From 0ffa593e01e9a9092c55ec9a1f51632b235dabb0 Mon Sep 17 00:00:00 2001
From: Dmitrii Dolgov <9erthalion6@gmail.com>
Date: Thu, 11 Jun 2026 22:03:07 +0200
Subject: [PATCH v3 1/3] Add USDT for nbtree page splits and suffix truncation

Add new USDT for nbtree:

* nbtree__page__split with a single argument BlockNumber to trace page
  splits, which is usefull for understanding B-Tree performance.

* nbtree__page__truncate with a single integer argument representing
  number of truncated columns, which tells ups truncation effectiveness.
---
 src/backend/access/nbtree/nbtinsert.c | 3 +++
 src/backend/access/nbtree/nbtutils.c  | 2 ++
 src/backend/utils/probes.d            | 3 +++
 3 files changed, 8 insertions(+)

diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c
index d5d964301c1..bc72c8bdc9e 100644
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -24,6 +24,7 @@
 #include "common/pg_prng.h"
 #include "lib/qunique.h"
 #include "miscadmin.h"
+#include "pg_trace.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
 #include "utils/injection_point.h"
@@ -2105,6 +2106,8 @@ _bt_split(Relation rel, Relation heaprel, BTScanInsert itup_key, Buffer buf,
 		pfree(lefthighkey);
 
 	/* split's done */
+	TRACE_POSTGRESQL_NBTREE_PAGE_SPLIT(origpagenumber);
+
 	return rbuf;
 }
 
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c
index 014faa1622f..e384354acee 100644
--- a/src/backend/access/nbtree/nbtutils.c
+++ b/src/backend/access/nbtree/nbtutils.c
@@ -24,6 +24,7 @@
 #include "common/int.h"
 #include "lib/qunique.h"
 #include "miscadmin.h"
+#include "pg_trace.h"
 #include "storage/lwlock.h"
 #include "storage/subsystems.h"
 #include "utils/datum.h"
@@ -737,6 +738,7 @@ _bt_truncate(Relation rel, IndexTuple lastleft, IndexTuple firstright,
 	if (keepnatts <= nkeyatts)
 	{
 		BTreeTupleSetNAtts(pivot, keepnatts, false);
+		TRACE_POSTGRESQL_NBTREE_PAGE_TRUNCATE(nkeyatts - keepnatts);
 		return pivot;
 	}
 
diff --git a/src/backend/utils/probes.d b/src/backend/utils/probes.d
index f70577b38f2..4b841e3a11b 100644
--- a/src/backend/utils/probes.d
+++ b/src/backend/utils/probes.d
@@ -97,4 +97,7 @@ provider postgresql {
 	probe wal__switch();
 	probe wal__buffer__write__dirty__start();
 	probe wal__buffer__write__dirty__done();
+
+	probe nbtree__page__split(BlockNumber);
+	probe nbtree__page__truncate(int);
 };

base-commit: 91b1872ff2de16cd353598edbc650a185e649226
-- 
2.55.0