On Wed, Sep 17, 2025 at 04:45:14PM -0400, Bruce Momjian wrote:
> On Wed, Sep 17, 2025 at 11:46:58AM -0400, Peter Geoghegan wrote:
> > I suggest the following alternative, which has the merit of being a
> > bit less verbose:
> >
> > "Skip scan allows B-Tree index scans to find the most efficient way of
> > navigating through a multicolumn index when one or more of its columns
> > initially lacks a = condition and comes before a column that is
> > directly used by the query. Such an index scan can now be broken down
> > into multiple "index searches" by generating an implementation level =
> > condition on any underspecified columns. This allows the scan to skip
> > over irrelevant sections of the index, though only when the generated
> > = condition is on a column that has relatively few distinct values."
> >
> > Note that "index searches" is a term that now appears in EXPLAIN ANALYZE output.
>
> I went with this text, which is more "aspirational" rather than
> "proscriptive", and the right level of detail:
>
> This allows multi-column btree indexes to be used in more cases
> such as when there are no restrictions on the first or early
> indexed columns (or they are non-equality ones), and there are
> useful restrictions on later indexed columns.
With our GA release dates close, I committed the attached patch.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
Do not let urgent matters crowd out time for investment in the future.
