hpcc-systems/HPCC-Platform — pull request #2139 by jakesmith (2012-04-20 09:23:40+00:00)
Title: gh-1988 - exit non-grouped existaggregate early

For a non-grouped TAKexistsaggregate, once the 1st record is read, there's
not need to read rest of input

Signed-off-by: Jake Smith