http://www.oaktable.net/content/sorted-hash-clusters-rip

根据老先生的测试实例，发觉cluster 的sort功能，完全是为了tpcc测试而存在的，非等值的查询语句，都会走错误的计划，得出错误的结果。

这回oracle麻烦大了...

 

execute dbms_random.seed(0)create cluster sorted_hash_cluster (	hash_value	number(6,0),	sort_value	varchar2(2)	sort)size 300hashkeys 100;create table sorted_hash_table (	hash_value	number(6,0),	sort_value	varchar2(2),	v1		varchar2(10),	padding		varchar2(30))cluster sorted_hash_cluster (	hash_value, sort_value);begin	for i in 1..5000 loop		insert into sorted_hash_table values(			trunc(dbms_random.value(0,99)),			dbms_random.string('U',2),			lpad(i,10),			rpad('x',30,'x')		);		commit;	end loop;end;/begin	dbms_stats.gather_table_stats(		ownname		 => user,		tabname		 =>'sorted_hash_table'	);end;/select count(*) from sorted_hash_table where hash_value = 92;select count(*) from sorted_hash_table where hash_value = 92 and sort_value is null;select count(*) from sorted_hash_table where hash_value = 92 and sort_value is not null;select * from sorted_hash_table where hash_value = 92 and sort_value >= 'YR';select * from sorted_hash_table where hash_value = 92 and sort_value > 'YR';

oracle这3000W的数值，原来是这么出来的...

 

http://www.tpc.org/tpcc/results/tpcc_perf_results.asp