I download Percona Toolkit 3.1.0. When i run pt-query-digest for slow log, result: No events processed. Here are the steps：
1: /usr/local/bin/pt-query-digest -filter ‘$event>{arg} =~ m/^select/i’ /data/mysql/mysql3306/log/slow.log.
result is normal.
2: When run --filter ‘(($event->{Full_scan} || “”) eq “Yes”) || (($event->{Full_join} || “”) eq “Yes”)’ get error: No events processed.
/usr/local/bin/pt-query-digest --filter ‘(($event->{Full_scan} || “”) eq “Yes”) || (($event->{Full_join} || “”) eq “Yes”)’ /data/mysql/mysql3306/log/slow.log
#No events processed.
How to fix this issue