Re: Planner question - "bit" data types

Bruce Momjian wrote:
> Alvaro Herrera wrote:
> > Karl Denninger escribi?:
> >
> > > The individual boolean fields don't kill me and in terms of some of the
> > > application issues they're actually rather easy to code for.
> > >
> > > The problem with re-coding for them is extensibility (by those who
> > > install and administer the package); a mask leaves open lots of extra
> > > bits for "site-specific" use, where hard-coding booleans does not, and
> > > since the executable is a binary it instantly becomes a huge problem for
> > > everyone but me.
> >
> > Did you try hiding the bitmask operations inside a function as Tom
> > suggested?
>
> Yes. In addition, functions that are part of expression indexes do get
> their own optimizer statistics, so it does allow you to get optimizer
> stats for your test without having to use booleans.
>
> I see this documented in the 8.0 release notes:
>
> * "ANALYZE" now collects statistics for expression indexes (Tom)
> Expression indexes (also called functional indexes) allow users
> to index not just columns but the results of expressions and
> function calls. With this release, the optimizer can gather and
> use statistics about the contents of expression indexes. This will
> greatly improve the quality of planning for queries in which an
> expression index is relevant.
>
> Is this in our main documentation somewhere?

Added with attached, applied patch.

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