!1101 支持插件自定义会话级变量

Merge pull request !1101 from chenxiaobin/extension_session

src/include/commands/extension.h

@@ -42,4 +42,6 @@ extern void AlterExtensionNamespace(List* names, const char* newschema);
 
 extern void AlterExtensionOwner_oid(Oid extensionOid, Oid newOwnerId);
 
+extern void RepallocSessionVarsArrayIfNecessary();
+
 #endif /* EXTENSION_H */

src/include/knl/knl_guc/knl_session_attr_common.h

@@ -208,6 +208,8 @@ typedef struct knl_session_attr_common {
     char* router_att;
     bool enable_router;
     int gpc_clean_timeout;
+    uint32 extension_session_vars_array_size;
+    void** extension_session_vars_array;
 } knl_session_attr_common;
 
 #endif /* SRC_INCLUDE_KNL_KNL_SESSION_ATTR_COMMON_H_ */

src/include/knl/knl_instance.h

@@ -870,6 +870,7 @@ typedef struct knl_instance_context {
     void *raw_parser_hook[DB_CMPT_MAX];
     void *plsql_parser_hook[DB_CMPT_MAX];
 #endif
+    pg_atomic_uint32 extensionNum;
 } knl_instance_context;
 
 extern long random();

src/include/utils/postinit.h

@@ -160,6 +160,8 @@ private:
 
     void InitSettings();
 
+    void InitExtensionVariable();
+
     void FinishInit();
 
     void AuditUserLogin();