v8-0001-Add-checkpoint-and-redo-LSN-to-LogCheckpointEnd-l.patch

From adc02d1a4b319e982db0aa6ba96fcacf0b7d94f5 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Tue, 1 Feb 2022 04:34:54 +0000
Subject: [PATCH v8] Add checkpoint and redo LSN to LogCheckpointEnd log
 message

It is useful (for debugging purposes) if the checkpoint end message
has the checkpoint LSN(end) and REDO LSN(start). 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 dfe2a0bcce..34074b1e6e 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8923,7 +8923,8 @@ 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,
@@ -8936,14 +8937,17 @@ 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,
@@ -8956,7 +8960,9 @@ 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