Re: CLUSTER, REINDEX, VACUUM in "read only" transaction?

On Fri, Oct 10, 2008 at 09:41:39AM -0400, Tom Lane wrote:
> So I was looking for other omissions in utility.c, and I noticed that
> check_xact_readonly() doesn't reject CLUSTER, REINDEX, or VACUUM.
> Now the notion of "read only" that we're trying to enforce is pretty
> weak (I think it's effectively "no writes to non-temp tables").
> But I can't see that CLUSTER is a read-only operation even under the
> weakest definitions, and I'm not seeing the rationale for REINDEX or
> VACUUM here either.
>
> Comments?
>
> regards, tom lane
>

CLUSTER, REINDEX, and VACUUM are read-only to me because they do not
change what I will call the actual working data in the database. Also,
how could you address problems with index imbalance or heap organization?

Regards,
Ken