From 168a6a87d705cfe17d9a76fda420d7107bb5d43f Mon Sep 17 00:00:00 2001
From: Anastasia Lubennikova <anastasia@neon.tech>
Date: Fri, 13 Sep 2024 03:31:54 +0100
Subject: [PATCH] Fix wal-redo unwrap() failure for timeline chains that have 0
 records in some timeline

---
 pageserver/src/tenant/timeline.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/pageserver/src/tenant/timeline.rs b/pageserver/src/tenant/timeline.rs
index 6809cb1da4..6806f0ac9f 100644
--- a/pageserver/src/tenant/timeline.rs
+++ b/pageserver/src/tenant/timeline.rs
@@ -5206,10 +5206,18 @@ impl Timeline {
                     .cloned()
                     .collect::<Vec<_>>();
                 records = &records[scratch.len()..];
+
                 if later.is_none() {
                     assert!(records.is_empty());
                 }
 
+                // if we don't have any records for this timeline (which is possible)
+                // go to the previous one
+                if scratch.is_empty() {
+                    tracing::info!("no records for timeline {}", older.timeline_id);
+                    continue;
+                }
+
                 // this is only used for logging on the next round
                 let last_lsn = scratch.last().unwrap().0;