From a451b7d44249b8655db8d40476ace9f84d76ab88 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Mon, 3 Aug 2020 13:04:42 -0700
Subject: [PATCH] Add nbtree page deletion assertion.

Add a documenting assertion that's similar to the nearby assertion added
by commit cd8c73a3.  This conveys that the entire call to _bt_pagedel()
does no work if it isn't possible to get a descent stack for the initial
scanblkno page.
---
 src/backend/access/nbtree/nbtpage.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c
index 70bac0052f..53dff32680 100644
--- a/src/backend/access/nbtree/nbtpage.c
+++ b/src/backend/access/nbtree/nbtpage.c
@@ -1697,6 +1697,7 @@ _bt_pagedel(Relation rel, Buffer leafbuf, TransactionId *oldestBtpoXact)
 				if (_bt_leftsib_splitflag(rel, leftsib, leafblkno))
 				{
 					ReleaseBuffer(leafbuf);
+					Assert(ndeleted == 0);
 					return ndeleted;
 				}