Re: reg* checks in pg_upgrade are out of date

On 2018-11-22 08:49:23 -0500, Andrew Dunstan wrote:
>
> On 11/21/18 7:12 PM, Andres Freund wrote:
> > Hi,
> >
> > It seems the list of reg* types and the check for them in pg_upgrade
> > have gone out of sync. We have the following reg* types:
> >
> > SELECT typname FROM pg_type WHERE typname LIKE 'reg%' order by typname;
> > ┌───────────────┐
> > │ typname │
> > ├───────────────┤
> > │ regclass │
> > │ regconfig │
> > │ regdictionary │
> > │ regnamespace │
> > │ regoper │
> > │ regoperator │
> > │ regproc │
> > │ regprocedure │
> > │ regrole │
> > │ regtype │
> > └───────────────┘
> > (10 rows)
> >
> > but pg_upgrade doesn't consider all of them:
> >
> > /*
> > * While several relkinds don't store any data, e.g. views, they can
> > * be used to define data types of other columns, so we check all
> > * relkinds.
> > */
> > res = executeQueryOrDie(conn,
> > "SELECT n.nspname, c.relname, a.attname "
> > "FROM pg_catalog.pg_class c, "
> > " pg_catalog.pg_namespace n, "
> > " pg_catalog.pg_attribute a "
> > "WHERE c.oid = a.attrelid AND "
> > " NOT a.attisdropped AND "
> > " a.atttypid IN ( "
> > " 'pg_catalog.regproc'::pg_catalog.regtype, "
> > " 'pg_catalog.regprocedure'::pg_catalog.regtype, "
> > " 'pg_catalog.regoper'::pg_catalog.regtype, "
> > " 'pg_catalog.regoperator'::pg_catalog.regtype, "
> > /* regclass.oid is preserved, so 'regclass' is OK */
> > /* regtype.oid is preserved, so 'regtype' is OK */
> > " 'pg_catalog.regconfig'::pg_catalog.regtype, "
> > " 'pg_catalog.regdictionary'::pg_catalog.regtype) AND "
> > " c.relnamespace = n.oid AND "
> > " n.nspname NOT IN ('pg_catalog', 'information_schema')");
> >
> > (I don't get the order here btw)
> >
> > ISTM when regrole and regnamespace were added, pg_upgrade wasn't
> > considered. It turns out that regrole is safe, because we preserve user
> > oids, but regnamespace isn't afaict. I don't think it's extremely
> > likely that users store such reg* columns in tables, but we probably
> > still should fix this.
> >
>
> yeah, I think you're right, both about the need to fix it and the
> unlikelihood of it occurring in the wild.

I've done so, and backpatched to 9.5, where these types where added.

Greetings,

Andres Freund