Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions

On Fri, Aug 21, 2020 at 9:14 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Thu, Aug 20, 2020 at 5:42 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> >
> > On Thu, Aug 20, 2020 at 2:30 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > >
> > > Right, I think this can happen if one has changed those by BufFileSeek
> > > before doing truncate. We should fix that case as well.
> >
> > Right.
> >
> > > > I will work on those along with your other comments and
> > > > submit the updated patch.
> >
> > I have fixed this in the attached patch along with your other
> > comments. I have also attached a contrib module that is just used for
> > testing the truncate API.
> >
>
> Few comments:
> ==============
> +void
> +BufFileTruncateShared(BufFile *file, int fileno, off_t offset)
> {
> ..
> + if ((i != fileno || offset == 0) && i != 0)
> + {
> + SharedSegmentName(segment_name, file->name, i);
> + FileClose(file->files[i]);
> + if (!SharedFileSetDelete(file->fileset, segment_name, true))
> + ereport(ERROR,
> + (errcode_for_file_access(),
> + errmsg("could not delete shared fileset \"%s\": %m",
> + segment_name)));
> + numFiles--;
> + newOffset = MAX_PHYSICAL_FILESIZE;
> +
> + if (i == fileno)
> + newFile--;
> + }
>
> Here, shouldn't it be i <= fileno? Because we need to move back the
> curFile up to newFile whenever curFile is greater than newFile
>

I think now I have understood why you have added this condition but
probably a comment on the lines "This is required to indicate that we
have removed the given fileno" would be better for future readers.

--
With Regards,
Amit Kapila.