RE: [BUG]Update Toast data failure in logical replication

tanghy <tanghy.fnst@fujitsu.com>

From: "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>

To: Dilip Kumar <dilipbalaut@gmail.com>

Cc: pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2021-06-02T09:07:08Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

WAL log unchanged toasted replica identity key attributes.
- 5e01001ffb38 15.0 landed
- b5e060473273 10.21 landed
- 1cd5802ac69a 11.16 landed
- ce349cf176e2 12.11 landed
- caa231be97df 13.7 landed
- 04645bbcae72 14.3 landed
Add new wal_level, logical, sufficient for logical decoding.
- e55704d8b2fe 9.4.0 cited
Add the notion of REPLICA IDENTITY for a table.
- 07cacba983ef 9.4.0 cited

On Wed, Jun 2, 2021 2:44 PM Dilip Kumar <dilipbalaut@gmail.com> wrote: 
> Attached patch fixes that, I haven't yet added the test case.  Once
> someone confirms on the approach then I will add a test case to the
> patch.

	key_tuple = heap_form_tuple(desc, values, nulls);
	*copy = true;
...
		key_tuple = toast_flatten_tuple(oldtup, desc);
 		heap_freetuple(oldtup);
 	}
+	/*
+	 * If key tuple doesn't have any external data and key is not changed then
+	 * just free the key tuple and return NULL.
+	 */
+	else if (!key_changed)
+	{
+		heap_freetuple(key_tuple);
+		return NULL;
+	}
 
 	return key_tuple;
 }

I think "*copy = false" should be added before return NULL because we don't return a modified copy tuple here. Thoughts?

Regards
Tang