On Wed, Aug 18, 2021 at 3:45 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Wed, Aug 18, 2021 at 11:24 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > On Tue, Aug 17, 2021 at 4:34 PM Andres Freund <andres(at)anarazel(dot)de> wrote:
> > >
> > > On 2021-08-17 10:54:30 +0530, Amit Kapila wrote:
> > > > 5. How can we provide a strict mechanism to not allow to use dsm APIs
> > > > for non-dsm FileSet? One idea could be that we can have a variable
> > > > (probably bool) in SharedFileSet structure which will be initialized
> > > > in SharedFileSetInit based on whether the caller has provided dsm
> > > > segment. Then in other DSM-based APIs, we can check if it is used for
> > > > the wrong type.
> > >
> > > Well, isn't the issue here that it's not a shared file set in case you
> > > explicitly don't want to share it? ISTM that the proper way to address
> > > this would be to split out a FileSet from SharedFileSet that's then used
> > > for worker.c and sharedfileset.c.
> > >
> >
> > Okay, but note that to accomplish the same, we need to tweak the
> > BufFile (buffile.c) APIs as well so that they can work with FileSet.
> > As per the initial analysis, there doesn't seem to be any problem with
> > that though.
>
> I was looking into this, so if we want to do that I think the outline
> will look like this
>
> - There will be a fileset.c and fileset.h files, and we will expose a
> new structure FileSet, which will be the same as SharedFileSet, except
> mutext and refcount. The fileset.c will expose FileSetInit(),
> FileSetCreate(), FileSetOpen(), FileSetDelete() and FileSetDeleteAll()
> interfaces.
>
> - sharefileset.c will internally call the fileset.c's interfaces. The
> SharedFileSet structure will also contain FileSet and other members
> i.e. mutex and refcount.
>
> - the buffile.c's interfaces which are ending with Shared e.g.
> BufFileCreateShared, BufFileOpenShared, should be converted to
> BufFileCreate and
> BufFileOpen respectively. And the input to these interfaces can be
> converted to FileSet instead of SharedFileSet.
Here is the first draft based on the idea we discussed, 0001, splits
sharedfileset.c in sharedfileset.c and fileset.c and 0002 is same
patch I submitted earlier(use single fileset throughout the worker),
just it is rebased on top of 0001. Please let me know your thoughts.
--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com