From 66c0df81090bb0f93e468b53cec485f2a4605554 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <christian@neon.tech>
Date: Wed, 15 Jan 2025 21:49:26 +0100
Subject: [PATCH] doc comment on BatchedFeMessage explaining WeakHandle;
 https://github.com/neondatabase/neon/pull/10386#discussion_r1916968951

---
 pageserver/src/page_service.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pageserver/src/page_service.rs b/pageserver/src/page_service.rs
index 623972140a..9fe3b307b5 100644
--- a/pageserver/src/page_service.rs
+++ b/pageserver/src/page_service.rs
@@ -560,6 +560,9 @@ struct BatchedTestRequest {
     timer: SmgrOpTimer,
 }
 
+/// NB: we only hold [`timeline::handle::WeakHandle`] inside this enum,
+/// so that we don't keep the [`Timeline::gate`] open while the batch
+/// is being built up inside the [`spsc_fold`] (pagestream pipelining).
 enum BatchedFeMessage {
     Exists {
         span: Span,