Re: CLUSTER not lose indexes

Alvaro Herrera wrote:
> > In general, I'm not thrilled about expending more code on the existing
> > fundamentally-broken implementation of CLUSTER.  We need to look at
> > making use of the ability to write a new version of a table (or index)
> > under a new relfilenode value, without changing the table's OID.
> > However, some parts of your patch will probably still be needed when
> > someone gets around to making that happen, so I won't object for now.

OK, I remember now.  In renamerel(), the new clustered file is renamed
to the old table name.  However, it has a new oid.  The idea of
relfilenode was that we want to cluster the table and keep the same
relation oid.  That way, other system tables that reference that OID
will still work.

Seems like renamerel will have to stay because it is used by ALTER TABLE
RENAME, so we just need some new code that updates the relfilenode of
the old pg_class row to point to the new clustered file.  Swapping
relfilenodes between the old and new pg_class rows and deleting the new
table should do the trick of deleting the non-clustered file and the
temp pg_class row at the same time.

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