v1-0001-Add-checkpoint-and-redo-LSN-to-LogCheckpointEnd-l.patch

From a641d82e8eb4fa9582a0f83a6f8da5ff468d1710 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Thu, 23 Dec 2021 15:03:30 +0000
Subject: [PATCH v1] Add checkpoint and redo LSN to LogCheckpointEnd log
 message

It is useful (for debugging purposes) if the checkpoint end message
has the checkpoint LSN and REDO LSN. It gives more context while
analyzing checkpoint-related issues. The pg_controldata gives the
last checkpoint LSN and REDO LSN, but having this info alongside
the log message helps analyze issues that happened previously,
connect the dots and identify the root cause.
---
 src/backend/access/transam/xlog.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 1e1fbe957f..9816f7d328 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8924,7 +8924,8 @@ LogCheckpointEnd(bool restartpoint)
 						"%d WAL file(s) added, %d removed, %d recycled; "
 						"write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s; "
 						"sync files=%d, longest=%ld.%03d s, average=%ld.%03d s; "
-						"distance=%d kB, estimate=%d kB",
+						"distance=%d kB, estimate=%d kB; "
+						"LSN=%X/%X, REDO LSN=%X/%X",
 						CheckpointStats.ckpt_bufs_written,
 						(double) CheckpointStats.ckpt_bufs_written * 100 / NBuffers,
 						CheckpointStats.ckpt_segs_added,
@@ -8937,14 +8938,17 @@ LogCheckpointEnd(bool restartpoint)
 						longest_msecs / 1000, (int) (longest_msecs % 1000),
 						average_msecs / 1000, (int) (average_msecs % 1000),
 						(int) (PrevCheckPointDistance / 1024.0),
-						(int) (CheckPointDistanceEstimate / 1024.0))));
+						(int) (CheckPointDistanceEstimate / 1024.0),
+						LSN_FORMAT_ARGS(ControlFile->checkPoint),
+						LSN_FORMAT_ARGS(ControlFile->checkPointCopy.redo))));
 	else
 		ereport(LOG,
 				(errmsg("checkpoint complete: wrote %d buffers (%.1f%%); "
 						"%d WAL file(s) added, %d removed, %d recycled; "
 						"write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s; "
 						"sync files=%d, longest=%ld.%03d s, average=%ld.%03d s; "
-						"distance=%d kB, estimate=%d kB",
+						"distance=%d kB, estimate=%d kB; "
+						"LSN=%X/%X, REDO LSN=%X/%X",
 						CheckpointStats.ckpt_bufs_written,
 						(double) CheckpointStats.ckpt_bufs_written * 100 / NBuffers,
 						CheckpointStats.ckpt_segs_added,
@@ -8957,7 +8961,9 @@ LogCheckpointEnd(bool restartpoint)
 						longest_msecs / 1000, (int) (longest_msecs % 1000),
 						average_msecs / 1000, (int) (average_msecs % 1000),
 						(int) (PrevCheckPointDistance / 1024.0),
-						(int) (CheckPointDistanceEstimate / 1024.0))));
+						(int) (CheckPointDistanceEstimate / 1024.0),
+						LSN_FORMAT_ARGS(ControlFile->checkPoint),
+						LSN_FORMAT_ARGS(ControlFile->checkPointCopy.redo))));
 }
 
 /*
-- 
2.25.1