Re: Add an option to skip loading missing publication to avoid logical replication failure

On Mon, Mar 3, 2025 at 2:30 PM vignesh C <vignesh21(at)gmail(dot)com> wrote:
>
> On Tue, 25 Feb 2025 at 15:32, vignesh C <vignesh21(at)gmail(dot)com> wrote:
> >
> > The attached script has the script that was used for testing. Here the
> > NUM_RECORDS count should be changed accordingly for each of the tests
> > and while running the test with the patch change uncomment the drop
> > publication command.
>
> I have done further analysis on the test and changed the test to
> compare it better with HEAD. The execution time is in milliseconds.
> Brach/records | 100 | 1000 | 10000 | 100000 | 1000000
> Head | 10.43 | 15.86 | 64.44 | 550.56 | 8991.04
> Patch | 11.35 | 17.26 | 73.50 | 640.21 | 10104.72
> % diff | -8.82 | -8.85 | -14.08 | -16.28 | -12.38
>
> There is a performance degradation in the range of 8.8 to 16.2 percent.
>

- /* Validate the entry */
- if (!entry->replicate_valid)
+ /*
+ * If the publication is invalid, check for updates.
+ * This optimization ensures that the next block, which queries the system
+ * tables and builds the relation entry, runs only if a new publication was
+ * created.
+ */
+ if (!publications_valid && data->publications)
+ {
+ bool skipped_pub = false;
+ List *publications;
+
+ publications = LoadPublications(data->publication_names, &skipped_pub);

The publications_valid flag indicates whether the publications cache
is valid or not; the flag is set to false for any invalidation in the
pg_publication catalog. I wonder that instead of using the same flag
what if we use a separate publications_skipped flag? If that works,
you don't even need to change the current location where we
LoadPublications.

--
With Regards,
Amit Kapila.