The problem of mycat's sudden collapse

mycat has a memory error during operation, crashes, and then automatically restarts; how to find the root cause of the problem?
glibc detected java: double free or corruption (out): 0x00007f9338011b30 *
JVM exited unexpectedly.
JVM exited in response to signal UNKNOWN (6).

Feb.27,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b32d14-2be4c.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b32d14-2be4c.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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