RE: Skipping logical replication transactions on subscriber side

Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>

From: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>, Alexey Lesovsky <lesovsky@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Amit Kapila <amit.kapila16@gmail.com>
Date: 2021-08-16T06:59:36Z
Lists: pgsql-hackers
On Thu, Aug 12, 2021 1:53 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> I've attached the updated patches. FYI I've included the patch
> (v8-0005) that fixes the assertion failure during shared fileset cleanup to make
> cfbot tests happy.

Hi,

Thanks for the new patches.
I have a few comments on the v8-0001 patch.

1)
+
+	if (TransactionIdIsNormal(errarg->remote_xid))
+		appendStringInfo(&buf, _(" in transaction id %u with commit timestamp %s"),
+						 errarg->remote_xid,
+						 errarg->commit_ts == 0
+						 ? "(unset)"
+						 : timestamptz_to_str(errarg->commit_ts));
+
+	errcontext("%s", buf.data);

I think we can output the timestamp in a separete check which can be more
consistent with the other code style in apply_error_callback()
(ie)
+	if (errarg->commit_ts != 0)
+		appendStringInfo(&buf, _(" with commit timestamp %s"),
+						timestamptz_to_str(errarg->commit_ts));


2)
+/*
+ * Get string representing LogicalRepMsgType.
+ */
+char *
+logicalrep_message_type(LogicalRepMsgType action)
+{
...
+
+	elog(ERROR, "invalid logical replication message type \"%c\"", action);
+}

Some old compilers might complain that the function doesn't have a return value
at the end of the function, maybe we can code like the following:

+char *
+logicalrep_message_type(LogicalRepMsgType action)
+{
+	switch (action)
+	{
+		case LOGICAL_REP_MSG_BEGIN:
+			return "BEGIN";
...
+		default:
+			elog(ERROR, "invalid logical replication message type \"%c\"", action);
+	}
+	return NULL;				/* keep compiler quiet */
+}


3)
Do we need to invoke set_apply_error_context_xact() in the function
apply_handle_stream_prepare() to save the xid and timestamp ?

Best regards,
Hou zj

Commits

  1. Test ALIGNOF_DOUBLE==4 compatibility under ALIGNOF_DOUBLE==8.

  2. Reorder subskiplsn in pg_subscription to avoid alignment issues.

  3. Add ALTER SUBSCRIPTION ... SKIP.

  4. Optionally disable subscriptions on error.

  5. Update docs of logical replication for commit 8d74fc96db.

  6. Respect permissions within logical replication.

  7. Fix regression test failure caused by commit 8d74fc96db.

  8. Add a view to show the stats of subscription workers.

  9. Add logical change details to logical replication worker errcontext.

  10. Rename LOGICAL_REP_MSG_STREAM_END to LOGICAL_REP_MSG_STREAM_STOP.

  11. Fix typo in protocol.sgml.

  12. Remove unused argument in apply_handle_commit_internal().

  13. Fix replication of in-progress transactions in tablesync worker.

  14. Reorder pg_sequence columns to avoid alignment issue