Github user linwen commented on the issue:
https://github.com/apache/hawq/pull/1397
It is a good optimization point. If a lot of columns will be projected, we
can only fetch joinkey and do a bloomfilter check, if doesn't match, no need to
fetch other columns.
But in this PR, if bloomfilter is not enable, it will fetch joinkey in the
first loop, and fetch other columns in the second loop, which needs a little
refine further. ---
