diff --git a/src/Common/FileCache.h b/src/Common/FileCache.h
index 4d2654d1491..f809f57f389 100644
--- a/src/Common/FileCache.h
+++ b/src/Common/FileCache.h
@@ -22,9 +22,8 @@
 namespace DB
 {
 
-/**
- * Local cache for remote filesystem files, represented as a set of non-overlapping non-empty file segments.
- */
+/// Local cache for remote filesystem files, represented as a set of non-overlapping non-empty file segments.
+/// Different caching algorithms are implemented based on IFileCachePriority.
 class FileCache : private boost::noncopyable
 {
     friend class FileSegment;
diff --git a/src/Common/IFileCachePriority.h b/src/Common/IFileCachePriority.h
index 84e1a386d24..568b778d296 100644
--- a/src/Common/IFileCachePriority.h
+++ b/src/Common/IFileCachePriority.h
@@ -61,6 +61,7 @@ public:
 
         virtual size_t hits() const = 0;
 
+        /// Point the iterator to the next higher priority cache record.
         virtual void next() const = 0;
 
         virtual bool valid() const = 0;
@@ -72,6 +73,8 @@ public:
         /// Deletes an existing cached record.
         virtual void remove(std::lock_guard<std::mutex> &) = 0;
 
+        /// Get an iterator to handle write operations. Write iterators should only
+        /// be allowed to call remove, use and incrementSize methods.
         virtual WriteIterator getWriteIterator() const = 0;
 
         virtual void incrementSize(size_t, std::lock_guard<std::mutex> &) = 0;
diff --git a/src/Common/LRUFileCachePriority.h b/src/Common/LRUFileCachePriority.h
index bc9badc0af6..10ad21672dd 100644
--- a/src/Common/LRUFileCachePriority.h
+++ b/src/Common/LRUFileCachePriority.h
@@ -5,8 +5,8 @@
 namespace DB
 {
 
-/// Based on the LRU algorithm implementation, the data with the lowest priority is stored at
-/// the head of the queue, and the data with the highest priority is stored at the tail.
+/// Based on the LRU algorithm implementation, the record with the lowest priority is stored at
+/// the head of the queue, and the record with the highest priority is stored at the tail.
 class LRUFileCachePriority : public IFileCachePriority
 {
 public: