!1835 添加execInitExprHook

Merge pull request !1835 from 仲夏十三/dolphin

src/gausskernel/runtime/executor/execQual.cpp

@@ -5184,6 +5184,11 @@ Datum ExecEvalExprSwitchContext(ExprState* expression, ExprContext* econtext, bo
  */
 ExprState* ExecInitExpr(Expr* node, PlanState* parent)
 {
+    if (u_sess->hook_cxt.execInitExprHook != NULL) {
+        ExprState* expr = ((execInitExprFunc)(u_sess->hook_cxt.execInitExprHook))(node, parent);
+        if (expr != NULL)
+            return expr;
+    }
     ExprState* state = NULL;
 
     gstrace_entry(GS_TRC_ID_ExecInitExpr);

src/include/executor/executor.h

@@ -152,6 +152,7 @@ extern THR_LOCAL PGDLLIMPORT ExecutorEnd_hook_type ExecutorEnd_hook;
 typedef bool (*ExecutorCheckPerms_hook_type)(List*, bool);
 extern THR_LOCAL PGDLLIMPORT ExecutorCheckPerms_hook_type ExecutorCheckPerms_hook;
 
+typedef ExprState* (*execInitExprFunc)(Expr* node, PlanState* parent);
 /*
  * prototypes from functions in execAmi.c
  */

src/include/knl/knl_session.h

@@ -2637,6 +2637,7 @@ typedef struct knl_u_clientConnTime_context {
 typedef struct knl_u_hook_context {
     void *analyzerRoutineHook;
     void *transformStmtHook;
+    void *execInitExprHook;
 } knl_u_hook_context;
 
 typedef struct knl_session_context {