foo
Merge branch 'piggyback_master' of https://github.com/mpws2013n1/postgres into piggyback_master
code formatting
renaming
started implementing fd check
allocate memory for attribute descriptors in result column structs and differentiate between src and result column
Add function declaration for printFDStatistics
initialize attribute Descriptor infomation
Merge branch 'piggyback_master' of https://github.com/mpws2013n1/postgres into piggyback_master
refactored n_distinct to distinct_status
remove column names list in piggyback in favor of attDesc in columnStatistics
merge with prefinal stats
reordering in execMain for finding correct position for ExecInitNode (around line 980)