Every RegExp is slightly different. When it comes to Pig’s match functionality, does:
X = FILTER A BY (f1 matches 'apache');
==
X = FILTER A BY (f1 matches '^apache$');
or
X = FILTER A BY (f1 matches '.*apache.*');
? In other words, is .* automatically implied in a match or does it always need to be included?
The format of regular expressions in Pig is that supported by Java as described here.
In other words, nothing is implied, if you want
.*you have to specifically add it to thematchesstatement just like you would do in Java in aPattern.compile.