Re: [BUG] Logical replication failure "ERROR: could not map filenode "base/13237/442428" to relation OID" with catalog modifying txns

On Wed, Jul 20, 2022 at 12:11 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Tue, Jul 19, 2022 at 7:28 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
> > On Tue, Jul 19, 2022 at 9:25 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> > > On Tue, Jul 19, 2022 at 1:10 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> > > >
> > >
> > > > BTW on backbranches, I think that the reason why we add
> > > > initial_running_xacts stuff to ReorderBuffer is that we cannot modify
> > > > SnapBuild that could be serialized. Can we add a (private) array for
> > > > the initial running xacts in snapbuild.c instead of adding new
> > > > variables to ReorderBuffer?
> > > >
> > >
> > > While thinking about this, I wonder if the current patch for back
> > > branches can lead to an ABI break as it changes the exposed structure?
> > > If so, it may be another reason to change it to some other way
> > > probably as you are suggesting.
> >
> > Yeah, it changes the size of ReorderBuffer, which is not good.
> >
>
> So, are you planning to give a try with your idea of making a private
> array for the initial running xacts?

Yes.

>  I am not sure but I guess you are
> proposing to add it in SnapBuild structure, if so, that seems safe as
> that structure is not exposed.

We cannot add it in SnapBuild as it gets serialized to the disk.

>
> > Changing the function names and arguments would also break ABI. So
> > probably we cannot do the above idea of removing
> > ReorderBufferInitialXactsSetCatalogChanges() as well.
> >
>
> Why do you think we can't remove
> ReorderBufferInitialXactsSetCatalogChanges() from the back branch
> patch? I think we don't need to change the existing function
> ReorderBufferXidHasCatalogChanges() but instead can have a wrapper
> like SnapBuildXidHasCatalogChanges() similar to master branch patch.

IIUC we need to change SnapBuildCommitTxn() but it's exposed.

Currently, we call like DecodeCommit() -> SnapBuildCommitTxn() ->
ReorderBufferXidHasCatalogChanges(). If we have a wrapper function, we
call like DecodeCommit() -> SnapBuildCommitTxn() ->
SnapBuildXidHasCatalogChanges() ->
ReorderBufferXidHasCatalogChanges(). In
SnapBuildXidHasCatalogChanges(), we need to check if the transaction
has XACT_XINFO_HAS_INVALS, which means DecodeCommit() needs to pass
either parsed->xinfo or (parsed->xinfo & XACT_XINFO_HAS_INVALS != 0)
down to SnapBuildXidHasCatalogChanges(). However, since
SnapBuildCommitTxn(), between DecodeCommit() and
SnapBuildXidHasCatalogChanges(), is exposed we cannot change it.

Another idea would be to have functions, say
SnapBuildCommitTxnWithXInfo() and SnapBuildCommitTxn_ext(). The latter
does actual work of handling transaction commits and both
SnapBuildCommitTxn() and SnapBuildCommit() call
SnapBuildCommitTxnWithXInfo() with different arguments.

Regards,

-- 
Masahiko Sawada
EDB:  https://www.enterprisedb.com/