37 lines
830 B
MySQL
37 lines
830 B
MySQL
-- Copyright 2018 Tanel Poder. All rights reserved. More info at http://tanelpoder.com
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-- Licensed under the Apache License, Version 2.0. See LICENSE.txt for terms & conditions.
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drop table t1;
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drop table t2;
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set echo on
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create table t1 as select rownum a from dual connect by level < 10;
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create table t2 as select rownum+10 b from dual connect by level < 10;
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exec dbms_stats.gather_table_stats(user,'T1');
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exec dbms_stats.gather_table_stats(user,'T2');
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--alter session set events '10053 trace name context forever';
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--alter session set "_optimizer_trace"=all;
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--alter session set events '10046 trace name context forever, level 4';
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select * from t1;
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select * from t2;
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select a
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from t1
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where a in (select b from t2);
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@x
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select a
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from t1
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where a in (select /*+ PRECOMPUTE_SUBQUERY */b from t2);
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@x
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set echo off
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