diff --git a/src/share/parameter/ob_parameter_seed.ipp b/src/share/parameter/ob_parameter_seed.ipp
index d32b676f82..d904b57ba8 100644
--- a/src/share/parameter/ob_parameter_seed.ipp
+++ b/src/share/parameter/ob_parameter_seed.ipp
@@ -1666,8 +1666,8 @@ DEF_BOOL(_enable_in_range_optimization, OB_TENANT_PARAMETER, "True",
 DEF_BOOL(_force_explict_500_malloc, OB_CLUSTER_PARAMETER, "False",
          "Force 500 memory for explicit allocation",
          ObParameterAttr(Section::OBSERVER, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));
-DEF_CAP(range_optimizer_max_mem_size, OB_TENANT_PARAMETER, "128M", "[16M,1G]",
-        "to limit the memory consumption for the query range optimizer. Range: [16M,1G]",
+DEF_CAP(range_optimizer_max_mem_size, OB_TENANT_PARAMETER, "128M", "[0M,)",
+        "to limit the memory consumption for the query range optimizer. Range: [0M,+∞), 0 stands for unlimited",
         ObParameterAttr(Section::TENANT, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));
 DEF_TIME(_schema_memory_recycle_interval, OB_CLUSTER_PARAMETER, "15m", "[0s,)",
         "the time interval between the schedules of schema memory recycle task. "
diff --git a/src/sql/rewrite/ob_query_range.cpp b/src/sql/rewrite/ob_query_range.cpp
index f6bead0220..d4ab630390 100644
--- a/src/sql/rewrite/ob_query_range.cpp
+++ b/src/sql/rewrite/ob_query_range.cpp
@@ -180,6 +180,9 @@ int ObQueryRange::init_query_range_ctx(ObIAllocator &allocator,
     query_range_ctx_->phy_rowid_for_table_loc_ = phy_rowid_for_table_loc;
     query_range_ctx_->ignore_calc_failure_ = ignore_calc_failure;
     query_range_ctx_->range_optimizer_max_mem_size_ = exec_ctx->get_my_session()->get_range_optimizer_max_mem_size();
+    if (0 == query_range_ctx_->range_optimizer_max_mem_size_) {
+      query_range_ctx_->range_optimizer_max_mem_size_ = INT64_MAX;
+    }
     query_range_ctx_->use_in_optimization_ = use_in_optimization;
   }
   for (int64_t i = 0; OB_SUCC(ret) && i < range_columns.count(); ++i) {