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

On Wed, Jul 22, 2020 at 10:20 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Wed, Jul 22, 2020 at 9:18 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Mon, Jul 20, 2020 at 6:46 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> > >
> > > There was one warning in release mode in the last version in 0004 so
> > > attaching a new version.
> > >
> >
> > Today, I was reviewing patch
> > v38-0001-WAL-Log-invalidations-at-command-end-with-wal_le and found a
> > small problem with it.
> >
> > + /*
> > + * Execute the invalidations for xid-less transactions,
> > + * otherwise, accumulate them so that they can be processed at
> > + * the commit time.
> > + */
> > + if (!ctx->fast_forward)
> > + {
> > + if (TransactionIdIsValid(xid))
> > + {
> > + ReorderBufferAddInvalidations(reorder, xid, buf->origptr,
> > +   invals->nmsgs, invals->msgs);
> > + ReorderBufferXidSetCatalogChanges(ctx->reorder, xid,
> > +   buf->origptr);
> > + }
> >
> > I think we need to set ReorderBufferXidSetCatalogChanges even when
> > ctx->fast-forward is true because we are dependent on that flag for
> > snapshot build (see SnapBuildCommitTxn).  We are already doing the
> > same way in DecodeCommit where even though we skip adding
> > invalidations for fast-forward cases but we do set the flag to
> > indicate that this txn has catalog changes.  Is there any reason to do
> > things differently here?
>
> I think it is wrong,  we should set the
> ReorderBufferXidSetCatalogChanges, even if it is in fast-forward mode.
>

Thanks for the change.  I have one more minor comment in the patch
0001-WAL-Log-invalidations-at-command-end-with-wal_le.

 /*
+ * Invalidations logged with wal_level=logical.
+ */
+typedef struct xl_xact_invalidations
+{
+ int nmsgs; /* number of shared inval msgs */
+ SharedInvalidationMessage msgs[FLEXIBLE_ARRAY_MEMBER];
+} xl_xact_invalidations;

I see that we already have a structure xl_xact_invals in the code
which has the same members, so I think it is better to use that
instead of defining a new one.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com