COUNT требует предшествующего оператора GROUP ALL для глобальных подсчетов и оператора GROUP BY для подсчета групп.
Вы можете использовать любой из следующих:
scans = LOAD '/hive/scans/*' USING PigStorage(',') AS (thetime:long,product_id:long,lat:double,lon:double,user:chararray,category:chararray,title:chararray);
productscans = FILTER scans BY (title MATCHES 'proactiv');
grouped = GROUP productscans ALL;
count = FOREACH grouped GENERATE COUNT(productscans);
DUMP scancount;
Или
scans = LOAD '/hive/scans/*' USING PigStorage(',') AS (thetime:long,product_id:long,lat:double,lon:double,user:chararray,category:chararray,title:chararray);
productscans = FILTER scans BY (title MATCHES 'proactiv');
grouped = GROUP productscans ALL;
count = FOREACH grouped GENERATE COUNT($1);
DUMP scancount;