Github user paul-rogers commented on the issue:
https://github.com/apache/drill/pull/968
@jinfengni, how unreliable is the project push-down rule? In general, it is
hard to reason about software when parts are unreliable. Should every use of
the projection push down rule implement a "just in case" fallback as was done
for HBase? Should we add that to all storage plugins?
Or, can we fix the projection push-down rule to make it more reliable? It
seems that one of your fixes did just that. An HBase query before your fix to
the rule didn't expand the wildcard, but the same query, after your projection
rule fix, does expand the wildcard.
What are the scenarios in which the rule does not work? Can we fix them in
the planner?
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