diff --git a/source/libs/stream/src/streamBackendRocksdb.c b/source/libs/stream/src/streamBackendRocksdb.c
index 3581a4c0ff9ab31836ba72ea8c73fba2e9ea2e0f..cebe4e8204777926bf6aabf3352436595b84011d 100644
--- a/source/libs/stream/src/streamBackendRocksdb.c
+++ b/source/libs/stream/src/streamBackendRocksdb.c
@@ -81,6 +81,8 @@ const char* compareParKeyName(void* name);
 const char* comparePartagKeyName(void* name);
 
 void* streamBackendInit(const char* path) {
+  uint32_t dbMemLimit = nextPow2(tsMaxStreamBackendCache) << 20;
+
   qDebug("start to init stream backend at %s", path);
   SBackendHandle* pHandle = taosMemoryCalloc(1, sizeof(SBackendHandle));
   pHandle->list = tdListNew(sizeof(SCfComparator));
@@ -89,22 +91,23 @@ void* streamBackendInit(const char* path) {
   pHandle->cfInst = taosHashInit(64, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), false, HASH_NO_LOCK);
 
   rocksdb_env_t* env = rocksdb_create_default_env();  // rocksdb_envoptions_create();
-  rocksdb_env_set_low_priority_background_threads(env, tsNumOfSnodeStreamThreads);
-  rocksdb_env_set_high_priority_background_threads(env, tsNumOfSnodeStreamThreads);
 
-  rocksdb_cache_t* cache = rocksdb_cache_create_lru(64 << 20);
+  int32_t nBGThread = tsNumOfSnodeStreamThreads <= 2 ? 1 : tsNumOfSnodeStreamThreads / 2;
+  rocksdb_env_set_low_priority_background_threads(env, nBGThread);
+  rocksdb_env_set_high_priority_background_threads(env, nBGThread);
+
+  rocksdb_cache_t* cache = rocksdb_cache_create_lru(dbMemLimit / 2);
 
   rocksdb_options_t* opts = rocksdb_options_create();
   rocksdb_options_set_env(opts, env);
   rocksdb_options_set_create_if_missing(opts, 1);
   rocksdb_options_set_create_missing_column_families(opts, 1);
-  rocksdb_options_set_max_total_wal_size(opts, 128 << 20);
+  rocksdb_options_set_max_total_wal_size(opts, dbMemLimit);
   rocksdb_options_set_recycle_log_file_num(opts, 6);
   rocksdb_options_set_max_write_buffer_number(opts, 3);
   rocksdb_options_set_info_log_level(opts, 0);
-  uint32_t dbLimit = nextPow2(tsMaxStreamBackendCache);
-  rocksdb_options_set_db_write_buffer_size(opts, dbLimit << 20);
-  rocksdb_options_set_write_buffer_size(opts, (dbLimit << 20) / 2);
+  rocksdb_options_set_db_write_buffer_size(opts, dbMemLimit);
+  rocksdb_options_set_write_buffer_size(opts, dbMemLimit / 2);
 
   pHandle->env = env;
   pHandle->dbOpt = opts;