diff --git a/cache/cache_bench_tool.cc b/cache/cache_bench_tool.cc
index 2d5c35340..87245c0b3 100644
--- a/cache/cache_bench_tool.cc
+++ b/cache/cache_bench_tool.cc
@@ -3,6 +3,7 @@
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).
 
+#include "cache_key.h"
 #ifdef GFLAGS
 #include <cinttypes>
 #include <cstddef>
@@ -214,7 +215,8 @@ struct KeyGen {
     EncodeFixed64(key_data + 10, key);
     key_data[18] = char{4};
     EncodeFixed64(key_data + 19, key);
-    return Slice(&key_data[off], sizeof(key_data) - off);
+    assert(27 >= kCacheKeySize);
+    return Slice(&key_data[off], kCacheKeySize);
   }
 };
 
@@ -321,8 +323,9 @@ class CacheBench {
     Random64 rnd(1);
     KeyGen keygen;
     for (uint64_t i = 0; i < 2 * FLAGS_cache_size; i += FLAGS_value_bytes) {
-      cache_->Insert(keygen.GetRand(rnd, max_key_, max_log_), createValue(rnd),
-                     &helper1, FLAGS_value_bytes);
+      Status s = cache_->Insert(keygen.GetRand(rnd, max_key_, max_log_),
+                                createValue(rnd), &helper1, FLAGS_value_bytes);
+      assert(s.ok());
     }
   }
 
@@ -542,8 +545,9 @@ class CacheBench {
                              FLAGS_value_bytes);
         } else {
           // do insert
-          cache_->Insert(key, createValue(thread->rnd), &helper2,
-                         FLAGS_value_bytes, &handle);
+          Status s = cache_->Insert(key, createValue(thread->rnd), &helper2,
+                                    FLAGS_value_bytes, &handle);
+          assert(s.ok());
         }
       } else if (random_op < insert_threshold_) {
         if (handle) {
@@ -551,8 +555,9 @@ class CacheBench {
           handle = nullptr;
         }
         // do insert
-        cache_->Insert(key, createValue(thread->rnd), &helper3,
-                       FLAGS_value_bytes, &handle);
+        Status s = cache_->Insert(key, createValue(thread->rnd), &helper3,
+                                  FLAGS_value_bytes, &handle);
+        assert(s.ok());
       } else if (random_op < lookup_threshold_) {
         if (handle) {
           cache_->Release(handle);
diff --git a/cache/cache_key.h b/cache/cache_key.h
index 525b13d90..0858f3c8e 100644
--- a/cache/cache_key.h
+++ b/cache/cache_key.h
@@ -65,6 +65,8 @@ class CacheKey {
   uint64_t offset_etc64_;
 };
 
+constexpr uint8_t kCacheKeySize = static_cast<uint8_t>(sizeof(CacheKey));
+
 // A file-specific generator of cache keys, sometimes referred to as the
 // "base" cache key for a file because all the cache keys for various offsets
 // within the file are computed using simple arithmetic. The basis for the
diff --git a/cache/fast_lru_cache.h b/cache/fast_lru_cache.h
index e628895a4..9fcd694f2 100644
--- a/cache/fast_lru_cache.h
+++ b/cache/fast_lru_cache.h
@@ -22,10 +22,11 @@
 #include "util/distributed_mutex.h"
 
 namespace ROCKSDB_NAMESPACE {
+
 namespace fast_lru_cache {
 
 // LRU cache implementation using an open-address hash table.
-
+//
 // Every slot in the hash table is an LRUHandle. Because handles can be
 // referenced externally, we can't discard them immediately once they are
 // deleted (via a delete or an LRU eviction) or replaced by a new version
@@ -51,7 +52,7 @@ namespace fast_lru_cache {
 // - Not R --> R: When an unreferenced element becomes referenced. This can only
 //    happen if the element is V, since references to an element can only be
 //    created when it's visible.
-
+//
 // Internally, the cache uses an open-addressed hash table to index the handles.
 // We use tombstone counters to keep track of displacements.
 // Because of the tombstones and the two possible visibility states of an
@@ -70,9 +71,6 @@ namespace fast_lru_cache {
 // slot. In any case, the slot becomes available. When a handle is inserted
 // into that slot, it becomes a visible element again.
 
-constexpr uint8_t kCacheKeySize =
-    static_cast<uint8_t>(sizeof(ROCKSDB_NAMESPACE::CacheKey));
-
 // The load factor p is a real number in (0, 1) such that at all
 // times at most a fraction p of all slots, without counting tombstones,
 // are occupied by elements. This means that the probability that a