diff --git a/src/common/backend/utils/adt/tsrank.cpp b/src/common/backend/utils/adt/tsrank.cpp
index 5abf78cf5..58ef32aa0 100644
--- a/src/common/backend/utils/adt/tsrank.cpp
+++ b/src/common/backend/utils/adt/tsrank.cpp
@@ -342,9 +342,10 @@ static float calc_rank(const float* w, TSVector t, TSQuery q, int4 method)
 
 static float* getWeights(ArrayType* win)
 {
-    static float ws[lengthof(weights)];
     int i;
     float4* arrdata = NULL;
+    float* ws = u_sess->utils_cxt.tsrankWs;
+    Assert(sizeof(u_sess->utils_cxt.tsrankWs) == sizeof(weights));
 
     if (win == NULL)
         return weights;
diff --git a/src/include/knl/knl_session.h b/src/include/knl/knl_session.h
index 871cf6fd4..d57a16f6d 100644
--- a/src/include/knl/knl_session.h
+++ b/src/include/knl/knl_session.h
@@ -70,6 +70,8 @@
 #include "tcop/dest.h"
 #include "og_record_time.h"
 
+#define TSRANK_WEIGHTS_LEN    4
+
 typedef void (*pg_on_exit_callback)(int code, Datum arg);
 
 /* all session level attribute which expose to user. */
@@ -691,6 +693,9 @@ typedef struct knl_u_utils_context {
 	
     HTAB* set_user_params_htab;
     DestReceiver* spi_printtupDR;
+
+    /* var in tsrank.cpp */
+    float tsrankWs[TSRANK_WEIGHTS_LEN];
 } knl_u_utils_context;
 
 typedef struct knl_u_security_context {