2026-03-12 20:23:15

tpt/aot/demo4.sql

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+-- Copyright 2018 Tanel Poder. All rights reserved. More info at http://tanelpoder.com
+-- Licensed under the Apache License, Version 2.0. See LICENSE.txt for terms & conditions.
+
+--------------------------------------------------------------------------------
+--
+-- File name:   demo4.sql
+--
+-- Purpose:     Advanced Oracle Troubleshooting Seminar demo script
+--              Causes optimizer to loop in CBO code for very long time
+--
+-- Author:      Tanel Poder ( http://www.tanelpoder.com )
+-- Copyright:   (c) Tanel Poder
+--
+--------------------------------------------------------------------------------
+
+prompt Starting demo4...
+
+set termout off feedback off
+
+drop table t;
+
+create table t as select * from all_objects where 1=0;
+
+exec dbms_stats.gather_table_stats(user,'T');
+alter session set "_optimizer_search_limit"=100;
+
+select * 
+from 
+ t t1
+,t t2
+,t t3
+,t t4
+,t t5
+,t t6
+,t t7
+,t t8
+,t t9
+,t t10
+,t t11
+,t t12
+,t t13
+,t t14
+,t t15
+,t t16
+,t t17
+,t t18
+,t t19
+,t t20
+,t t21
+,t t22
+,t t23
+,t t24
+,t t25
+,t t26
+,t t27
+,t t28
+,t t29
+,t t30
+,t t31
+,t t32
+,t t33
+,t t34
+,t t35
+,t t36
+,t t37
+,t t38
+,t t39
+,t t40
+,t t41
+,t t42
+,t t43
+,t t44
+,t t45
+,t t46
+,t t47
+,t t48
+,t t49
+,t t50
+,t t51
+,t t52
+,t t53
+,t t54
+,t t55
+,t t56
+,t t57
+,t t58
+,t t59
+,t t60
+,t t61
+,t t62
+,t t63
+,t t64
+,t t65
+,t t66
+,t t67
+,t t68
+,t t69
+,t t70
+,t t71
+,t t72
+,t t73
+,t t74
+,t t75
+,t t76
+,t t77
+,t t78
+,t t79
+,t t80
+,t t81
+,t t82
+,t t83
+,t t84
+,t t85
+,t t86
+,t t87
+,t t88
+,t t89
+,t t90
+,t t91
+,t t92
+,t t93
+,t t94
+,t t95
+,t t96
+,t t97
+,t t98
+,t t99
+/
+
+set termout on feedback on
+