Bug#40145. Argument for LOAD_FILE() can be too long and sometimes

a query with two or more these functions truncated. Therefore data 
from each LOAD_FILE() copied into its local variables and then used
in a query.

mysql-test/r/general_log_func.result

@@ -27,9 +27,10 @@ INSERT into t1(name) values('Record_3');
 INSERT into t1(name) values('Record_4');
 ## There should be a difference ##
 SET @@session.max_allowed_packet= 1024*1024*1024;
-select
-STRCMP(load_file('MYSQLD_LOGFILE.orig'), load_file('MYSQLD_LOGFILE.copy'));
-STRCMP(load_file('MYSQLD_LOGFILE.orig'), load_file('MYSQLD_LOGFILE.copy'))
+SET @orig_file= load_file('MYSQLD_LOGFILE.orig');
+SET @copy_file= load_file('MYSQLD_LOGFILE.copy');
+SELECT STRCMP(@orig_file, @copy_file);
+STRCMP(@orig_file, @copy_file)
 1
 ## Dropping tables ##
 DROP TABLE t1;

mysql-test/t/general_log_func.test

@@ -81,8 +81,10 @@ INSERT into t1(name) values('Record_4');
 --echo ## There should be a difference ##
 SET @@session.max_allowed_packet= 1024*1024*1024;
 --replace_result $MYSQLD_LOGFILE MYSQLD_LOGFILE
-eval select
-  STRCMP(load_file('$MYSQLD_LOGFILE.orig'), load_file('$MYSQLD_LOGFILE.copy'));
+eval SET @orig_file= load_file('$MYSQLD_LOGFILE.orig');
+--replace_result $MYSQLD_LOGFILE MYSQLD_LOGFILE
+eval SET @copy_file= load_file('$MYSQLD_LOGFILE.copy');
+eval SELECT STRCMP(@orig_file, @copy_file);
 --remove_file $MYSQLD_LOGFILE.copy
 --remove_file $MYSQLD_LOGFILE.orig