On Mon, Jul 4, 2022 at 9:42 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Mon, May 30, 2022 at 11:13 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
> > I've attached three POC patches:
> >
>
> I think it will be a good idea if you can add a short commit message
> at least to say which patch is proposed for HEAD and which one is for
> back branches. Also, it would be good if you can add some description
> of the fix in the commit message. Let's remove poc* from the patch
> name.
Updated.
>
> Review poc_add_running_catchanges_xacts_to_serialized_snapshot
> =====================================================
> 1.
> + /*
> + * Array of transactions that were running when the snapshot serialization
> + * and changed system catalogs,
>
> The part of the sentence after serialization is not very clear.
Updated.
>
> 2.
> - if (ReorderBufferXidHasCatalogChanges(builder->reorder, subxid))
> + if (ReorderBufferXidHasCatalogChanges(builder->reorder, subxid) ||
> + bsearch(&xid, builder->catchanges.xip, builder->catchanges.xcnt,
> + sizeof(TransactionId), xidComparator) != NULL)
>
> Why are you using xid instead of subxid in bsearch call? Can we add a
> comment to say why it is okay to use xid if there is a valid reason?
> But note, we are using subxid to add to the committed xact array so
> not sure if this is a good idea but I might be missing something.
You're right, subxid should be used here.
>
> Suggestions for improvement in comments:
> - /*
> - * Update the transactions that are running and changes
> catalogs that are
> - * not committed.
> - */
> + /* Update the catalog modifying transactions that are yet not
> committed. */
> if (builder->catchanges.xip)
> pfree(builder->catchanges.xip);
> builder->catchanges.xip =
> ReorderBufferGetCatalogChangesXacts(builder->reorder,
> @@ -1647,7 +1644,7 @@ SnapBuildSerialize(SnapBuild *builder, XLogRecPtr lsn)
> COMP_CRC32C(ondisk->checksum, ondisk_c, sz);
> ondisk_c += sz;
>
> - /* copy catalog-changes xacts */
> + /* copy catalog modifying xacts */
> sz = sizeof(TransactionId) * builder->catchanges.xcnt;
> memcpy(ondisk_c, builder->catchanges.xip, sz);
> COMP_CRC32C(ondisk->checksum, ondisk_c, sz);
Updated.
I'll post a new version patch in the next email with replying to other comments.
Regards,
--
Masahiko Sawada
EDB: https://www.enterprisedb.com/