wip: opt: do not use histograms for constrains outside the min and max

[mgartner]

No description provided.

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

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[cockroach-teamcity]

This change is 

[blathers-crl]

Your pull request contains more than 1000 changes. It is strongly encouraged to split big PRs into smaller chunks.

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[mgartner]

There was some promise with this experiment, but we ran into problems with inequality filters. With a query like SELECT * FROM t WHERE v > 5000 where 5000 is greater than the max value in v's histogram, we would fallback to assuming a selectivity of 1/3 for v > 5000. This could be a high over-estimation, leading to bad plans in some cases.

We'll continue to think about a change similar to this in the future. For now I'll close it.