killfest/region", 0x7FFF8CBFE130, 0) = 0
14738/41: openat(AT_FDCWD, "./Killfest/region/r.8.53.mca", O_RDWR|O_CREAT, 0666) = 314
14738/41: pread(314, "\0\0\0\0\0\0\0\0\0\0\0\0".., 8192, 0) = 8192
14738/41: pread(314, "\0\001D202 x9CED98CD n9B".., 4096, 12288) = 4096
14738/56: lwp_mutex_timedlock(0x01D34020, 0x00000000, 0x00000000) = 0
14738/37: sysconfig(_CONFIG_NPROC_ONLN) = 6
14738/41: fstatat(315, NULL, 0x7FFF8CBFE120, 0) = 0
14738/37: getpid() = 14738 [16130]
14738/37: pset_bind(PS_QUERY, P_PID, 14738, 0x7FFF8EBFD468) = 0
14738/41: pwrite(315, "\0\0\0\0\0\0\0\0\0\0\0\0".., 8192, 0) = 8192
14738/37: pset_info(PS_NONE, 0x00000000, 0x7FFF8EBFD46C, 0x00000000) = 0
14738/41: fdsync(315, FSYNC) = 0
14738/41: close(315) = 0
14738/41: fstatat(AT_FDCWD, "./Killfest/region", 0x7FFF8CBFE250, 0) = 0
14738/41: fstatat(AT_FDCWD, "./Killfest/region", 0x7FFF8CBFE130, 0) = 0
14738/41: openat(AT_FDCWD, "./Killfest/region/r.11.-52.mca", O_RDWR|O_CREAT, 0666) = 315
14738/41: pread(315, "\0\0\0\0\0\0\0\0\0\0\0\0".., 8192, 0) = 8192
14738/41: pread(315, "\0\001DB02 x9CED98CD nD3".., 4096, 8192) = 4096
14738/41: fstatat(316, NULL, 0x7FFF8CBFE120, 0) = 0
14738/37: sysconfig(_CONFIG_NPROC_ONLN) = 6
14738/37: getpid() = 14738 [16130]
14738/41: pwrite(316, "\0\0\0\0\0\0\0\0\0\0\0\0".., 8192, 0) = 8192
14738/37: pset_bind(PS_QUERY, P_PID, 14738, 0x7FFF8EBFD468) = 0
14738/37: pset_info(PS_NONE, 0x00000000, 0x7FFF8EBFD46C, 0x00000000) = 0
14738/41: fdsync(316, FSYNC) = 0
14738/41: close(316) = 0
14738/41: fstatat(AT_FDCWD, "./Killfest/region", 0x7FFF8CBFE250, 0) = 0
14738/41: fstatat(AT_FDCWD, "./Killfest/region", 0x7FFF8CBFE130, 0) = 0
14738/41: openat(AT_FDCWD, "./Killfest/region/r.10.53.mca", O_RDWR|O_CREAT, 0666) = 316
14738/41: pread(316, "\0\0\0\0\0\0\0\0\0\0\0\0".., 8192, 0) = 8192
14738/41: pread(316, "\0\001E902 x9CED98 ] nD3".., 4096, 8192) = 4096
14738/37: sysconfig(_CONFIG_NPROC_ONLN) = 6
14738/37: getpid() = 14738 [16130]
14738/41: fstatat(317, NULL, 0x7FFF8CBFE120, 0) = 0
14738/37: pset_bind(PS_QUERY, P_PID, 14738, 0x7FFF8EBFD468) = 0
14738/37: pset_info(PS_NONE, 0x00000000, 0x7FFF8EBFD46C, 0x00000000) = 0
14738/41: pwrite(317, "\0\0\0\0\0\0\0\0\0\0\0\0".., 8192, 0) = 8192
14738/41: fdsync(317, FSYNC) = 0
14738/41: close(317) = 0

Happy to gather whatever you like on this. 

Cheers!

Goatyguy.