From 1a1d7b80760e09579f3b8740cf4765eb2983c018 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Wed, 17 Feb 2021 13:49:02 +0000
Subject: [PATCH] Keep the remaining 10% of cached entries

---
 internal/caching/impl_inmemorylru.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/internal/caching/impl_inmemorylru.go b/internal/caching/impl_inmemorylru.go
index 44e38fd3d..f0915d7ca 100644
--- a/internal/caching/impl_inmemorylru.go
+++ b/internal/caching/impl_inmemorylru.go
@@ -93,7 +93,12 @@ func cacheCleaner(caches ...*InMemoryLRUCachePartition) {
 	for {
 		time.Sleep(time.Minute)
 		for _, cache := range caches {
-			cache.lru.RemoveOldest()
+			// Hold onto the last 10% of the cache entries, since
+			// otherwise a quiet period might cause us to evict all
+			// cache entries entirely.
+			if cache.lru.Len() > cache.maxEntries/10 {
+				cache.lru.RemoveOldest()
+			}
 		}
 	}
 }