update
Sorry, it was SQL_LOG_UPDATE=0
The previous one (SQL_LOG_OFF=1) will only affect the general log file. And, in addition, they have different semantics. :-(
summary:

my $query = qq{
SET SQL_LOG_OFF=1; # no logs to the general log
SET SQL_LOG_UPDATE=0; # no logs to the update log.
UPDATE $table SET bigField = $BLOB_value WHERE ID=1;
SET SQL_LOG_OFF=0; # logs to the general log
SET SQL_LOG_UPDATE=1; # logs to the update log.
UPDATE $another SET smallfield = $smallvalue WHERE ID =3;
};
$dbh->do($query);
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