Re: Make pg_waldump report replication origin ID, LSN, and timestamp.

[Michael Paquier]

On Wed, Dec 08, 2021 at 05:03:30PM +0900, Masahiko Sawada wrote:
> Agreed. I've attached an updated patch that incorporated your review
> comments. Please review it.

That looks correct to me.  One thing that I have noticed while
reviewing is that we don't check XactCompletionApplyFeedback() in
xact_desc_commit(), which would happen if a transaction needs to do
a remote_apply on a standby.  synchronous_commit is a user-settable
parameter, so it seems to me that it could be useful for debugging?

That's not related to your patch, but while we are looking at the
area..
--
Michael

From c821c67698535ded147e8686c182d91462a16599 Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@paquier.xyz>
Date: Thu, 9 Dec 2021 16:00:53 +0900
Subject: [PATCH v3] Make pg_waldump report replication origin ID, LSN, and
 timestamp.

Commit 7b8a899bdeb made pg_waldump report the detail of information
about PREPARE TRANSACTION record, like global transaction
identifier. However, replication origin LSN and timestamp were not
reporeted. These are helpful when diagnosing 2PC-related troubles on
the subsciber side.

This commit makes xact_desc_prepare() and xact_desc_abort() report
replication origin ID, LSN, and timestamp.
---
 src/backend/access/rmgrdesc/xactdesc.c | 32 ++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/src/backend/access/rmgrdesc/xactdesc.c b/src/backend/access/rmgrdesc/xactdesc.c
index 4b0d10f073..fca03a00d9 100644
--- a/src/backend/access/rmgrdesc/xactdesc.c
+++ b/src/backend/access/rmgrdesc/xactdesc.c
@@ -16,6 +16,7 @@
 
 #include "access/transam.h"
 #include "access/xact.h"
+#include "replication/origin.h"
 #include "storage/sinval.h"
 #include "storage/standbydefs.h"
 #include "utils/timestamp.h"
@@ -299,6 +300,9 @@ xact_desc_commit(StringInfo buf, uint8 info, xl_xact_commit *xlrec, RepOriginId
 							   parsed.tsId,
 							   XactCompletionRelcacheInitFileInval(parsed.xinfo));
 
+	if (XactCompletionApplyFeedback(parsed.xinfo))
+		appendStringInfoString(buf, "; apply_feedback");
+
 	if (XactCompletionForceSyncCommit(parsed.xinfo))
 		appendStringInfoString(buf, "; sync");
 
@@ -312,7 +316,7 @@ xact_desc_commit(StringInfo buf, uint8 info, xl_xact_commit *xlrec, RepOriginId
 }
 
 static void
-xact_desc_abort(StringInfo buf, uint8 info, xl_xact_abort *xlrec)
+xact_desc_abort(StringInfo buf, uint8 info, xl_xact_abort *xlrec, RepOriginId origin_id)
 {
 	xl_xact_parsed_abort parsed;
 
@@ -326,10 +330,18 @@ xact_desc_abort(StringInfo buf, uint8 info, xl_xact_abort *xlrec)
 
 	xact_desc_relations(buf, "rels", parsed.nrels, parsed.xnodes);
 	xact_desc_subxacts(buf, parsed.nsubxacts, parsed.subxacts);
+
+	if (parsed.xinfo & XACT_XINFO_HAS_ORIGIN)
+	{
+		appendStringInfo(buf, "; origin: node %u, lsn %X/%X, at %s",
+						 origin_id,
+						 LSN_FORMAT_ARGS(parsed.origin_lsn),
+						 timestamptz_to_str(parsed.origin_timestamp));
+	}
 }
 
 static void
-xact_desc_prepare(StringInfo buf, uint8 info, xl_xact_prepare *xlrec)
+xact_desc_prepare(StringInfo buf, uint8 info, xl_xact_prepare *xlrec, RepOriginId origin_id)
 {
 	xl_xact_parsed_prepare parsed;
 
@@ -345,6 +357,16 @@ xact_desc_prepare(StringInfo buf, uint8 info, xl_xact_prepare *xlrec)
 
 	standby_desc_invalidations(buf, parsed.nmsgs, parsed.msgs, parsed.dbId,
 							   parsed.tsId, xlrec->initfileinval);
+
+	/*
+	 * Check if the replication origin has been set in this record in the
+	 * same way as PrepareRedoAdd().
+	 */
+	if (origin_id != InvalidRepOriginId)
+		appendStringInfo(buf, "; origin: node %u, lsn %X/%X, at %s",
+						 origin_id,
+						 LSN_FORMAT_ARGS(parsed.origin_lsn),
+						 timestamptz_to_str(parsed.origin_timestamp));
 }
 
 static void
@@ -375,13 +397,15 @@ xact_desc(StringInfo buf, XLogReaderState *record)
 	{
 		xl_xact_abort *xlrec = (xl_xact_abort *) rec;
 
-		xact_desc_abort(buf, XLogRecGetInfo(record), xlrec);
+		xact_desc_abort(buf, XLogRecGetInfo(record), xlrec,
+						XLogRecGetOrigin(record));
 	}
 	else if (info == XLOG_XACT_PREPARE)
 	{
 		xl_xact_prepare *xlrec = (xl_xact_prepare *) rec;
 
-		xact_desc_prepare(buf, XLogRecGetInfo(record), xlrec);
+		xact_desc_prepare(buf, XLogRecGetInfo(record), xlrec,
+						  XLogRecGetOrigin(record));
 	}
 	else if (info == XLOG_XACT_ASSIGNMENT)
 	{
-- 
2.34.1

signature.asc
Description: PGP signature