Re: [HACKERS] WAL logging problem in 9.4.3?

By the way, the previous version looks somewhat different from what I
thought I posted..

At Sun, 26 Jan 2020 20:57:00 -0800, Noah Misch <noah@leadboat.com> wrote in 
> On Mon, Jan 27, 2020 at 01:44:13PM +0900, Kyotaro Horiguchi wrote:
> > > The purpose of this loop is to create relcache entries for rels locked in the
> > > current transaction.  (The "r == NULL" case happens for rels no longer visible
> > > in catalogs.  It is harmless.)  Since RelationIdGetRelationCache() never
> > > creates a relcache entry, calling it defeats that purpose.
> > > RelationIdGetRelation() is the right function to call.
> > 
> > I thought that the all required entry exist in the cache but actually
> > it's safer that recreate dropped caches. Does the following works?
> > 
> >     r = RelationIdGetRelation(relid);
> > +       /* if not found, fetch a "dropped" entry if any  */
> > +    if (r == NULL)
> > +        r = RelationIdGetRelationCache(relid);
> >     if (r == NULL)
> >         continue;
> 
> That does not materially change the function's behavior.  Notice that the
> function does one thing with "r", which is to call RelationClose(r).  The
> function calls RelationIdGetRelation() for its side effects, not for its
> return value.

..Right.  The following loop accesses relcache hash directly and no
need for storing returned r to the array rels..

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center