From 2764c4db1ba4c32863823b83a5b66f9af6c9492c Mon Sep 17 00:00:00 2001
From: "houzj.fnst" <63178771+sherlockcpp@users.noreply.github.com>
Date: Mon, 20 Jul 2020 13:53:27 +0800
Subject: [PATCH 1/5] Update pool_select_walker.c

---
 src/utils/pool_select_walker.c | 92 +++++++++++++++++++++++++++++++++---------
 1 file changed, 72 insertions(+), 20 deletions(-)

diff --git a/src/utils/pool_select_walker.c b/src/utils/pool_select_walker.c
index b9075b5..7a19117 100644
--- a/src/utils/pool_select_walker.c
+++ b/src/utils/pool_select_walker.c
@@ -339,20 +339,12 @@ function_call_walker(Node *node, void *context)
 
 		if (length > 0)
 		{
-			if (length == 1)	/* no schema qualification? */
-			{
-				fname = strVal(linitial(fcall->funcname));
-			}
-			else
-			{
-				fname = strVal(lsecond(fcall->funcname));	/* with schema
-															 * qualification */
-			}
+			fname = make_function_name_from_funccall(fcall);
 
 			ereport(DEBUG1,
 					(errmsg("function call walker, function name: \"%s\"", fname)));
 
-			if (ctx->pg_terminate_backend_pid == 0 && strcmp("pg_terminate_backend", fname) == 0)
+			if (ctx->pg_terminate_backend_pid == 0 && strcmp("pg_terminate_backend", strVal(llast(fcall->funcname))) == 0)
 			{
 				if (list_length(fcall->args) == 1)
 				{
@@ -995,15 +987,7 @@ non_immutable_function_call_walker(Node *node, void *context)
 
 		if (length > 0)
 		{
-			if (length == 1)	/* no schema qualification? */
-			{
-				fname = strVal(linitial(fcall->funcname));
-			}
-			else
-			{
-				fname = strVal(lsecond(fcall->funcname));	/* with schema
-															 * qualification */
-			}
+			fname = strVal(llast(fcall->funcname));
 
 			ereport(DEBUG1,
 					(errmsg("non immutable function walker. checking function \"%s\"", fname)));
@@ -1210,7 +1194,6 @@ select_table_walker(Node *node, void *context)
 		}
 	}
 
-	/* Skip Data-Modifying Statements in SELECT. */
 	else if (IsA(node, InsertStmt) || IsA(node, DeleteStmt) || IsA(node, UpdateStmt))
 	{
 		return false;
@@ -1255,6 +1238,75 @@ makeRangeVarFromNameList(List *names)
 }
 
 /*
+ * Extract function name from FuncCall. Make schema qualification name if
+ * necessary.  The returned function name is in static area. So next
+ * call to this function will break previous result.
+ */
+char *
+make_function_name_from_funccall(FuncCall *fcall)
+{
+	/*
+	 * Function name. Max size is calculated as follows: schema
+	 * name(POOL_NAMEDATALEN byte) + quotation marks for schmea name(2 byte) +
+	 * period(1 byte) + function name (POOL_NAMEDATALEN byte) + quotation marks
+	 * for function name(2 byte) + NULL(1 byte)
+	 */
+	static char funcname[POOL_NAMEDATALEN * 2 + 1 + 2 * 2 + 1];
+	List 	   *names;
+
+	if(fcall == NULL)
+	{
+		ereport(WARNING,
+				(errmsg("FuncCall argument is NULL, while getting function name from FuncCall")));
+		return "";
+	}
+
+	*funcname = '\0';
+	names = fcall->funcname;
+
+	switch (list_length(names))
+	{
+		case 1:
+			strcat(funcname, "\"");
+			strncat(funcname, strVal(linitial(names)), POOL_NAMEDATALEN);
+			strcat(funcname, "\"");
+			break;
+		case 2:
+			strcat(funcname, "\"");
+			strncat(funcname, strVal(linitial(names)), POOL_NAMEDATALEN);
+			strcat(funcname, "\"");
+
+			strcat(funcname, ".");
+
+			strcat(funcname, "\"");
+			strncat(funcname, strVal(lsecond(names)), POOL_NAMEDATALEN);
+			strcat(funcname, "\"");
+			break;
+		case 3:
+			strcat(funcname, "\"");
+			strncat(funcname, strVal(lsecond(names)), POOL_NAMEDATALEN);
+			strcat(funcname, "\"");
+
+			strcat(funcname, ".");
+
+			strcat(funcname, "\"");
+			strncat(funcname, strVal(lthird(names)), POOL_NAMEDATALEN);
+			strcat(funcname, "\"");
+
+			break;
+		default:
+			ereport(WARNING,
+					(errmsg("invalid function name, too many indirections, while getting function name from FuncCall")));
+			break;
+	}
+
+	ereport(DEBUG1,
+			(errmsg("make function name from funccall: funcname:\"%s\"", funcname)));
+
+	return funcname;
+}
+
+/*
  * Extract table name from RageVar.  Make schema qualification name if
  * necessary.  The returned table name is in static area. So next
  * call to this function will break previous result.
-- 
1.8.3.1