Try to fix the race conditions between
SET GLOBAL innodb_ft_aux_table = ...;
and access to the INFORMATION_SCHEMA tables that depend on
this variable.
innodb_ft_aux_table: Replaces
fts_internal_tbl_name,fts_internal_tbl_name2. Just store the
user-specified parameter as is.
innodb_ft_aux_table_id: The table_id corresponding to
SET GLOBAL innodb_ft_aux_table, or 0 if the table does not exist
or does not contain FULLTEXT INDEX. If the table is renamed later,
the INFORMATION_SCHEMA tables will continue to refer to the table.
If the table is dropped or rebuilt, the INFORMATION_SCHEMA tables
will not find the table.