Re: [PERFORM] Planner selects different execution plans depending on limit

Jeff Janes <jeff(dot)janes(at)gmail(dot)com> writes:
> On Thu, Sep 13, 2012 at 10:33 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Just pretend it's a table.
>> ALTER TABLE index_name ALTER COLUMN column_name SET STATISTICS ...
>>
>> You'll need to look at the index (eg with \d) to see what the name of
>> the desired column is, since index expressions have system-assigned
>> column names.

> Is this documented anywhere? I couldn't find it. If not, which
> section would be the best one to add it to?

It's not documented, mainly because it hasn't reached the level of being
a supported feature. I'd like to figure out how to get pg_dump to dump
such settings before we call it supported. (The stumbling block is
exactly that index column names aren't set in stone, so it's not clear
that the ALTER command would do the right thing on dump-and-reload.)

regards, tom lane