Function DispatchSetPGVariable

src/backend/utils/misc/guc.c:9252–9346

}

static void
DispatchSetPGVariable(const char *name, List *args, bool is_local)
{
	ListCell   *l;
	StringInfoData buffer;

	if (Gp_role != GP_ROLE_DISPATCH || IsBootstrapProcessingMode())
		return;

	/*
	 * client_encoding is always kept at SQL_ASCII in QE processes. (See also
	 * cdbconn_doConnectStart().)
	 */
	if (strcmp(name, "client_encoding") == 0)
		return;

	initStringInfo( &buffer );

	if (args == NIL)
	{
		appendStringInfo(&buffer, "RESET %s", name);
	}
	else
	{
		appendStringInfo(&buffer, "SET ");
		if (is_local)
			appendStringInfo(&buffer, "LOCAL ");

		appendStringInfo(&buffer, "%s TO ", quote_identifier(name));

		/*
		 * GPDB: We handle the timezone GUC specially. This is because the
		 * timezone GUC can be set with the SET TIME ZONE .. syntax which is an
		 * alias for SET timezone. Instead of dispatching the SET TIME ZONE ..
		 * as a special case, we dispatch the already set time zone from the QD
		 * with the usual SET syntax flavor (SET timezone TO <>).
		 * Please refer to Issue: #9055 for additional detail.
		 * #9055 - https://github.com/greenplum-db/gpdb/issues/9055
		 */
		if (strcmp(name, "timezone") == 0)
			appendStringInfo(&buffer, "%s",
							 quote_literal_cstr(GetConfigOptionByName("timezone",
																	  NULL,
																	  false)));
		else
		{
			foreach(l, args)
			{
				Node	   *arg = (Node *) lfirst(l);
				char	   *val;
				A_Const	   *con;

				if (l != list_head(args))
					appendStringInfo(&buffer, ", ");

				if (IsA(arg, TypeCast))
				{
					TypeCast   *tc = (TypeCast *) arg;