Revisit query compilation performance PR after 6.3

[divega]

We got a PR from @cjpearson in 6.3 that appear to have some significant query compilation performance improvements that could benefit some customers (including @chrfin): #430.

Unfortunately there was a bug discovered in the last minute that forced us to revert in #1251.

This issue is to track revisiting the original PR and try to get it fixed for a later version.

We don't plan to be proactive about this but we will consider contributions.

[chrfin]

@divega Please take a look at #1239 as I think this fixes the problem and could be merged after 6.3 release to have the improvements back in for the first nightly after the release...