diff --git a/src/gausskernel/storage/access/transam/multixact.cpp b/src/gausskernel/storage/access/transam/multixact.cpp
index fccc7cf85..f29f2eb24 100644
--- a/src/gausskernel/storage/access/transam/multixact.cpp
+++ b/src/gausskernel/storage/access/transam/multixact.cpp
@@ -1278,13 +1278,10 @@ static const char *MXStatusToString(MultiXactStatus status)
 
 static char *mxid_to_string(MultiXactId multi, int nmembers, MultiXactMember *members)
 {
-    static char *str = NULL;
+    char *str = NULL;
     StringInfoData buf;
     int i;
 
-    if (str != NULL)
-        pfree(str);
-
     initStringInfo(&buf);
 
     appendStringInfo(&buf, XID_FMT " %d[" XID_FMT " (%s)", multi, nmembers,
@@ -1295,7 +1292,7 @@ static char *mxid_to_string(MultiXactId multi, int nmembers, MultiXactMember *me
     }
 
     appendStringInfoChar(&buf, ']');
-    str = MemoryContextStrdup(TopMemoryContext, buf.data);
+    str = MemoryContextStrdup(SESS_GET_MEM_CXT_GROUP(MEMORY_CONTEXT_STORAGE), buf.data);
     pfree(buf.data);
     return str;
 }