Database error

From FOnline: 2238 Wiki

A database query syntax error has occurred. This may indicate a bug in the software. The last attempted database query was:

(SQL query hidden)

from within function "SpecialRecentchangeslinked::doMainQuery". Database returned error "1021: Disk full (/tmp/#sql-temptable-5a5f3-48d98-a28.MAI); waiting for someone to free some space... (errno: 28 "No space left on device") (localhost)".