Re: [HACKERS] Some notes on optimizer cost estimates

> "Hiroshi Inoue" <Inoue(at)tpf(dot)co(dot)jp> writes:
> > I've wondered why we cound't analyze database without vacuum.
> > We couldn't run vacuum light-heartedly because it acquires an
> > exclusive lock for the target table.
>
> There is probably no real good reason, except backwards compatibility,
> why the ANALYZE function (obtaining pg_statistic data) is part of
> VACUUM at all --- it could just as easily be a separate command that
> would only use read access on the database. Bruce is thinking about
> restructuring VACUUM, so maybe now is a good time to think about
> splitting out the ANALYZE code too.

I put it in vacuum because at the time I didn't know how to do such
things and vacuum already scanned the table. I just linked on the the
scan. Seemed like a good idea at the time.

It is nice that ANALYZE is done during vacuum. I can't imagine why you
would want to do an analyze without adding a vacuum to it. I guess
that's why I made them the same command.

If I made them separate commands, both would have to scan the table,
though the analyze could do it without the exclusive lock, which would
be good.

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