Horton

RE: Skipping logical replication transactions on subscriber side

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

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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: 2021-08-18T06:33:15Z
Lists: pgsql-hackers 
On Tues, Aug 17, 2021 1:01 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> On Mon, Aug 16, 2021 at 3:59 PM houzj.fnst@fujitsu.com <houzj.fnst@fujitsu.com> wrote:
> > 3)
> > Do we need to invoke set_apply_error_context_xact() in the function
> > apply_handle_stream_prepare() to save the xid and timestamp ?
> 
> Yes. I think that v8-0001 patch already set xid and timestamp just after parsing
> stream_prepare message. You meant it's not necessary?

Sorry, I thought of something wrong, please ignore the above comment.

> 
> I'll submit the updated patches soon.

I was thinking about the place to set the errcallback.callback.

apply_dispatch(StringInfo s)
 {
 	LogicalRepMsgType action = pq_getmsgbyte(s);
+	ErrorContextCallback errcallback;
+	bool		set_callback = false;
+
+	/*
+	 * Push apply error context callback if not yet. Other fields will be
+	 * filled during applying the change.  Since this function can be called
+	 * recursively when applying spooled changes, we set the callback only
+	 * once.
+	 */
+	if (apply_error_callback_arg.command == 0)
+	{
+		errcallback.callback = apply_error_callback;
+		errcallback.previous = error_context_stack;
+		error_context_stack = &errcallback;
+		set_callback = true;
+	}
...
+	/* Pop the error context stack */
+	if (set_callback)
+		error_context_stack = errcallback.previous;

It seems we can put the above code in the function LogicalRepApplyLoop()
around invoking apply_dispatch(), and in that approach we don't need to worry
about the recursively case. What do you think ?

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