From 72c45c66c65245aa548722213c3859c0610051b7 Mon Sep 17 00:00:00 2001
From: Dhruba Borthakur <dhruba@fb.com>
Date: Sat, 29 Sep 2012 18:02:02 -0700
Subject: [PATCH] Print the block cache size in the LOG.

Summary: Print the block cache size in the LOG.

Test Plan: run db_bench and look at LOG. This is helpful while I was debugging one use-case.

Reviewers: heyongqiang, MarkCallaghan

Reviewed By: heyongqiang

Differential Revision: https://reviews.facebook.net/D5739
---
 include/leveldb/cache.h | 3 +++
 util/cache.cc           | 5 +++++
 util/options.cc         | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/include/leveldb/cache.h b/include/leveldb/cache.h
index a7bd2afa7..f0aa4b130 100644
--- a/include/leveldb/cache.h
+++ b/include/leveldb/cache.h
@@ -82,6 +82,9 @@ class Cache {
   // its cache keys.
   virtual uint64_t NewId() = 0;
 
+  // returns the maximum configured capacity of the cache
+  virtual size_t GetCapacity() = 0;
+
  private:
   void LRU_Remove(Handle* e);
   void LRU_Append(Handle* e);
diff --git a/util/cache.cc b/util/cache.cc
index dedb370b3..6dfa4d121 100644
--- a/util/cache.cc
+++ b/util/cache.cc
@@ -276,6 +276,7 @@ class ShardedLRUCache : public Cache {
   port::Mutex id_mutex_;
   uint64_t last_id_;
   int numShardBits;
+  size_t capacity_;
 
   static inline uint32_t HashSlice(const Slice& s) {
     return Hash(s.data(), s.size(), 0);
@@ -287,6 +288,7 @@ class ShardedLRUCache : public Cache {
 
   void init(size_t capacity, int numbits) {
     numShardBits = numbits;
+    capacity_ = capacity;
     int numShards = 1 << numShardBits;
     shard_ = new LRUCache[numShards];
     const size_t per_shard = (capacity + (numShards - 1)) / numShards;
@@ -329,6 +331,9 @@ class ShardedLRUCache : public Cache {
     MutexLock l(&id_mutex_);
     return ++(last_id_);
   }
+  virtual uint64_t GetCapacity() {
+    return capacity_;
+  }
 };
 
 }  // end anonymous namespace
diff --git a/util/options.cc b/util/options.cc
index bd9027be9..f8c02df09 100644
--- a/util/options.cc
+++ b/util/options.cc
@@ -7,6 +7,7 @@
 #include "leveldb/comparator.h"
 #include "leveldb/env.h"
 #include "leveldb/filter_policy.h"
+#include "leveldb/cache.h"
 
 namespace leveldb {
 
@@ -56,6 +57,7 @@ Options::Dump(
     Log(log,"     Options.write_buffer_size: %zd", write_buffer_size);
     Log(log,"        Options.max_open_files: %d", max_open_files);
     Log(log,"           Options.block_cache: %p", block_cache);
+    Log(log,"      Options.block_cache_size: %zd", block_cache->GetCapacity());
     Log(log,"            Options.block_size: %zd", block_size);
     Log(log,"Options.block_restart_interval: %d", block_restart_interval);
     Log(log,"           Options.compression: %d", compression);