imporve 'scan' performance for #309

Author: yinqiwen

src/.kv_engine

@@ -1 +1 @@
-lmdb
+rocksdb

src/Makefile

@@ -223,7 +223,7 @@ else
 ifeq ($(storage_engine), rocksdb)
   STORAGE_ENGINE=$(ROCKSDB_LIBA)
   STORAGE_ENGINE_PATH=$(ROCKSDB_PATH)
-  INCS+=-I${ROCKSDB_PATH}/include
+  INCS+=-I${ROCKSDB_PATH}/include -I${ROCKSDB_PATH}
   LIBS:= ${ROCKSDB_LIBA} ${SNAPPY_LIBA} ${LIBS} -lz -lbz2
   CXXFLAGS+=-D__USE_ROCKSDB__ -std=c++11
 else

src/command/keys.cpp

@@ -299,7 +299,9 @@ OP_NAMESPACE_BEGIN
             {
                 if (k.GetType() != KEY_META)
                 {
-                    iter->Next();
+                    //iter->Next();
+                    KeyObject next(ctx.ns, KEY_END, k.GetKey());
+                    iter->Jump(next);
                     continue;
                 }
                 k.GetKey().ToString(match_element);

src/db/rocksdb/rocksdb_engine.cpp

@@ -36,6 +36,7 @@
 #include "thread/spin_mutex_lock.hpp"
 #include "db/db.hpp"
 
+
 OP_NAMESPACE_BEGIN
 
     static inline rocksdb::Slice to_rocksdb_slice(const Slice& slice)
@@ -1309,6 +1310,7 @@ OP_NAMESPACE_BEGIN
         std::map<rocksdb::MemoryUtil::UsageType, uint64_t> usage_by_type;
         std::unordered_set<const rocksdb::Cache*> cache_set;
         std::vector<rocksdb::DB*> dbs(1, m_db);
+        cache_set.insert(m_db->GetDBOptions().row_cache.get());
         rocksdb::MemoryUtil::GetApproximateMemoryUsageByType(dbs, cache_set, &usage_by_type);
         for (size_t i = 0; i < rocksdb::MemoryUtil::kNumUsageTypes; ++i)
         {