Re: making relfilenodes 56 bits

On Fri, Jul 22, 2022 at 4:21 PM vignesh C <vignesh21@gmail.com> wrote:
>
> On Wed, Jul 20, 2022 at 4:57 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> >
> > On Mon, Jul 18, 2022 at 4:51 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> > >
> > > I was doing some more testing by setting the FirstNormalRelFileNumber
> > > to a high value(more than 32 bits) I have noticed a couple of problems
> > > there e.g. relpath is still using OIDCHARS macro which says max
> > > relfilenumber file name can be only 10 character long which is no
> > > longer true.  So there we need to change this value to 20 and also
> > > need to carefully rename the macros and other variable names used for
> > > this purpose.
> > >
> > > Similarly there was some issue in macro in buf_internal.h while
> > > fetching the relfilenumber.  So I will relook into all those issues
> > > and repost the patch soon.
> >
> > I have fixed these existing issues and there was also some issue in
> > pg_dump.c which was creating problems in upgrading to the same version
> > while using a higher range of the relfilenumber.
> >
> > There was also an issue where the user table from the old cluster's
> > relfilenode could conflict with the system table of the new cluster.
> > As a solution currently for system table object (while creating
> > storage first time) we are keeping the low range of relfilenumber,
> > basically we are using the same relfilenumber as OID so that during
> > upgrade the normal user table from the old cluster will not conflict
> > with the system tables in the new cluster.  But with this solution
> > Robert told me (in off list chat) a problem that in future if we want
> > to make relfilenumber completely unique within a cluster by
> > implementing the CREATEDB differently then we can not do that as we
> > have created fixed relfilenodes for the system tables.
> >
> > I am not sure what exactly we can do to avoid that because even if we
> > do something  to avoid that in the new cluster the old cluster might
> > be already using the non-unique relfilenode so after upgrading the new
> > cluster will also get those non-unique relfilenode.
>
> Thanks for the patch, my comments from the initial review:
> 1) Since we have changed the macros to inline functions, should we
> change the function names similar to the other inline functions in the
> same file like: ClearBufferTag, InitBufferTag & BufferTagsEqual:
> -#define BUFFERTAGS_EQUAL(a,b) \
> -( \
> -       RelFileLocatorEquals((a).rlocator, (b).rlocator) && \
> -       (a).blockNum == (b).blockNum && \
> -       (a).forkNum == (b).forkNum \
> -)
> +static inline void
> +CLEAR_BUFFERTAG(BufferTag *tag)
> +{
> +       tag->rlocator.spcOid = InvalidOid;
> +       tag->rlocator.dbOid = InvalidOid;
> +       tag->rlocator.relNumber = InvalidRelFileNumber;
> +       tag->forkNum = InvalidForkNumber;
> +       tag->blockNum = InvalidBlockNumber;
> +}
>
> 2) We could move this macros along with the other macros at the top of the file:
> +/*
> + * The freeNext field is either the index of the next freelist entry,
> + * or one of these special values:
> + */
> +#define FREENEXT_END_OF_LIST   (-1)
> +#define FREENEXT_NOT_IN_LIST   (-2)
>
> 3) typo thn should be then:
> + * can raise it as necessary if we end up with more mapped relations. For
> + * now, we just pick a round number that is modestly larger thn the expected
> + * number of mappings.
> + */
>

Few more typos in 0004 patch as well:

the a value
interger
previosly
currenly

> 4) There is one whitespace issue:
> git am v10-0004-Widen-relfilenumber-from-32-bits-to-56-bits.patch
> Applying: Widen relfilenumber from 32 bits to 56 bits
> .git/rebase-apply/patch:1500: space before tab in indent.
> (relfilenumber)))); \
> warning: 1 line adds whitespace errors.
>
> Regards,
> Vignesh
>

Regards,
Amul